DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Module-level power electronics, such as DC power optimizers, microinverters, and those found in AC modules, are increasing in popularity in smaller-scale photovoltaic (PV) systems as their prices continue to decline. Therefore, it is important to provide PV modelers with guidelines about how to model these distributed power electronics appropriately in PV modeling software. This paper extends the work completed at NREL that provided recommendations to model the performance of distributed power electronics in NREL’s popular PVWatts calculator [1], to provide similar guidelines for modeling these technologies in NREL's more complex System Advisor Model (SAM). Module-level power electronics - such asmore » DC power optimizers, microinverters, and those found in AC modules-- are increasing in popularity in smaller-scale photovoltaic (PV) systems as their prices continue to decline. Therefore, it is important to provide PV modelers with guidelines about how to model these distributed power electronics appropriately in PV modeling software.« less

On Distributed PV Hosting Capacity Estimation, Sensitivity Study, and Improvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mather, Barry

This paper first studies the estimated distributed PV hosting capacities of seventeen utility distribution feeders using the Monte Carlo simulation based stochastic analysis, and then analyzes the sensitivity of PV hosting capacity to both feeder and photovoltaic system characteristics. Furthermore, an active distribution network management approach is proposed to maximize PV hosting capacity by optimally switching capacitors, adjusting voltage regulator taps, managing controllable branch switches and controlling smart PV inverters. The approach is formulated as a mixed-integer nonlinear optimization problem and a genetic algorithm is developed to obtain the solution. Multiple simulation cases are studied and the effectiveness of themore » proposed approach on increasing PV hosting capacity is demonstrated.« less

Grid Simulation and Power Hardware-in-the-Loop | Grid Modernization | NREL

Science.gov Websites

used PHIL to investigate the effects of advanced solar PV inverters on Hawaii's grid. A variety of PV Evaluating the Performance of Methods for Coordinated Control of Distributed Residential PV/Energy Storage photovoltaics (PV)-battery energy storage inverter control applied across an electric distribution system

Optimization of a stand-alone Solar PV-Wind-DG Hybrid System for Distributed Power Generation at Sagar Island

NASA Astrophysics Data System (ADS)

Roy, P. C.; Majumder, A.; Chakraborty, N.

2010-10-01

An estimation of a stand-alone solar PV and wind hybrid system for distributed power generation has been made based on the resources available at Sagar island, a remote area distant to grid operation. Optimization and sensitivity analysis has been made to evaluate the feasibility and size of the power generation unit. A comparison of the different modes of hybrid system has been studied. It has been estimated that Solar PV-Wind-DG hybrid system provides lesser per unit electricity cost. Capital investment is observed to be lesser when the system run with Wind-DG compared to Solar PV-DG.

Quasi-static time-series simulation using OpenDSS in IEEE distribution feeder model with high PV penetration and its impact on solar forecasting

NASA Astrophysics Data System (ADS)

Mohammed, Touseef Ahmed Faisal

Since 2000, renewable electricity installations in the United States (excluding hydropower) have more than tripled. Renewable electricity has grown at a compounded annual average of nearly 14% per year from 2000-2010. Wind, Concentrated Solar Power (CSP) and solar Photo Voltaic (PV) are the fastest growing renewable energy sectors. In 2010 in the U.S., solar PV grew over 71% and CSP grew by 18% from the previous year. Globally renewable electricity installations have more than quadrupled from 2000-2010. Solar PV generation grew by a factor of more than 28 between 2000 and 2010. The amount of CSP and solar PV installations are increasing on the distribution grid. These PV installations transmit electrical current from the load centers to the generating stations. But the transmission and distribution grid have been designed for uni-directional flow of electrical energy from generating stations to load centers. This causes imbalances in voltage and switchgear of the electrical circuitry. With the continuous rise in PV installations, analysis of voltage profile and penetration levels remain an active area of research. Standard distributed photovoltaic (PV) generators represented in simulation studies do not reflect the exact location and variability properties such as distance between interconnection points to substations, voltage regulators, solar irradiance and other environmental factors. Quasi-Static simulations assist in peak load planning hour and day ahead as it gives a time sequence analysis to help in generation allocation. Simulation models can be daily, hourly or yearly depending on duty cycle and dynamics of the system. High penetration of PV into the power grid changes the voltage profile and power flow dynamically in the distribution circuits due to the inherent variability of PV. There are a number of modeling and simulations tools available for the study of such high penetration PV scenarios. This thesis will specifically utilize OpenDSS, a open source Distribution System Simulator developed by Electric Power Research Institute, to simulate grid voltage profile with a large scale PV system under quasi-static time series considering variations of PV output in seconds, minutes, and the average daily load variations. A 13 bus IEEE distribution feeder model is utilized with distributed residential and commercial scale PV at different buses for simulation studies. Time series simulations are discussed for various modes of operation considering dynamic PV penetration at different time periods in a day. In addition, this thesis demonstrates simulations taking into account the presence of moving cloud for solar forecasting studies.

Analysis of PV Advanced Inverter Functions and Setpoints under Time Series Simulation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seuss, John; Reno, Matthew J.; Broderick, Robert Joseph

Utilities are increasingly concerned about the potential negative impacts distributed PV may have on the operational integrity of their distribution feeders. Some have proposed novel methods for controlling a PV system's grid - tie inverter to mitigate poten tial PV - induced problems. This report investigates the effectiveness of several of these PV advanced inverter controls on improving distribution feeder operational metrics. The controls are simulated on a large PV system interconnected at several locations within two realistic distribution feeder models. Due to the time - domain nature of the advanced inverter controls, quasi - static time series simulations aremore » performed under one week of representative variable irradiance and load data for each feeder. A para metric study is performed on each control type to determine how well certain measurable network metrics improve as a function of the control parameters. This methodology is used to determine appropriate advanced inverter settings for each location on the f eeder and overall for any interconnection location on the feeder.« less

Evaluating the effect placement capacitor and distributed photovoltaic generation for power system losses minimization in radial distribution system

NASA Astrophysics Data System (ADS)

Rahman, Yuli Asmi; Manjang, Salama; Yusran, Ilham, Amil Ahmad

2018-03-01

Power loss minimization have many advantagess to the distribution system radial among others reduction of power flow in feeder lines, freeing stress on feeder loading, deterrence of power procurement from the grid and also the cost of loss compensating instruments. This paper, presents capacitor and photovoltaic (PV) placement as alternative means to decrease power system losses. The paper aims to evaluate the best alternative for decreasing power system losses and improving voltage profile in the radial distribution system. To achieve the objectives of paper, they are used three cases tested by Electric Transient and Analysis Program (ETAP) simulation. Firstly, it performs simulation of placement capacitor. Secondly, simulated placement of PV. Lastly, it runs simulation of placement capacitor and PV simultaneously. The simulations were validated using the IEEE 34-bus test system. As a result, they proved that the installation of capacitor and PV integration simultaneously leading to voltage profile correction and power losses minimization significantly.

Mitigating Interconnection Challenges of the High Penetration Utility-Interconnected Photovoltaic (PV) in the Electrical Distribution Systems: Cooperative Research and Development Final Report, CRADA Number CRD-14-563

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, Sudipta

Various interconnection challenges exist when connecting distributed PV into the electrical distribution grid in terms of safety, reliability, and stability of the electric power systems. Some of the urgent areas for research, as identified by inverter manufacturers, installers and utilities, are potential for transient overvoltage from PV inverters, multi-inverter anti-islanding, impact of smart inverters on volt-VAR support, impact of bidirectional power flow, and potential for distributed generation curtailment solutions to mitigate grid stability challenges. Under this project, NREL worked with SolarCity to address these challenges through research, testing and analysis at the Energy System Integration Facility (ESIF). Inverters from differentmore » manufacturers were tested at ESIF and NREL's unique power hardware-in-the-loop (PHIL) capability was utilized to evaluate various system-level impacts. Through the modeling, simulation, and testing, this project eliminated critical barriers on high PV penetration and directly supported the Department of Energy's SunShot goal of increasing the solar PV on the electrical grid.« less

Photovoltaics as a terrestrial energy source. Volume 2: System value

NASA Technical Reports Server (NTRS)

Smith, J. L.

1980-01-01

Assumptions and techniques employed by the electric utility industry and other electricity planners to make estimates of the future value of photovoltaic (PV) systems interconnected with U.S. electric utilities were examined. Existing estimates of PV value and their interpretation and limitations are discussed. PV value is defined as the marginal private savings accruing to potential PV owners. For utility-owned PV systems, these values are shown to be the after-tax savings in conventional fuel and capacity displaced by the PV output. For non-utility-owned (distributed) systems, the utility's savings in fuel and capacity must first be translated through the electric rate structure (prices) to the potential PV system owner. Base-case estimates of the average value of PV systems to U.S. utilities are presented. The relationship of these results to the PV Program price goals and current energy policy is discussed; the usefulness of PV output quantity goals is also reviewed.

Fuzzy-driven energy storage system for mitigating voltage unbalance factor on distribution network with photovoltaic system

NASA Astrophysics Data System (ADS)

Wong, Jianhui; Lim, Yun Seng; Morris, Stella; Morris, Ezra; Chua, Kein Huat

2017-04-01

The amount of small-scaled renewable energy sources is anticipated to increase on the low-voltage distribution networks for the improvement of energy efficiency and reduction of greenhouse gas emission. The growth of the PV systems on the low-voltage distribution networks can create voltage unbalance, voltage rise, and reverse-power flow. Usually these issues happen with little fluctuation. However, it tends to fluctuate severely as Malaysia is a region with low clear sky index. A large amount of clouds often passes over the country, hence making the solar irradiance to be highly scattered. Therefore, the PV power output fluctuates substantially. These issues can lead to the malfunction of the electronic based equipment, reduction in the network efficiency and improper operation of the power protection system. At the current practice, the amount of PV system installed on the distribution network is constraint by the utility company. As a result, this can limit the reduction of carbon footprint. Therefore, energy storage system is proposed as a solution for these power quality issues. To ensure an effective operation of the distribution network with PV system, a fuzzy control system is developed and implemented to govern the operation of an energy storage system. The fuzzy driven energy storage system is able to mitigate the fluctuating voltage rise and voltage unbalance on the electrical grid by actively manipulates the flow of real power between the grid and the batteries. To verify the effectiveness of the proposed fuzzy driven energy storage system, an experimental network integrated with 7.2kWp PV system was setup. Several case studies are performed to evaluate the response of the proposed solution to mitigate voltage rises, voltage unbalance and reduce the amount of reverse power flow under highly intermittent PV power output.

Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olalla, Carlos; Maksimovic, Dragan; Deline, Chris

Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

DOE PAGES

Olalla, Carlos; Maksimovic, Dragan; Deline, Chris; ...

2017-04-26

Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

Enhanced power quality based single phase photovoltaic distributed generation system

NASA Astrophysics Data System (ADS)

Panda, Aurobinda; Pathak, M. K.; Srivastava, S. P.

2016-08-01

This article presents a novel control strategy for a 1-ϕ 2-level grid-tie photovoltaic (PV) inverter to enhance the power quality (PQ) of a PV distributed generation (PVDG) system. The objective is to obtain the maximum benefits from the grid-tie PV inverter by introducing current harmonics as well as reactive power compensation schemes in its control strategy, thereby controlling the PV inverter to achieve multiple functions in the PVDG system such as: (1) active power flow control between the PV inverter and the grid, (2) reactive power compensation, and (3) grid current harmonics compensation. A PQ enhancement controller (PQEC) has been designed to achieve the aforementioned objectives. The issue of underutilisation of the PV inverter in nighttime has also been addressed in this article and for the optimal use of the system; the PV inverter is used as a shunt active power filter in nighttime. A prototype model of the proposed system is developed in the laboratory, to validate the effectiveness of the control scheme, and is tested with the help of the dSPACE DS1104 platform.

Quantitative Analysis Method of Output Loss due to Restriction for Grid-connected PV Systems

NASA Astrophysics Data System (ADS)

Ueda, Yuzuru; Oozeki, Takashi; Kurokawa, Kosuke; Itou, Takamitsu; Kitamura, Kiyoyuki; Miyamoto, Yusuke; Yokota, Masaharu; Sugihara, Hiroyuki

Voltage of power distribution line will be increased due to reverse power flow from grid-connected PV systems. In the case of high density grid connection, amount of voltage increasing will be higher than the stand-alone grid connection system. To prevent the over voltage of power distribution line, PV system's output will be restricted if the voltage of power distribution line is close to the upper limit of the control range. Because of this interaction, amount of output loss will be larger in high density case. This research developed a quantitative analysis method for PV systems output and losses to clarify the behavior of grid connected PV systems. All the measured data are classified into the loss factors using 1 minute average of 1 second data instead of typical 1 hour average. Operation point on the I-V curve is estimated to quantify the loss due to the output restriction using module temperature, array output voltage, array output current and solar irradiance. As a result, loss due to output restriction is successfully quantified and behavior of output restriction is clarified.

Establishment of key grid-connected performance index system for integrated PV-ES system

NASA Astrophysics Data System (ADS)

Li, Q.; Yuan, X. D.; Qi, Q.; Liu, H. M.

2016-08-01

In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

LCP- LIFETIME COST AND PERFORMANCE MODEL FOR DISTRIBUTED PHOTOVOLTAIC SYSTEMS

NASA Technical Reports Server (NTRS)

Borden, C. S.

1994-01-01

The Lifetime Cost and Performance (LCP) Model was developed to assist in the assessment of Photovoltaic (PV) system design options. LCP is a simulation of the performance, cost, and revenue streams associated with distributed PV power systems. LCP provides the user with substantial flexibility in specifying the technical and economic environment of the PV application. User-specified input parameters are available to describe PV system characteristics, site climatic conditions, utility purchase and sellback rate structures, discount and escalation rates, construction timing, and lifetime of the system. Such details as PV array orientation and tilt angle, PV module and balance-of-system performance attributes, and the mode of utility interconnection are user-specified. LCP assumes that the distributed PV system is utility grid interactive without dedicated electrical storage. In combination with a suitable economic model, LCP can provide an estimate of the expected net present worth of a PV system to the owner, as compared to electricity purchased from a utility grid. Similarly, LCP might be used to perform sensitivity analyses to identify those PV system parameters having significant impact on net worth. The user describes the PV system configuration to LCP via the basic electrical components. The module is the smallest entity in the PV system which is modeled. A PV module is defined in the simulation by its short circuit current, which varies over the system lifetime due to degradation and failure. Modules are wired in series to form a branch circuit. Bypass diodes are allowed between modules in the branch circuits. Branch circuits are then connected in parallel to form a bus. A collection of buses is connected in parallel to form an increment to capacity of the system. By choosing the appropriate series-parallel wiring design, the user can specify the current, voltage, and reliability characteristics of the system. LCP simulation of system performance is site-specific and follows a three-step procedure. First the hourly power produced by the PV system is computed using a selected year's insolation and temperature profile. For this step it is assumed that there are no module failures or degradation. Next, the monthly simulation is performed involving a month to month progression through the lifetime of the system. In this step, the effects of degradation, failure, dirt accumulation and operations/maintenance efforts on PV system performance over time are used to compute the monthly power capability fraction. The resulting monthly power capability fractions are applied to the hourly power matrix from the first step, giving the anticipated hourly energy output over the lifetime of the system. PV system energy output is compared with the PV system owner's electricity demand for each hour. The amount of energy to be purchased from or sold to the utility grid is then determined. Monthly expenditures on the PV system and the purchase of electricity from the utility grid are also calculated. LCP generates output reports pertaining to the performance of the PV system, and system costs and revenues. The LCP model, written in SIMSCRIPT 2.5 for batch execution on an IBM 370 series computer, was developed in 1981.

Generic solar photovoltaic system dynamic simulation model specification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, Abraham; Behnke, Michael Robert; Elliott, Ryan Thomas

This document is intended to serve as a specification for generic solar photovoltaic (PV) system positive-sequence dynamic models to be implemented by software developers and approved by the WECC MVWG for use in bulk system dynamic simulations in accordance with NERC MOD standards. Two specific dynamic models are included in the scope of this document. The first, a Central Station PV System model, is intended to capture the most important dynamic characteristics of large scale (> 10 MW) PV systems with a central Point of Interconnection (POI) at the transmission level. The second, a Distributed PV System model, is intendedmore » to represent an aggregation of smaller, distribution-connected systems that comprise a portion of a composite load that might be modeled at a transmission load bus.« less

Market assessment of photovoltaic power systems for agricultural applications in Mexico

NASA Technical Reports Server (NTRS)

Steigelmann, W.; Asmon, I.

1981-01-01

The first year of cost-competitiveness, the market potential, and the environment in which PV systems would be marketed and employed were examined. Market elements specific to Mexico addressed include: (1) useful applications and estimates of the potential market for PV systems; (2) power requirements and load profiles for applications compatible with PV usage; (3) operating and cost characteristics of power systems that compete against PV; (4) national development goals in rural electrification and rural services, technology programs and government policies that influence the demand for PV in Mexico; (5) financing mechanisms and capital available for PV acquisition; (6) channels for distribution, installation and maintenance of PV systems; and (7) appropriate methods for conducting business in Mexico.

Market assessment of photovoltaic power systems for agricultural applications in Mexico

NASA Astrophysics Data System (ADS)

Steigelmann, W.; Asmon, I.

1981-07-01

The first year of cost-competitiveness, the market potential, and the environment in which PV systems would be marketed and employed were examined. Market elements specific to Mexico addressed include: (1) useful applications and estimates of the potential market for PV systems; (2) power requirements and load profiles for applications compatible with PV usage; (3) operating and cost characteristics of power systems that compete against PV; (4) national development goals in rural electrification and rural services, technology programs and government policies that influence the demand for PV in Mexico; (5) financing mechanisms and capital available for PV acquisition; (6) channels for distribution, installation and maintenance of PV systems; and (7) appropriate methods for conducting business in Mexico.

Distributed solar photovoltaic array location and extent dataset for remote sensing object identification

PubMed Central

Bradbury, Kyle; Saboo, Raghav; L. Johnson, Timothy; Malof, Jordan M.; Devarajan, Arjun; Zhang, Wuming; M. Collins, Leslie; G. Newell, Richard

2016-01-01

Earth-observing remote sensing data, including aerial photography and satellite imagery, offer a snapshot of the world from which we can learn about the state of natural resources and the built environment. The components of energy systems that are visible from above can be automatically assessed with these remote sensing data when processed with machine learning methods. Here, we focus on the information gap in distributed solar photovoltaic (PV) arrays, of which there is limited public data on solar PV deployments at small geographic scales. We created a dataset of solar PV arrays to initiate and develop the process of automatically identifying solar PV locations using remote sensing imagery. This dataset contains the geospatial coordinates and border vertices for over 19,000 solar panels across 601 high-resolution images from four cities in California. Dataset applications include training object detection and other machine learning algorithms that use remote sensing imagery, developing specific algorithms for predictive detection of distributed PV systems, estimating installed PV capacity, and analysis of the socioeconomic correlates of PV deployment. PMID:27922592

Distributed solar photovoltaic array location and extent dataset for remote sensing object identification

NASA Astrophysics Data System (ADS)

Bradbury, Kyle; Saboo, Raghav; L. Johnson, Timothy; Malof, Jordan M.; Devarajan, Arjun; Zhang, Wuming; M. Collins, Leslie; G. Newell, Richard

2016-12-01

Earth-observing remote sensing data, including aerial photography and satellite imagery, offer a snapshot of the world from which we can learn about the state of natural resources and the built environment. The components of energy systems that are visible from above can be automatically assessed with these remote sensing data when processed with machine learning methods. Here, we focus on the information gap in distributed solar photovoltaic (PV) arrays, of which there is limited public data on solar PV deployments at small geographic scales. We created a dataset of solar PV arrays to initiate and develop the process of automatically identifying solar PV locations using remote sensing imagery. This dataset contains the geospatial coordinates and border vertices for over 19,000 solar panels across 601 high-resolution images from four cities in California. Dataset applications include training object detection and other machine learning algorithms that use remote sensing imagery, developing specific algorithms for predictive detection of distributed PV systems, estimating installed PV capacity, and analysis of the socioeconomic correlates of PV deployment.

Distributed solar photovoltaic array location and extent dataset for remote sensing object identification.

PubMed

Bradbury, Kyle; Saboo, Raghav; L Johnson, Timothy; Malof, Jordan M; Devarajan, Arjun; Zhang, Wuming; M Collins, Leslie; G Newell, Richard

2016-12-06

Earth-observing remote sensing data, including aerial photography and satellite imagery, offer a snapshot of the world from which we can learn about the state of natural resources and the built environment. The components of energy systems that are visible from above can be automatically assessed with these remote sensing data when processed with machine learning methods. Here, we focus on the information gap in distributed solar photovoltaic (PV) arrays, of which there is limited public data on solar PV deployments at small geographic scales. We created a dataset of solar PV arrays to initiate and develop the process of automatically identifying solar PV locations using remote sensing imagery. This dataset contains the geospatial coordinates and border vertices for over 19,000 solar panels across 601 high-resolution images from four cities in California. Dataset applications include training object detection and other machine learning algorithms that use remote sensing imagery, developing specific algorithms for predictive detection of distributed PV systems, estimating installed PV capacity, and analysis of the socioeconomic correlates of PV deployment.

Distribution system costs associated with the deployment of photovoltaic systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horowitz, Kelsey A. W.; Palmintier, Bryan; Mather, Barry

The broadening of our energy system to include increasing amounts of wind and solar has led to significant debate about the total costs and benefits associated with different types of generators - with potentially far-reaching policy implications. This has included debate about the cost associated with integrating these generators onto the electric grid. For photovoltaics (PV), this encompasses costs incurred on both the bulk power and distribution systems, as well as the value provided to them. These costs and benefits, in particular those associated with integrating PV onto the distribution system, are not well understood. We seek to advance themore » state of understanding of 'grid integration costs' for the distribution system by reviewing prior literature and outlining a transparent, bottom-up approach that can be used to calculate these costs. We provide a clear delineation of costs to integrate PV in to the distribution system within the larger context of total costs and benefits associated with PV generators. We emphasize that these costs are situationally dependent, and that a single 'cost of integration' cannot be obtained. We additionally emphasize that benefits must be considered when evaluating the competitiveness of the technology in a given situation.« less

Ceiling-mounted personalized ventilation system integrated with a secondary air distribution system--a human response study in hot and humid climate.

PubMed

Yang, B; Sekhar, S C; Melikov, A K

2010-08-01

The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration of PV systems with the work station. A newly developed ceiling-mounted PV system addresses these challenges and provides a practical solution while retaining much of the apparent benefits of PV systems. Assessments of thermal environment, air movement, and air quality for ceiling-mounted PV system were performed with tropically acclimatized subjects in a Field Environmental Chamber. Thirty-two subjects performed normal office work and could choose to be exposed to four different PV airflow rates (4, 8, 12, and 16 L/s), thus offering themselves a reasonable degree of individual control. Ambient temperatures of 26 and 23.5 degrees C and PV air temperatures of 26, 23.5, and 21 degrees C were employed. The local and whole body thermal sensations were reduced when PV airflow rates were increased. Inhaled air temperature was perceived cooler and perceived air quality and air freshness improved when PV airflow rate was increased or temperature was reduced. The newly developed ceiling-mounted PV system offers a practical solution to the integration of PV air terminal devices (ATDs) in the vicinity of the workstation. By remotely locating the PV ATDs on the ceiling directly above the occupants and under their control, the conditioned outdoor air is now provided to the occupants through the downward momentum of the air. A secondary air-conditioning and air distribution system offers additional cooling in the room and maintains a higher ambient temperature, thus offering significant benefits in conserving energy. The results of this study provide designers and consultants with needed knowledge for design of PV systems.

Electric Vehicles Charging Scheduling Strategy Considering the Uncertainty of Photovoltaic Output

NASA Astrophysics Data System (ADS)

Wei, Xiangxiang; Su, Su; Yue, Yunli; Wang, Wei; He, Luobin; Li, Hao; Ota, Yutaka

2017-05-01

The rapid development of electric vehicles and distributed generation bring new challenges to security and economic operation of the power system, so the collaborative research of the EVs and the distributed generation have important significance in distribution network. Under this background, an EVs charging scheduling strategy considering the uncertainty of photovoltaic(PV) output is proposed. The characteristics of EVs charging are analysed first. A PV output prediction method is proposed with a PV database then. On this basis, an EVs charging scheduling strategy is proposed with the goal to satisfy EVs users’ charging willingness and decrease the power loss in distribution network. The case study proves that the proposed PV output prediction method can predict the PV output accurately and the EVs charging scheduling strategy can reduce the power loss and stabilize the fluctuation of the load in distributed network.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narang, David; Ayyanar, Raja; Gemin, Paul

APS’s renewable energy portfolio, driven in part by Arizona’s Renewable Energy Standard (RES) currently includes more than 1100 MW of installed capacity, equating to roughly 3000 GWh of annual production. Overall renewable production is expected to grow to 6000 GWh by 2025. It is expected that distributed photovoltaics, driven primarily by lower cost, will contribute to much of this growth and that by 2025, distributed installations will account for half of all renewable production (3000GHW). As solar penetration increases, additional analysis may be required for routine utility processes to ensure continued safe and reliable operation of the electric distribution network.more » Such processes include residential or commercial interconnection requests and load shifting during normal feeder operations. Circuits with existing high solar penetration will also have to be studied and results will need to be evaluated for adherence to utility practices or strategy. Increased distributed PV penetration may offer benefits such as load offsetting, but it also has the potential to adversely impact distribution system operation. These effects may be exacerbated by the rapid variability of PV production. Detailed effects of these phenomena in distributed PV applications continue to be studied. Comprehensive, high-resolution electrical models of the distribution system were developed to analyze the impacts of PV on distribution circuit protection systems (including coordination and anti-islanding), predict voltage regulation and phase balance issues, and develop volt/VAr control schemes. Modeling methods were refined by validating against field measurements. To augment the field measurements, methods were developed to synthesize high resolution load and PV generation data to facilitate quasi-static time series simulations. The models were then extended to explore boundary conditions for PV hosting capability of the feeder and to simulate common utility practices such as feeder reconfiguration. The modeling and analysis methodology was implemented using open source tools and a process was developed to aid utility engineers in future interconnection requests. Methods to increase PV hosting capacity were also explored during the course of the study. A 700kVA grid-supportive inverter was deployed on the feeder and each grid support mode was demonstrated. Energy storage was explored through simulation and models were developed to calculate the optimum size and placement needed to increase PV hosting capacity. A tool was developed to aid planners in assigning relative costs and benefits to various strategies for increasing PV hosting capacity beyond current levels. Following the completion of the project, APS intends to use the tools and methods to improve the framework of future PV integration on its system. The tools and methods are also expected to aid other utilities to accelerate distributed PV deployment.« less

Voltage Support Study of Smart PV Inverters on a High-Photovoltaic Penetration Utility Distribution Feeder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Pratt, Annabelle; Bialek, Tom

2016-11-21

This paper reports on tools and methodologies developed to study the impact of adding rooftop photovoltaic (PV) systems, with and without the ability to provide voltage support, on the voltage profile of distribution feeders. Simulation results are provided from a study of a specific utility feeder. The simulation model of the utility distribution feeder was built in OpenDSS and verified by comparing the simulated voltages to field measurements. First, we set all PV systems to operate at unity power factor and analyzed the impact on feeder voltages. Then we conducted multiple simulations with voltage support activated for all the smartmore » PV inverters. These included different constant power factor settings and volt/VAR controls.« less

Does the visual system of the flying fox resemble that of primates? The distribution of calcium-binding proteins in the primary visual pathway of Pteropus poliocephalus.

PubMed

Ichida, J M; Rosa, M G; Casagrande, V A

2000-01-31

It has been proposed that flying foxes and echolocating bats evolved independently from early mammalian ancestors in such a way that flying foxes form one of the suborders most closely related to primates. A major piece of evidence offered in support of a flying fox-primate link is the highly developed visual system of flying foxes, which is theorized to be primate-like in several different ways. Because the calcium-binding proteins parvalbumin (PV) and calbindin (CB) show distinct and consistent distributions in the primate visual system, the distribution of these same proteins was examined in the flying fox (Pteropus poliocephalus) visual system. Standard immunocytochemical techniques reveal that PV labeling within the lateral geniculate nucleus (LGN) of the flying fox is sparse, with clearly labeled cells located only within layer 1, adjacent to the optic tract. CB labeling in the LGN is profuse, with cells labeled in all layers throughout the nucleus. Double labeling reveals that all PV+ cells also contain CB, and that these cells are among the largest in the LGN. In primary visual cortex (V1) PV and CB label different classes of non-pyramidal neurons. PV+ cells are found in all cortical layers, although labeled cells are found only rarely in layer I. CB+ cells are found primarily in layers II and III. The density of PV+ neuropil correlates with the density of cytochrome oxidase staining; however, no CO+ or PV+ or CB+ patches or blobs are found in V1. These results show that the distribution of calcium-binding proteins in the flying fox LGN is unlike that found in primates, in which antibodies for PV and CB label specific separate populations of relay cells that exist in different layers. Indeed, the pattern of calcium-binding protein distribution in the flying fox LGN is different from that reported in any other terrestrial mammal. Within V1 no PV+ patches, CO blobs, or patchy distribution of CB+ neuropil that might reveal interblobs characteristic of primate V1 are found; however, PV and CB are found in separate populations of non-pyramidal neurons. The types of V1 cells labeled with antibodies to PV and CB in all mammals examined including the flying fox suggest that the similarities in the cellular distribution of these proteins in cortex reflect the fact that this feature is common to all mammals.

Review of Interconnection Practices and Costs in the Western States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bird, Lori A; Flores-Espino, Francisco; Volpi, Christina M

The objective of this report is to evaluate the nature of barriers to interconnecting distributed PV, assess costs of interconnection, and compare interconnection practices across various states in the Western Interconnection. The report addresses practices for interconnecting both residential and commercial-scale PV systems to the distribution system. This study is part of a larger, joint project between the Western Interstate Energy Board (WIEB) and the National Renewable Energy Laboratory (NREL), funded by the U.S. Department of Energy, to examine barriers to distributed PV in the 11 states wholly within the Western Interconnection.

Performance of a Dynamically Controlled Inverter in a Photovoltaic System Interconnected with a Secondary Network Distribution System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coddington, M. H.; Kroposki, B. D.; Basso, T.

In 2008, a 300 kW{sub peak} photovoltaic (PV) system was installed on the rooftop of the Colorado Convention Center (CCC). The installation was unique for the electric utility, Xcel Energy, as it had not previously permitted a PV system to be interconnected on a building served by the local secondary network distribution system (network). The PV system was installed with several provisions; one to prevent reverse power flow, another called a dynamically controlled inverter (DCI), that curtails the output of the PV inverters to maintain an amount of load supplied by Xcel Energy at the CCC. The DCI system utilizesmore » current transformers (CTs) to sense power flow to insure that a minimum threshold is maintained from Xcel Energy through the network transformers. The inverters are set to track the load on each of the three phases and curtail power from the PV system when the generated PV system current reaches 95% of the current on any phase. This is achieved by the DCI, which gathers inputs from current transformers measuring the current from the PV array, Xcel, and the spot network load. Preventing reverse power flow is a critical technical requirement for the spot network which serve this part of the CCC. The PV system was designed with the expectation that the DCI system would not curtail the PV system, as the expected minimum load consumption was historically higher than the designed PV system size. However, the DCI system has operated many days during the course of a year, and the performance has been excellent. The DCI system at the CCC was installed as a secondary measure to insure that a minimum level of power flows to the CCC from the Xcel Energy network. While this DCI system was intended for localized control, the system could also reduce output percent if an external smart grid control signal was employed. This paper specifically focuses on the performance of the innovative design at this installation; however, the DCI system could also be used for new s- art grid-enabled distribution systems where renewables power contributions at certain conditions or times may need to be curtailed.« less

Interconnection Assessment Methodology and Cost Benefit Analysis for High-Penetration PV Deployment in the Arizona Public Service System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baggu, Murali; Giraldez, Julieta; Harris, Tom

In an effort to better understand the impacts of high penetrations of photovoltaic (PV) generators on distribution systems, Arizona Public Service and its partners completed a multi-year project to develop the tools and knowledge base needed to safely and reliably integrate high penetrations of utility- and residential-scale PV. Building upon the APS Community Power Project-Flagstaff Pilot, this project investigates the impact of PV on a representative feeder in northeast Flagstaff. To quantify and catalog the effects of the estimated 1.3 MW of PV that will be installed on the feeder (both smaller units at homes and large, centrally located systems),more » high-speed weather and electrical data acquisition systems and digital 'smart' meters were designed and installed to facilitate monitoring and to build and validate comprehensive, high-resolution models of the distribution system. These models are being developed to analyze the impacts of PV on distribution circuit protection systems (including coordination and anti-islanding), predict voltage regulation and phase balance issues, and develop volt/VAr control schemes. This paper continues from a paper presented at the 2014 IEEE PVSC conference that described feeder model evaluation and high penetration advanced scenario analysis, specifically feeder reconfiguration. This paper presents results from Phase 5 of the project. Specifically, the paper discusses tool automation; interconnection assessment methodology and cost benefit analysis.« less

Real-Time Monitoring System for a Utility-Scale Photovoltaic Power Plant.

PubMed

Moreno-Garcia, Isabel M; Palacios-Garcia, Emilio J; Pallares-Lopez, Victor; Santiago, Isabel; Gonzalez-Redondo, Miguel J; Varo-Martinez, Marta; Real-Calvo, Rafael J

2016-05-26

There is, at present, considerable interest in the storage and dispatchability of photovoltaic (PV) energy, together with the need to manage power flows in real-time. This paper presents a new system, PV-on time, which has been developed to supervise the operating mode of a Grid-Connected Utility-Scale PV Power Plant in order to ensure the reliability and continuity of its supply. This system presents an architecture of acquisition devices, including wireless sensors distributed around the plant, which measure the required information. It is also equipped with a high-precision protocol for synchronizing all data acquisition equipment, something that is necessary for correctly establishing relationships among events in the plant. Moreover, a system for monitoring and supervising all of the distributed devices, as well as for the real-time treatment of all the registered information, is presented. Performances were analyzed in a 400 kW transformation center belonging to a 6.1 MW Utility-Scale PV Power Plant. In addition to monitoring the performance of all of the PV plant's components and detecting any failures or deviations in production, this system enables users to control the power quality of the signal injected and the influence of the installation on the distribution grid.

Coordinative Voltage Control Strategy with Multiple Resources for Distribution Systems of High PV Penetration: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Xiangqi; Zhang, Yingchen

This paper presents an optimal voltage control methodology with coordination among different voltage-regulating resources, including controllable loads, distributed energy resources such as energy storage and photovoltaics (PV), and utility voltage-regulating devices such as voltage regulators and capacitors. The proposed methodology could effectively tackle the overvoltage and voltage regulation device distortion problems brought by high penetrations of PV to improve grid operation reliability. A voltage-load sensitivity matrix and voltage-regulator sensitivity matrix are used to deploy the resources along the feeder to achieve the control objectives. Mixed-integer nonlinear programming is used to solve the formulated optimization control problem. The methodology has beenmore » tested on the IEEE 123-feeder test system, and the results demonstrate that the proposed approach could actively tackle the voltage problem brought about by high penetrations of PV and improve the reliability of distribution system operation.« less

Power Hardware-in-the-Loop-Based Anti-Islanding Evaluation and Demonstration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoder, Karl; Langston, James; Hauer, John

2015-10-01

The National Renewable Energy Laboratory (NREL) teamed with Southern California Edison (SCE), Clean Power Research (CPR), Quanta Technology (QT), and Electrical Distribution Design (EDD) to conduct a U.S. Department of Energy (DOE) and California Public Utility Commission (CPUC) California Solar Initiative (CSI)-funded research project investigating the impacts of integrating high-penetration levels of photovoltaics (PV) onto the California distribution grid. One topic researched in the context of high-penetration PV integration onto the distribution system is the ability of PV inverters to (1) detect islanding conditions (i.e., when the distribution system to which the PV inverter is connected becomes disconnected from themore » utility power connection) and (2) disconnect from the islanded system within the time specified in the performance specifications outlined in IEEE Standard 1547. This condition may cause damage to other connected equipment due to insufficient power quality (e.g., over-and under-voltages) and may also be a safety hazard to personnel that may be working on feeder sections to restore service. NREL teamed with the Florida State University (FSU) Center for Advanced Power Systems (CAPS) to investigate a new way of testing PV inverters for IEEE Standard 1547 unintentional islanding performance specifications using power hardware-in-loop (PHIL) laboratory testing techniques.« less

Limits and Economic Effects of Distributed PV Generation in North and South Carolina

NASA Astrophysics Data System (ADS)

Holt, Kyra Moore

The variability of renewable sources, such as wind and solar, when integrated into the electrical system must be compensated by traditional generation sources in-order to maintain the constant balance of supply and demand required for grid stability. The goal of this study is to analyze the effects of increasing large levels of solar Photovoltaic (PV) penetration (in terms of a percentage of annual energy production) on a test grid with similar characteristics to the Duke Energy Carolinas (DEC) and Progress Energy Carolinas (PEC) regions of North and South Carolina. PV production is modeled entering the system at the distribution level and regional PV capacity is based on household density. A gridded hourly global horizontal irradiance (GHI) dataset is used to capture the variable nature of PV generation. A unit commitment model (UCM) is then used determine the hourly dispatch of generators based on generator parameters and costs to supply generation to meet demand. Annual modeled results for six different scenarios are evaluated to determine technical, environmental and economic effects of varying levels of distributed PV penetration on the system. This study finds that the main limiting factor for PV integration in the DEC and PEC balancing authority regions is defined by the large generating capacity of base-load nuclear plants within the system. This threshold starts to affect system stability at integration levels of 5.7%. System errors, defined by imbalances caused by over or under generation with respect to demand, are identified in the model however the validity of these errors in real world context needs further examination due to the lack of high frequency irradiance data and modeling limitations. Operational system costs decreased as expected with PV integration although further research is needed to explore the impacts of the capital costs required to achieve the penetration levels found in this study. PV system generation was found to mainly displace coal generation creating a loss of revenue for generator owners. In all scenarios, CO 2 emissions were reduced with PV integration. This reduction could be used to meet impending EPA state-specific CO2 emissions targets.

Distribution system model calibration with big data from AMI and PV inverters

DOE PAGES

Peppanen, Jouni; Reno, Matthew J.; Broderick, Robert J.; ...

2016-03-03

Efficient management and coordination of distributed energy resources with advanced automation schemes requires accurate distribution system modeling and monitoring. Big data from smart meters and photovoltaic (PV) micro-inverters can be leveraged to calibrate existing utility models. This paper presents computationally efficient distribution system parameter estimation algorithms to improve the accuracy of existing utility feeder radial secondary circuit model parameters. The method is demonstrated using a real utility feeder model with advanced metering infrastructure (AMI) and PV micro-inverters, along with alternative parameter estimation approaches that can be used to improve secondary circuit models when limited measurement data is available. Lastly, themore » parameter estimation accuracy is demonstrated for both a three-phase test circuit with typical secondary circuit topologies and single-phase secondary circuits in a real mixed-phase test system.« less

Distribution system model calibration with big data from AMI and PV inverters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peppanen, Jouni; Reno, Matthew J.; Broderick, Robert J.

Efficient management and coordination of distributed energy resources with advanced automation schemes requires accurate distribution system modeling and monitoring. Big data from smart meters and photovoltaic (PV) micro-inverters can be leveraged to calibrate existing utility models. This paper presents computationally efficient distribution system parameter estimation algorithms to improve the accuracy of existing utility feeder radial secondary circuit model parameters. The method is demonstrated using a real utility feeder model with advanced metering infrastructure (AMI) and PV micro-inverters, along with alternative parameter estimation approaches that can be used to improve secondary circuit models when limited measurement data is available. Lastly, themore » parameter estimation accuracy is demonstrated for both a three-phase test circuit with typical secondary circuit topologies and single-phase secondary circuits in a real mixed-phase test system.« less

Optimal Configuration of PV System with Different Solar Cell Arrays

NASA Astrophysics Data System (ADS)

Machida, Sadayuki; Tani, Tatsuo

Photovoltaic (PV) power generation is spreading steadily, and the dispersed PV array system is increasing from the architectural restrictions. In the case of dispersed array system, if the arrays are installed in a different azimuth or if the module that constitutes array is different, mismatching loss will be generated when a single inverter is used to convert the output of arrays, because of the difference of optimal operating voltage. The loss is related to the array configuration. However the relation between array configuration and power generation output is not clear. In order to avoid generation of mismatching loss, introducing a distributed inverter system such as string inverter system or AC modules system is considered. However it is not clear which is more advantageous between a distributed system and a concentrated system. In this paper, we verified the output characteristics of two different solar cell arrays with various strings, azimuths and tilt angles, and clarified the relation between array configuration and power generation output by the computer simulations. We also compared the distributed inverter system with the concentrated inverter system, and clarified the optimal configuration of PV system with different solar cell arrays.

Deployment strategy for battery energy storage system in distribution network based on voltage violation regulation

NASA Astrophysics Data System (ADS)

Wu, H.; Zhou, L.; Xu, T.; Fang, W. L.; He, W. G.; Liu, H. M.

2017-11-01

In order to improve the situation of voltage violation caused by the grid-connection of photovoltaic (PV) system in a distribution network, a bi-level programming model is proposed for battery energy storage system (BESS) deployment. The objective function of inner level programming is to minimize voltage violation, with the power of PV and BESS as the variables. The objective function of outer level programming is to minimize the comprehensive function originated from inner layer programming and all the BESS operating parameters, with the capacity and rated power of BESS as the variables. The differential evolution (DE) algorithm is applied to solve the model. Based on distribution network operation scenarios with photovoltaic generation under multiple alternative output modes, the simulation results of IEEE 33-bus system prove that the deployment strategy of BESS proposed in this paper is well adapted to voltage violation regulation invariable distribution network operation scenarios. It contributes to regulating voltage violation in distribution network, as well as to improve the utilization of PV systems.

Location and Size Planning of Distributed Photovoltaic Generation in Distribution network System Based on K-means Clustering Analysis

NASA Astrophysics Data System (ADS)

Lu, Siqi; Wang, Xiaorong; Wu, Junyong

2018-01-01

The paper presents a method to generate the planning scenarios, which is based on K-means clustering analysis algorithm driven by data, for the location and size planning of distributed photovoltaic (PV) units in the network. Taken the power losses of the network, the installation and maintenance costs of distributed PV, the profit of distributed PV and the voltage offset as objectives and the locations and sizes of distributed PV as decision variables, Pareto optimal front is obtained through the self-adaptive genetic algorithm (GA) and solutions are ranked by a method called technique for order preference by similarity to an ideal solution (TOPSIS). Finally, select the planning schemes at the top of the ranking list based on different planning emphasis after the analysis in detail. The proposed method is applied to a 10-kV distribution network in Gansu Province, China and the results are discussed.

High-Penetration PV Integration Handbook for Distribution Engineers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seguin, Rich; Woyak, Jeremy; Costyk, David

2016-01-01

This handbook has been developed as part of a five-year research project which began in 2010. The National Renewable Energy Laboratory (NREL), Southern California Edison (SCE), Quanta Technology, Satcon Technology Corporation, Electrical Distribution Design (EDD), and Clean Power Research (CPR) teamed together to analyze the impacts of high-penetration levels of photovoltaic (PV) systems interconnected onto the SCE distribution system. This project was designed specifically to leverage the experience that SCE and the project team would gain during the significant installation of 500 MW of commercial scale PV systems (1-5 MW typically) starting in 2010 and completing in 2015 within SCE’smore » service territory through a program approved by the California Public Utility Commission (CPUC).« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seal, Brian; Huque, Aminul; Rogers, Lindsey

In 2011, EPRI began a four-year effort under the Department of Energy (DOE) SunShot Initiative Solar Energy Grid Integration Systems - Advanced Concepts (SEGIS-AC) to demonstrate smart grid ready inverters with utility communication. The objective of the project was to successfully implement and demonstrate effective utilization of inverters with grid support functionality to capture the full value of distributed photovoltaic (PV). The project leveraged ongoing investments and expanded PV inverter capabilities, to enable grid operators to better utilize these grid assets. Developing and implementing key elements of PV inverter grid support capabilities will increase the distribution system’s capacity for highermore » penetration levels of PV, while reducing the cost. The project team included EPRI, Yaskawa-Solectria Solar, Spirae, BPL Global, DTE Energy, National Grid, Pepco, EDD, NPPT and NREL. The project was divided into three phases: development, deployment, and demonstration. Within each phase, the key areas included: head-end communications for Distributed Energy Resources (DER) at the utility operations center; methods for coordinating DER with existing distribution equipment; back-end PV plant master controller; and inverters with smart-grid functionality. Four demonstration sites were chosen in three regions of the United States with different types of utility operating systems and implementations of utility-scale PV inverters. This report summarizes the project and findings from field demonstration at three utility sites.« less

Real-Time Monitoring System for a Utility-Scale Photovoltaic Power Plant

PubMed Central

Moreno-Garcia, Isabel M.; Palacios-Garcia, Emilio J.; Pallares-Lopez, Victor; Santiago, Isabel; Gonzalez-Redondo, Miguel J.; Varo-Martinez, Marta; Real-Calvo, Rafael J.

2016-01-01

There is, at present, considerable interest in the storage and dispatchability of photovoltaic (PV) energy, together with the need to manage power flows in real-time. This paper presents a new system, PV-on time, which has been developed to supervise the operating mode of a Grid-Connected Utility-Scale PV Power Plant in order to ensure the reliability and continuity of its supply. This system presents an architecture of acquisition devices, including wireless sensors distributed around the plant, which measure the required information. It is also equipped with a high-precision protocol for synchronizing all data acquisition equipment, something that is necessary for correctly establishing relationships among events in the plant. Moreover, a system for monitoring and supervising all of the distributed devices, as well as for the real-time treatment of all the registered information, is presented. Performances were analyzed in a 400 kW transformation center belonging to a 6.1 MW Utility-Scale PV Power Plant. In addition to monitoring the performance of all of the PV plant’s components and detecting any failures or deviations in production, this system enables users to control the power quality of the signal injected and the influence of the installation on the distribution grid. PMID:27240365

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bank, J.; Mather, B.

This paper, presented at the IEEE Green Technologies Conference 2013, utilizes information from high resolution data acquisition systems developed at the National Renewable Energy Laboratory and deployed on a high-penetration PV distribution system to analyze the variability of different electrical parameters. High-resolution solar irradiance data is also available in the same area which is used to characterize the available resource and how it affects the electrical characteristics of the study circuit. This paper takes a data-driven look at the variability caused by load and compares those results against times when significant PV production is present. Comparisons between the variability inmore » system load and the variability of distributed PV generation are made.« less

Southern California Edison Grid Integration Evaluation: Cooperative Research and Development Final Report, CRADA Number CRD-10-376

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mather, Barry

2015-07-09

The objective of this project is to use field verification to improve DOE’s ability to model and understand the impacts of, as well as develop solutions for, high penetration PV deployments in electrical utility distribution systems. The Participant will work with NREL to assess the existing distribution system at SCE facilities and assess adding additional PV systems into the electric power system.

Statistical Evaluation of Voltage Variation of Power Distribution System with Clustered Home-Cogeneration Systems

NASA Astrophysics Data System (ADS)

Kato, Takeyoshi; Minagata, Atsushi; Suzuoki, Yasuo

This paper discusses the influence of mass installation of a home co-generation system (H-CGS) using a polymer electrolyte fuel cell (PEFC) on the voltage profile of power distribution system in residential area. The influence of H-CGS is compared with that of photovoltaic power generation systems (PV systems). The operation pattern of H-CGS is assumed based on the electricity and hot-water demand observed in 10 households for a year. The main results are as follows. With the clustered H-CGS, the voltage of each bus is higher by about 1-3% compared with the conventional system without any distributed generators. Because H-CGS tends to increase the output during the early evening, H-CGS contributes to recover the voltage drop during the early evening, resulting in smaller voltage variation of distribution system throughout a day. Because of small rated power output about 1kW, the influence on voltage profile by the clustered H-CGS is smaller than that by the clustered PV systems. The highest voltage during the day time is not so high as compared with the distribution system with the clustered PV systems, even if the reverse power flow from H-CGS is allowed.

Coordinated microgrid investment and planning process considering the system operator

DOE PAGES

Armendáriz, M.; Heleno, M.; Cardoso, G.; ...

2017-05-12

Nowadays, a significant number of distribution systems are facing problems to accommodate more photovoltaic (PV) capacity, namely due to the overvoltages during the daylight periods. This has an impact on the private investments in distributed energy resources (DER), since it occurs exactly when the PV prices are becoming attractive, and the opportunity to an energy transition based on solar technologies is being wasted. In particular, this limitation of the networks is a barrier for larger consumers, such as commercial and public buildings, aiming at investing in PV capacity and start operating as microgrids connected to the MV network. To addressmore » this challenge, this paper presents a coordinated approach to the microgrid investment and planning problem, where the system operator and the microgrid owner collaborate to improve the voltage control capabilities of the distribution network, increasing the PV potential. The results prove that this collaboration has the benefit of increasing the value of the microgrid investments while improving the quality of service of the system and it should be considered in the future regulatory framework.« less

Coordinated microgrid investment and planning process considering the system operator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armendáriz, M.; Heleno, M.; Cardoso, G.

Nowadays, a significant number of distribution systems are facing problems to accommodate more photovoltaic (PV) capacity, namely due to the overvoltages during the daylight periods. This has an impact on the private investments in distributed energy resources (DER), since it occurs exactly when the PV prices are becoming attractive, and the opportunity to an energy transition based on solar technologies is being wasted. In particular, this limitation of the networks is a barrier for larger consumers, such as commercial and public buildings, aiming at investing in PV capacity and start operating as microgrids connected to the MV network. To addressmore » this challenge, this paper presents a coordinated approach to the microgrid investment and planning problem, where the system operator and the microgrid owner collaborate to improve the voltage control capabilities of the distribution network, increasing the PV potential. The results prove that this collaboration has the benefit of increasing the value of the microgrid investments while improving the quality of service of the system and it should be considered in the future regulatory framework.« less

Energy balance of the global photovoltaic (PV) industry--is the PV industry a net electricity producer?

PubMed

Dale, Michael; Benson, Sally M

2013-04-02

A combination of declining costs and policy measures motivated by greenhouse gas (GHG) emissions reduction and energy security have driven rapid growth in the global installed capacity of solar photovoltaics (PV). This paper develops a number of unique data sets, namely the following: calculation of distribution of global capacity factor for PV deployment; meta-analysis of energy consumption in PV system manufacture and deployment; and documentation of reduction in energetic costs of PV system production. These data are used as input into a new net energy analysis of the global PV industry, as opposed to device level analysis. In addition, the paper introduces a new concept: a model tracking energetic costs of manufacturing and installing PV systems, including balance of system (BOS) components. The model is used to forecast electrical energy requirements to scale up the PV industry and determine the electricity balance of the global PV industry to 2020. Results suggest that the industry was a net consumer of electricity as recently as 2010. However, there is a >50% that in 2012 the PV industry is a net electricity provider and will "pay back" the electrical energy required for its early growth before 2020. Further reducing energetic costs of PV deployment will enable more rapid growth of the PV industry. There is also great potential to increase the capacity factor of PV deployment. These conclusions have a number of implications for R&D and deployment, including the following: monitoring of the energy embodied within PV systems; designing more efficient and durable systems; and deploying PV systems in locations that will achieve high capacity factors.

Solar PV O&M Standards and Best Practices – Existing Gaps and Improvement Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Balfour, John R.; Keating, T. J.

2014-11-01

As greater numbers of photovoltaic (PV) systems are being installed, operations & maintenance (O&M) activities will need to be performed to ensure the PV system is operating as designed over its useful lifetime. To mitigate risks to PV system availability and performance, standardized procedures for O&M activities are needed to ensure high reliability and long-term system bankability. Efforts are just getting underway to address the need for standard O&M procedures as PV gains a larger share of U.S. generation capacity. Due to the existing landscape of how and where PV is installed, including distributed generation from small and medium PVmore » systems, as well as large, centralized utility-scale PV, O&M activities will require different levels of expertise and reporting, making standards even more important. This report summarizes recent efforts made by solar industry stakeholders to identify the existing standards and best practices applied to solar PV O&M activities, and determine the gaps that have yet to be, or are currently being addressed by industry.« less

Solar PV O&M Standards and Best Practices - Existing Gaps and Improvement Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Balfour, John R.; Keating, T. J.

2014-11-01

As greater numbers of photovoltaic (PV) systems are being installed, operations & maintenance (O&M) activities will need to be performed to ensure the PV system is operating as designed over its useful lifetime. To mitigate risks to PV system availability and performance, standardized procedures for O&M activities are needed to ensure high reliability and long-term system bankability. Efforts are just getting underway to address the need for standard O&M procedures as PV gains a larger share of U.S. generation capacity. Due to the existing landscape of how and where PV is installed, including distributed generation from small and medium PVmore » systems, as well as large, centralized utility-scale PV, O&M activities will require different levels of expertise and reporting, making standards even more important. This report summarizes recent efforts made by solar industry stakeholders to identify the existing standards and best practices applied to solar PV O&M activities, and determine the gaps that have yet to be, or are currently being addressed by industry.« less

Locational Sensitivity Investigation on PV Hosting Capacity and Fast Track PV Screening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mather, Barry; Ainsworth, Nathan

A 15% PV penetration threshold is commonly used by utilities to define photovoltaic (PV) screening methods where PV penetration is defined as the ratio of total solar PV capacity on a line section to peak load. However, this method doesn't take into account PV locational impact or feeder characteristics that could strongly change the feeder's capability to host PVs. This paper investigates the impact of PV location and phase connection type on PV hosting capacity, and then proposes a fast-track PV screening approach that leverages various PV hosting capacity metric responding to different PV locations and types. The proposed studymore » could help utilities to evaluate PV interconnection requests and also help increase the PV hosting capacity of distribution feeders without adverse impacts on system voltages.« less

Distribution System Upgrade Unit Cost Database

DOE Data Explorer

Horowitz, Kelsey

2017-11-30

This database contains unit cost information for different components that may be used to integrate distributed photovotaic (D-PV) systems onto distribution systems. Some of these upgrades and costs may also apply to integration of other distributed energy resources (DER). Which components are required, and how many of each, is system-specific and should be determined by analyzing the effects of distributed PV at a given penetration level on the circuit of interest in combination with engineering assessments on the efficacy of different solutions to increase the ability of the circuit to host additional PV as desired. The current state of the distribution system should always be considered in these types of analysis. The data in this database was collected from a variety of utilities, PV developers, technology vendors, and published research reports. Where possible, we have included information on the source of each data point and relevant notes. In some cases where data provided is sensitive or proprietary, we were not able to specify the source, but provide other information that may be useful to the user (e.g. year, location where equipment was installed). NREL has carefully reviewed these sources prior to inclusion in this database. Additional information about the database, data sources, and assumptions is included in the "Unit_cost_database_guide.doc" file included in this submission. This guide provides important information on what costs are included in each entry. Please refer to this guide before using the unit cost database for any purpose.

A Study on Grid-Square Statistics Based Estimation of Regional Electricity Demand and Regional Potential Capacity of Distributed Generators

NASA Astrophysics Data System (ADS)

Kato, Takeyoshi; Sugimoto, Hiroyuki; Suzuoki, Yasuo

We established a procedure for estimating regional electricity demand and regional potential capacity of distributed generators (DGs) by using a grid square statistics data set. A photovoltaic power system (PV system) for residential use and a co-generation system (CGS) for both residential and commercial use were taken into account. As an example, the result regarding Aichi prefecture was presented in this paper. The statistical data of the number of households by family-type and the number of employees by business category for about 4000 grid-square with 1km × 1km area was used to estimate the floor space or the electricity demand distribution. The rooftop area available for installing PV systems was also estimated with the grid-square statistics data set. Considering the relation between a capacity of existing CGS and a scale-index of building where CGS is installed, the potential capacity of CGS was estimated for three business categories, i.e. hotel, hospital, store. In some regions, the potential capacity of PV systems was estimated to be about 10,000kW/km2, which corresponds to the density of the existing area with intensive installation of PV systems. Finally, we discussed the ratio of regional potential capacity of DGs to regional maximum electricity demand for deducing the appropriate capacity of DGs in the model of future electricity distribution system.

SunShot 2030 for Photovoltaics (PV): Envisioning a Low-cost PV Future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, Wesley J.; Frew, Bethany A.; Gagnon, Pieter J.

In this report we summarize the implications, impacts, and deployment potential of reaching the SunShot 2030 targets for the electricity system in the contiguous United States. We model 25 scenarios of the U.S. power sector using the Regional Energy Deployment Systems (ReEDS) and Distributed Generation (dGen) capacity expansion models. The scenarios cover a wide range of sensitivities to capture future uncertainties relating to fuel prices, retirements, renewable energy capital costs, and load growth. We give special attention to the potential for storage costs to also rapidly decline due to its large synergies with low-cost solar. The ReEDS and dGen modelsmore » project utility- and distributed-scale power sector evolution, respectively, for the United States. Both models have been designed with special emphasis on capturing the unique traits of renewable energy, including variability and grid integration requirements. Across the suite of scenarios modeled, we find that reaching the SunShot 2030 target has the potential to lead to significant capacity additions of PV in the United States. By 2050, PV penetration levels are projected to reach 28-46 percent of total generation. If storage also sees significant reductions in cost, then the 2050 solar penetration levels could reach 41-64 percent. PV deployment is projected to occur in all of the lower 48 states, though the specific deployment level is scenario dependent. The growth in PV is projected to be dominated by utility-scale systems, but the actual mix between utility and distributed systems could ultimately vary depending on how policies, system costs, and rate structures evolve.« less

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

2017-04-11

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

Voltage management of distribution networks with high penetration of distributed photovoltaic generation sources

NASA Astrophysics Data System (ADS)

Alyami, Saeed

Installation of photovoltaic (PV) units could lead to great challenges to the existing electrical systems. Issues such as voltage rise, protection coordination, islanding detection, harmonics, increased or changed short-circuit levels, etc., need to be carefully addressed before we can see a wide adoption of this environmentally friendly technology. Voltage rise or overvoltage issues are of particular importance to be addressed for deploying more PV systems to distribution networks. This dissertation proposes a comprehensive solution to deal with the voltage violations in distribution networks, from controlling PV power outputs and electricity consumption of smart appliances in real time to optimal placement of PVs at the planning stage. The dissertation is composed of three parts: the literature review, the work that has already been done and the future research tasks. An overview on renewable energy generation and its challenges are given in Chapter 1. The overall literature survey, motivation and the scope of study are also outlined in the chapter. Detailed literature reviews are given in the rest of chapters. The overvoltage and undervoltage phenomena in typical distribution networks with integration of PVs are further explained in Chapter 2. Possible approaches for voltage quality control are also discussed in this chapter, followed by the discussion on the importance of the load management for PHEVs and appliances and its benefits to electric utilities and end users. A new real power capping method is presented in Chapter 3 to prevent overvoltage by adaptively setting the power caps for PV inverters in real time. The proposed method can maintain voltage profiles below a pre-set upper limit while maximizing the PV generation and fairly distributing the real power curtailments among all the PV systems in the network. As a result, each of the PV systems in the network has equal opportunity to generate electricity and shares the responsibility of voltage regulation. The method does not require global information and can be implemented either under a centralized supervisory control scheme or in a distributed way via consensus control. Chapter 4 investigates autonomous operation schedules for three types of intelligent appliances (or residential controllable loads) without receiving external signals for cost saving and for assisting the management of possible photovoltaic generation systems installed in the same distribution network. The three types of controllable loads studied in the chapter are electric water heaters, refrigerators deicing loads, and dishwashers, respectively. Chapter 5 investigates the method to mitigate overvoltage issues at the planning stage. A probabilistic method is presented in the chapter to evaluate the overvoltage risk in a distribution network with different PV capacity sizes under different load levels. Kolmogorov--Smirnov test (K--S test) is used to identify the most proper probability distributions for solar irradiance in different months. To increase accuracy, an iterative process is used to obtain the maximum allowable injection of active power from PVs. Conclusion and discussions on future work are given in Chapter 6.

Development and Testing of a Prototype Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) has developed and tested a prototype 2 kW DC grid-tied photovoltaic (PV) power system at the Center. The PV system has generated in excess of 6700 kWh since operation commenced in July 2006. The PV system is providing power to the GRC grid for use by all. Operation of the prototype PV system has been completely trouble free. A grid-tied PV power system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility. The project transfers space technology to terrestrial use via nontraditional partners. GRC personnel glean valuable experience with PV power systems that are directly applicable to various space power systems, and provide valuable space program test data. PV power systems help to reduce harmful emissions and reduce the Nation s dependence on fossil fuels. Power generated by the PV system reduces the GRC utility demand, and the surplus power aids the community. Present global energy concerns reinforce the need for the development of alternative energy systems. Modern PV panels are readily available, reliable, efficient, and economical with a life expectancy of at least 25 years. Modern electronics has been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy of at least 25 years. Based upon the success of the prototype PV system, additional PV power system expansion at GRC is under consideration. The prototype grid-tied PV power system was successfully designed and developed which served to validate the basic principles described, and the theoretical work that was performed. The report concludes that grid-tied photovoltaic power systems are reliable, maintenance free, long life power systems, and are of significant value to NASA and the community.

Development of an Advanced Grid-Connected PV-ECS System Considering Solar Energy Estimation

NASA Astrophysics Data System (ADS)

Rahman, Md. Habibur; Yamashiro, Susumu; Nakamura, Koichi

In this paper, the development and the performance of a viable distributed grid-connected power generation system of Photovoltaic-Energy Capacitor System (PV-ECS) considering solar energy estimation have been described. Instead of conventional battery Electric Double Layer Capacitors (EDLC) are used as storage device and Photovoltaic (PV) panel to generate power from solar energy. The system can generate power by PV, store energy when the demand of load is low and finally supply the stored energy to load during the period of peak demand. To realize the load leveling function properly the system will also buy power from grid line when load demand is high. Since, the power taken from grid line depends on the PV output power, a procedure has been suggested to estimate the PV output power by calculating solar radiation. In order to set the optimum value of the buy power, a simulation program has also been developed. Performance of the system has been studied for different load patterns in different weather conditions by using the estimated PV output power with the help of the simulation program.

Photovoltaic System Modeling. Uncertainty and Sensitivity Analyses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Clifford W.; Martin, Curtis E.

2015-08-01

We report an uncertainty and sensitivity analysis for modeling AC energy from ph otovoltaic systems . Output from a PV system is predicted by a sequence of models. We quantify u ncertainty i n the output of each model using empirical distribution s of each model's residuals. We propagate uncertainty through the sequence of models by sampli ng these distributions to obtain a n empirical distribution of a PV system's output. We consider models that: (1) translate measured global horizontal, direct and global diffuse irradiance to plane - of - array irradiance; (2) estimate effective irradiance; (3) predict cell temperature;more » (4) estimate DC voltage, current and power ; (5) reduce DC power for losses due to inefficient maximum power point tracking or mismatch among modules; and (6) convert DC to AC power . O ur analysis consider s a notional PV system com prising an array of FirstSolar FS - 387 modules and a 250 kW AC inverter ; we use measured irradiance and weather at Albuquerque, NM. We found the uncertainty in PV syste m output to be relatively small, on the order of 1% for daily energy. We found that unce rtainty in the models for POA irradiance and effective irradiance to be the dominant contributors to uncertainty in predicted daily energy. Our analysis indicates that efforts to reduce the uncertainty in PV system output predictions may yield the greatest improvements by focusing on the POA and effective irradiance models.« less

Air Quality Improvements of Increased Integration of Renewables: Solar Photovoltaics Penetration Scenarios

NASA Astrophysics Data System (ADS)

Duran, P.; Holloway, T.; Brinkman, G.; Denholm, P.; Littlefield, C. M.

2011-12-01

Solar photovoltaics (PV) are an attractive technology because they can be locally deployed and tend to yield high production during periods of peak electric demand. These characteristics can reduce the need for conventional large-scale electricity generation, thereby reducing emissions of criteria air pollutants (CAPs) and improving ambient air quality with regard to such pollutants as nitrogen oxides, sulfur oxides and fine particulates. Such effects depend on the local climate, time-of-day emissions, available solar resources, the structure of the electric grid, and existing electricity production among other factors. This study examines the air quality impacts of distributed PV across the United States Eastern Interconnection. In order to accurately model the air quality impact of distributed PV in space and time, we used the National Renewable Energy Lab's (NREL) Regional Energy Deployment System (ReEDS) model to form three unique PV penetration scenarios in which new PV construction is distributed spatially based upon economic drivers and natural solar resources. Those scenarios are 2006 Eastern Interconnection business as usual, 10% PV penetration, and 20% PV penetration. With the GridView (ABB, Inc) dispatch model, we used historical load data from 2006 to model electricity production and distribution for each of the three scenarios. Solar PV electric output was estimated using historical weather data from 2006. To bridge the gap between dispatch and air quality modeling, we will create emission profiles for electricity generating units (EGUs) in the Eastern Interconnection from historical Continuous Emissions Monitoring System (CEMS) data. Via those emissions profiles, we will create hourly emission data for EGUs in the Eastern Interconnect for each scenario during 2006. Those data will be incorporated in the Community Multi-scale Air Quality (CMAQ) model using the Sparse Matrix Operator Kernel Emissions (SMOKE) model. Initial results indicate that PV penetration significantly reduces conventional peak electricity production and that, due to reduced emissions during periods of extremely active photochemistry, air quality could see benefits.

Residential load and rooftop PV generation: an Australian distribution network dataset

NASA Astrophysics Data System (ADS)

Ratnam, Elizabeth L.; Weller, Steven R.; Kellett, Christopher M.; Murray, Alan T.

2017-09-01

Despite the rapid uptake of small-scale solar photovoltaic (PV) systems in recent years, public availability of generation and load data at the household level remains very limited. Moreover, such data are typically measured using bi-directional meters recording only PV generation in excess of residential load rather than recording generation and load separately. In this paper, we report a publicly available dataset consisting of load and rooftop PV generation for 300 de-identified residential customers in an Australian distribution network, with load centres covering metropolitan Sydney and surrounding regional areas. The dataset spans a 3-year period, with separately reported measurements of load and PV generation at 30-min intervals. Following a detailed description of the dataset, we identify several means by which anomalous records (e.g. due to inverter failure) are identified and excised. With the resulting 'clean' dataset, we identify key customer-specific and aggregated characteristics of rooftop PV generation and residential load.

Optimal placement and sizing of wind / solar based DG sources in distribution system

NASA Astrophysics Data System (ADS)

Guan, Wanlin; Guo, Niao; Yu, Chunlai; Chen, Xiaoguang; Yu, Haiyang; Liu, Zhipeng; Cui, Jiapeng

2017-06-01

Proper placement and sizing of Distributed Generation (DG) in distribution system can obtain maximum potential benefits. This paper proposes quantum particle swarm algorithm (QPSO) based wind turbine generation unit (WTGU) and photovoltaic (PV) array placement and sizing approach for real power loss reduction and voltage stability improvement of distribution system. Performance modeling of wind and solar generation system are described and classified into PQ\\PQ (V)\\PI type models in power flow. Considering the WTGU and PV based DGs in distribution system is geographical restrictive, the optimal area and DG capacity limits of each bus in the setting area need to be set before optimization, the area optimization method is proposed . The method has been tested on IEEE 33-bus radial distribution systems to demonstrate the performance and effectiveness of the proposed method.

NREL/SCE High Penetration PV Integration Project: FY13 Annual Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mather, B. A.; Shah, S.; Norris, B. L.

2014-06-01

In 2010, the National Renewable Energy Laboratory (NREL), Southern California Edison (SCE), Quanta Technology, Satcon Technology Corporation, Electrical Distribution Design (EDD), and Clean Power Research (CPR) teamed to analyze the impacts of high penetration levels of photovoltaic (PV) systems interconnected onto the SCE distribution system. This project was designed specifically to benefit from the experience that SCE and the project team would gain during the installation of 500 megawatts (MW) of utility-scale PV systems (with 1-5 MW typical ratings) starting in 2010 and completing in 2015 within SCE's service territory through a program approved by the California Public Utility Commissionmore » (CPUC). This report provides the findings of the research completed under the project to date.« less

Characteristics of low-priced solar PV systems in the U.S.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nemet, Gregory F.; O’Shaughnessy, Eric; Wiser, Ryan

Despite impressive declines in average prices, there is wide dispersion in the prices of U.S. solar photovoltaic (PV) systems; prices span more than a factor of four. What are the characteristics of the systems with low-prices? Using detailed characteristics of 42,611 small-scale (<15 kW) PV systems installed in 15 U.S. states during 2013, we identify the most important factors that make a system likely to be low-priced (LP). Comparing LP and non-LP systems, we find statistically significant differences in nearly all characteristics for which we have data. Logit and probit model results robustly indicate that LP systems are associated with:more » markets with few active installers; experienced installers; customer ownership; large systems; retrofits; and thin-film, low-efficiency, and Chinese modules. We also find significant differences across states, with LP systems much more likely to occur in some states, such as Arizona, New Jersey, and New Mexico, and less likely in others, such as California. Our focus on the left tail of the price distribution provides implications for policy that are distinct from recent studies of mean prices. While those studies find that PV subsidies increase mean prices, we find that subsidies also generate LP systems. PV subsidies appear to simultaneously shift and broaden the price distribution. Much of this broadening occurs in a particular location, northern California.« less

High Penetration Solar PV Deployment Sunshine State Solar Grid Initiative (SUNGRIN)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meeker, Rick; Steurer, Mischa; Faruque, MD Omar

The report provides results from the Sunshine State Solar Grid Initiative (SUNGRIN) high penetration solar PV deployment project led by Florida State University’s (FSU) Center for Advanced Power Systems (CAPS). FSU CAPS and industry and university partners have completed a five-year effort aimed at enabling effective integration of high penetration levels of grid-connected solar PV generation. SUNGRIN has made significant contributions in the development of simulation-assisted techniques, tools, insight and understanding associated with solar PV effects on electric power system (EPS) operation and the evaluation of mitigation options for maintaining reliable operation. An important element of the project was themore » partnership and participation of six major Florida utilities and the Florida Reliability Coordinating Council (FRCC). Utilities provided details and data associated with actual distribution circuits having high-penetration PV to use as case studies. The project also conducted foundational work supporting future investigations of effects at the transmission / bulk power system level. In the final phase of the project, four open-use models with built-in case studies were developed and released, along with synthetic solar PV data sets, and tools and techniques for model reduction and in-depth parametric studies of solar PV impact on distribution circuits. Along with models and data, at least 70 supporting MATLAB functions have been developed and made available, with complete documentation.« less

Validation of PV-RPM Code in the System Advisor Model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Lavrova, Olga; Freeman, Janine

2017-04-01

This paper describes efforts made by Sandia National Laboratories (SNL) and the National Renewable Energy Laboratory (NREL) to validate the SNL developed PV Reliability Performance Model (PV - RPM) algorithm as implemented in the NREL System Advisor Model (SAM). The PV - RPM model is a library of functions that estimates component failure and repair in a photovoltaic system over a desired simulation period. The failure and repair distributions in this paper are probabilistic representations of component failure and repair based on data collected by SNL for a PV power plant operating in Arizona. The validation effort focuses on whethermore » the failure and repair dist ributions used in the SAM implementation result in estimated failures that match the expected failures developed in the proof - of - concept implementation. Results indicate that the SAM implementation of PV - RPM provides the same results as the proof - of - concep t implementation, indicating the algorithms were reproduced successfully.« less

Past Seminars and Workshops | Energy Systems Integration Facility | NREL

Science.gov Websites

Distributed Optimization and Control of Sustainable Power Systems Workshop Integrating PV in Distributed Grids Unintentional Islands in Power Systems with Distributed Resources Webinar Smart Grid Educational Series Energy

PV water pumping: NEOS Corporation recent PV water pumping activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lane, C.

1995-11-01

NEOS Corporation has been very active in PV-powered water pumping, particularly with respect to electric utilities. Most of the recent activity has been through the Photovoltaic Services Network (PSN). The PSN is an independent, not-for-profit organization comprised of all types of electric utilities: rural electric coops, public power districts, investor-owned utilities, and power marketing agencies. The PSN`s mission is to work pro-actively to promote utility involvement in PV through education and training. PV information is distributed by the PSN in three primary forms: (1) consultation with PSN technical service representatives: (2) literature generated by the PSN; and (3) literature publishedmore » by other organizations. The PSN can also provide assistance to members in developing PV customer service programs. The PSN`s product support activities include consolidation of information on existing packaged PV systems and facilitation of the development of new PV product packages that meet utility-defined specifications for cost performance, and reliability. The PSN`s initial product support efforts will be focused on commercially available packaged PV systems for a variety of off-grid applications. In parallel with this effort, if no products exist that meet the PSN`s functional specifications, the PSN will initiate the second phase of product development support process by encouraging the development of new packaged systems. Through these services and product support activities, the PSN anticipates engaging all segments for the PV industry, thus providing benefits to PV systems suppliers as well as local PV service contractors.This paper describes field testing of pv power systems for water pumping.« less

Distributed photovoltaic architecture powering a DC bus: Impact of duty cycle and load variations on the efficiency of the generator

NASA Astrophysics Data System (ADS)

Allouache, Hadj; Zegaoui, Abdallah; Boutoubat, Mohamed; Bokhtache, Aicha Aissa; Kessaissia, Fatma Zohra; Charles, Jean-Pierre; Aillerie, Michel

2018-05-01

This paper focuses on a photovoltaic generator feeding a load via a boost converter in a distributed PV architecture. The principal target is the evaluation of the efficiency of a distributed photovoltaic architecture powering a direct current (DC) PV bus. This task is achieved by outlining an original way for tracking the Maximum Power Point (MPP) taking into account load variations and duty cycle on the electrical quantities of the boost converter and on the PV generator output apparent impedance. Thereafter, in a given sized PV system, we analyze the influence of the load variations on the behavior of the boost converter and we deduce the limits imposed by the load on the DC PV bus. The simultaneous influences of 1- the variation of the duty cycle of the boost converter and 2- the load power on the parameters of the various components of the photovoltaic chain and on the boost performances are clearly presented as deduced by simulation.

Grid Integrated Distributed PV (GridPV) Version 2.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reno, Matthew J.; Coogan, Kyle

2014-12-01

This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functio ns are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in th e OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included tomore » show potential uses of the toolbox functions. Each function i n the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.« less

Dynamic analysis of combined photovoltaic source and synchronous generator connected to power grid

NASA Astrophysics Data System (ADS)

Mahabal, Divya

In the world of expanding economy and technology, the energy demand is likely to increase even with the global efforts of saving and increasing energy efficiency. Higher oil prices, effects of greenhouse gases, and concerns over other environmental impacts gave way to Distributed Generation (DG). With adequate awareness and support, DG's can meet these rising energy demands at lower prices compared to conventional methods. Extensive research is taking place in different areas like fuel cells, photovoltaic cells, wind turbines, and gas turbines. DG's when connected to a grid increase the overall efficiency of the power grid. It is believed that three-fifth of the world's electricity would account for renewable energy by middle of 21st century. This thesis presents the dynamic analysis of a grid connected photovoltaic (PV) system and synchronous generator. A grid is considered as an infinite bus. The photovol-taic system and synchronous generator act as small scale distributed energy resources. The output of the photovoltaic system depends on the light intensity, temperature, and irradiance levels of sun. The maximum power point tracking and DC/AC converter are also modeled for the photovoltaic system. The PV system is connected to the grid through DC/AC system. Different combinations of PV and synchronous generator are modeled with the grid to study the dynamics of the proposed system. The dynamics of the test system is analyzed by subjecting the system to several disturbances under various conditions. All modules are individually modeled and con-nected using MATLAB/Simulink software package. Results from the study show that, as the penetration of renewable energy sources like PV increases into the power system, the dynamics of the system becomes faster. When considering cases such as load switching, PV cannot deliver more power as the performance of PV depends on environmental conditions. Synchronous generator in power system can produce the required amount of power. As the main aim of this research is to use renewable sources like PV in the system, it is advantageous to use a combination of both PV and synchronous generator in the system.

Uncertainty and sensitivity analysis for photovoltaic system modeling.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Clifford W.; Pohl, Andrew Phillip; Jordan, Dirk

2013-12-01

We report an uncertainty and sensitivity analysis for modeling DC energy from photovoltaic systems. We consider two systems, each comprised of a single module using either crystalline silicon or CdTe cells, and located either at Albuquerque, NM, or Golden, CO. Output from a PV system is predicted by a sequence of models. Uncertainty in the output of each model is quantified by empirical distributions of each model's residuals. We sample these distributions to propagate uncertainty through the sequence of models to obtain an empirical distribution for each PV system's output. We considered models that: (1) translate measured global horizontal, directmore » and global diffuse irradiance to plane-of-array irradiance; (2) estimate effective irradiance from plane-of-array irradiance; (3) predict cell temperature; and (4) estimate DC voltage, current and power. We found that the uncertainty in PV system output to be relatively small, on the order of 1% for daily energy. Four alternative models were considered for the POA irradiance modeling step; we did not find the choice of one of these models to be of great significance. However, we observed that the POA irradiance model introduced a bias of upwards of 5% of daily energy which translates directly to a systematic difference in predicted energy. Sensitivity analyses relate uncertainty in the PV system output to uncertainty arising from each model. We found that the residuals arising from the POA irradiance and the effective irradiance models to be the dominant contributors to residuals for daily energy, for either technology or location considered. This analysis indicates that efforts to reduce the uncertainty in PV system output should focus on improvements to the POA and effective irradiance models.« less

The Evolving Market Structure of the U.S. Residential Solar PV Installation Industry, 2000-2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J

Market structure refers to the number of firms and the distribution of market shares among firms within an industry. In The Evolving Market Structure of the U.S. Residential Solar PV Installation Industry, 2000-2016, we examine market structure in the context of residential solar PV. We find that over 8,000 companies have installed at least one residential PV system, with about 2,900 companies active in 2016. The majority of residential PV installers are relatively small companies, with about half of installers installing fewer than five systems. At the same time, a subset of high-volume installers accumulated market share, especially beginning aroundmore » 2010 with the emergence of alternative customer financing options.« less

Design of a Glenn Research Center Solar Field Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) designed, developed, and installed, a 37.5 kW DC photovoltaic (PV) Solar Field in the GRC West Area in the 1970s for the purpose of testing PV panels for various space and terrestrial applications. The PV panels are arranged to provide a nominal 120 VDC. The GRC Solar Field has been extremely successful in meeting its mission. The PV panels and the supporting electrical systems are all near their end of life. GRC has designed a 72 kW DC grid-tied PV power system to replace the existing GRC West Area Solar Field. The 72 kW DC grid-tied PV power system will provide DC solar power for GRC PV testing applications, and provide AC facility power for all times that research power is not required. A grid-tied system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility for use by all. The project transfers space technology to terrestrial use via nontraditional partners. GRC personnel glean valuable experience with PV power systems that are directly applicable to various space power systems, and provide valuable space program test data. PV power systems help to reduce harmful emissions and reduce the Nation s dependence on fossil fuels. Power generated by the PV system reduces the GRC utility demand, and the surplus power aids the community. Present global energy concerns reinforce the need for the development of alternative energy systems. Modern PV panels are readily available, reliable, efficient, and economical with a life expectancy of at least 25 years. Modern electronics has been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy of at least 25 years. The report concludes that the GRC West Area grid-tied PV power system design is viable for a reliable, maintenance free, long life power system that is of significant value to NASA and the community.

Energy Systems Integration: Data Call -- Become a Data Partner

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-01-01

This project aims to advance the understanding of costs associated with integrating PV onto the electric power distribution system while maintaining reliable grid operations. We have developed a bottom-up framework for calculating these costs as a function of PV penetration levels on specific feeders. This framework will used to inform and improve utility planning decisions, increase the transparency and speed associated with the interconnection process, and provide policymakers with more information on the total cost of energy from PV.

Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

DOEpatents

Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

2014-09-09

A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

Solar Plus: A Holistic Approach to Distributed Solar PV

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J.; Ardani, Kristen B.; Cutler, Dylan S.

Solar 'plus' refers to an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize customer economics. The solar plus approach increases customer system value through technologies such as electric batteries, smart domestic water heaters, smart air-conditioner (AC) units, and electric vehicles We use an NREL optimization model to explore the customer-side economics of solar plus under various utility rate structures and net metering rates. We explore optimal solar plus applications in five case studies with different net metering rates and rate structures. The model deploys different configurations of PV, batteries, smart domesticmore » water heaters, and smart AC units in response to different rate structures and customer load profiles. The results indicate that solar plus improves the customer economics of PV and may mitigate some of the negative impacts of evolving rate structures on PV economics. Solar plus may become an increasingly viable model for optimizing PV customer economics in an evolving rate environment.« less

Effective information channels for reducing costs of environmentally- friendly technologies: evidence from residential PV markets

NASA Astrophysics Data System (ADS)

Rai, Varun; Robinson, Scott A.

2013-03-01

Realizing the environmental benefits of solar photovoltaics (PV) will require reducing costs associated with perception, informational gaps and technological uncertainties. To identify opportunities to decrease costs associated with residential PV adoption, in this letter we use multivariate regression models to analyze a unique, household-level dataset of PV adopters in Texas (USA) to systematically quantify the effect of different information channels on aspiring PV adopters’ decision-making. We find that the length of the decision period depends on the business model, such as whether the system was bought or leased, and on special opportunities to learn, such as the influence of other PV owners in the neighborhood. This influence accrues passively through merely witnessing PV systems in the neighborhood, increasing confidence and motivation, as well as actively through peer-to-peer communications. Using these insights we propose a new framework to provide public information on PV that could drastically reduce barriers to PV adoption, thereby accelerating its market penetration and environmental benefits. This framework could also serve as a model for other distributed generation technologies.

Design and Scheduling of Microgrids using Benders Decomposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagarajan, Adarsh; Ayyanar, Raja

2016-11-21

The distribution feeder laterals in a distribution feeder with relatively high PV generation as compared to the load can be operated as microgrids to achieve reliability, power quality and economic benefits. However, renewable resources are intermittent and stochastic in nature. A novel approach for sizing and scheduling an energy storage system and microturbine for reliable operation of microgrids is proposed. The size and schedule of an energy storage system and microturbine are determined using Benders' decomposition, considering PV generation as a stochastic resource.

Revolution…Now The Future Arrives for Five Clean Energy Technologies – 2015 Update

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

In 2013, the U.S. Department of Energy (DOE) released the Revolution Now report, highlighting four transformational technologies: land-based wind power, silicon photovoltaic (PV) solar modules, light-emitting diodes (LEDs), and electric vehicles (EVs). That study and its 2014 update showed how dramatic reductions in cost are driving a surge in consumer, industrial, and commercial adoption for these clean energy technologies—as well as yearly progress. In addition to presenting the continued progress made over the last year in these areas, this year’s update goes further. Two separate sections now cover large, central, utility-scale PV plants and smaller, rooftop, distributed PV systems tomore » highlight how both have achieved significant deployment nationwide, and have done so through different innovations, such as easier access to capital for utility-scale PV and reductions of non-hardware costs and third-party ownership for distributed PV. Along with these core technologies« less

Solar Photovoltaic (PV) Distributed Generation Systems - Control and Protection

NASA Astrophysics Data System (ADS)

Yi, Zhehan

This dissertation proposes a comprehensive control, power management, and fault detection strategy for solar photovoltaic (PV) distribution generations. Battery storages are typically employed in PV systems to mitigate the power fluctuation caused by unstable solar irradiance. With AC and DC loads, a PV-battery system can be treated as a hybrid microgrid which contains both DC and AC power resources and buses. In this thesis, a control power and management system (CAPMS) for PV-battery hybrid microgrid is proposed, which provides 1) the DC and AC bus voltage and AC frequency regulating scheme and controllers designed to track set points; 2) a power flow management strategy in the hybrid microgrid to achieve system generation and demand balance in both grid-connected and islanded modes; 3) smooth transition control during grid reconnection by frequency and phase synchronization control between the main grid and microgrid. Due to the increasing demands for PV power, scales of PV systems are getting larger and fault detection in PV arrays becomes challenging. High-impedance faults, low-mismatch faults, and faults occurred in low irradiance conditions tend to be hidden due to low fault currents, particularly, when a PV maximum power point tracking (MPPT) algorithm is in-service. If remain undetected, these faults can considerably lower the output energy of solar systems, damage the panels, and potentially cause fire hazards. In this dissertation, fault detection challenges in PV arrays are analyzed in depth, considering the crossing relations among the characteristics of PV, interactions with MPPT algorithms, and the nature of solar irradiance. Two fault detection schemes are then designed as attempts to address these technical issues, which detect faults inside PV arrays accurately even under challenging circumstances, e.g., faults in low irradiance conditions or high-impedance faults. Taking advantage of multi-resolution signal decomposition (MSD), a powerful signal processing technique based on discrete wavelet transformation (DWT), the first attempt is devised, which extracts the features of both line-to-line (L-L) and line-to-ground (L-G) faults and employs a fuzzy inference system (FIS) for the decision-making stage of fault detection. This scheme is then improved as the second attempt by further studying the system's behaviors during L-L faults, extracting more efficient fault features, and devising a more advanced decision-making stage: the two-stage support vector machine (SVM). For the first time, the two-stage SVM method is proposed in this dissertation to detect L-L faults in PV system with satisfactory accuracies. Numerous simulation and experimental case studies are carried out to verify the proposed control and protection strategies. Simulation environment is set up using the PSCAD/EMTDC and Matlab/Simulink software packages. Experimental case studies are conducted in a PV-battery hybrid microgrid using the dSPACE real-time controller to demonstrate the ease of hardware implementation and the controller performance. Another small-scale grid-connected PV system is set up to verify both fault detection algorithms which demonstrate promising performances and fault detecting accuracies.

Improving Advanced Inverter Control Convergence in Distribution Power Flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagarajan, Adarsh; Palmintier, Bryan; Ding, Fei

Simulation of modern distribution system powerflow increasingly requires capturing the impact of advanced PV inverter voltage regulation on powerflow. With Volt/var control, the inverter adjusts its reactive power flow as a function of the point of common coupling (PCC) voltage. Similarly, Volt/watt control curtails active power production as a function of PCC voltage. However, with larger systems and higher penetrations of PV, this active/reactive power flow itself can cause significant changes to the PCC voltage potentially introducing oscillations that slow the convergence of system simulations. Improper treatment of these advanced inverter functions could potentially lead to incorrect results. This papermore » explores a simple approach to speed such convergence by blending in the previous iteration's reactive power estimate to dampen these oscillations. Results with a single large (5MW) PV system and with multiple 500kW advanced inverters show dramatic improvements using this approach.« less

Supply and Demand Control of Distributed Generators in a Microgrid for New Energy

NASA Astrophysics Data System (ADS)

Shimakage, Toyonari; Sumita, Jiro; Uchiyama, Noriyuki; Kato, Takeyoshi; Suzuoki, Yasuo

We report the operational results of distributed generators (DGs) in a microgrid and present the effects after incorporating photovoltaic power generation (PV) systems into the microgrid for electric power system. The microgrid was constructed at the EXPO 2005 Aichi site as part of a demonstration promoted by NEDO. A solution is needed to problems where instability in the DGs that utilize natural energy such as solar light and wind force negatively influence existing electric power systems. So, we developed energy control system and controlled DGs output to reduce the fluctuation at the grid connected point caused by PV system's instability output. Our microgrid consists of DGs such as PV systems, fuel cells, and NaS batteries, and these DGs are controlled by an energy control system. We verified practical effectiveness of the installing the microgrid as follows. (1) 99.5% of the power imbalance in the supply and demand over 30 minutes was within a range of ±3% under normal operating conditions, (2) the microgrid contributes to the load leveling, (3) energy control system smoothes the power flow fluctuation of PV system output at the grid connected point, (4) in the future, installing a microgrid will help reduce the additional LFC (Load Frequency Control) capacity.

Development and Testing of the Glenn Research Center Visitor's Center Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) has developed, installed, and tested a 12 kW DC grid-tied photovoltaic (PV) power system at the GRC Visitor s Center. This system utilizes a unique ballast type roof mount for installing the photovoltaic panels on the roof of the Visitor s Center with no alterations or penetrations to the roof. The PV system has generated in excess of 15000 kWh since operation commenced in August 2008. The PV system is providing power to the GRC grid for use by all. Operation of the GRC Visitor s Center PV system has been completely trouble free. A grid-tied PV power system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility. The project transfers space technology to terrestrial use via nontraditional partners. GRC personnel glean valuable experience with PV power systems that are directly applicable to various space power systems, and provides valuable space program test data. PV power systems help to reduce harmful emissions and reduce the Nation s dependence on fossil fuels. Power generated by the PV system reduces the GRC utility demand, and the surplus power aids the community. Present global energy concerns reinforce the need for the development of alternative energy systems. Modern PV panels are readily available, reliable, efficient, and economical with a life expectancy of at least 25 years. Modern electronics has been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy of at least 25 years. Based upon the success of the GRC Visitor s Center PV system, additional PV power system expansion at GRC is under consideration. The GRC Visitor s Center grid-tied PV power system was successfully designed and developed which served to validate the basic principles described, and the theoretical work that was performed. The report concludes that grid-tied photovoltaic power systems are reliable, maintenance free, long life power systems, and are of significant value to NASA and the community.

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov Websites

us at the ESIF. NREL Releases High-Pen PV Handbook for Distribution Engineers As solar photovoltaic PV for Ancillary Services NREL, AES, the Puerto Rico Electric Power Authority, First Solar, and the technologies, such as solar, demand response, and smart consumer appliances Advances in grid design and

Why do electricity policy and competitive markets fail to use advanced PV systems to improve distribution power quality?

DOE Office of Scientific and Technical Information (OSTI.GOV)

McHenry, Mark P.; Johnson, Jay; Hightower, Mike

The increasing pressure for network operators to meet distribution network power quality standards with increasing peak loads, renewable energy targets, and advances in automated distributed power electronics and communications is forcing policy-makers to understand new means to distribute costs and benefits within electricity markets. Discussions surrounding how distributed generation (DG) exhibits active voltage regulation and power factor/reactive power control and other power quality capabilities are complicated by uncertainties of baseline local distribution network power quality and to whom and how costs and benefits of improved electricity infrastructure will be allocated. DG providing ancillary services that dynamically respond to the networkmore » characteristics could lead to major network improvements. With proper market structures renewable energy systems could greatly improve power quality on distribution systems with nearly no additional cost to the grid operators. Renewable DG does have variability challenges, though this issue can be overcome with energy storage, forecasting, and advanced inverter functionality. This paper presents real data from a large-scale grid-connected PV array with large-scale storage and explores effective mitigation measures for PV system variability. As a result, we discuss useful inverter technical knowledge for policy-makers to mitigate ongoing inflation of electricity network tariff components by new DG interconnection requirements or electricity markets which value power quality and control.« less

Why do electricity policy and competitive markets fail to use advanced PV systems to improve distribution power quality?

DOE PAGES

McHenry, Mark P.; Johnson, Jay; Hightower, Mike

2016-01-01

The increasing pressure for network operators to meet distribution network power quality standards with increasing peak loads, renewable energy targets, and advances in automated distributed power electronics and communications is forcing policy-makers to understand new means to distribute costs and benefits within electricity markets. Discussions surrounding how distributed generation (DG) exhibits active voltage regulation and power factor/reactive power control and other power quality capabilities are complicated by uncertainties of baseline local distribution network power quality and to whom and how costs and benefits of improved electricity infrastructure will be allocated. DG providing ancillary services that dynamically respond to the networkmore » characteristics could lead to major network improvements. With proper market structures renewable energy systems could greatly improve power quality on distribution systems with nearly no additional cost to the grid operators. Renewable DG does have variability challenges, though this issue can be overcome with energy storage, forecasting, and advanced inverter functionality. This paper presents real data from a large-scale grid-connected PV array with large-scale storage and explores effective mitigation measures for PV system variability. As a result, we discuss useful inverter technical knowledge for policy-makers to mitigate ongoing inflation of electricity network tariff components by new DG interconnection requirements or electricity markets which value power quality and control.« less

The Value of Transparency in Distributed Solar PV Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J; Zamzam, Ahmed S

Market transparency refers to the degree of customer awareness of product options and fair market prices for a given good. In The Value of Transparency in Distributed Solar PV Markets, we use residential solar photovoltaic (PV) quote data to study the value of transparency in distributed solar PV markets. We find that improved market transparency results in lower installation offer prices. Further, the results of this study suggest that PV customers benefit from gaining access to more PV quotes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NREL and the Hawaiian Electric Companies are collaborating with the solar and inverter industries to implement advanced inverters, allowing greater solar photovoltaic (PV) penetrations that will support the State of Hawaii's goal to achieve 100% renewable energy by 2045. Advanced inverters will help maintain stable grid operations by riding through grid disturbances when the PV output is needed, operating autonomously to smooth voltage fluctuations, and coordinating the start-up and reconnection of PV systems and other distributed energy resources.

Examining System-Wide Impacts of Solar PV Control Systems with a Power Hardware-in-the-Loop Platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Tess L.; Fuller, Jason C.; Schneider, Kevin P.

2014-06-08

High penetration levels of distributed solar PV power generation can lead to adverse power quality impacts, such as excessive voltage rise, voltage flicker, and reactive power values that result in unacceptable voltage levels. Advanced inverter control schemes have been developed that have the potential to mitigate many power quality concerns. However, local closed-loop control may lead to unintended behavior in deployed systems as complex interactions can occur between numerous operating devices. To enable the study of the performance of advanced control schemes in a detailed distribution system environment, a test platform has been developed that integrates Power Hardware-in-the-Loop (PHIL) withmore » concurrent time-series electric distribution system simulation. In the test platform, GridLAB-D, a distribution system simulation tool, runs a detailed simulation of a distribution feeder in real-time mode at the Pacific Northwest National Laboratory (PNNL) and supplies power system parameters at a point of common coupling. At the National Renewable Energy Laboratory (NREL), a hardware inverter interacts with grid and PV simulators emulating an operational distribution system. Power output from the inverters is measured and sent to PNNL to update the real-time distribution system simulation. The platform is described and initial test cases are presented. The platform is used to study the system-wide impacts and the interactions of inverter control modes—constant power factor and active Volt/VAr control—when integrated into a simulated IEEE 8500-node test feeder. We demonstrate that this platform is well-suited to the study of advanced inverter controls and their impacts on the power quality of a distribution feeder. Additionally, results are used to validate GridLAB-D simulations of advanced inverter controls.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deline, C.

Computer modeling is able to predict the performance of distributed power electronics (microinverters, power optimizers) in PV systems. However, details about partial shade and other mismatch must be known in order to give the model accurate information to go on. This talk will describe recent updates in NREL’s System Advisor Model program to model partial shading losses with and without distributed power electronics, along with experimental validation results. Computer modeling is able to predict the performance of distributed power electronics (microinverters, power optimizers) in PV systems. However, details about partial shade and other mismatch must be known in order tomore » give the model accurate information to go on. This talk will describe recent updates in NREL’s System Advisor Model program to model partial shading losses.« less

Operational Simulation Tools and Long Term Strategic Planning for High Penetrations of PV in the Southeastern United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuohy, Aidan; Smith, Jeff; Rylander, Matt

2016-07-11

Increasing levels of distributed and utility scale Solar Photovoltaics (PV) will have an impact on many utility functions, including distribution system operations, bulk system performance, business models and scheduling of generation. In this project, EPRI worked with Southern Company Services and its affiliates and the Tennessee Valley Authority to assist these utilities in their strategic planning efforts for integrating PV, based on modeling, simulation and analysis using a set of innovative tools. Advanced production simulation models were used to investigate operating reserve requirements. To leverage existing work and datasets, this last task was carried out on the California system. Overall,more » the project resulted in providing useful information to both of the utilities involved and through the final reports and interactions during the project. The results from this project can be used to inform the industry about new and improved methodologies for understanding solar PV penetration, and will influence ongoing and future research. This report summarizes each of the topics investigated over the 2.5-year project period.« less

Solar Plus: A Holistic Approach to Distributed Solar PV | Solar Research |

Science.gov Websites

NREL Plus: A Holistic Approach to Distributed Solar PV Solar Plus: A Holistic Approach to Distributed Solar PV A new NREL report analyzes "solar plus," an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize

High-Penetration Photovoltaics Standards and Codes Workshop, Denver, Colorado, May 20, 2010: Workshop Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coddington, M.; Kroposki, B.; Basso, T.

Effectively interconnecting high-level penetration of photovoltaic (PV) systems requires careful technical attention to ensuring compatibility with electric power systems. Standards, codes, and implementation have been cited as major impediments to widespread use of PV within electric power systems. On May 20, 2010, in Denver, Colorado, the National Renewable Energy Laboratory, in conjunction with the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE), held a workshop to examine the key technical issues and barriers associated with high PV penetration levels with an emphasis on codes and standards. This workshop included building upon results of the Highmore » Penetration of Photovoltaic (PV) Systems into the Distribution Grid workshop held in Ontario California on February 24-25, 2009, and upon the stimulating presentations of the diverse stakeholder presentations.« less

Feeder Voltage Regulation with High-Penetration PV Using Advanced Inverters and a Distribution Management System: A Duke Energy Case Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmintier, Bryan; Giraldez, Julieta; Gruchalla, Kenny

2016-11-01

Duke Energy, Alstom Grid, and the National Renewable Energy Laboratory teamed up to better understand the impacts of solar photovoltaics (PV) on distribution system operations. The core goal of the project is to compare the operational - specifically, voltage regulation - impacts of three classes of PV inverter operations: 1.) Active power only (Baseline); 2.) Local inverter control (e.g., PF...not equal...1, Q(V), etc.); and 3.) Integrated volt-VAR control (centralized through the distribution management system). These comparisons were made using multiple approaches, each of which represents an important research-and-development effort on its own: a) Quasi-steady-state time-series modeling for approximately 1 yearmore » of operations using the Alstom eTerra (DOTS) system as a simulation engine, augmented by Python scripting for scenario and time-series control and using external models for an advanced inverter; b) Power-hardware-in-the-loop (PHIL) testing of a 500-kVA-class advanced inverter and traditional voltage regulating equipment. This PHIL testing used cosimulation to link full-scale feeder simulation using DOTS in real time to hardware testing; c) Advanced visualization to provide improved insights into time-series results and other PV operational impacts; and d) Cost-benefit analysis to compare the financial and business-model impacts of each integration approach.« less

Comparative Analysis and Considerations for PV Interconnection Standards in the United States and China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, David Wenzhong; Muljadi, Eduard; Tian, Tian

The main objectives of this report are to evaluate China's photovoltaic (PV) interconnection standards and the U.S. counterparts and to propose recommendations for future revisions to these standards. This report references the 2013 report Comparative Study of Standards for Grid-Connected PV System in China, the U.S. and European Countries, which compares U.S., European, and China's PV grid interconnection standards; reviews various metrics for the characterization of distribution network with PV; and suggests modifications to China's PV interconnection standards and requirements. The recommendations are accompanied by assessments of four high-penetration PV grid interconnection cases in the United States to illustrate solutionsmore » implemented to resolve issues encountered at different sites. PV penetration in China and in the United States has significantly increased during the past several years, presenting comparable challenges depending on the conditions of the grid at the point of interconnection; solutions are generally unique to each interconnected PV installation or PV plant.« less

Distributed photovoltaic systems: Utility interface issues and their present status

NASA Technical Reports Server (NTRS)

Hassan, M.; Klein, J.

1981-01-01

Major technical issues involving the integration of distributed photovoltaics (PV) into electric utility systems are defined and their impacts are described quantitatively. An extensive literature search, interviews, and analysis yielded information about the work in progress and highlighted problem areas in which additional work and research are needed. The findings from the literature search were used to determine whether satisfactory solutions to the problems exist or whether satisfactory approaches to a solution are underway. It was discovered that very few standards, specifications, or guidelines currently exist that will aid industry in integrating PV into the utility system. Specific areas of concern identified are: (1) protection, (2) stability, (3) system unbalance, (4) voltage regulation and reactive power requirements, (5) harmonics, (6) utility operations, (7) safety, (8) metering, and (9) distribution system planning and design.

The Value of Transparency in Distributed Solar PV Markets | Solar Research

Science.gov Websites

| NREL The Value of Transparency in Distributed Solar PV Markets The Value of Transparency in Distributed Solar PV Markets NREL research analyzes data from a U.S. quote aggregator to study the effects of transparency on distributed solar photovoltaic (PV) markets. The study shows lower prices in more transparent

Characteristics of Low-Priced Solar Photovoltaic Systems in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nemet, Gregory F.; O'Shaughnessy, Eric; Wiser, Ryan H.

2016-01-01

Despite impressive recent cost reductions, there is wide dispersion in the prices of installed solar photovoltaic (PV) systems. We identify the most important factors that make a system likely to be low priced (LP). Our sample consists of detailed characteristics for 42,611 small-scale (< 15 kW) PV systems installed in 15 U.S. states during 2013. Using four definitions of LP systems, we compare LP and non-LP systems and find statistically significant differences in nearly all factors explored, including competition, installer scale, markets, demographics, ownership, policy, and system components. Logit and probit model results robustly indicate that LP systems are associatedmore » with markets with few active installers; experienced installers; customer ownership; large systems; retrofits; and thin-film, low-efficiency, and Chinese modules. We also find significant differences across states, with LP systems much more likely to occur in some than in others. Our focus on the left tail of the price distribution provides implications for policy that are distinct from recent studies of mean prices. While those studies find that PV subsidies increase mean prices, we find that subsidies also generate LP systems. PV subsidies appear to simultaneously shift and broaden the price distribution. Much of this broadening occurs in a particular location, northern California, which is worthy of further investigation with new data.« less

Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2011-01-01

A grid-tied photovoltaic (PV) power system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility. Operating costs of a PV power system are low compared to conventional power technologies. This method can displace the highest-cost electricity during times of peak demand in most climatic regions, and thus reduce grid loading. Net metering is often used, in which independent power producers such as PV power systems are connected to the utility grid via the customers main service panels and meters. When the PV power system is generating more power than required at that location, the excess power is provided to the utility grid. The customer pays the net of the power purchased when the on-site power demand is greater than the onsite power production, and the excess power is returned to the utility grid. Power generated by the PV system reduces utility demand, and the surplus power aids the community. Modern PV panels are readily available, reliable, efficient, and economical, with a life expectancy of at least 25 years. Modern electronics have been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy equal to the modern PV panels. The grid-tied PV power system was successfully designed and developed, and this served to validate the basic principles developed, and the theoretical work that was performed. Grid-tied PV power systems are reliable, maintenance- free, long-life power systems, and are of significant value to NASA and the community. Of particular value are the analytical tools and capabilities that have been successfully developed. Performance predictions can be made confidently for grid-tied PV systems of various scales. The work was done under the NASA Hybrid Power Management (HPM) Program, which is the integration of diverse power devices in an optimal configuration for space and terrestrial applications.

Space Station Freedom photovoltaic power module design status

NASA Technical Reports Server (NTRS)

Jimenez, Amador P.; Hoberecht, Mark A.

1989-01-01

Electric power generation for the Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during phase I operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units to achieve modularization. The design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

Space Station Freedom photovoltaic power module design status

NASA Technical Reports Server (NTRS)

Jimenez, Amador P.; Hoberecht, Mark A.

1989-01-01

Electric power generation for Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during Phase 1 operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units (ORU's) to achieve modularization. Design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

Chris Deline | NREL

Science.gov Websites

., Meydbray, J., Donovan, M., and Forrest, J. 2014. Photovoltaic Shading Testbed for Module-Level Power Renewable Energy Laboratory (NREL) in Golden, Colorado, in the photovoltaic (PV) performance and reliability performance and stabilization, mismatch and partial shading in PV systems, and distributed power electronics

Simulation of Distributed PV Power Output in Oahu Hawaii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lave, Matthew Samuel

2016-08-01

Distributed solar photovoltaic (PV) power generation in Oahu has grown rapidly since 2008. For applications such as determining the value of energy storage, it is important to have PV power output timeseries. Since these timeseries of not typically measured, here we produce simulated distributed PV power output for Oahu. Simulated power output is based on (a) satellite-derived solar irradiance, (b) PV permit data by neighborhood, and (c) population data by census block. Permit and population data was used to model locations of distributed PV, and irradiance data was then used to simulate power output. PV power output simulations are presentedmore » by sub-neighborhood polygons, neighborhoods, and for the whole island of Oahu. Summary plots of annual PV energy and a sample week timeseries of power output are shown, and a the files containing the entire timeseries are described.« less

Impact of Alternative Rate Structures on Distributed Solar Customer Electricity Bills

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLaren, Joyce A

Electric utilities are increasingly proposing changes to residential rate structures, in order to address concerns about their inability to recover fixed system costs from customers with grid connected distributed generation. The most common proposals have been to increase fixed charges, set minimum bills or instigate residential demand charges. This presentation provides results of an analysis to explore how these rate design alternatives impact electricity bills for PV and non-PV customers.

The Impact of Rate Design and Net Metering on the Bill Savings from Distributed PV for Residential Customers in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darghouth, Naim; Barbose, Galen; Wiser, Ryan

2010-03-30

Net metering has become a widespread policy in the U.S. for supporting distributed photovoltaics (PV) adoption. Though specific design details vary, net metering allows customers with PV to reduce their electric bills by offsetting their consumption with PV generation, independent of the timing of the generation relative to consumption - in effect, compensating the PV generation at retail electricity rates (Rose et al. 2009). While net metering has played an important role in jump-starting the residential PV market in the U.S., challenges to net metering policies have emerged in a number of states and contexts, and alternative compensation methods aremore » under consideration. Moreover, one inherent feature of net metering is that the value of the utility bill savings it provides to customers with PV depends heavily on the structure of the underlying retail electricity rate, as well as on the characteristics of the customer and PV system. Consequently, the value of net metering - and the impact of moving to alternative compensation mechanisms - can vary substantially from one customer to the next. For these reasons, it is important for policymakers and others that seek to support the development of distributed PV to understand both how the bill savings varies under net metering, and how the bill savings under net metering compares to other possible compensation mechanisms. To advance this understanding, we analyze the bill savings from PV for residential customers of California's two largest electric utilities, Pacific Gas and Electric (PG&E) and Southern California Edison (SCE). The analysis is based on hourly load data from a sample of 215 residential customers located in the service territories of the two utilities, matched with simulated hourly PV production for the same time period based on data from the nearest of 73 weather stations in the state.« less

Technologies to Increase PV Hosting Capacity in Distribution Feeders: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mather, Barry; Gotseff, Peter

This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for amore » low cost. Additionally, the tool developed for these studies is described.« less

Technologies to Increase PV Hosting Capacity in Distribution Feeders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mather, Barry; Gotseff, Peter

This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for amore » low cost. Additionally, the tool developed for these studies is described.« less

Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

DOE PAGES

Xiao, Bailu; Hang, Lijun; Mei, Jun; ...

2014-09-04

This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is alsomore » proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.« less

System and method for design and optimization of grid connected photovoltaic power plant with multiple photovoltaic module technologies

DOEpatents

Thomas, Bex George; Elasser, Ahmed; Bollapragada, Srinivas; Galbraith, Anthony William; Agamy, Mohammed; Garifullin, Maxim Valeryevich

2016-03-29

A system and method of using one or more DC-DC/DC-AC converters and/or alternative devices allows strings of multiple module technologies to coexist within the same PV power plant. A computing (optimization) framework estimates the percentage allocation of PV power plant capacity to selected PV module technologies. The framework and its supporting components considers irradiation, temperature, spectral profiles, cost and other practical constraints to achieve the lowest levelized cost of electricity, maximum output and minimum system cost. The system and method can function using any device enabling distributed maximum power point tracking at the module, string or combiner level.

Performance evaluation of a 2-mode PV grid connected system in Thailand -- Case study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jivacate, C.; Mongconvorawan, S.; Sinratanapukdee, E.

A PV grid connected system with small battery bank has been set up in a rural district, North Thailand in order to demonstrate a 2-mode operation concept. The objective is to gain experience on the PV grid connected concept without battery storage. However, due to the evening peak demand and a rather weak distribution grid which is typical in rural areas, small battery bank is still required to enable the maximum energy transfer to grid for the time being before moving fully to the no battery mode. The analyzed data seems to indicate possible performance improvement by re-arranging the numbermore » of PV modules and battery in the string.« less

Multiobjective Particle Swarm Optimization for the optimal design of photovoltaic grid-connected systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kornelakis, Aris

2010-12-15

Particle Swarm Optimization (PSO) is a highly efficient evolutionary optimization algorithm. In this paper a multiobjective optimization algorithm based on PSO applied to the optimal design of photovoltaic grid-connected systems (PVGCSs) is presented. The proposed methodology intends to suggest the optimal number of system devices and the optimal PV module installation details, such that the economic and environmental benefits achieved during the system's operational lifetime period are both maximized. The objective function describing the economic benefit of the proposed optimization process is the lifetime system's total net profit which is calculated according to the method of the Net Present Valuemore » (NPV). The second objective function, which corresponds to the environmental benefit, equals to the pollutant gas emissions avoided due to the use of the PVGCS. The optimization's decision variables are the optimal number of the PV modules, the PV modules optimal tilt angle, the optimal placement of the PV modules within the available installation area and the optimal distribution of the PV modules among the DC/AC converters. (author)« less

Solar plus: Optimization of distributed solar PV through battery storage and dispatchable load in residential buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Cutler, Dylan; Ardani, Kristen

As utility electricity rates evolve, pairing solar photovoltaic (PV) systems with battery storage has potential to ensure the value proposition of residential solar by mitigating economic uncertainty. In addition to batteries, load control technologies can reshape customer load profiles to optimize PV system use. The combination of PV, energy storage, and load control provides an integrated approach to PV deployment, which we call 'solar plus'. The U.S. National Renewable Energy Laboratory's Renewable Energy Optimization (REopt) model is utilized to evaluate cost-optimal technology selection, sizing, and dispatch in residential buildings under a variety of rate structures and locations. The REopt modelmore » is extended to include a controllable or 'smart' domestic hot water heater model and smart air conditioner model. We find that the solar plus approach improves end user economics across a variety of rate structures - especially those that are challenging for PV - including lower grid export rates, non-coincident time-of-use structures, and demand charges.« less

Solar plus: Optimization of distributed solar PV through battery storage and dispatchable load in residential buildings

DOE PAGES

O'Shaughnessy, Eric; Cutler, Dylan; Ardani, Kristen; ...

2018-01-11

As utility electricity rates evolve, pairing solar photovoltaic (PV) systems with battery storage has potential to ensure the value proposition of residential solar by mitigating economic uncertainty. In addition to batteries, load control technologies can reshape customer load profiles to optimize PV system use. The combination of PV, energy storage, and load control provides an integrated approach to PV deployment, which we call 'solar plus'. The U.S. National Renewable Energy Laboratory's Renewable Energy Optimization (REopt) model is utilized to evaluate cost-optimal technology selection, sizing, and dispatch in residential buildings under a variety of rate structures and locations. The REopt modelmore » is extended to include a controllable or 'smart' domestic hot water heater model and smart air conditioner model. We find that the solar plus approach improves end user economics across a variety of rate structures - especially those that are challenging for PV - including lower grid export rates, non-coincident time-of-use structures, and demand charges.« less

Coordinated control of active and reactive power of distribution network with distributed PV cluster via model predictive control

NASA Astrophysics Data System (ADS)

Ji, Yu; Sheng, Wanxing; Jin, Wei; Wu, Ming; Liu, Haitao; Chen, Feng

2018-02-01

A coordinated optimal control method of active and reactive power of distribution network with distributed PV cluster based on model predictive control is proposed in this paper. The method divides the control process into long-time scale optimal control and short-time scale optimal control with multi-step optimization. The models are transformed into a second-order cone programming problem due to the non-convex and nonlinear of the optimal models which are hard to be solved. An improved IEEE 33-bus distribution network system is used to analyse the feasibility and the effectiveness of the proposed control method

A study on assimilating potential vorticity data

NASA Astrophysics Data System (ADS)

Li, Yong; Ménard, Richard; Riishøjgaard, Lars Peter; Cohn, Stephen E.; Rood, Richard B.

1998-08-01

The correlation that exists between the potential vorticity (PV) field and the distribution of chemical tracers such as ozone suggests the possibility of using tracer observations as proxy PV data in atmospheric data assimilation systems. Especially in the stratosphere, there are plentiful tracer observations but a general lack of reliable wind observations, and the correlation is most pronounced. The issue investigated in this study is how model dynamics would respond to the assimilation of PV data. First, numerical experiments of identical-twin type were conducted with a simple univariate nuding algorithm and a global shallow water model based on PV and divergence (PV-D model). All model fields are successfully reconstructed through the insertion of complete PV data alone if an appropriate value for the nudging coefficient is used. A simple linear analysis suggests that slow modes are recovered rapidly, at a rate nearly independent of spatial scale. In a more realistic experiment, appropriately scaled total ozone data from the NIMBUS-7 TOMS instrument were assimilated as proxy PV data into the PV-D model over a 10-day period. The resulting model PV field matches the observed total ozone field relatively well on large spatial scales, and the PV, geopotential and divergence fields are dynamically consistent. These results indicate the potential usefulness that tracer observations, as proxy PV data, may offer in a data assimilation system.

Sensitivities of projected 1980 photovoltaic system costs to major system cost drivers

NASA Technical Reports Server (NTRS)

Zimmerman, L. W.; Smith, J. L.

1984-01-01

The sensitivity of projected 1990 photovoltaic (PV) system costs to major system cost drivers was examined. It includes: (1) module costs and module efficiencies; (2) area related balance of system (BOS) costs; (3) inverter costs and efficiencies; and (4) module marketing and distribution markups and system integration fees. Recent PV system cost experiences and the high costs of electricity from the systems are reviewed. The 1990 system costs are projected for five classes of PV systems, including four ground mounted 5-MWp systems and one residential 5-kWp system. System cost projections are derived by first projecting costs and efficiencies for all subsystems and components. Sensitivity analyses reveal that reductions in module cost and engineering and system integration fees seem to have the greatest potential for contributing to system cost reduction. Although module cost is clearly the prime candidate for fruitful PV research and development activities, engineering and system integration fees seem to be more amenable to reduction through appropriate choice of system size and market strategy. Increases in inverter and module efficiency yield significant benefits, especially for systems with high area related costs.

The active control strategy on the output power for photovoltaic-storage systems based on extended PQ-QV-PV Node

NASA Astrophysics Data System (ADS)

Xu, Chen; Zhou, Bao-Rong; Zhai, Jian-Wei; Zhang, Yong-Jun; Yi, Ying-Qi

2017-05-01

In order to solve the problem of voltage exceeding specified limits and improve the penetration of photovoltaic in distribution network, we can make full use of the active power regulation ability of energy storage(ES) and the reactive power regulation ability of grid-connected photovoltaic inverter to provide support of active power and reactive power for distribution network. A strategy of actively controlling the output power for photovoltaic-storage system based on extended PQ-QV-PV node by analyzing the voltage regulating mechanism of point of commom coupling(PCC) of photovoltaic with energy storage(PVES) by controlling photovoltaic inverter and energy storage. The strategy set a small wave range of voltage to every photovoltaic by making the type of PCC convert among PQ, PV and QV. The simulation results indicate that the active control method can provide a better solution to the problem of voltage exceeding specified limits when photovoltaic is connectted to electric distribution network.

Examining System-Wide Impacts of Solar PV Control Systems with a Power Hardware-in-the-Loop Platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Tess L.; Fuller, Jason C.; Schneider, Kevin P.

2014-10-11

High penetration levels of distributed solar PV power generation can lead to adverse power quality impacts such as excessive voltage rise, voltage flicker, and reactive power values that result in unacceptable voltage levels. Advanced inverter control schemes have been proposed that have the potential to mitigate many power quality concerns. However, closed-loop control may lead to unintended behavior in deployed systems as complex interactions can occur between numerous operating devices. In order to enable the study of the performance of advanced control schemes in a detailed distribution system environment, a Hardware-in-the-Loop (HIL) platform has been developed. In the HIL system,more » GridLAB-D, a distribution system simulation tool, runs in real-time mode at the Pacific Northwest National Laboratory (PNNL) and supplies power system parameters at a point of common coupling to hardware located at the National Renewable Energy Laboratory (NREL). Hardware inverters interact with grid and PV simulators emulating an operational distribution system and power output from the inverters is measured and sent to PNNL to update the real-time distribution system simulation. The platform is described and initial test cases are presented. The platform is used to study the system-wide impacts and the interactions of controls applied to inverters that are integrated into a simulation of the IEEE 8500-node test feeder, with inverters in either constant power factor control or active volt/VAR control. We demonstrate that this HIL platform is well-suited to the study of advanced inverter controls and their impacts on the power quality of a distribution feeder. Additionally, the results from HIL are used to validate GridLAB-D simulations of advanced inverter controls.« less

A distributed monitoring system for photovoltaic arrays based on a two-level wireless sensor network

NASA Astrophysics Data System (ADS)

Su, F. P.; Chen, Z. C.; Zhou, H. F.; Wu, L. J.; Lin, P. J.; Cheng, S. Y.; Li, Y. F.

2017-11-01

In this paper, a distributed on-line monitoring system based on a two-level wireless sensor network (WSN) is proposed for real time status monitoring of photovoltaic (PV) arrays to support the fine management and maintenance of PV power plants. The system includes the sensing nodes installed on PV modules (PVM), sensing and routing nodes installed on combiner boxes of PV sub-arrays (PVA), a sink node and a data management centre (DMC) running on a host computer. The first level WSN is implemented by the low-cost wireless transceiver nRF24L01, and it is used to achieve single hop communication between the PVM nodes and their corresponding PVA nodes. The second level WSN is realized by the CC2530 based ZigBee network for multi-hop communication among PVA nodes and the sink node. The PVM nodes are used to monitor the PVM working voltage and backplane temperature, and they send the acquired data to their PVA node via the nRF24L01 based first level WSN. The PVA nodes are used to monitor the array voltage, PV string current and environment irradiance, and they send the acquired and received data to the DMC via the ZigBee based second level WSN. The DMC is designed using the MATLAB GUIDE and MySQL database. Laboratory experiment results show that the system can effectively acquire, display, store and manage the operating and environment parameters of PVA in real time.

Nonlinear Dynamics and Bifurcation Analysis of a Boost Converter for Battery Charging in Photovoltaic Applications

NASA Astrophysics Data System (ADS)

Al-Hindawi, Mohammed M.; Abusorrah, Abdullah; Al-Turki, Yusuf; Giaouris, Damian; Mandal, Kuntal; Banerjee, Soumitro

Photovoltaic (PV) systems with a battery back-up form an integral part of distributed generation systems and therefore have recently attracted a lot of interest. In this paper, we consider a system of charging a battery from a PV panel through a current mode controlled boost dc-dc converter. We analyze its complete nonlinear/nonsmooth dynamics, using a piecewise model of the converter and realistic nonlinear v-i characteristics of the PV panel. Through this study, it is revealed that system design without taking into account the nonsmooth dynamics of the converter combined with the nonlinear v-i characteristics of the PV panel can lead to unpredictable responses of the overall system with high current ripple and other undesirable phenomena. This analysis can lead to better designed converters that can operate under a wide variation of the solar irradiation and the battery's state of charge. We show that the v-i characteristics of the PV panel combined with the battery's output voltage variation can increase or decrease the converter's robustness, both under peak current mode control and average current mode control. We justify the observation in terms of the change in the discrete-time map caused by the nonlinear v-i characteristics of the PV panel. The theoretical results are validated experimentally.

The Value of Transparency in Distributed Solar PV Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J.; Margolis, Robert M.

Distributed solar photovoltaic (PV) markets are relatively non-transparent: PV price and product information is not readily available, searching for this information is costly (in terms of time and effort), and customers are mostly unfamiliar with the new technology. Quote aggregation, where third-party companies collect PV quotes on behalf of customers, may be one way to increase PV market transparency. In this paper, quote aggregation data are analyzed to study the value of transparency for distributed solar PV markets. The results suggest that easier access to more quotes results in lower prices. We find that installers tend to offer lower pricesmore » in more competitive market environments. We supplement the empirical analysis with key findings from interviews of residential PV installers.« less

Modelling and control of a microgrid including photovoltaic and wind generation

NASA Astrophysics Data System (ADS)

Hussain, Mohammed Touseef

Extensive increase of distributed generation (DG) penetration and the existence of multiple DG units at distribution level have introduced the notion of micro-grid. This thesis develops a detailed non-linear and small-signal dynamic model of a microgrid that includes PV, wind and conventional small scale generation along with their power electronics interfaces and the filters. The models developed evaluate the amount of generation mix from various DGs for satisfactory steady state operation of the microgrid. In order to understand the interaction of the DGs on microgrid system initially two simpler configurations were considered. The first one consists of microalternator, PV and their electronics, and the second system consists of microalternator and wind system each connected to the power system grid. Nonlinear and linear state space model of each microgrid are developed. Small signal analysis showed that the large participation of PV/wind can drive the microgrid to the brink of unstable region without adequate control. Non-linear simulations are carried out to verify the results obtained through small-signal analysis. The role of the extent of generation mix of a composite microgrid consisting of wind, PV and conventional generation was investigated next. The findings of the smaller systems were verified through nonlinear and small signal modeling. A central supervisory capacitor energy storage controller interfaced through a STATCOM was proposed to monitor and enhance the microgrid operation. The potential of various control inputs to provide additional damping to the system has been evaluated through decomposition techniques. The signals identified to have damping contents were employed to design the supervisory control system. The controller gains were tuned through an optimal pole placement technique. Simulation studies demonstrate that the STATCOM voltage phase angle and PV inverter phase angle were the best inputs for enhanced stability boundaries.

Status and Needs of Power Electronics for Photovoltaic Inverters

NASA Astrophysics Data System (ADS)

Qin, Y. C.; Mohan, N.; West, R.; Bonn, R.

2002-06-01

Photovoltaics is the utility connected distributed energy resource (DER) that is in widespread use today. It has one element, the inverter, which is common with all DER sources except rotating generators. The inverter is required to transfer dc energy to ac energy. With all the DER technologies, (solar, wind, fuel cells, and microturbines) the inverter is still an immature product that will result in reliability problems in fielded systems. Today, the PV inverter is a costly and complex component of PV systems that produce ac power. Inverter MTFF (mean time to first failure) is currently unacceptable. Low inverter reliability contributes to unreliable fielded systems and a loss of confidence in renewable technology. The low volume of PV inverters produced restricts the manufacturing to small suppliers without sophisticated research and reliability programs or manufacturing methods. Thus, the present approach to PV inverter supply has low probability of meeting DOE reliability goals.

Optimal charge control strategies for stationary photovoltaic battery systems

NASA Astrophysics Data System (ADS)

Li, Jiahao; Danzer, Michael A.

2014-07-01

Battery systems coupled to photovoltaic (PV) modules for example fulfill one major function: they locally decouple PV generation and consumption of electrical power leading to two major effects. First, they reduce the grid load, especially at peak times and therewith reduce the necessity of a network expansion. And second, they increase the self-consumption in households and therewith help to reduce energy expenses. For the management of PV batteries charge control strategies need to be developed to reach the goals of both the distribution system operators and the local power producer. In this work optimal control strategies regarding various optimization goals are developed on the basis of the predicted household loads and PV generation profiles using the method of dynamic programming. The resulting charge curves are compared and essential differences discussed. Finally, a multi-objective optimization shows that charge control strategies can be derived that take all optimization goals into account.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horowitz, Kelsey A; Ding, Fei; Mather, Barry A

This presentation was given at the 2017 NREL Workshop 'Benchmarking Distribution Grid Integration Costs Under High Distributed PV Penetrations.' It provides a brief overview of recent and ongoing NREL work on distribution system grid integration costs, as well as challenges and needs from the community.

Extreme Cost Reductions with Multi-Megawatt Centralized Inverter Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwabe, Ulrich; Fishman, Oleg

2015-03-20

The objective of this project was to fully develop, demonstrate, and commercialize a new type of utility scale PV system. Based on patented technology, this includes the development of a truly centralized inverter system with capacities up to 100MW, and a high voltage, distributed harvesting approach. This system promises to greatly impact both the energy yield from large scale PV systems by reducing losses and increasing yield from mismatched arrays, as well as reduce overall system costs through very cost effective conversion and BOS cost reductions enabled by higher voltage operation.

Power quality and protection of electric distribution systems with small, dispersed generation devices

NASA Astrophysics Data System (ADS)

Rizy, D. T.; Jewell, W. T.

1984-10-01

There are several operational problems associated with the connection of small power sources, such as wind turbines and photovoltaic (PV) arrays, to an electric distribution system. In one study the harmonic distortion produced by a subdivision of PV arrays connected through line-commutated inverters was simulated. A second simulation study evaluated protection problems associated with the operation of dispersed ac generators. The purpose of these studies was to examine the adequacy of the electric utility industry's traditional practices and hardware for the operation of dispersed power sources. The results of these simulation studies are discussed and recommendations are given for hardware and system operation needed for accommodating this new technology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darghouth, Naïm R.; Wiser, Ryan; Barbose, Galen

The substantial increase in deployment of customer-sited solar photovoltaics (PV) in the United States has been driven by a combination of steeply declining costs, financing innovations, and supportive policies. Among those supportive policies is net metering, which in most states effectively allows customers to receive compensation for distributed PV generation at the full retail electricity price. The current design of retail electricity rates and the presence of net metering have elicited concerns that the possible under-recovery of fixed utility costs from PV system owners may lead to a feedback loop of increasing retail prices that accelerate PV adoption and furthermore » rate increases. However, a separate and opposing feedback loop could offset this effect: increased PV deployment may lead to a shift in the timing of peak-period electricity prices that could reduce the bill savings received under net metering where time-varying retail electricity rates are used, thereby dampening further PV adoption. In this paper, we examine the impacts of these two competing feedback dynamics on U.S. distributed PV deployment through 2050 for both residential and commercial customers, across states. Our results indicate that, at the aggregate national level, the two feedback effects nearly offset one another and therefore produce a modest net effect, although their magnitude and direction vary by customer segment and by state. We also model aggregate PV deployment trends under various rate designs and net-metering rules, accounting for feedback dynamics. Our results demonstrate that future adoption of distributed PV is highly sensitive to retail rate structures. Whereas flat, time-invariant rates with net metering lead to higher aggregate national deployment levels than the current mix of rate structures (+5% in 2050), rate structures with higher monthly fixed customer charges or PV compensation at levels lower than the full retail rate can dramatically erode aggregate customer adoption of PV (from -14% to -61%, depending on the design). Moving towards time-varying rates, on the other hand, may accelerate near- and medium-term deployment (through 2030), but is found to slow adoption in the longer term (-22% in 2050).« less

Understanding Processes and Timelines for Distributed Photovoltaic

Science.gov Websites

data from more than 30,000 PV systems across 87 utilities in 16 states to better understand how solar photovoltaic (PV) interconnection process time frames in the United States. This study includes an analysis of Analysis Metrics" that shows the four steps involved in the utility interconnection process for solar

Photovoltaic technology for sustainability: An investigation of the distributed utility concept as a policy framework

NASA Astrophysics Data System (ADS)

Letendre, Steven Emery

The U.S. electric utility sector in its current configuration is unsustainable. The majority of electricity in the United States is produced using finite fossil fuels. In addition, significant potential exists to improve the nation's efficient use of energy. A sustainable electric utility sector will be characterized by increased use of renewable energy sources and high levels of end-use efficiency. This dissertation analyzes two alternative policy approaches designed to move the U.S. electric utility sector toward sustainability. One approach is labeled incremental which involves maintaining the centralized structure of the electric utility sector but facilitating the introduction of renewable energy and efficiency into the electrical system through the pricing mechanism. A second policy approach was described in which structural changes are encouraged based on the emerging distributed utility (DU) concept. A structural policy orientation attempts to capture the unique localized benefits that distributed renewable resources and energy efficiency offer to electric utility companies and their customers. A market penetration analysis of PV in centralized energy supply and distributed peak-shaving applications is conducted for a case-study electric utility company. Sensitivity analysis was performed based on incremental and structural policy orientations. The analysis provides compelling evidence which suggests that policies designed to bring about structural change in the electric utility sector are needed to move the industry toward sustainability. Specifically, the analysis demonstrates that PV technology, a key renewable energy option likely to play an important role in a renewable energy future, will begin to penetrate the electrical system in distributed peak-shaving applications long before the technology is introduced as a centralized energy supply option. Most policies to date, which I term incremental, attempt to encourage energy efficiency and renewables through the pricing system. Based on past policy experience, it is unlikely that such an approach would allow PV to compete in Delaware as an energy supply option in the next ten to twenty years. Alternatively, a market-based, or green pricing, approach will not create significant market opportunities for PV as a centralized energy supply option. However, structural policies designed to encourage the explicit recognition of the localized benefits of distributed resources could result in PV being introduced into the electrical system early in the next century.

A PV view of the zonal mean distribution of temperature and wind in the extratropical troposphere

NASA Technical Reports Server (NTRS)

Sun, De-Zheng; Lindzen, Richard S.

1994-01-01

The dependence of the temperature and wind distribution of the zonal mean flow in the extratropical troposphere on the gradient of pontential vorticity along isentropes is examined. The extratropics here refer to the region outside the Hadley circulation. Of particular interest is whether the distribution of temperature and wind corresponding to a constant potential vorticity (PV) along isentropes resembles the observed, and the implications of PV homogenization along isentropes for the role of the tropics. With the assumption that PV is homogenized along isentropes, it is found that the temperature distribution in the extratropical troposphere may be determined by a linear, first-order partial differential equation. When the observed surface temperature distribution and tropical lapse rate are used as the boundary conditions, the solution of the equation is close to the observed temperature distribution except in the upper troposphere adjacent to the Hadley circulation, where the troposphere with no PV gradient is considerably colder. Consequently, the jet is also stronger. It is also found that the meridional distribution of the balanced zonal wind is very sensitive to the meridional distribution of the tropopause temperature. The result may suggest that the requirement of the global momentum balance has no practical role in determining the extratropical temperature distribution. The authors further investigated the sensitivity of the extratropical troposphere with constant PV along isentropes to changes in conditions at the tropical boundary (the edge of the Hadley circulation). It is found that the temperature and wind distributions in the extratropical troposphere are sensitive to the vertical distribution of PV at the tropical boundary. With a surface distribution of temperature that decreases linearly with latitude, the jet maximum occurs at the tropical boundary and moves with it. The overall pattern of wind distribution is not sensitive to the change of the position of the tropical boundary. Finally, the temperature and wind distributions of an extratropical troposphere with a finite PV gradient are calculated. It is found that the larger the isentropic PV gradient, the warmer the troposphere and the weaker the jet.

Optimization and life-cycle cost of health clinic PV system for a rural area in southern Iraq using HOMER software

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Karaghouli, Ali; Kazmerski, L.L.

2010-04-15

This paper addresses the need for electricity of rural areas in southern Iraq and proposes a photovoltaic (PV) solar system to power a health clinic in that region. The total daily health clinic load is 31.6 kW h and detailed loads are listed. The National Renewable Energy Laboratory (NREL) optimization computer model for distributed power, ''HOMER,'' is used to estimate the system size and its life-cycle cost. The analysis shows that the optimal system's initial cost, net present cost, and electricity cost is US$ 50,700, US$ 60,375, and US$ 0.238/kW h, respectively. These values for the PV system are comparedmore » with those of a generator alone used to supply the load. We found that the initial cost, net present cost of the generator system, and electricity cost are US$ 4500, US$ 352,303, and US$ 1.332/kW h, respectively. We conclude that using the PV system is justified on humanitarian, technical, and economic grounds. (author)« less

A 50 kilowatt distributed grid-connected photovoltaic generation system for the University of Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, B.H.; Muknahallipatna, S.; Cupal, J.J.

The University of Wyoming (UW) campus is serving as the site for a 50 kilowatt solar photovoltaic (PV) system. Three sub-systems were sited and built on the UW campus in 1996. The first sub-system, a 10 kW roof-integrated system of PV roof tiles is located on the roof of the Engineering building. The second sub-system--a 5 kW rack-mounted, ballasted PV system is on a walkway roof of the Engineering building. The third sub-system is a 35 kW shade structure system and located adjacent to the parking lot of the university`s football stadium. The three sub-systems differ in their design strategymore » since each is being used for research and education at the university. Each sub-system, being located at some distance away from one another, supplies a different part of the campus grid. Efforts continue at setting up a central monitoring system which will receive data remotely from all locations. A part of this monitoring system is complete. While the initial monitoring data shows satisfactory performance, a number of reliability problems with PV modules and inverters have delayed full functionality of the system.« less

Simulation of an active cooling system for photovoltaic modules

NASA Astrophysics Data System (ADS)

Abdelhakim, Lotfi

2016-06-01

Photovoltaic cells are devices that convert solar radiation directly into electricity. However, solar radiation increases the photovoltaic cells temperature [1] [2]. The temperature has an influence on the degradation of the cell efficiency and the lifetime of a PV cell. This work reports on a water cooling technique for photovoltaic panel, whereby the cooling system was placed at the front surface of the cells to dissipate excess heat away and to block unwanted radiation. By using water as a cooling medium for the photovoltaic solar cells, the overheating of closed panel is greatly reduced without prejudicing luminosity. The water also acts as a filter to remove a portion of solar spectrum in the infrared band but allows transmission of the visible spectrum most useful for the PV operation. To improve the cooling system efficiency and electrical efficiency, uniform flow rate among the cooling system is required to ensure uniform distribution of the operating temperature of the PV cells. The aims of this study are to develop a 3D thermal model to simulate the cooling and heat transfer in Photovoltaic panel and to recommend a cooling technique for the PV panel. The velocity, pressure and temperature distribution of the three-dimensional flow across the cooling block were determined using the commercial package, Fluent. The second objective of this work is to study the influence of the geometrical dimensions of the panel, water mass flow rate and water inlet temperature on the flow distribution and the solar panel temperature. The results obtained by the model are compared with experimental results from testing the prototype of the cooling device.

Experimental comparison of PV-smoothing controllers using distributed generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Jay Dean; Ellis, Abraham; Denda, Atsushi

The power output variability of photovoltaic systems can affect local electrical grids in locations with high renewable energy penetrations or weak distribution or transmission systems. In those rare cases, quick controllable generators (e.g., energy storage systems) or loads can counteract the destabilizing effects by compensating for the power fluctuations. Previously, control algorithms for coordinated and uncoordinated operation of a small natural gas engine-generator (genset) and a battery for smoothing PV plant output were optimized using MATLAB/Simulink simulations. The simulations demonstrated that a traditional generation resource such as a natural gas genset in combination with a battery would smooth the photovoltaicmore » output while using a smaller battery state of charge (SOC) range and extending the life of the battery. This paper reports on the experimental implementation of the coordinated and uncoordinated controllers to verify the simulations and determine the differences in the controllers. The experiments were performed with the PNM PV and energy storage Prosperity site and a gas engine-generator located at the Aperture Center at Mesa Del Sol in Albuquerque, New Mexico. Two field demonstrations were performed to compare the different PV smoothing control algorithms: (1) implementing the coordinated and uncoordinated controls while switching off a subsection of the PV array at precise times on successive clear days, and (2) comparing the results of the battery and genset outputs for the coordinated control on a high variability day with simulations of the coordinated and uncoordinated controls. It was found that for certain PV power profiles the SOC range of the battery may be larger with the coordinated control, but the total amp-hours through the battery-which approximates battery wear-will always be smaller with the coordinated control.« less

Simulation Tools and Techniques for Analyzing the Impacts of Photovoltaic System Integration

NASA Astrophysics Data System (ADS)

Hariri, Ali

Solar photovoltaic (PV) energy integration in distribution networks is one of the fastest growing sectors of distributed energy integration. The growth in solar PV integration is incentivized by various clean power policies, global interest in solar energy, and reduction in manufacturing and installation costs of solar energy systems. The increase in solar PV integration has raised a number of concerns regarding the potential impacts that might arise as a result of high PV penetration. Some impacts have already been recorded in networks with high PV penetration such as in China, Germany, and USA (Hawaii and California). Therefore, network planning is becoming more intricate as new technologies are integrated into the existing electric grid. The integrated new technologies pose certain compatibility concerns regarding the existing electric grid infrastructure. Therefore, PV integration impact studies are becoming more essential in order to have a better understanding of how to advance the solar PV integration efforts without introducing adverse impacts into the network. PV impact studies are important for understanding the nature of the new introduced phenomena. Understanding the nature of the potential impacts is a key factor for mitigating and accommodating for said impacts. Traditionally, electric power utilities relied on phasor-based power flow simulations for planning their electric networks. However, the conventional, commercially available, phasor-based simulation tools do not provide proper visibility across a wide spectrum of electric phenomena. Moreover, different types of simulation approaches are suitable for specific types of studies. For instance, power flow software cannot be used for studying time varying phenomena. At the same time, it is not practical to use electromagnetic transient (EMT) tools to perform power flow solutions. Therefore, some electric phenomena caused by the variability of PV generation are not visible using the conventional utility simulation software. On the other hand, EMT simulation tools provide high accuracy and visibility over a wide bandwidth of frequencies at the expense of larger processing and memory requirements, limited network size, and long simulation time. Therefore, there is a gap in simulation tools and techniques that can efficiently and effectively identify potential PV impact. New planning simulation tools are needed in order to accommodate for the simulation requirements of new integrated technologies in the electric grid. The dissertation at hand starts by identifying some of the potential impacts that are caused by high PV penetration. A phasor-based quasi-static time series (QSTS) analysis tool is developed in order to study the slow dynamics that are caused by the variations in the PV generation that lead to voltage fluctuations. Moreover, some EMT simulations are performed in order to study the impacts of PV systems on the electric network harmonic levels. These studies provide insights into the type and duration of certain impacts, as well as the conditions that may lead to adverse phenomena. In addition these studies present an idea about the type of simulation tools that are sufficient for each type of study. After identifying some of the potential impacts, certain planning tools and techniques are proposed. The potential PV impacts may cause certain utilities to refrain from integrating PV systems into their networks. However, each electric network has a certain limit beyond which the impacts become substantial and may adversely interfere with the system operation and the equipment along the feeder; this limit is referred to as the hosting limit (or hosting capacity). Therefore, it is important for utilities to identify the PV hosting limit on a specific electric network in order to safely and confidently integrate the maximum possible PV systems. In the following dissertation, two approaches have been proposed for identifying the hosing limit: 1. Analytical approach: this is a theoretical mathematical approach that demonstrated the understanding of the fundamentals of electric power system operation. It provides an easy way to estimate the maximum amount of PV power that can be injected at each node in the network. This approach has been tested and validated. 2. Stochastic simulation software approach: this approach provides a comprehensive simulation software that can be used in order to identify the PV hosting limit. The software performs a large number of stochastic simulation while varying the PV system size and location. The collected data is then analyzed for violations in the voltage levels, voltage fluctuations and reverse power flow. (Abstract shortened by ProQuest.).

The Effects of Market Concentration on Residential Solar PV Prices: Competition, Installer Scale, and Soft Costs

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J

Competition among residential solar photovoltaic (PV) installers may reduce PV price markups and yield lower prices. At the same time, competition may reduce installer experience and opportunities for cost reductions through learning-by-doing and economies of scale. These dynamics suggest that PV non-hardware or 'soft' costs and installed prices depend on the distribution of market shares among installers, also known as market concentration. This study leverages a rich data set of 226,769 residential PV systems to examine the relationship between market concentration, soft costs, and PV prices. The results show that PV prices are lower, on average, in more concentrated markets,more » i.e., markets with fewer installers or where few installers hold high market share. The study provides evidence that this relationship is non-linear, such that prices are minimized in markets with an optimal balance of the benefits of market concentration and the benefits of competition.« less

The influence of utility-interactive PV system characteristics to ac power networks

NASA Astrophysics Data System (ADS)

Takeda, Y.; Takigawa, K.; Kaminosono, H.

Two basic experimental photovoltaic (PV) systems have been built for the study of variation of power quality, aspects of safety, and technical problems. One system uses a line-commutated inverter, while the other system uses a self-commutated inverter. A description is presented of the operating and generating characteristics of the two systems. The systems were connected to an ac simulated network which simulates an actual power distribution system. Attention is given to power generation characteristics, the control characteristics, the harmonics characteristics, aspects of coordination with the power network, and questions regarding the reliability of photovoltaic modules.

Photovoltaic Impact Assessment of Smart Inverter Volt-VAR Control on Distribution System Conservation Voltage Reduction and Power Quality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Nagarajan, Adarsh; Chakraborty, Sudipta

This report presents an impact assessment study of distributed photovoltaic (PV) with smart inverter Volt-VAR control on conservation voltage reduction (CVR) energy savings and distribution system power quality. CVR is a methodology of flattening and lowering a distribution system voltage profile in order to conserve energy. Traditional CVR relies on operating utility voltage regulators and switched capacitors. However, with the increased penetration of distributed PV systems, smart inverters provide the new opportunity to control local voltage and power factor by regulating the reactive power output, leading to a potential increase in CVR energy savings. This report proposes a methodology tomore » implement CVR scheme by operating voltage regulators, capacitors, and autonomous smart inverter Volt-VAR control in order to achieve increased CVR benefit. Power quality is an important consideration when operating a distribution system, especially when implementing CVR. It is easy to measure the individual components that make up power quality, but a comprehensive method to incorporate all of these values into a single score has yet to be undertaken. As a result, this report proposes a power quality scoring mechanism to measure the relative power quality of distribution systems using a single number, which is aptly named the 'power quality score' (PQS). Both the CVR and PQS methodologies were applied to two distribution system models, one obtained from the Hawaiian Electric Company (HECO) and another obtained from Pacific Gas and Electric (PG&E). These two models were converted to the OpenDSS platform using previous model conversion tools that were developed by NREL. Multiple scenarios including various PV penetration levels and smart inverter densities were simulated to analyze the impact of smart inverter Volt-VAR support on CVR energy savings and feeder power quality. In order to analyze the CVR benefit and PQS, an annual simulation was conducted for each scenario.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, Kyri; Dall'Anese, Emiliano; Summers, Tyler

This paper outlines a data-driven, distributionally robust approach to solve chance-constrained AC optimal power flow problems in distribution networks. Uncertain forecasts for loads and power generated by photovoltaic (PV) systems are considered, with the goal of minimizing PV curtailment while meeting power flow and voltage regulation constraints. A data- driven approach is utilized to develop a distributionally robust conservative convex approximation of the chance-constraints; particularly, the mean and covariance matrix of the forecast errors are updated online, and leveraged to enforce voltage regulation with predetermined probability via Chebyshev-based bounds. By combining an accurate linear approximation of the AC power flowmore » equations with the distributionally robust chance constraint reformulation, the resulting optimization problem becomes convex and computationally tractable.« less

Envisioning a Low-Cost Solar Future: Exploring the Potential Impact of Achieving the SunShot 2030 Targets for Photovoltaics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, Wesley J; Frew, Bethany A; Gagnon, Pieter J

In the context of recent dramatic solar energy cost reductions, the U.S. Department of Energy set new levelized cost of energy goals for photovoltaics (PV) to achieve by 2030 to enable significantly greater PV adoption: $0.03/kWh for utility-scale, $0.04/kWh for commercial, and $0.05/kWh for residential PV systems. We analyze the potential impacts of achieving these 'SunShot 2030' cost targets for the contiguous United States using the Regional Energy Deployment System (ReEDS) and Distributed Generation (dGen) capacity expansion models. We consider the impacts under a wide range of future conditions. We find that PV could provide 13%-18% of U.S. electricity demandmore » in 2030 and 28%-64% of demand if the SunShot 2030 goals are achieved, with PV deployment increasing in every state. The availability of low-cost storage has the largest impact on projected deployment, followed by natural gas prices and electricity demand. For comparison, PV deployed under a business-as-usual scenario could provide only 5% of generation in 2030 and 17% in 2050. We find that the high levels of PV deployment explored here lead to lower electricity prices and system costs, lower carbon dioxide emissions, lower water consumption, increased renewable energy curtailment, and increased storage deployment compared with the business-as-usual scenario.« less

Financing, Overhead, and Profit: An In-Depth Discussion of Costs Associated with Third-Party Financing of Residential and Commercial Photovoltaic Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feldman, D.; Friedman, B.; Margolis, R.

Previous work quantifying the non-hardware balance-of-system costs -- or soft costs -- associated with building a residential or commercial photovoltaic (PV) system has left a significant portion unsegmented in an 'other soft costs' category. This report attempts to better quantify the 'other soft costs' by focusing on the financing, overhead, and profit of residential and commercial PV installations for a specific business model. This report presents results from a bottom-up data-collection and analysis of the upfront costs associated with developing, constructing, and arranging third-party-financed residential and commercial PV systems. It quantifies the indirect corporate costs required to install distributed PVmore » systems as well as the transactional costs associated with arranging third-party financing.« less

Trans-oceanic Remote Power Hardware-in-the-Loop: Multi-site Hardware, Integrated Controller, and Electric Network Co-simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundstrom, Blake R.; Palmintier, Bryan S.; Rowe, Daniel

Electric system operators are increasingly concerned with the potential system-wide impacts of the large-scale integration of distributed energy resources (DERs) including voltage control, protection coordination, and equipment wear. This prompts a need for new simulation techniques that can simultaneously capture all the components of these large integrated smart grid systems. This paper describes a novel platform that combines three emerging research areas: power systems co-simulation, power hardware in the loop (PHIL) simulation, and lab-lab links. The platform is distributed, real-time capable, allows for easy internet-based connection from geographically-dispersed participants, and is software platform agnostic. We demonstrate its utility by studyingmore » real-time PHIL co-simulation of coordinated solar PV firming control of two inverters connected in multiple electric distribution network models, prototypical of U.S. and Australian systems. Here, the novel trans-pacific closed-loop system simulation was conducted in real-time using a power network simulator and physical PV/battery inverter at power at the National Renewable Energy Laboratory in Golden, CO, USA and a physical PV inverter at power at the Commonwealth Scientific and Industrial Research Organisation's Energy Centre in Newcastle, NSW, Australia. This capability enables smart grid researchers throughout the world to leverage their unique simulation capabilities for multi-site collaborations that can effectively simulate and validate emerging smart grid technology solutions.« less

Trans-oceanic Remote Power Hardware-in-the-Loop: Multi-site Hardware, Integrated Controller, and Electric Network Co-simulation

DOE PAGES

Lundstrom, Blake R.; Palmintier, Bryan S.; Rowe, Daniel; ...

2017-07-24

Electric system operators are increasingly concerned with the potential system-wide impacts of the large-scale integration of distributed energy resources (DERs) including voltage control, protection coordination, and equipment wear. This prompts a need for new simulation techniques that can simultaneously capture all the components of these large integrated smart grid systems. This paper describes a novel platform that combines three emerging research areas: power systems co-simulation, power hardware in the loop (PHIL) simulation, and lab-lab links. The platform is distributed, real-time capable, allows for easy internet-based connection from geographically-dispersed participants, and is software platform agnostic. We demonstrate its utility by studyingmore » real-time PHIL co-simulation of coordinated solar PV firming control of two inverters connected in multiple electric distribution network models, prototypical of U.S. and Australian systems. Here, the novel trans-pacific closed-loop system simulation was conducted in real-time using a power network simulator and physical PV/battery inverter at power at the National Renewable Energy Laboratory in Golden, CO, USA and a physical PV inverter at power at the Commonwealth Scientific and Industrial Research Organisation's Energy Centre in Newcastle, NSW, Australia. This capability enables smart grid researchers throughout the world to leverage their unique simulation capabilities for multi-site collaborations that can effectively simulate and validate emerging smart grid technology solutions.« less

Photovoltaic-Model-Based Solar Irradiance Estimators: Performance Comparison and Application to Maximum Power Forecasting

NASA Astrophysics Data System (ADS)

Scolari, Enrica; Sossan, Fabrizio; Paolone, Mario

2018-01-01

Due to the increasing proportion of distributed photovoltaic (PV) production in the generation mix, the knowledge of the PV generation capacity has become a key factor. In this work, we propose to compute the PV plant maximum power starting from the indirectly-estimated irradiance. Three estimators are compared in terms of i) ability to compute the PV plant maximum power, ii) bandwidth and iii) robustness against measurements noise. The approaches rely on measurements of the DC voltage, current, and cell temperature and on a model of the PV array. We show that the considered methods can accurately reconstruct the PV maximum generation even during curtailment periods, i.e. when the measured PV power is not representative of the maximum potential of the PV array. Performance evaluation is carried out by using a dedicated experimental setup on a 14.3 kWp rooftop PV installation. Results also proved that the analyzed methods can outperform pyranometer-based estimations, with a less complex sensing system. We show how the obtained PV maximum power values can be applied to train time series-based solar maximum power forecasting techniques. This is beneficial when the measured power values, commonly used as training, are not representative of the maximum PV potential.

The dark side of photovoltaic — 3D simulation of glare assessing risk and discomfort

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rose, Thomas; Wollert, Alexander

2015-04-15

Photovoltaic (PV) systems form an important force in the implementation of renewable energies, but as we all know, the force has always its dark side. Besides efficiency considerations and discussions about architectures of power distribution networks, the increasing numbers of installations of PV systems for implementing renewable energies have secondary effects. PV systems can generate glare due to optical reflections and hence might be a serious concern. On the one hand, glare could affect safety, e.g. regarding traffic. On the other hand, glare is a constant source of discomfort in vicinities of PV systems. Hence, assessment of glare is decisivemore » for the success of renewable energies near municipalities and traffic zones for the success of solar power. Several courts decided on the change of PV systems and even on their de-installation because of glare effects. Thus, location-based assessments are required to limit potential reflections and to avoid risks for public infrastructure or discomfort of residents. The question arises on how to calculate reflections accurately according to the environment's topography. Our approach is founded in a 3D-based simulation methodology to calculate and visualize reflections based on the geometry of the environment of PV systems. This computational model is implemented by an interactive tool for simulation and visualization. Hence, project planners receive flexible assistance for adjusting the parameters of solar panels amid the planning process and in particular before the installation of a PV system. - Highlights: • Solar panels cause glare that impacts neighborhoods and traffic infrastructures. • Glare might cause disability and discomfort. • 3D environment for the calculation of glare • Interactive tool to simulate and visualize reflections • Impact assessment of solar power plant farms.« less

Distribution-Agnostic Stochastic Optimal Power Flow for Distribution Grids: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, Kyri; Dall'Anese, Emiliano; Summers, Tyler

2016-09-01

This paper outlines a data-driven, distributionally robust approach to solve chance-constrained AC optimal power flow problems in distribution networks. Uncertain forecasts for loads and power generated by photovoltaic (PV) systems are considered, with the goal of minimizing PV curtailment while meeting power flow and voltage regulation constraints. A data- driven approach is utilized to develop a distributionally robust conservative convex approximation of the chance-constraints; particularly, the mean and covariance matrix of the forecast errors are updated online, and leveraged to enforce voltage regulation with predetermined probability via Chebyshev-based bounds. By combining an accurate linear approximation of the AC power flowmore » equations with the distributionally robust chance constraint reformulation, the resulting optimization problem becomes convex and computationally tractable.« less

Design description of the Schuchuli Village photovoltaic power system

NASA Technical Reports Server (NTRS)

Ratajczak, A. F.; Vasicek, R. W.; Delombard, R.

1981-01-01

A stand alone photovoltaic (PV) power system for the village of Schuchuli (Gunsight), Arizona, on the Papago Indian Reservation is a limited energy, all 120 V (d.c.) system to which loads cannot be arbitrarily added and consists of a 3.5 kW (peak) PV array, 2380 ampere-hours of battery storage, an electrical equipment building, a 120 V (d.c.) electrical distribution network, and equipment and automatic controls to provide control power for pumping water into an existing water system; operating 15 refrigerators, a clothes washing machine, a sewing machine, and lights for each of the homes and communal buildings. A solar hot water heater supplies hot water for the washing machine and communal laundry. Automatic control systems provide voltage control by limiting the number of PV strings supplying power during system operation and battery charging, and load management for operating high priority at the expense of low priority loads as the main battery becomes depleted.

Intermediate photovoltaic system application experiment operational performance report: Volume 5, for Beverly High School, Beverly, Mass.

NASA Astrophysics Data System (ADS)

1982-02-01

Performance data for the month of January, 1982 for a grid connected photovoltaic power supply in Massachusetts are presented. Data include: monthly and daily electrical energy produced; monthly and daily solar energy incident on the array; monthly and daily array efficiency; plots of energy produced as a function of power level, voltage, cell temperature and time of day; power conditioner input, output and efficiency for each of two individual units and for the total power conditioning system; photovoltaic system efficiency; capacity factor; PV system to load and grid to load energies and corresponding dollar values; daily energy supplies to the load by the PV system; daily PV system availability; monthly and hourly insolation; monthly and hourly temperature average; monthly and hourly wind speed; wind direction distribution; average heating and cooling degree days; number of freeze/thaw cycles; and the data acquisition mode and recording interval plot.

Review of droop-controlled bi-directional inverter in conducting islanded operation of photovoltaic systems

NASA Astrophysics Data System (ADS)

Khaw, Ace Lin Yi; Wong, Jianhui; Lim, Yun Seng

2017-04-01

Global warming due to the excessive greenhouse gas emissions has led to the emergence of green technologies in Malaysia, particularly photovoltaic (PV) systems. Under the current regulatory framework, islanded operation of the PV system is not permissible. As a result, any renewable energy sources will be disconnected immediately in the event of grid outages. This practice is to ensure the safety of working personnel, as well as the customer equipment connected within the distribution networks. In addition, there is no synchronizing equipment to aid the reconnection of the islanded network to the grid. However, with the shutdown of the Distributed Generator (DG) during islanded operation, the customers are not able to utilize the available renewable energy and the number of power interruption is not improved with the renewable energy sources. Therefore, the main objective of this paper is to investigate the feasibility of the PV system in conducting islanding operation with the use of Energy Storage System (ESS). This paper also proposes a control algorithm to maintain the voltage and frequency excursion within the statutory limit by manipulating the real and reactive power flow of the ESS within the transition period between grid connected and islanding operation.

A method for evaluating photovoltaic potential in China based on GIS platform

NASA Astrophysics Data System (ADS)

Wang, L. Z.; Tan, H. W.; Ji, L.; Wang, D.

2017-11-01

Solar photovoltaic systems are commonly utilized in China. However, the associated research is still lack of its resource potential analysis in all regions in China. Based on the existed data about solar radiation and system conversion efficiency data, a new method for distributed photovoltaic potential assessment has been presented. The experiment of three kinds of solar photovoltaic system has been set up for the purpose of analyzing the relationship between conversion efficiency and environmental parameters. This paper fits the relationship between conversion efficiency and solar radiation intensity. This method takes into account the amount of solar radiation that is effectively generated and drives away the weak values. With the spatial analysis function of geographic information system (GIS) platform, frequency distribution of solar radiation intensity and PV potential in China can be derived. Furthermore, analytical results show that monocrystalline-silicon PV generation in the north-western and northern areas have reached a level of more than 200 kWh/(m2.a), making those areas be suitable for the development of PV system. However, the potential for southwest areas reaches a level of only 130 kWh/(m2.a). This paper can provide the baseline reference for solar energy development planning.

The Varied Impacts of Energy Storage and Photovoltaics on Fossil Fuel Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Studarus, Karen E.; Thayer, Brandon L.; Barrett, Emily L.

The emissions consequences of smart grid technologies can be significant but are not always intuitive. This is particularly true in the implementation of energy storage (ES) to enable the installation of solar photovoltaic (PV) systems. Using the web calculator at https://eqt.pnnl.gov and prototypical distribution feeders, this paper explores the COmore » $${_2}$$, SO$${_2}$$ and NO$${_x}$$ impacts of ES deployed with solar PV, where the energy storage system is operated to minimize load variation. Five regions of the country were explored using 15 prototypical distribution feeders and 2015 historical data. Impacts vary in direction, magnitude, and trend, and require a context-dependent screening method for faithful representation.« less

Energetic performance analysis of a commercial water-based photovoltaic thermal system (PV/T) under summer conditions

NASA Astrophysics Data System (ADS)

Nardi, I.; Ambrosini, D.; de Rubeis, T.; Paoletti, D.; Muttillo, M.; Sfarra, S.

2017-11-01

In the last years, the importance of integrating the production of electricity with the production of sanitary hot water led to the development of new solutions, i.e. PV/T systems. It is well known that hybrid photovoltaic-thermal systems, able to produce electricity and thermal energy at the same time with better energetic performance in comparison with two separate systems, present many advantages for application in a residential building. A PV/T is constituted generally by a common PV panel with a metallic pipe, in which fluid flows. Pipe accomplishes two roles: it absorbs the heat from the PV panel, thus increasing, or at least maintaining its efficiency; furthermore, it stores the heat for sanitary uses. In this work, the thermal and electrical efficiencies of a commercial PV/T panel have been evaluated during the summer season in different days, to assess the effect of environmental conditions on the system total efficiency. Moreover, infrared thermographic diagnosis in real time has been effected during the operating mode in two conditions: with cooling and without cooling; cooling was obtained by natural flowing water. This analysis gave information about the impact of a non-uniform temperature distribution on the thermal and electrical performance. Furthermore, measurements have been performed in two different operating modes: 1) production of solely electrical energy and 2) simultaneous production of thermal and electrical energy. Finally, total efficiency is largely increased by using a simple solar concentrator nearby the panel.

Novel Methods to Determine Feeder Locational PV Hosting Capacity and PV Impact Signatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reno, Matthew J.; Coogan, Kyle; Seuss, John

Often PV hosting capacity analysis is performed for a limited number of distribution feeders. For medium - voltage distribution feeders, previous results generally analyze less than 20 feeders, and then the results are extrapolated out to similar types of feeders. Previous hosting capacity research has often focused on determining a single value for the hosting capacity for the entire feeder, whereas this research expands previous hosting capacity work to investigate all the regions of the feeder that may allow many different hosting capacity values wit h an idea called locational hosting capacity (LHC)to determine the largest PV size that canmore » be interconnected at different locations (buses) on the study feeders. This report discusses novel methods for analyzing PV interconnections with advanced simulati on methods. The focus is feeder and location - specific impacts of PV that determine the locational PV hosting capacity. Feeder PV impact signature are used to more precisely determine the local maximum hosting capacity of individual areas of the feeder. T he feeder signature provides improved interconnection screening with certain zones that show the risk of impact to the distribution feeder from PV interconnections.« less

Simulation of an active cooling system for photovoltaic modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelhakim, Lotfi

Photovoltaic cells are devices that convert solar radiation directly into electricity. However, solar radiation increases the photovoltaic cells temperature [1] [2]. The temperature has an influence on the degradation of the cell efficiency and the lifetime of a PV cell. This work reports on a water cooling technique for photovoltaic panel, whereby the cooling system was placed at the front surface of the cells to dissipate excess heat away and to block unwanted radiation. By using water as a cooling medium for the photovoltaic solar cells, the overheating of closed panel is greatly reduced without prejudicing luminosity. The water alsomore » acts as a filter to remove a portion of solar spectrum in the infrared band but allows transmission of the visible spectrum most useful for the PV operation. To improve the cooling system efficiency and electrical efficiency, uniform flow rate among the cooling system is required to ensure uniform distribution of the operating temperature of the PV cells. The aims of this study are to develop a 3D thermal model to simulate the cooling and heat transfer in Photovoltaic panel and to recommend a cooling technique for the PV panel. The velocity, pressure and temperature distribution of the three-dimensional flow across the cooling block were determined using the commercial package, Fluent. The second objective of this work is to study the influence of the geometrical dimensions of the panel, water mass flow rate and water inlet temperature on the flow distribution and the solar panel temperature. The results obtained by the model are compared with experimental results from testing the prototype of the cooling device.« less

Using the Spatial Distribution of Installers to Define Solar Photovoltaic Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Nemet, Gregory F.; Darghouth, Naim

2016-09-01

Solar PV market research to date has largely relied on arbitrary jurisdictional boundaries, such as counties, to study solar PV market dynamics. This paper seeks to improve solar PV market research by developing a methodology to define solar PV markets. The methodology is based on the spatial distribution of solar PV installers. An algorithm is developed and applied to a rich dataset of solar PV installations to study the outcomes of the installer-based market definitions. The installer-based approach exhibits several desirable properties. Specifically, the higher market granularity of the installer-based approach will allow future PV market research to study themore » relationship between market dynamics and pricing with more precision.« less

Analysis to Inform CA Grid Integration Rules for PV: Final Report on Inverter Settings for Transmission and Distribution System Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Jeff; Rylander, Matthew; Boemer, Jens

The fourth solicitation of the California Solar Initiative (CSI) Research, Development, Demonstration and Deployment (RD&D) Program established by the California Public Utilities Commission (CPUC) supported the Electric Power Research Institute (EPRI), National Renewable Energy Laboratory (NREL), and Sandia National Laboratories (SNL) with data provided from Pacific Gas and Electric (PG&E), Southern California Edison (SCE), and San Diego Gas and Electric (SDG&E) conducted research to determine optimal default settings for distributed energy resource advanced inverter controls. The inverter functions studied are aligned with those developed by the California Smart Inverter Working Group (SIWG) and those being considered by the IEEE 1547more » Working Group. The advanced inverter controls examined to improve the distribution system response included power factor, volt-var, and volt-watt. The advanced inverter controls examined to improve the transmission system response included frequency and voltage ride-through as well as Dynamic Voltage Support. This CSI RD&D project accomplished the task of developing methods to derive distribution focused advanced inverter control settings, selecting a diverse set of feeders to evaluate the methods through detailed analysis, and evaluating the effectiveness of each method developed. Inverter settings focused on the transmission system performance were also evaluated and verified. Based on the findings of this work, the suggested advanced inverter settings and methods to determine settings can be used to improve the accommodation of distributed energy resources (PV specifically). The voltage impact from PV can be mitigated using power factor, volt-var, or volt-watt control, while the bulk system impact can be improved with frequency/voltage ride-through.« less

Application of Distributed DC/DC Electronics in Photovoltaic Systems

NASA Astrophysics Data System (ADS)

Kabala, Michael

In a typical residential, commercial or utility grade photovoltaic (PV) system, PV modules are connected in series and in parallel to form an array that is connected to a standard DC/AC inverter, which is then connected directly to the grid. This type of standard installation; however, does very little to maximize the energy output of the solar array if certain conditions exist. These conditions could include age, temperature, irradiance and other factors that can cause mismatch between PV modules in an array that severely cripple the output power of the system. Since PV modules are typically connected in series to form a string, the output of the entire string is limited by the efficiency of the weakest module. With PV module efficiencies already relatively low, it is critical to extract the maximum power out of each module in order to make solar energy an economically viable competitor to oil and gas. Module level DC/DC electronics with maximum power point (MPP) tracking solves this issue by decoupling each module from the string in order for the module to operate independently of the geometry and complexity of the surrounding system. This allows each PV module to work at its maximum power point by transferring the maximum power the module is able to deliver directly to the load by either boosting (stepping up) the voltage or bucking (stepping down) the voltage. The goal of this thesis is to discuss the development of a per-module DC/DC converter in order to maximize the energy output of a PV module and reduce the overall cost of the system by increasing the energy harvest.

Robust Operation of Soft Open Points in Active Distribution Networks with High Penetration of Photovoltaic Integration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Ji, Haoran; Wang, Chengshan

Distributed generators (DGs) including photovoltaic panels (PVs) have been integrated dramatically in active distribution networks (ADNs). Due to the strong volatility and uncertainty, the high penetration of PV generation immensely exacerbates the conditions of voltage violation in ADNs. However, the emerging flexible interconnection technology based on soft open points (SOPs) provides increased controllability and flexibility to the system operation. For fully exploiting the regulation ability of SOPs to address the problems caused by PV, this paper proposes a robust optimization method to achieve the robust optimal operation of SOPs in ADNs. A two-stage adjustable robust optimization model is built tomore » tackle the uncertainties of PV outputs, in which robust operation strategies of SOPs are generated to eliminate the voltage violations and reduce the power losses of ADNs. A column-and-constraint generation (C&CG) algorithm is developed to solve the proposed robust optimization model, which are formulated as second-order cone program (SOCP) to facilitate the accuracy and computation efficiency. Case studies on the modified IEEE 33-node system and comparisons with the deterministic optimization approach are conducted to verify the effectiveness and robustness of the proposed method.« less

Rooftop solar photovoltaic potential in cities: how scalable are assessment approaches?

NASA Astrophysics Data System (ADS)

Castellanos, Sergio; Sunter, Deborah A.; Kammen, Daniel M.

2017-12-01

Distributed photovoltaics (PV) have played a critical role in the deployment of solar energy, currently making up roughly half of the global PV installed capacity. However, there remains significant unused economically beneficial potential. Estimates of the total technical potential for rooftop PV systems in the United States calculate a generation comparable to approximately 40% of the 2016 total national electric-sector sales. To best take advantage of the rooftop PV potential, effective analytic tools that support deployment strategies and aggressive local, state, and national policies to reduce the soft cost of solar energy are vital. A key step is the low-cost automation of data analysis and business case presentation for structure-integrated solar energy. In this paper, the scalability and resolution of various methods to assess the urban rooftop PV potential are compared, concluding with suggestions for future work in bridging methodologies to better assist policy makers.

Intelligent Energy Management System for PV-Battery-based Microgrids in Future DC Homes

NASA Astrophysics Data System (ADS)

Chauhan, R. K.; Rajpurohit, B. S.; Gonzalez-Longatt, F. M.; Singh, S. N.

2016-06-01

This paper presents a novel intelligent energy management system (IEMS) for a DC microgrid connected to the public utility (PU), photovoltaic (PV) and multi-battery bank (BB). The control objectives of the proposed IEMS system are: (i) to ensure the load sharing (according to the source capacity) among sources, (ii) to reduce the power loss (high efficient) in the system, and (iii) to enhance the system reliability and power quality. The proposed IEMS is novel because it follows the ideal characteristics of the battery (with some assumptions) for the power sharing and the selection of the closest source to minimize the power losses. The IEMS allows continuous and accurate monitoring with intelligent control of distribution system operations such as battery bank energy storage (BBES) system, PV system and customer utilization of electric power. The proposed IEMS gives the better operational performance for operating conditions in terms of load sharing, loss minimization, and reliability enhancement of the DC microgrid.

Optical analysis of a photovoltaic V-trough system installed in western India.

PubMed

Maiti, Subarna; Sarmah, Nabin; Bapat, Pratap; Mallick, Tapas K

2012-12-20

The low concentrating photovoltaic (PV) system such as a 2× V-trough system can be a promising choice for enhancing the power output from conventional PV panels with the inclusion of thermal management. This system is more attractive when the reflectors are retrofitted to the stationary PV panels installed in a high aspect ratio in the north-south direction and are tracked 12 times a year manually according to preset angles, thus eliminating the need of diurnal expensive tracking. In the present analysis, a V-trough system facing exactly the south direction is considered, where the tilt angle of the PV panels' row is kept constant at 18.34°. The system is installed on the terrace of CSIR-Central Salt and Marine Chemicals Research Institute in Bhavnagar, Gujarat, India (21.47 N, 71.15 E). The dimension of the entire PV system is 9.64 m×0.55 m. The V-troughs made of anodized aluminum reflectors (70% specular reflectivity) had the same dimensions. An in-house developed; experimentally validated Monte Carlo ray-trace model was used to study the effect of the angular variation of the reflectors throughout a year for the present assembly. Results of the ray trace for the optimized angles showed the maximum simulated optical efficiency to be 85.9%. The spatial distribution of solar intensity over the 0.55 m dimension of the PV panel due to the V-trough reflectors was also studied for the optimized days in periods that included solstices and equinoxes. The measured solar intensity profiles with and without the V-trough system were used to calculate the actual optical efficiencies for several sunny days in the year, and results were validated with the simulated efficiencies within an average error limit of 10%.

Economic assessment photovoltaic/battery systems

NASA Astrophysics Data System (ADS)

Day, J. T.; Hayes, T. P.; Hobbs, W. J.

1981-02-01

The economics of residential PV/battery systems were determined from the utility perspective using detailed computer simulation to determine marginal costs. Brief consideration is also given to the economics of customer ownership, utility distribution system impact, and the implications of PURPA.

Regional PV power estimation and forecast to mitigate the impact of high photovoltaic penetration on electric grid.

NASA Astrophysics Data System (ADS)

Pierro, Marco; De Felice, Matteo; Maggioni, Enrico; Moser, David; Perotto, Alessandro; Spada, Francesco; Cornaro, Cristina

2017-04-01

The growing photovoltaic generation results in a stochastic variability of the electric demand that could compromise the stability of the grid and increase the amount of energy reserve and the energy imbalance cost. On regional scale, solar power estimation and forecast is becoming essential for Distribution System Operators, Transmission System Operator, energy traders, and aggregators of generation. Indeed the estimation of regional PV power can be used for PV power supervision and real time control of residual load. Mid-term PV power forecast can be employed for transmission scheduling to reduce energy imbalance and related cost of penalties, residual load tracking, trading optimization, secondary energy reserve assessment. In this context, a new upscaling method was developed and used for estimation and mid-term forecast of the photovoltaic distributed generation in a small area in the north of Italy under the control of a local DSO. The method was based on spatial clustering of the PV fleet and neural networks models that input satellite or numerical weather prediction data (centered on cluster centroids) to estimate or predict the regional solar generation. It requires a low computational effort and very few input information should be provided by users. The power estimation model achieved a RMSE of 3% of installed capacity. Intra-day forecast (from 1 to 4 hours) obtained a RMSE of 5% - 7% while the one and two days forecast achieve to a RMSE of 7% and 7.5%. A model to estimate the forecast error and the prediction intervals was also developed. The photovoltaic production in the considered region provided the 6.9% of the electric consumption in 2015. Since the PV penetration is very similar to the one observed at national level (7.9%), this is a good case study to analyse the impact of PV generation on the electric grid and the effects of PV power forecast on transmission scheduling and on secondary reserve estimation. It appears that, already with 7% of PV penetration, the distributed PV generation could have a great impact both on the DSO energy need and on the transmission scheduling capability. Indeed, for some hours of the days in summer time, the photovoltaic generation can provide from 50% to 75% of the energy that the local DSO should buy from Italian TSO to cover the electrical demand. Moreover, mid-term forecast can reduce the annual energy imbalance between the scheduled transmission and the actual one from 10% of the TSO energy supply (without considering the PV forecast) to 2%. Furthermore, it was shown that prediction intervals could be used not only to estimate the probability of a specific PV generation bid on the energy market, but also to reduce the energy reserve predicted for the next day. Two different methods for energy reserve estimation were developed and tested. The first is based on a clear sky model while the second makes use of the PV prediction intervals with the 95% of confidence level. The latter reduces the amount of the day-ahead energy reserve of 36% with respect the clear sky method.

Eric O'Shaughnessy | NREL

Science.gov Websites

of residential solar PV markets. Eric leads the lab's solar data partnerships program. Eric's current green power market research. Research Interests Economic analysis, econometrics, distributed solar PV . Ardani, R. Margolis. 2018. Solar plus: Optimization of distributed solar PV through battery storage and

A Modular Multilevel Converter with Power Mismatch Control for Grid-Connected Photovoltaic Systems

DOE PAGES

Duman, Turgay; Marti, Shilpa; Moonem, M. A.; ...

2017-05-17

A modular multilevel power converter configuration for grid connected photovoltaic (PV) systems is proposed. The converter configuration replaces the conventional bulky line frequency transformer with several high frequency transformers, potentially reducing the balance of systems cost of PV systems. The front-end converter for each port is a neutral-point diode clamped (NPC) multi-level dc-dc dual-active bridge (ML-DAB) which allows maximum power point tracking (MPPT). The integrated high frequency transformer provides the galvanic isolation between the PV and grid side and also steps up the low dc voltage from PV source. Following the ML-DAB stage, in each port, is a NPC inverter.more » N number of NPC inverters’ outputs are cascaded to attain the per-phase line-to-neutral voltage to connect directly to the distribution grid (i.e., 13.8 kV). The cascaded NPC (CNPC) inverters have the inherent advantage of using lower rated devices, smaller filters and low total harmonic distortion required for PV grid interconnection. The proposed converter system is modular, scalable, and serviceable with zero downtime with lower foot print and lower overall cost. A novel voltage balance control at each module based on power mismatch among N-ports, have been presented and verified in simulation. Analysis and simulation results are presented for the N-port converter. The converter performance has also been verified on a hardware prototype.« less

A Modular Multilevel Converter with Power Mismatch Control for Grid-Connected Photovoltaic Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duman, Turgay; Marti, Shilpa; Moonem, M. A.

A modular multilevel power converter configuration for grid connected photovoltaic (PV) systems is proposed. The converter configuration replaces the conventional bulky line frequency transformer with several high frequency transformers, potentially reducing the balance of systems cost of PV systems. The front-end converter for each port is a neutral-point diode clamped (NPC) multi-level dc-dc dual-active bridge (ML-DAB) which allows maximum power point tracking (MPPT). The integrated high frequency transformer provides the galvanic isolation between the PV and grid side and also steps up the low dc voltage from PV source. Following the ML-DAB stage, in each port, is a NPC inverter.more » N number of NPC inverters’ outputs are cascaded to attain the per-phase line-to-neutral voltage to connect directly to the distribution grid (i.e., 13.8 kV). The cascaded NPC (CNPC) inverters have the inherent advantage of using lower rated devices, smaller filters and low total harmonic distortion required for PV grid interconnection. The proposed converter system is modular, scalable, and serviceable with zero downtime with lower foot print and lower overall cost. A novel voltage balance control at each module based on power mismatch among N-ports, have been presented and verified in simulation. Analysis and simulation results are presented for the N-port converter. The converter performance has also been verified on a hardware prototype.« less

Distributed PV Adoption in Maine Through 2021

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gagnon, Pieter; Sigrin, Ben

2015-11-06

NREL has used its dSolar (distributed solar) model to generate low-medium-high estimates of distributed PV adoption in Maine through 2021. This presentation gives a high-level overview of the model and modeling results.

An evaluation of the precipitation distribution associated with landfalling tropical systems

NASA Astrophysics Data System (ADS)

Atallah, Eyad H.

Several recent landfalling tropical cyclones (e.g. Dennis, Floyd, and Irene 1999) have highlighted a need for a refinement in the forecasting paradigms and techniques in the area of quantitative precipitation forecasting (QPF). Accordingly, several landfalling tropical storms were composited based on the precipitation distribution relative to the cyclone track (i.e. left of, right of, or along track), and cases from each composite were examined using a potential vorticity (PV) and quasi-geostrophic (QG) framework. Results indicate that a left of track precipitation distribution (e.g. Floyd 1999) is characteristic of tropical systems undergoing extratropical transition (ET). In these cases, a significant positively tilted mid-latitude trough approaches the cyclone from the northwest, shifting precipitation to the north-northwest of the cyclone. PV redistribution through diabatic heating then leads to enhanced ridging over and downstream of the tropical cyclone resulting in an increase in the cyclonic advection of vorticity by the thermal wind. Precipitation distribution is heaviest to the right of the track of the storm when downstream intensification of the ridge is important (e.g. David, 1979). Enhancement of the downstream ridge ahead of a weak mid-latitude trough accentuates the PV gradient between the tropical system and the downstream ridge. This, in combination with a slight acceleration in the movement of the tropical system, produces a region of enhanced positive PV advection (implied ascent) between the tropical system and the downstream ridge. Precipitation is heaviest along/very near the track of a storm when shear values are low and/or oriented along the track of the tropical cyclone (e.g. Fran 1996). Without large scale forcing for vertical motion associated with a midlatitude trough, most of the ascent remains concentrated near the storm core in the region of greatest diabatic heating and maximum wind speeds. In all cases, the diabatic enhancement of the downstream ridge is instrumental in the redistribution of precipitation about the tropical system. Unfortunately, this process is not well simulated in operational forecast models, leading to systematic errors in QPF.

The Impact of Utility Tariff Evolution on Behind-the-Meter PV Adoption

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, Wesley J; Gagnon, Pieter J; Frew, Bethany A

This analysis uses a new method to link the NREL Regional Energy Deployment System (ReEDS) capacity expansion model with the NREL distributed generation market demand model (dGen) to explore the impact that the evolution of retail electricity tariffs can have on the adoption of distributed photovoltaics (DPV). The evolution most notably takes the form of decreased mid-day electricity costs, as low-cost PV reduces the marginal cost of electricity during those hours and the changes are subsequently communicated to electricity consumers through tariffs. We find that even under the low PV prices of the new SunShot targets the financial performance ofmore » DPV under evolved tariffs still motivates behind-the-meter adoption, despite significant reduction in the costs of electricity during afternoon periods driven by deployment of cheap utility-scale PV. The amount of DPV in 2050 in these low-cost futures ranged from 206 GW to 263 GW, a 13-fold and 16-fold increase over 2016 adoption levels respectively. From a utility planner's perspective, the representation of tariff evolution has noteworthy impacts on forecasted DPV adoption in scenarios with widespread time-of-use tariffs. Scenarios that projected adoption under a portfolio of time-of-use tariffs, but did not represent the evolution of those tariffs, predicted up to 36 percent more DPV in 2050, compared to scenarios that did not represent that evolution. Lastly, we find that a reduction in DPV deployment resulting from evolved tariffs had a negligible impact on the total generation from PV - both utility-scale and distributed - in the scenarios we examined. Any reduction in DPV generation was replaced with utility-scale PV generation, to arrive at the quantity that makes up the least-cost portfolio.« less

Photovoltaics as a terrestrial energy source. Volume 1: An introduction

NASA Technical Reports Server (NTRS)

Smith, J. L.

1980-01-01

Photovoltaic (PV) systems were examined their potential for terrestrial application and future development. Photovoltaic technology, existing and potential photovoltaic applications, and the National Photovoltaics Program are reviewed. The competitive environment for this electrical source, affected by the presence or absence of utility supplied power is evaluated in term of systems prices. The roles of technological breakthroughs, directed research and technology development, learning curves, and commercial demonstrations in the National Program are discussed. The potential for photovoltaics to displace oil consumption is examined, as are the potential benefits of employing PV in either central-station or non-utility owned, small, distributed systems.

Data Transparency | Distributed Generation Interconnection Collaborative |

Science.gov Websites

quality and availability are increasingly vital for reducing the costs of distributed generation completion in certain areas, increasing accountability for utility application processing. As distributed PV NREL, HECO, TSRG Improving Data Transparency for the Distributed PV Interconnection Process: Emergent

Distributed photovoltaic system impact upon utility load/supply management practices

NASA Astrophysics Data System (ADS)

Vachtsevanos, G. J.; Meliopoulos, A. P.; Paraskevopoulos, B. K.

A methodology is described for simulation of the economic and technical factors of photovoltaic (PV) installations interfacing with utility load/management operations. A probabalistic technique is used to model the expected demand, reliability of the generating units, costs and profits from each unit, expected unserviced energy, and the loss of load probability. The available power from PV arrays is treated stochastically with statistical weighting on the basis of site meteorological data. The goal is to include the PV power while minimizing operational costs, taking into account the level of penetration of the total PV output. Two sample simulations for a utility with a diverse generating mix demonstrate that overall costs would decrease in both cases with PVs on-line through the emphasis on cheaper-fueled generators and peak-load shaving when possible.

Advanced, Cost-Based Indices for Forecasting the Generation of Photovoltaic Power

NASA Astrophysics Data System (ADS)

Bracale, Antonio; Carpinelli, Guido; Di Fazio, Annarita; Khormali, Shahab

2014-01-01

Distribution systems are undergoing significant changes as they evolve toward the grids of the future, which are known as smart grids (SGs). The perspective of SGs is to facilitate large-scale penetration of distributed generation using renewable energy sources (RESs), encourage the efficient use of energy, reduce systems' losses, and improve the quality of power. Photovoltaic (PV) systems have become one of the most promising RESs due to the expected cost reduction and the increased efficiency of PV panels and interfacing converters. The ability to forecast power-production information accurately and reliably is of primary importance for the appropriate management of an SG and for making decisions relative to the energy market. Several forecasting methods have been proposed, and many indices have been used to quantify the accuracy of the forecasts of PV power production. Unfortunately, the indices that have been used have deficiencies and usually do not directly account for the economic consequences of forecasting errors in the framework of liberalized electricity markets. In this paper, advanced, more accurate indices are proposed that account directly for the economic consequences of forecasting errors. The proposed indices also were compared to the most frequently used indices in order to demonstrate their different, improved capability. The comparisons were based on the results obtained using a forecasting method based on an artificial neural network. This method was chosen because it was deemed to be one of the most promising methods available due to its capability for forecasting PV power. Numerical applications also are presented that considered an actual PV plant to provide evidence of the forecasting performances of all of the indices that were considered.

A sensor-less LED dimming system based on daylight harvesting with BIPV systems.

PubMed

Yoo, Seunghwan; Kim, Jonghun; Jang, Cheol-Yong; Jeong, Hakgeun

2014-01-13

Artificial lighting in office buildings typically requires 30% of the total energy consumption of the building, providing a substantial opportunity for energy savings. To reduce the energy consumed by indoor lighting, we propose a sensor-less light-emitting diode (LED) dimming system using daylight harvesting. In this study, we used light simulation software to quantify and visualize daylight, and analyzed the correlation between photovoltaic (PV) power generation and indoor illumination in an office with an integrated PV system. In addition, we calculated the distribution of daylight illumination into the office and dimming ratios for the individual control of LED lights. Also, we were able directly to use the electric power generated by PV system. As a result, power consumption for electric lighting was reduced by 40 - 70% depending on the season and the weather conditions. Thus, the dimming system proposed in this study can be used to control electric lighting to reduce energy use cost-effectively and simply.

On the Path to SunShot. Utility Regulatory and Business Model Reforms for Addressing the Financial Impacts of Distributed Solar on Utilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbose, Galen; Miller, John; Sigrin, Ben

Net-energy metering (NEM) has helped drive the rapid growth of distributed PV (DPV) but has raised concerns about electricity cost shifts, utility financial losses, and inefficient resource allocation. These concerns have motivated real and proposed reforms to utility regulatory and business models. This report explores the challenges and opportunities associated with such reforms in the context of the U.S. Department of Energy's SunShot Initiative. Most of the reforms to date address NEM concerns by reducing the benefits provided to DPV customers and thus constraining DPV deployment. Eliminating NEM nationwide, by compensating exports of PV electricity at wholesale rather than retailmore » rates, could cut cumulative DPV deployment by 20% in 2050 compared with a continuation of current policies. This would slow the PV cost reductions that arise from larger scale and market certainty. It could also thwart achievement of the SunShot deployment goals even if the initiative's cost targets are achieved. This undesirable prospect is stimulating the development of alternative reform strategies that address concerns about distributed PV compensation without inordinately harming PV economics and growth. These alternatives fall into the categories of facilitating higher-value DPV deployment, broadening customer access to solar, and aligning utility profits and earnings with DPV. Specific strategies include utility ownership and financing of DPV, community solar, distribution network operators, services-driven utilities, performance-based incentives, enhanced utility system planning, pricing structures that incentivize high-value DPV configurations, and decoupling and other ratemaking reforms that reduce regulatory lag. These approaches represent near- and long-term solutions for preserving the legacy of the SunShot Initiative.« less

Was it worthwhile? Where have the benefits of rooftop solar photovoltaic generation exceeded the cost?

NASA Astrophysics Data System (ADS)

Vaishnav, Parth; Horner, Nathaniel; Azevedo, Inês L.

2017-09-01

We estimate the lifetime magnitude and distribution of the private and public benefits and costs of currently installed distributed solar PV systems in the United States. Using data for recently-installed systems, we estimate the balance of benefits and costs associated with installing a non-utility solar PV system today. We also study the geographical distribution of the various subsidies that are made available to owners of rooftop solar PV systems, and compare it to distributions of population and income. We find that, after accounting for federal subsidies and local rebates and assuming a discount rate of 7%, the private benefits of new installations will exceed private costs only in seven of the 19 states for which we have data and only if customers can sell excess power to the electric grid at the retail price. These states are characterized by abundant sunshine (California, Texas and Nevada) or by high electricity prices (New York). Public benefits from reduced air pollution and climate change impact exceed the costs of the various subsidies offered system owners for less than 10% of the systems installed, even assuming a 2% discount rate. Subsidies flowed disproportionately to counties with higher median incomes in 2006. In 2014, the distribution of subsidies was closer to that of population income, but subsidies still flowed disproportionately to the better-off. The total, upfront, subsidy per kilowatt of installed capacity has fallen from 5200 in 2006 to 1400 in 2014, but the absolute magnitude of subsidy has soared as installed capacity has grown explosively. We see considerable differences in the balance of costs and benefits even within states, indicating that local factors such as system price and solar resource are important, and that policies (e.g. net metering) could be made more efficient by taking local conditions into account.

Wall shear stress in portal vein of cirrhotic patients with portal hypertension.

PubMed

Wei, Wei; Pu, Yan-Song; Wang, Xin-Kai; Jiang, An; Zhou, Rui; Li, Yu; Zhang, Qiu-Juan; Wei, Ya-Juan; Chen, Bin; Li, Zong-Fang

2017-05-14

To investigate wall shear stress (WSS) magnitude and distribution in cirrhotic patients with portal hypertension using computational fluid dynamics. Idealized portal vein (PV) system models were reconstructed with different angles of the PV-splenic vein (SV) and superior mesenteric vein (SMV)-SV. Patient-specific models were created according to enhanced computed tomography images. WSS was simulated by using a finite-element analyzer, regarding the blood as a Newtonian fluid and the vessel as a rigid wall. Analysis was carried out to compare the WSS in the portal hypertension group with that in healthy controls. For the idealized models, WSS in the portal hypertension group (0-10 dyn/cm 2 ) was significantly lower than that in the healthy controls (10-20 dyn/cm 2 ), and low WSS area (0-1 dyn/cm 2 ) only occurred in the left wall of the PV in the portal hypertension group. Different angles of PV-SV and SMV-SV had different effects on the magnitude and distribution of WSS, and low WSS area often occurred in smaller PV-SV angle and larger SMV-SV angle. In the patient-specific models, WSS in the cirrhotic patients with portal hypertension (10.13 ± 1.34 dyn/cm 2 ) was also significantly lower than that in the healthy controls ( P < 0.05). Low WSS area often occurred in the junction area of SV and SMV into the PV, in the area of the division of PV into left and right PV, and in the outer wall of the curving SV in the control group. In the cirrhotic patients with portal hypertension, the low WSS area extended to wider levels and the magnitude of WSS reached lower levels, thereby being more prone to disturbed flow occurrence. Cirrhotic patients with portal hypertension show dramatic hemodynamic changes with lower WSS and greater potential for disturbed flow, representing a possible causative factor of PV thrombosis.

Wall shear stress in portal vein of cirrhotic patients with portal hypertension

PubMed Central

Wei, Wei; Pu, Yan-Song; Wang, Xin-Kai; Jiang, An; Zhou, Rui; Li, Yu; Zhang, Qiu-Juan; Wei, Ya-Juan; Chen, Bin; Li, Zong-Fang

2017-01-01

AIM To investigate wall shear stress (WSS) magnitude and distribution in cirrhotic patients with portal hypertension using computational fluid dynamics. METHODS Idealized portal vein (PV) system models were reconstructed with different angles of the PV-splenic vein (SV) and superior mesenteric vein (SMV)-SV. Patient-specific models were created according to enhanced computed tomography images. WSS was simulated by using a finite-element analyzer, regarding the blood as a Newtonian fluid and the vessel as a rigid wall. Analysis was carried out to compare the WSS in the portal hypertension group with that in healthy controls. RESULTS For the idealized models, WSS in the portal hypertension group (0-10 dyn/cm2) was significantly lower than that in the healthy controls (10-20 dyn/cm2), and low WSS area (0-1 dyn/cm2) only occurred in the left wall of the PV in the portal hypertension group. Different angles of PV-SV and SMV-SV had different effects on the magnitude and distribution of WSS, and low WSS area often occurred in smaller PV-SV angle and larger SMV-SV angle. In the patient-specific models, WSS in the cirrhotic patients with portal hypertension (10.13 ± 1.34 dyn/cm2) was also significantly lower than that in the healthy controls (P < 0.05). Low WSS area often occurred in the junction area of SV and SMV into the PV, in the area of the division of PV into left and right PV, and in the outer wall of the curving SV in the control group. In the cirrhotic patients with portal hypertension, the low WSS area extended to wider levels and the magnitude of WSS reached lower levels, thereby being more prone to disturbed flow occurrence. CONCLUSION Cirrhotic patients with portal hypertension show dramatic hemodynamic changes with lower WSS and greater potential for disturbed flow, representing a possible causative factor of PV thrombosis. PMID:28566887

Power Budget Analysis for High Altitude Airships

NASA Technical Reports Server (NTRS)

Choi, Sang H.; Elliott, James R.; King, Glen C.

2006-01-01

The High Altitude Airship (HAA) has various potential applications and mission scenarios that require onboard energy harvesting and power distribution systems. The energy source considered for the HAA s power budget is solar photon energy that allows the use of either photovoltaic (PV) cells or advanced thermoelectric (ATE) converters. Both PV cells and an ATE system utilizing high performance thermoelectric materials were briefly compared to identify the advantages of ATE for HAA applications in this study. The ATE can generate a higher quantity of harvested energy than PV cells by utilizing the cascaded efficiency of a three-staged ATE in a tandem mode configuration. Assuming that each stage of ATE material has the figure of merit of 5, the cascaded efficiency of a three-staged ATE system approaches the overall conversion efficiency greater than 60%. Based on this estimated efficiency, the configuration of a HAA and the power utility modules are defined.

Performance comparison investigation on solar photovoltaic-thermoelectric generation and solar photovoltaic-thermoelectric cooling hybrid systems under different conditions

NASA Astrophysics Data System (ADS)

Wu, Shuang-Ying; Zhang, Yi-Chen; Xiao, Lan; Shen, Zu-Guo

2018-07-01

The performance of solar photovoltaic-thermoelectric generation hybrid system (PV-TGS) and solar photovoltaic-thermoelectric cooling hybrid system (PV-TCS) under different conditions were theoretically analysed and compared. To test the practicality of these two hybrid systems, the performance of stand-alone PV system was also studied. The results show that PV-TGS and PV-TCS in most cases will result in the system with a better performance than stand-alone PV system. The advantage of PV-TGS is emphasised in total output power and conversion efficiency which is even poorer in PV-TCS than that in stand-alone PV system at the ambient wind speed uw being below 3 m/s. However, PV-TCS has obvious advantage on lowering the temperature of PV cell. There is an obvious increase in tendency on the performance of PV-TGS and PV-TCS when the cooling capacity of two hybrid systems varies from around 0.06 to 0.3 W/K. And it is also proved that not just a-Si in PV-TGS can produce a better performance than the stand-alone PV system alone at most cases.

Distributed Storage Inverter and Legacy Generator Integration Plus Renewable Solution for Microgrids

DTIC Science & Technology

2015-07-01

24 6.6 DEMONSTRATION 6: PV + STORAGE SUPPORT MANAGING VARIABLE SOLAR ...Table 2. Energy generated by solar PV for 1 month. .......................................................... 23 Table 3. NG generators energy...saving with solar PV . ........................................................ 24 Table 4. NG generators fuel saving with solar PV

Electric Transport Traction Power Supply System With Distributed Energy Sources

NASA Astrophysics Data System (ADS)

Abramov, E. Y.; Schurov, N. I.; Rozhkova, M. V.

2016-04-01

The paper states the problem of traction substation (TSS) leveling of daily-load curve for urban electric transport. The circuit of traction power supply system (TPSS) with distributed autonomous energy source (AES) based on photovoltaic (PV) and energy storage (ES) units is submitted here. The distribution algorithm of power flow for the daily traction load curve leveling is also introduced in this paper. In addition, it illustrates the implemented experiment model of power supply system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cory, K.; Coughlin, J.; Coggeshall, C.

State and local governments have grown increasingly aware of the economic, environmental, and societal benefits of taking a lead role in U.S. implementation of renewable energy, particularly distributed photovoltaic (PV) installations. Recently, solar energy's cost premium has declined as a result of technology improvements and an increase in the cost of traditional energy generation. At the same time, a nationwide public policy focus on carbon-free, renewable energy has created a wide range of financial incentives to lower the costs of deploying PV even further. These changes have led to exponential increases in the availability of capital for solar projects, andmore » tremendous creativity in the development of third-party ownership structures. As significant users of electricity, state and local governments can be an excellent example for solar PV system deployment on a national scale. Many public entities are not only considering deployment on public building rooftops, but also large-scale applications on available public lands. The changing marketplace requires that state and local governments be financially sophisticated to capture as much of the economic potential of a PV system as possible. This report examines ways that state and local governments can optimize the financial structure of deploying solar PV for public uses.« less

Using CAD software to simulate PV energy yield - The case of product integrated photovoltaic operated under indoor solar irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reich, N.H.; van Sark, W.G.J.H.M.; Turkenburg, W.C.

2010-08-15

In this paper, we show that photovoltaic (PV) energy yields can be simulated using standard rendering and ray-tracing features of Computer Aided Design (CAD) software. To this end, three-dimensional (3-D) sceneries are ray-traced in CAD. The PV power output is then modeled by translating irradiance intensity data of rendered images back into numerical data. To ensure accurate results, the solar irradiation data used as input is compared to numerical data obtained from rendered images, showing excellent agreement. As expected, also ray-tracing precision in the CAD software proves to be very high. To demonstrate PV energy yield simulations using this innovativemore » concept, solar radiation time course data of a few days was modeled in 3-D to simulate distributions of irradiance incident on flat, single- and double-bend shapes and a PV powered computer mouse located on a window sill. Comparisons of measured to simulated PV output of the mouse show that also in practice, simulation accuracies can be very high. Theoretically, this concept has great potential, as it can be adapted to suit a wide range of solar energy applications, such as sun-tracking and concentrator systems, Building Integrated PV (BIPV) or Product Integrated PV (PIPV). However, graphical user interfaces of 'CAD-PV' software tools are not yet available. (author)« less

Experiences of a grid connected solar array energy production

NASA Astrophysics Data System (ADS)

Hagymássy, Zoltán; Vántus, András

2015-04-01

Solar energy possibilities of Hungary are higher than in Central Europe generally. The Institute for Land Utilisation, Technology and Regional Development of the University of Debrecen installed a photovoltaic (PV) system. The PV system is structured into 3 subsystems (fields). The first subsystem has 24 pieces of Kyocera KC 120 W type modules, the second subsystem has 72 pieces of Siemens ST 40W, and the remaining has 72 pieces of Dunasolar DS 40W In order to be operable independently of each other three inverter modules (SB 2500) had been installed. The recorder can be connected directly to a desktop PC. Operating and meteorological dates are recorded by MS Excel every 15 minutes. The power plant is connected to a weather station, which contents a PT 100 type temperature and humidity combined measuring instrument, a CM 11 pyranometer, and a wind speed measuring instrument. The produced DC, and AC power, together with the produced energy are as well, and the efficiency can be determined for each used PV technology. The measured operating and meteorological dates are collected by Sunny Boy Control, produced by the SMA. The energy productions of the subsystems are measured continually and the subsystems are measured separately. As an expected, the produced energy of polycrystalline -Si PV module and monocrystalline -Si PV was higher than amorphous-Si PV module. It is well known that energy analysis is more suitable for energy balance when we design a system. The air temperature and the temperature of the panels and the global irradiation conditions were measured. In summertime the panel temperature reaches 60-80 degrees in a sunny day. The panel temperatures are in a spring sunny day approximately 30-40 degrees. It can be concluded that the global irradiation is a major impact feature to influence the amount of energy produced. The efficiency depends on several parameters (spectral distribution of the incoming light, temperature values, etc.). The energy efficiency of a PV system in general can be defined as the ratio of the output energy of the system to the input energy received on the photovoltaic surface. As an expected, the energy efficiencies of polycrystalline -Si PV module and monocrystalline -Si PV was higher than amorphous-Si PV module. Based on our study, in general it can be concluded that the energy efficiency is lower than theoretical.

Statistical Analysis of Solar PV Power Frequency Spectrum for Optimal Employment of Building Loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olama, Mohammed M; Sharma, Isha; Kuruganti, Teja

In this paper, a statistical analysis of the frequency spectrum of solar photovoltaic (PV) power output is conducted. This analysis quantifies the frequency content that can be used for purposes such as developing optimal employment of building loads and distributed energy resources. One year of solar PV power output data was collected and analyzed using one-second resolution to find ideal bounds and levels for the different frequency components. The annual, seasonal, and monthly statistics of the PV frequency content are computed and illustrated in boxplot format. To examine the compatibility of building loads for PV consumption, a spectral analysis ofmore » building loads such as Heating, Ventilation and Air-Conditioning (HVAC) units and water heaters was performed. This defined the bandwidth over which these devices can operate. Results show that nearly all of the PV output (about 98%) is contained within frequencies lower than 1 mHz (equivalent to ~15 min), which is compatible for consumption with local building loads such as HVAC units and water heaters. Medium frequencies in the range of ~15 min to ~1 min are likely to be suitable for consumption by fan equipment of variable air volume HVAC systems that have time constants in the range of few seconds to few minutes. This study indicates that most of the PV generation can be consumed by building loads with the help of proper control strategies, thereby reducing impact on the grid and the size of storage systems.« less

GridPV Toolbox

DOE Office of Scientific and Technical Information (OSTI.GOV)

Broderick, Robert; Quiroz, Jimmy; Grijalva, Santiago

2014-07-15

Matlab Toolbox for simulating the impact of solar energy on the distribution grid. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving GridPV Toolbox information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Ardani, Kristen; Cutler, Dylan

Solar 'plus' refers to an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize customer economics. The solar plus approach increases customer system value through technologies such as electric batteries, smart domestic water heaters, smart air-conditioner (AC) units, and electric vehicles We use an NREL optimization model to explore the customer-side economics of solar plus under various utility rate structures and net metering rates. We explore optimal solar plus applications in five case studies with different net metering rates and rate structures. The model deploys different configurations of PV, batteries, smart domesticmore » water heaters, and smart AC units in response to different rate structures and customer load profiles. The results indicate that solar plus improves the customer economics of PV and may mitigate some of the negative impacts of evolving rate structures on PV economics. Solar plus may become an increasingly viable model for optimizing PV customer economics in an evolving rate environment.« less

Reliability of hybrid photovoltaic DC micro-grid systems for emergency shelters and other applications

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.; Schleith, Susan

2014-10-01

Improvement of energy efficiency in the SunSmart Schools Emergency Shelters requires new methods for optimizing the energy consumption within the shelters. One major limitation in current systems is the requirement of converting direct current (DC) power generated from the PV array into alternating current (AC) power which is distributed throughout the shelters. Oftentimes, this AC power is then converted back to DC to run certain appliances throughout the shelters resulting in a significant waste of energy due to DC to AC and then again AC to DC conversion. This paper seeks to extract the maximum value out of PV systems by directly powering essential load components within the shelters that already run on DC power without the use of an inverter and above all to make the system reliable and durable. Furthermore, additional DC applications such as LED lighting, televisions, computers and fans operated with DC brushless motors will be installed as replacements to traditional devices in order to improve efficiency and reduce energy consumption. Cost of energy storage technologies continue to decline as new technologies scale up and new incentives are put in place. This will provide a cost effective way to stabilize the energy generation of a PV system as well as to provide continuous energy during night hours. It is planned to develop a pilot program of an integrated system that can provide uninterrupted DC power to essential base load appliances (heating, cooling, lighting, etc.) at the Florida Solar Energy Center (FSEC) command center for disaster management. PV arrays are proposed to be installed on energy efficient test houses at FSEC as well as at private homes having PV arrays where the owners volunteer to participate in the program. It is also planned to monitor the performance of the PV arrays and functioning of the appliances with the aim to improve their reliability and durability. After a successful demonstration of the hybrid DC microgrid based emergency shelter together with the monitoring system, it is planned to replicate it at other schools in Florida and elsewhere to provide continuous power for essential applications, maximizing the value of PV generation systems.

Publications | Energy Systems Integration Facility | NREL

Science.gov Websites

100% Renewable Grid: Operating Electric Power Systems with Extremely High Levels of Variable Renewable timeline. Feeder Voltage Regulation with High-Penetration PV Using Advanced Inverters and a Distribution Integrating High Levels of Variable Renewable Energy into Electric Power Systems, Journal of Modern Power

Distributed photovoltaic systems - Addressing the utility interface issues

NASA Astrophysics Data System (ADS)

Firstman, S. I.; Vachtsevanos, G. J.

This paper reviews work conducted in the United States on the impact of dispersed photovoltaic sources upon utility operations. The photovoltaic (PV) arrays are roof-mounted on residential houses and connected, via appropriate power conditioning equipment, to the utility grid. The presence of such small (4-6 Kw) dispersed generators on the distribution network raises questions of a technical, economic and institutional nature. After a brief identification of utility interface issues, the paper addresses such technical concerns as protection of equipment and personnel safety, power quality and utility operational stability. A combination of experimental and analytical approaches has been adopted to arrive at solutions to these problems. Problem areas, under various PV system penetration scenarios, are identified and conceptual designs of protection and control equipment and operating policies are developed so that system reliability is maintained while minimizing capital costs. It is hoped that the resolution of balance-of-system and grid interface questions will ascertain the economic viability of photovoltaic systems and assist in their widespread utilization in the future.

Photovoltaic Hosting Capacity of Feeders with Reactive Power Control and Tap Changers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceylan, Oğuzhan; Paudyal, Sumit; Bhattarai, Bishnu P.

This paper proposes an algorithm to determine photovoltaic (PV) hosting capacity of power distribution networks as a function of number of PV injection nodes, reactive power support from the PVs, and the sub-station load tap changers (LTCs). In the proposed method, several minute by minute simulations are run based on randomly chosen PV injection nodes, daily PV output profiles, and daily load profiles from a pool of high-resolution realistic data set. The simulation setup is built using OpenDSS and MATLAB. The performance of the proposed method is investigated in the IEEE 123-node distribution feeder for multiple scenarios. The case studiesmore » are performed particularly for one, two, five and ten PV injection nodes, and looking at the maximum voltage deviations. Case studies show that the PV hosting capacity of the 123-node feeder greatly differs with the number of PV injection nodes. We have also observed that the PV hosting capacity increases with reactive power support and higher tap position of sub-station LTC.« less

The possibility of developing hybrid PV/T solar system

NASA Astrophysics Data System (ADS)

Dobrnjac, M.; Zivkovic, P.; Babic, V.

2017-05-01

An alternative and cost-effective solution to developing integrated PV system is to use hybrid photovoltaic/thermal (PV/T) solar system. The temperature of PV modules increases due to the absorbed solar radiation that is not converted into electricity, causing a decrease in their efficiency. In hybrid PV/T solar systems the reduction of PV module temperature can be combined with a useful fluid heating. In this paper we present the possibility of developing a new hybrid PV/T solar system. Hybrid PV/T system can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We developed PV/T prototype consisted of commercial PV module and thermal panel with our original solution of aluminium absorber with special geometric shapes. The main advantages of our combined PV/T system are: removing of heat from the PV panel; extending the lifetime of photovoltaic cells; excess of the removing heat from PV part is used to heat the fluid in the thermal part of the panel; the possibility of using on the roof and facade constructions because less weight.

Golden Rays - July 2017 | Solar Research | Solar Research | NREL

Science.gov Websites

Operator, First Solar, and NREL tested a 300-MW PV plant to demonstrate that, with proper controls, PV can technique to measure charge-carrier transport in PV materials. Solar Plus: A Holistic Approach to Distribution Solar PV By optimizing how PV interacts with other electricity loads at the household- and grid

Coordinated Optimization of Distributed Energy Resources and Smart Loads in Distribution Systems: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Rui; Zhang, Yingchen

2016-08-01

Distributed energy resources (DERs) and smart loads have the potential to provide flexibility to the distribution system operation. A coordinated optimization approach is proposed in this paper to actively manage DERs and smart loads in distribution systems to achieve the optimal operation status. A three-phase unbalanced Optimal Power Flow (OPF) problem is developed to determine the output from DERs and smart loads with respect to the system operator's control objective. This paper focuses on coordinating PV systems and smart loads to improve the overall voltage profile in distribution systems. Simulations have been carried out in a 12-bus distribution feeder andmore » results illustrate the superior control performance of the proposed approach.« less

Coordinated Optimization of Distributed Energy Resources and Smart Loads in Distribution Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Rui; Zhang, Yingchen

2016-11-14

Distributed energy resources (DERs) and smart loads have the potential to provide flexibility to the distribution system operation. A coordinated optimization approach is proposed in this paper to actively manage DERs and smart loads in distribution systems to achieve the optimal operation status. A three-phase unbalanced Optimal Power Flow (OPF) problem is developed to determine the output from DERs and smart loads with respect to the system operator's control objective. This paper focuses on coordinating PV systems and smart loads to improve the overall voltage profile in distribution systems. Simulations have been carried out in a 12-bus distribution feeder andmore » results illustrate the superior control performance of the proposed approach.« less

Smart PV grid to reinforce the electrical network

NASA Astrophysics Data System (ADS)

AL-Hamad, Mohamed Y.; Qamber, Isa S.

2017-11-01

Photovoltaic (PV) became the new competitive energy resources of the planet and needs to be engaged in grid to break up the congestion in both Distribution and Transmission systems. The objective of this research is to reduce the load flow through the distribution and transmission equipment by 20%. This reduction will help in relief networks loaded equipment's in all networks. Many projects are starting to develop in the GCC countries and need to be organized to achieve maximum benefits from involving the Renewable Energy Sources (RES) in the network. The GCC countries have a good location for solar energy with high intensity of the solar radiation and clear sky along the year. The opportunities of the solar energy is to utilize and create a sustainable energy resource for this region. Moreover, the target of this research is to engage the PV technology in such a way to lower the over loaded equipment and increases the electricity demand at the consumer's side.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelekis, Alexios, E-mail: akelekis@med.uoa.gr; Filippiadis, Dimitrios K., E-mail: dfilippiadis@yahoo.gr; Vergadis, Chrysovalantis, E-mail: valvergadis@yahoo.gr

PurposeThrough a prospective comparison of patients with vertebral fractures and normal population, we illustrate effect of percutaneous vertebroplasty (PV) upon projection of load distribution changes.MethodsVertebroplasty group (36 symptomatic patients with osteoporotic vertebral fractures) was evaluated on an electronic baropodometer registering projection of weight bearing areas on feet. Load distribution between right and left foot (including rear-front of the same foot) during standing and walking was recorded and compared before (group V1) and the day after (group V2) PV. Control group (30 healthy asymptomatic volunteers-no surgery record) were evaluated on the same baropodometer.ResultsMean value of load distribution difference between rear-front ofmore » the same foot was 9.45 ± 6.79 % (54.72–45.28 %) upon standing and 14.76 ± 7.09 % (57.38–42.62 %) upon walking in the control group. Respective load distribution values before PV were 16.52 ± 11.23 and 30.91 ± 19.26 % and after PV were 10.08 ± 6.26 and 14.25 ± 7.68 % upon standing and walking respectively. Mean value of load distribution variation between the two feet was 6.36 and 14.6 % before and 4.62 and 10.4 % after PV upon standing and walking respectively. Comparison of load distribution variation (group V1–V2, group V1-control group) is statistically significant. Comparison of load distribution variation (group V2-control group) is not statistically significant. Comparison of load distribution variation among the two feet is statistically significant during walking but not statistically significant during standing.ConclusionsThere is a statistically significant difference when comparing load distribution variation prior vertebroplasty and that of normal population. After vertebroplasty, this difference normalizes in a statistically significant way. PV is efficient on equilibrium-load distribution improvement as well.« less

Development of a digital solar simulator based on full-bridge converter

NASA Astrophysics Data System (ADS)

Liu, Chen; Feng, Jian; Liu, Zhilong; Tong, Weichao; Ji, Yibo

2014-02-01

With the development of solar photovoltaic, distribution schemes utilized in power grid had been commonly application, and photovoltaic (PV) inverter is an essential equipment in grid. In this paper, a digital solar simulator based on full-bridge structure is presented. The output characteristic curve of system is electrically similar to silicon solar cells, which can greatly simplify research methods of PV inverter, improve the efficiency of research and development. The proposed simulator consists on a main control board based on TM320F28335, phase-shifted zero-voltage-switching (ZVS) DC-DC full-bridge converter and voltage and current sampling circuit, that allows emulating the voltage-current curve with the open-circuit voltage (Voc) of 900V and the short-circuit current (Isc) of 18A .When the system connected to a PV inverter, the inverter can quickly track from the open-circuit to the maximum power point and keep stability.

Temporal Decompostion of a Distribution System Quasi-Static Time-Series Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mather, Barry A; Hunsberger, Randolph J

This paper documents the first phase of an investigation into reducing runtimes of complex OpenDSS models through parallelization. As the method seems promising, future work will quantify - and further mitigate - errors arising from this process. In this initial report, we demonstrate how, through the use of temporal decomposition, the run times of a complex distribution-system-level quasi-static time series simulation can be reduced roughly proportional to the level of parallelization. Using this method, the monolithic model runtime of 51 hours was reduced to a minimum of about 90 minutes. As expected, this comes at the expense of control- andmore » voltage-errors at the time-slice boundaries. All evaluations were performed using a real distribution circuit model with the addition of 50 PV systems - representing a mock complex PV impact study. We are able to reduce induced transition errors through the addition of controls initialization, though small errors persist. The time savings with parallelization are so significant that we feel additional investigation to reduce control errors is warranted.« less

Compensation for Distributed Solar. A Survey of Options to Preserve Stakeholder Value

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flores-Espino, Francisco

2015-09-01

Compensation mechanisms for electricity generation systems installed behind the meter are under scrutiny in several jurisdictions in the United States. Legislators in 29 states introduced bills to amend net metering provisions in 2014, and in 33 states in the 2015 legislative session as of August 20, 2015. Some utilities have also sought to increase the revenue they receive from net-metered customers through rate redesign. The circumstances that have triggered the recent push for change include a growing percentage of net-metered customers, potential effects of distributed generation on cost allocation, decreasing photovoltaic (PV) system costs, the challenges of integrating high levelsmore » of solar generation in the distribution network, and increasing pressure on utility business models. This report presents a survey of options to charge and compensate PV customers, as well as options that may preserve utility revenues in scenarios with increased DG. These options could be used as building blocks to create a distributed generation (DG) compensation policy that may preserve the value of the different stakeholders and balance their interests.« less

Advanced Energy Storage Management in Distribution Network

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Guodong; Ceylan, Oguzhan; Xiao, Bailu

2016-01-01

With increasing penetration of distributed generation (DG) in the distribution networks (DN), the secure and optimal operation of DN has become an important concern. In this paper, an iterative mixed integer quadratic constrained quadratic programming model to optimize the operation of a three phase unbalanced distribution system with high penetration of Photovoltaic (PV) panels, DG and energy storage (ES) is developed. The proposed model minimizes not only the operating cost, including fuel cost and purchasing cost, but also voltage deviations and power loss. The optimization model is based on the linearized sensitivity coefficients between state variables (e.g., node voltages) andmore » control variables (e.g., real and reactive power injections of DG and ES). To avoid slow convergence when close to the optimum, a golden search method is introduced to control the step size and accelerate the convergence. The proposed algorithm is demonstrated on modified IEEE 13 nodes test feeders with multiple PV panels, DG and ES. Numerical simulation results validate the proposed algorithm. Various scenarios of system configuration are studied and some critical findings are concluded.« less

An approach for the estimation of the aggregated photovoltaic power generated in several European countries from meteorological data

NASA Astrophysics Data System (ADS)

Saint-Drenan, Yves-Marie; Wald, Lucien; Ranchin, Thierry; Dubus, Laurent; Troccoli, Alberto

2018-05-01

Classical approaches to the calculation of the photovoltaic (PV) power generated in a region from meteorological data require the knowledge of the detailed characteristics of the plants, which are most often not publicly available. An approach is proposed with the objective to obtain the best possible assessment of power generated in any region without having to collect detailed information on PV plants. The proposed approach is based on a model of PV plant coupled with a statistical distribution of the prominent characteristics of the configuration of the plant and is tested over Europe. The generated PV power is first calculated for each of the plant configurations frequently found in a given region and then aggregated taking into account the probability of occurrence of each configuration. A statistical distribution has been constructed from detailed information obtained for several thousands of PV plants representing approximately 2 % of the total number of PV plants in Germany and was then adapted to other European countries by taking into account changes in the optimal PV tilt angle as a function of the latitude and meteorological conditions. The model has been run with bias-adjusted ERA-interim data as meteorological inputs. The results have been compared to estimates of the total PV power generated in two countries: France and Germany, as provided by the corresponding transmission system operators. Relative RMSE of 4.2 and 3.8 % and relative biases of -2.4 and 0.1 % were found with three-hourly data for France and Germany. A validation against estimates of the country-wide PV-power generation provided by the ENTSO-E for 16 European countries has also been conducted. This evaluation is made difficult by the uncertainty on the installed capacity corresponding to the ENTSO-E data but it nevertheless allows demonstrating that the model output and TSO data are highly correlated in most countries. Given the simplicity of the proposed approach these results are very encouraging. The approach is particularly suited to climatic timescales, both historical and future climates, as demonstrated here.

A Fundamental Study on Spectrum Center Estimation of Solar Spectral Irradiation by the Statistical Pattern Recognition

NASA Astrophysics Data System (ADS)

Iijima, Aya; Suzuki, Kazumi; Wakao, Shinji; Kawasaki, Norihiro; Usami, Akira

With a background of environmental problems and energy issues, it is expected that PV systems will be introduced rapidly and connected with power grids on a large scale in the future. For this reason, the concern to which PV power generation will affect supply and demand adjustment in electric power in the future arises and the technique of correctly grasping the PV power generation becomes increasingly important. The PV power generation depends on solar irradiance, temperature of a module and solar spectral irradiance. Solar spectral irradiance is distribution of the strength of the light for every wavelength. As the spectrum sensitivity of solar cell depends on kind of solar cell, it becomes important for exact grasp of PV power generation. Especially the preparation of solar spectral irradiance is, however, not easy because the observational instrument of solar spectral irradiance is expensive. With this background, in this paper, we propose a new method based on statistical pattern recognition for estimating the spectrum center which is representative index of solar spectral irradiance. Some numerical examples obtained by the proposed method are also presented.

Heat Transfer Modelling of Glass Media within TPV Systems

NASA Astrophysics Data System (ADS)

Bauer, Thomas; Forbes, Ian; Penlington, Roger; Pearsall, Nicola

2004-11-01

Understanding and optimisation of heat transfer, and in particular radiative heat transfer in terms of spectral, angular and spatial radiation distributions is important to achieve high system efficiencies and high electrical power densities for thermophtovoltaics (TPV). This work reviews heat transfer models and uses the Discrete Ordinates method. Firstly one-dimensional heat transfer in fused silica (quartz glass) shields was examined for the common arrangement, radiator-air-glass-air-PV cell. It has been concluded that an alternative arrangement radiator-glass-air-PV cell with increased thickness of fused silica should have advantages in terms of improved transmission of convertible radiation and enhanced suppression of non-convertible radiation.

Lessons learned from hybrid wind/PV village power system installations in Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergey, M.

1995-09-01

In the last three years eight decentralized village power systems utilizing small wind turbines as the primary energy source have been installed in rural Mexico. Hybrid wind/PV systems have been installed in five States and by three vendors. Seven out of the eight systems, which range i size from 9.3--71.2kW in combined wind and PV capacity, utilize one or more 10 kW wind turbines. All of these installations have battery banks and use static inverters to provide AC power for distribution to homes, businesses, and community facilities. On all but one of the systems a diesel generator is used tomore » provide back-up power. This paper attempts to summarize the range of costs and economics, performance, and operational experiences for all eight installations. Several of the systems are monitored for performance, including one that is extensively monitored under a cooperative program between the Instituto de Investigaciones Electricas and Sandia National Laboratory. Lessons learned from these systems provide insights that may allow future village power systems of this architecture to be installed at lower costs, to be operated more effectively and efficiently, and to be better able to satisfy customer requirements.« less

Comparison of three different methods of perturbing the potential vorticity field in mesoscale forecasts of Mediterranean heavy precipitation events: PV-gradient, PV-adjoint and PV-satellite

NASA Astrophysics Data System (ADS)

Vich, M.; Romero, R.; Richard, E.; Arbogast, P.; Maynard, K.

2010-09-01

Heavy precipitation events occur regularly in the western Mediterranean region. These events often have a high impact on the society due to economic and personal losses. The improvement of the mesoscale numerical forecasts of these events can be used to prevent or minimize their impact on the society. In previous studies, two ensemble prediction systems (EPSs) based on perturbing the model initial and boundary conditions were developed and tested for a collection of high-impact MEDEX cyclonic episodes. These EPSs perturb the initial and boundary potential vorticity (PV) field through a PV inversion algorithm. This technique ensures modifications of all the meteorological fields without compromising the mass-wind balance. One EPS introduces the perturbations along the zones of the three-dimensional PV structure presenting the local most intense values and gradients of the field (a semi-objective choice, PV-gradient), while the other perturbs the PV field over the MM5 adjoint model calculated sensitivity zones (an objective method, PV-adjoint). The PV perturbations are set from a PV error climatology (PVEC) that characterizes typical PV errors in the ECMWF forecasts, both in intensity and displacement. This intensity and displacement perturbation of the PV field is chosen randomly, while its location is given by the perturbation zones defined in each ensemble generation method. Encouraged by the good results obtained by these two EPSs that perturb the PV field, a new approach based on a manual perturbation of the PV field has been tested and compared with the previous results. This technique uses the satellite water vapor (WV) observations to guide the correction of initial PV structures. The correction of the PV field intents to improve the match between the PV distribution and the WV image, taking advantage of the relation between dark and bright features of WV images and PV anomalies, under some assumptions. Afterwards, the PV inversion algorithm is applied to run a forecast with the corresponding perturbed initial state (PV-satellite). The non hydrostatic MM5 mesoscale model has been used to run all forecasts. The simulations are performed for a two-day period with a 22.5 km resolution domain (Domain 1 in http://mm5forecasts.uib.es) nested in the ECMWF large-scale forecast fields. The MEDEX cyclone of 10 June 2000, also known as the Montserrat Case, is a suitable testbed to compare the performance of each ensemble and the PV-satellite method. This case is characterized by an Atlantic upper-level trough and low-level cold front which generated a stationary mesoscale cyclone over the Spanish Mediterranean coast, advecting warm and moist air toward Catalonia from the Mediterranean Sea. The consequences of the resulting mesoscale convective system were 6-h accumulated rainfall amounts of 180 mm with estimated material losses to exceed 65 million euros by media. The performace of both ensemble forecasting systems and PV-satellite technique for our case study is evaluated through the verification of the rainfall field. Since the EPSs are probabilistic forecasts and the PV-satellite is deterministic, their comparison is done using the individual ensemble members. Therefore the verification procedure uses deterministic scores, like the ROC curve, the Taylor diagram or the Q-Q plot. These scores cover the different quality attributes of the forecast such as reliability, resolution, uncertainty and sharpness. The results show that the PV-satellite technique performance lies within the performance range obtained by both ensembles; it is even better than the non-perturbed ensemble member. Thus, perturbing randomly using the PV error climatology and introducing the perturbations in the zones given by each EPS captures the mismatch between PV and WV fields better than manual perturbations made by an expert forecaster, at least for this case study.

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov Websites

share and use information. NREL received the award for work it conducted with EPRI to demonstrate the data for residents, appraisers, and investors. Recognizing this, Denver developer iUnit is working with the use of distributed energy resources such as PV rooftop systems. Such advancements in

Investigation of energy management strategies for photovoltaic systems - An analysis technique

NASA Technical Reports Server (NTRS)

Cull, R. C.; Eltimsahy, A. H.

1982-01-01

Progress is reported in formulating energy management strategies for stand-alone PV systems, developing an analytical tool that can be used to investigate these strategies, applying this tool to determine the proper control algorithms and control variables (controller inputs and outputs) for a range of applications, and quantifying the relative performance and economics when compared to systems that do not apply energy management. The analysis technique developed may be broadly applied to a variety of systems to determine the most appropriate energy management strategies, control variables and algorithms. The only inputs required are statistical distributions for stochastic energy inputs and outputs of the system and the system's device characteristics (efficiency and ratings). Although the formulation was originally driven by stand-alone PV system needs, the techniques are also applicable to hybrid and grid connected systems.

Investigation of energy management strategies for photovoltaic systems - An analysis technique

NASA Astrophysics Data System (ADS)

Cull, R. C.; Eltimsahy, A. H.

Progress is reported in formulating energy management strategies for stand-alone PV systems, developing an analytical tool that can be used to investigate these strategies, applying this tool to determine the proper control algorithms and control variables (controller inputs and outputs) for a range of applications, and quantifying the relative performance and economics when compared to systems that do not apply energy management. The analysis technique developed may be broadly applied to a variety of systems to determine the most appropriate energy management strategies, control variables and algorithms. The only inputs required are statistical distributions for stochastic energy inputs and outputs of the system and the system's device characteristics (efficiency and ratings). Although the formulation was originally driven by stand-alone PV system needs, the techniques are also applicable to hybrid and grid connected systems.

Overgeneration from Solar Energy in California. A Field Guide to the Duck Chart

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul; O'Connell, Matthew; Brinkman, Gregory

In 2013, the California Independent System Operator published the 'duck chart,' which shows a significant drop in mid-day net load on a spring day as solar photovoltaics (PV) are added to the system. The chart raises concerns that the conventional power system will be unable to accommodate the ramp rate and range needed to fully utilize solar energy, particularly on days characterized by the duck shape. This could result in 'overgeneration' and curtailed renewable energy, increasing its costs and reducing its environmental benefits. This paper explores the duck chart in detail, examining how much PV might need to be curtailedmore » if additional grid flexibility measures are not taken, and how curtailment rates can be decreased by changing grid operational practices. It finds that under "business-as-usual"" types of assumptions and corresponding levels of grid flexibility in California, solar penetrations as low as 20% of annual energy could lead to marginal curtailment rates that exceed 30%. However, by allowing (or requiring) distributed PV and storage (including new installations that are part of the California storage mandate) to provide grid services, system flexibility could be greatly enhanced. Doing so could significantly reduce curtailment and allow much greater penetration of variable generation resources. Overall, the work described in this paper points to the need to fully integrate distributed resources into grid system planning and operations to allow maximum use of the solar resource.« less

Overgeneration from Solar Energy in California - A Field Guide to the Duck Chart

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul; Brinkman, Gregory; Jorgenson, Jennie

In 2013, the California Independent System Operator published the "duck chart,"" which shows a significant drop in mid-day net load on a spring day as solar photovoltaics (PV) are added to the system. The chart raises concerns that the conventional power system will be unable to accommodate the ramp rate and range needed to fully utilize solar energy, particularly on days characterized by the duck shape. This could result in "overgeneration"" and curtailed renewable energy, increasing its costs and reducing its environmental benefits. This paper explores the duck chart in detail, examining how much PV might need to be curtailedmore » if additional grid flexibility measures are not taken, and how curtailment rates can be decreased by changing grid operational practices. It finds that under business-as-usual types of assumptions and corresponding levels of grid flexibility in California, solar penetrations as low as 20 percent of annual energy could lead to marginal curtailment rates that exceed 30 percent. However, by allowing (or requiring) distributed PV and storage (including new installations that are part of the California storage mandate) to provide grid services, system flexibility could be greatly enhanced. Doing so could significantly reduce curtailment and allow much greater penetration of variable generation resources in achieving a 50 percent renewable portfolio standard. Overall, the work described in this paper points to the need to fully integrate distributed resources into grid system planning and operations to allow maximum use of the solar resource.« less

Distribution and Intrinsic Membrane Properties of Basal Forebrain GABAergic and Parvalbumin Neurons in the Mouse

PubMed Central

McKenna, James T.; Yang, Chun; Franciosi, Serena; Winston, Stuart; Abarr, Kathleen K.; Rigby, Matthew S.; Yanagawa, Yuchio; McCarley, Robert W.; Brown, Ritchie E.

2013-01-01

The basal forebrain (BF) strongly regulates cortical activation, sleep homeostasis, and attention. Many BF neurons involved in these processes are GABAergic, including a subpopulation of projection neurons containing the calcium-binding protein, parvalbumin (PV). However, technical difficulties in identification have prevented a precise mapping of the distribution of GABAergic and GABA/PV+ neurons in the mouse or a determination of their intrinsic membrane properties. Here we used mice expressing fluorescent proteins in GABAergic (GAD67-GFP knock-in mice) or PV+ neurons (PV-Tomato mice) to study these neurons. Immunohistochemical staining for GABA in GAD67-GFP mice confirmed that GFP selectively labeled BF GABAergic neurons. GFP+ neurons and fibers were distributed throughout the BF, with the highest density in the magnocellular preoptic area (MCPO). Immunohistochemistry for PV indicated that the majority of PV+ neurons in the BF were large (>20 μm) or medium-sized (15–20 μm) GFP+ neurons. Most medium and large-sized BF GFP+ neurons, including those retrogradely labeled from the neocortex, were fast-firing and spontaneously active in vitro. They exhibited prominent hyperpolarization-activated inward currents and subthreshold “spikelets,” suggestive of electrical coupling. PV+ neurons recorded in PV-Tomato mice had similar properties but had significantly narrower action potentials and a higher maximal firing frequency. Another population of smaller GFP+ neurons had properties similar to striatal projection neurons. The fast firing and electrical coupling of BF GABA/PV+ neurons, together with their projections to cortical interneurons and the thalamic reticular nucleus, suggest a strong and synchronous control of the neocortical fast rhythms typical of wakefulness and REM sleep. PMID:23254904

Mitigation of Hot-Spots in Photovoltaic Systems Using Distributed Power Electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olalla, Carlos; Hasan, Md. Nazmul; Deline, Chris

In the presence of partial shading and other mismatch factors, bypass diodes may not offer complete elimination of excessive power dissipation due to cell reverse biasing, commonly referred to as hot-spotting in photovoltaic (PV) systems. As a result, PV systems may experience higher failure rates and accelerated ageing. In this paper, a cell-level simulation model is used to assess occurrence of hot-spotting events in a representative residential rooftop system scenario featuring a moderate shading environment. The approach is further used to examine how well distributed power electronics converters mitigate the effects of partial shading and other sources of mismatch bymore » preventing activation of bypass diodes and thereby reducing the chances of heavy power dissipation and hot-spotting in mismatched cells. The simulation results confirm that the occurrence of heavy power dissipation is reduced in all distributed power electronics architectures, and that submodule-level converters offer nearly 100% mitigation of hot-spotting. In addition, the paper further elaborates on the possibility of hot-spot-induced permanent damage, predicting a lifetime energy loss above 15%. In conclusion, this energy loss is fully recoverable with submodule-level power converters that mitigate hot-spotting and prevent the damage.« less

Mitigation of Hot-Spots in Photovoltaic Systems Using Distributed Power Electronics

DOE PAGES

Olalla, Carlos; Hasan, Md. Nazmul; Deline, Chris; ...

2018-03-23

In the presence of partial shading and other mismatch factors, bypass diodes may not offer complete elimination of excessive power dissipation due to cell reverse biasing, commonly referred to as hot-spotting in photovoltaic (PV) systems. As a result, PV systems may experience higher failure rates and accelerated ageing. In this paper, a cell-level simulation model is used to assess occurrence of hot-spotting events in a representative residential rooftop system scenario featuring a moderate shading environment. The approach is further used to examine how well distributed power electronics converters mitigate the effects of partial shading and other sources of mismatch bymore » preventing activation of bypass diodes and thereby reducing the chances of heavy power dissipation and hot-spotting in mismatched cells. The simulation results confirm that the occurrence of heavy power dissipation is reduced in all distributed power electronics architectures, and that submodule-level converters offer nearly 100% mitigation of hot-spotting. In addition, the paper further elaborates on the possibility of hot-spot-induced permanent damage, predicting a lifetime energy loss above 15%. In conclusion, this energy loss is fully recoverable with submodule-level power converters that mitigate hot-spotting and prevent the damage.« less

How PV system ownership can impact the market value of residential homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Johnson, Jamie L.

2014-01-01

There are multiple ways for a homeowner to obtain the electricity generating and savings benefits offered by a photovoltaic (PV) system. These include purchasing a PV system through various financing mechanisms, or by leasing the PV system from a third party with multiple options that may include purchase, lease renewal or PV system removal. The different ownership options available to homeowners presents a challenge to appraisal and real estate professionals during a home sale or refinance in terms of how to develop a value that is reflective of the PV systems operational characteristics, local market conditions, and lender and underwritermore » requirements. This paper presents these many PV system ownership options with a discussion of what considerations an appraiser must make when developing the contributory value of a PV system to a residential property.« less

Climate, air quality and human health benefits of various solar photovoltaic deployment scenarios in China in 2030

NASA Astrophysics Data System (ADS)

Yang, Junnan; Li, Xiaoyuan; Peng, Wei; Wagner, Fabian; Mauzerall, Denise L.

2018-06-01

Solar photovoltaic (PV) electricity generation can greatly reduce both air pollutant and greenhouse gas emissions compared to fossil fuel electricity generation. The Chinese government plans to greatly scale up solar PV installation between now and 2030. However, different PV development pathways will influence the range of air quality and climate benefits. Benefits depend on how much electricity generated from PV is integrated into power grids and the type of power plant displaced. Using a coal-intensive power sector projection as the base case, we estimate the climate, air quality, and related human health benefits of various 2030 PV deployment scenarios. We use the 2030 government goal of 400 GW installed capacity but vary the location of PV installation and the extent of inter-provincial PV electricity transmission. We find that deploying distributed PV in the east with inter-provincial transmission maximizes potential CO2 reductions and air quality-related health benefits (4.2% and 1.2% decrease in national total CO2 emissions and air pollution-related premature deaths compared to the base case, respectively). Deployment in the east with inter-provincial transmission results in the largest benefits because it maximizes displacement of the dirtiest coal-fired power plants and minimizes PV curtailment, which is more likely to occur without inter-provincial transmission. We further find that the maximum co-benefits achieved with deploying PV in the east and enabling inter-provincial transmission are robust under various maximum PV penetration levels in both provincial and regional grids. We find large potential benefits of policies that encourage distributed PV deployment and facilitate inter-provincial PV electricity transmission in China.

2015 IECRE: PV System Certification Workshop | Photovoltaic Research | NREL

Science.gov Websites

IECRE: PV System Certification Workshop 2015 IECRE: PV System Certification Workshop Thursday the guidelines for certifying PV systems. This workshop included an introduction of IECRE followed by discussions targeting the most critical or controversial items. This workshop gathered wide input from the PV

[Natural forming causes of China population distribution].

PubMed

Fang, Yu; Ouyang, Zhi-Yun; Zheng, Hua; Xiao, Yi; Niu, Jun-Feng; Chen, Sheng-Bin; Lu, Fei

2012-12-01

The diverse natural environment in China causes the spatial heterogeneity of China population distribution. It is essential to understand the interrelations between the population distribution pattern and natural environment to enhance the understanding of the man-land relationship and the realization of the sustainable management for the population, resources, and environment. This paper analyzed the China population distribution by adopting the index of population density (PD) in combining with spatial statistic method and Lorenz curve, and discussed the effects of the natural factors on the population distribution and the interrelations between the population distribution and 16 indices including average annual precipitation (AAP), average annual temperature (AAT), average annual sunshine duration (AASD), precipitation variation (PV), temperature variation (TV), sunshine duration variation (SDV), relative humidity (RH), aridity index (AI), warmth index ( WI), > or = 5 degrees C annual accumulated temperature (AACT), average elevation (AE), relative height difference (RHD), surface roughness (SR), water system density (WSD), net primary productivity (NPP), and shortest distance to seashore (SDTS). There existed an obvious aggregation phenomenon in the population distribution in China. The PD was high in east China, medium in central China, and low in west China, presenting an obvious positive spatial association. The PD was significantly positively correlated with WSD, AAT, AAP, NPP, AACT, PV, RH, and WI, and significantly negatively correlated with RHD, AE, SDV, SR, and SDTS. The climate factors (AAT, WI, PV, and NPP), topography factors (SR and RHD), and water system factor (WSD) together determined the basic pattern of the population distribution in China. It was suggested that the monitoring of the eco-environment in the east China of high population density should be strengthened to avoid the eco-environmental degradation due to the expanding population, and the conservation of the eco-environment in the central and west China with vulnerable eco-environment should also be strengthened to enhance the population carrying ability of these regions and to mitigate the eco-environmental pressure in the east China of high population density.

Changes in Otx2 and parvalbumin immunoreactivity in the superior colliculus in the platelet-derived growth factor receptor-β knockout mice.

PubMed

Zhao, Juanjuan; Urakawa, Susumu; Matsumoto, Jumpei; Li, Ruixi; Ishii, Yoko; Sasahara, Masakiyo; Peng, Yuwen; Ono, Taketoshi; Nishijo, Hisao

2013-01-01

The superior colliculus (SC), a relay nucleus in the subcortical visual pathways, is implicated in socioemotional behaviors. Homeoprotein Otx2 and β subunit of receptors of platelet-derived growth factor (PDGFR- β ) have been suggested to play an important role in development of the visual system and development and maturation of GABAergic neurons. Although PDGFR- β -knockout (KO) mice displayed socio-emotional deficits associated with parvalbumin (PV-)immunoreactive (IR) neurons, their anatomical bases in the SC were unknown. In the present study, Otx2 and PV-immunolabeling in the adult mouse SC were investigated in the PDGFR- β KO mice. Although there were no differences in distribution patterns of Otx2 and PV-IR cells between the wild type and PDGFR- β KO mice, the mean numbers of both of the Otx2- and PV-IR cells were significantly reduced in the PDGFR- β KO mice. Furthermore, average diameters of Otx2- and PV-IR cells were significantly reduced in the PDGFR- β KO mice. These findings suggest that PDGFR- β plays a critical role in the functional development of the SC through its effects on Otx2- and PV-IR cells, provided specific roles of Otx2 protein and PV-IR cells in the development of SC neurons and visual information processing, respectively.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hacke, P.; Terwilliger, K.; Koch, S.

Three crystalline silicon module designs were distributed in five replicas each to five laboratories for testing according to the IEC 62804 (Committee Draft) system voltage durability qualification test for crystalline silicon photovoltaic (PV) modules. The stress tests were performed in environmental chambers at 60 degrees C, 85% relative humidity, 96 h, and with module nameplate system voltage applied.

Photovoltaics as a terrestrial energy source. Volume 3: An overview

NASA Technical Reports Server (NTRS)

Smith, J. L.

1980-01-01

Photovoltaic (PV) systems were evaluated in terms of their potential for terrestrial application A comprehensive overview of important issues which bear on photovoltaic (PV) systems development is presented. Studies of PV system costs, the societal implications of PV system development, and strategies in PV research and development in relationship to current energy policies are summarized.

System performance predictions for Space Station Freedom's electric power system

NASA Technical Reports Server (NTRS)

Kerslake, Thomas W.; Hojnicki, Jeffrey S.; Green, Robert D.; Follo, Jeffrey C.

1993-01-01

Space Station Freedom Electric Power System (EPS) capability to effectively deliver power to housekeeping and user loads continues to strongly influence Freedom's design and planned approaches for assembly and operations. The EPS design consists of silicon photovoltaic (PV) arrays, nickel-hydrogen batteries, and direct current power management and distribution hardware and cabling. To properly characterize the inherent EPS design capability, detailed system performance analyses must be performed for early stages as well as for the fully assembled station up to 15 years after beginning of life. Such analyses were repeatedly performed using the FORTRAN code SPACE (Station Power Analysis for Capability Evaluation) developed at the NASA Lewis Research Center over a 10-year period. SPACE combines orbital mechanics routines, station orientation/pointing routines, PV array and battery performance models, and a distribution system load-flow analysis to predict EPS performance. Time-dependent, performance degradation, low earth orbit environmental interactions, and EPS architecture build-up are incorporated in SPACE. Results from two typical SPACE analytical cases are presented: (1) an electric load driven case and (2) a maximum EPS capability case.

Prognostics and health management of photovoltaic systems

DOEpatents

Johnson, Jay; Riley, Daniel

2018-04-10

The various technologies presented herein relate to providing prognosis and health management (PHM) of a photovoltaic (PV) system. A PV PHM system can eliminate long-standing issues associated with detecting performance reduction in PV systems. The PV PHM system can utilize an ANN model with meteorological and power input data to facilitate alert generation in the event of a performance reduction without the need for information about the PV PHM system components and design. Comparisons between system data and the PHM model can provide scheduling of maintenance on an as-needed basis. The PHM can also provide an approach for monitoring system/component degradation over the lifetime of the PV system.

Modeling the Impacts of Solar Distributed Generation on U.S. Water Resources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amanda, Smith; Omitaomu, Olufemi A; Jaron, Peck

2015-01-01

Distributed electric power generation technologies typically use little or no water per unit of electrical energy produced; in particular, renewable energy sources such as solar PV systems do not require cooling systems and present an opportunity to reduce water usage for power generation. Within the US, the fuel mix used for power generation varies regionally, and certain areas use more water for power generation than others. The need to reduce water usage for power generation is even more urgent in view of climate change uncertainties. In this paper, we present an example case within the state of Tennessee, one ofmore » the top four states in water consumption for power generation and one of the states with little or no potential for developing centralized renewable energy generations. The potential for developing PV generation within Knox County, Tennessee, is studied, along with the potential for reducing water withdrawal and consumption within the Tennessee Valley stream region. Electric power generation plants in the region are quantified for their electricity production and expected water withdrawal and consumption over one year, where electrical generation data is provided over one year and water usage is modeled based on the cooling system(s) in use. Potential solar PV electrical production is modeled based on LiDAR data and weather data for the same year. Our proposed methodology can be summarized as follows: First, the potential solar generation is compared against the local grid demand. Next, electrical generation reductions are specified that would result in a given reduction in water withdrawal and a given reduction in water consumption, and compared with the current water withdrawal and consumption rates for the existing fuel mix. The increase in solar PV development that would produce an equivalent amount of power, is determined. In this way, we consider how targeted local actions may affect the larger stream region through thoughtful energy development. This model can be applied to other regions, other types of distributed generation, and used as a framework for modeling alternative growth scenarios in power production capacity in addition to modeling adjustments to existing capacity.« less

Optimal design and operation of a photovoltaic-electrolyser system using particle swarm optimisation

NASA Astrophysics Data System (ADS)

Sayedin, Farid; Maroufmashat, Azadeh; Roshandel, Ramin; Khavas, Sourena Sattari

2016-07-01

In this study, hydrogen generation is maximised by optimising the size and the operating conditions of an electrolyser (EL) directly connected to a photovoltaic (PV) module at different irradiance. Due to the variations of maximum power points of the PV module during a year and the complexity of the system, a nonlinear approach is considered. A mathematical model has been developed to determine the performance of the PV/EL system. The optimisation methodology presented here is based on the particle swarm optimisation algorithm. By this method, for the given number of PV modules, the optimal sizeand operating condition of a PV/EL system areachieved. The approach can be applied for different sizes of PV systems, various ambient temperatures and different locations with various climaticconditions. The results show that for the given location and the PV system, the energy transfer efficiency of PV/EL system can reach up to 97.83%.

Effect of Thermoelectric Cooling (TEC) module and the water flow heatsink on Photovoltaic (PV) panel performance

NASA Astrophysics Data System (ADS)

Amelia, A. R.; Jusoh, MA; Shamira Idris, Ida

2017-11-01

Photovoltaic (PV) panel suffers in low conversion efficiency of the output performance affected by the elevated operating temperature of the PV panel. It is important to keep the PV panel to operate at low temperature. To address this issue, this paper proposes the cooling system using thermoelectric cooling (TEC) and water block heatsink for enhancing the PV panel output performance. These both types cooling system were designed located on the back side of the PV panel to cool down the operating temperature of the PV panel. To evaluate the function for the existing cooling systems, the experiment was subsequently performed for PV panel without and with different design of the cooling system in outdoor weather conditions. By comparing the experimental results, it is concluded that by the hybrid cooling system which combining TEC module and the water block heatsink could improve the output performance of the PV panel. By the reduction temperature of the PV panel by 16.04 %, the average output power of the PV panel has been boosted up from 8.59 W to 9.03 W. In short, the output power of the PV panel was enhanced by the reduction of the operating temperature of the PV panel.

Breakeven Prices for Photovoltaics on Supermarkets in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ong, S.; Clark, N.; Denholm, P.

The photovoltaic (PV) breakeven price is the PV system price at which the cost of PV-generated electricity equals the cost of electricity purchased from the grid. This point is also called 'grid parity' and can be expressed as dollars per watt ($/W) of installed PV system capacity. Achieving the PV breakeven price depends on many factors, including the solar resource, local electricity prices, customer load profile, PV incentives, and financing. In the United States, where these factors vary substantially across regions, breakeven prices vary substantially across regions as well. In this study, we estimate current and future breakeven prices formore » PV systems installed on supermarkets in the United States. We also evaluate key drivers of current and future commercial PV breakeven prices by region. The results suggest that breakeven prices for PV systems installed on supermarkets vary significantly across the United States. Non-technical factors -- including electricity rates, rate structures, incentives, and the availability of system financing -- drive break-even prices more than technical factors like solar resource or system orientation. In 2020 (where we assume higher electricity prices and lower PV incentives), under base-case assumptions, we estimate that about 17% of supermarkets will be in utility territories where breakeven conditions exist at a PV system price of $3/W; this increases to 79% at $1.25/W (the DOE SunShot Initiative's commercial PV price target for 2020). These percentages increase to 26% and 91%, respectively, when rate structures favorable to PV are used.« less

Decentralized Optimal Dispatch of Photovoltaic Inverters in Residential Distribution Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dall'Anese, Emiliano; Dhople, Sairaj V.; Johnson, Brian B.

Summary form only given. Decentralized methods for computing optimal real and reactive power setpoints for residential photovoltaic (PV) inverters are developed in this paper. It is known that conventional PV inverter controllers, which are designed to extract maximum power at unity power factor, cannot address secondary performance objectives such as voltage regulation and network loss minimization. Optimal power flow techniques can be utilized to select which inverters will provide ancillary services, and to compute their optimal real and reactive power setpoints according to well-defined performance criteria and economic objectives. Leveraging advances in sparsity-promoting regularization techniques and semidefinite relaxation, this papermore » shows how such problems can be solved with reduced computational burden and optimality guarantees. To enable large-scale implementation, a novel algorithmic framework is introduced - based on the so-called alternating direction method of multipliers - by which optimal power flow-type problems in this setting can be systematically decomposed into sub-problems that can be solved in a decentralized fashion by the utility and customer-owned PV systems with limited exchanges of information. Since the computational burden is shared among multiple devices and the requirement of all-to-all communication can be circumvented, the proposed optimization approach scales favorably to large distribution networks.« less

The microeconomics of residential photovoltaics: Tariffs, network operation and maintenance, and ancillary services in distribution-level electricity markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boero, Riccardo; Backhaus, Scott N.; Edwards, Brian K.

Here, we develop a microeconomic model of a distribution-level electricity market that takes explicit account of residential photovoltaics (PV) adoption. The model allows us to study the consequences of most tariffs on PV adoption and the consequences of increased residential PV adoption under the assumption of economic sustainability for electric utilities. We also validated the model using U.S. data and extend it to consider different pricing schemes for operation and maintenance costs of the distribution network and for ancillary services. Results show that net metering promotes more environmental benefits and social welfare than other tariffs. But, if costs to operatemore » the distribution network increase, net metering will amplify the unequal distribution of surplus among households. In conclusion, maintaining the economic sustainability of electric utilities under net metering may become extremely difficult unless the uneven distribution of surplus is legitimated by environmental benefits.« less

The microeconomics of residential photovoltaics: Tariffs, network operation and maintenance, and ancillary services in distribution-level electricity markets

DOE PAGES

Boero, Riccardo; Backhaus, Scott N.; Edwards, Brian K.

2016-11-12

Here, we develop a microeconomic model of a distribution-level electricity market that takes explicit account of residential photovoltaics (PV) adoption. The model allows us to study the consequences of most tariffs on PV adoption and the consequences of increased residential PV adoption under the assumption of economic sustainability for electric utilities. We also validated the model using U.S. data and extend it to consider different pricing schemes for operation and maintenance costs of the distribution network and for ancillary services. Results show that net metering promotes more environmental benefits and social welfare than other tariffs. But, if costs to operatemore » the distribution network increase, net metering will amplify the unequal distribution of surplus among households. In conclusion, maintaining the economic sustainability of electric utilities under net metering may become extremely difficult unless the uneven distribution of surplus is legitimated by environmental benefits.« less

Fault detection and diagnosis of photovoltaic systems

NASA Astrophysics Data System (ADS)

Wu, Xing

The rapid growth of the solar industry over the past several years has expanded the significance of photovoltaic (PV) systems. One of the primary aims of research in building-integrated PV systems is to improve the performance of the system's efficiency, availability, and reliability. Although much work has been done on technological design to increase a photovoltaic module's efficiency, there is little research so far on fault diagnosis for PV systems. Faults in a PV system, if not detected, may not only reduce power generation, but also threaten the availability and reliability, effectively the "security" of the whole system. In this paper, first a circuit-based simulation baseline model of a PV system with maximum power point tracking (MPPT) is developed using MATLAB software. MATLAB is one of the most popular tools for integrating computation, visualization and programming in an easy-to-use modeling environment. Second, data collection of a PV system at variable surface temperatures and insolation levels under normal operation is acquired. The developed simulation model of PV system is then calibrated and improved by comparing modeled I-V and P-V characteristics with measured I--V and P--V characteristics to make sure the simulated curves are close to those measured values from the experiments. Finally, based on the circuit-based simulation model, a PV model of various types of faults will be developed by changing conditions or inputs in the MATLAB model, and the I--V and P--V characteristic curves, and the time-dependent voltage and current characteristics of the fault modalities will be characterized for each type of fault. These will be developed as benchmark I-V or P-V, or prototype transient curves. If a fault occurs in a PV system, polling and comparing actual measured I--V and P--V characteristic curves with both normal operational curves and these baseline fault curves will aid in fault diagnosis.

Sacramento Municipal Utility District PV and Smart Grid Pilot at Anatolia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rawson, Mark; Sanchez, Eddie Paul

2013-12-30

Under DE-FOA-0000085 High Penetration Solar Deployment, the U. S. Department of Energy funded agreements with SMUD and Navigant Consulting, SunPower, GridPoint, the National Renewable Energy Laboratory, and the California Energy Commission for this pilot demonstration project. Funding was $5,962,409.00. Cost share of $500,000 was also provided by the California Energy Commission. The project has strategic implications for SMUD, other utilities and the PV and energy-storage industries in business and resource planning, technology deployment and asset management. These implications include: -At this point, no dominant business models have emerged and the industry is open for new ideas. -Demonstrated two business modelsmore » for using distributed PV and energy storage, and brainstormed several dozen more, each with different pros and cons for SMUD, its customers and the industry. -Energy storage can be used to manage high penetrations of PV and mitigate potential issues such as reverse power flow, voltage control violations, power quality issues, increased wear and tear on utility equipment, and system wide power supply issues. - Smart meters are another tool utilities can use to manage high penetrations of PV. The necessary equipment and protocols exist, and the next step is to determine how to integrate the functionality with utility programs and what level of utility control is required. - Time-of-use rates for the residential customers who hosted energy storage systems did not cause a significant change in energy usage patterns. However, the rates we used were not optimized for PV and energy storage. Opportunities exist for utilities to develop new structures.« less

PVUSA: The value of photovoltaics in the distribution system. The Kerman Grid-Support Project

NASA Astrophysics Data System (ADS)

Wenger, Howard J.; Hoff, Thomas E.

1995-05-01

As part of the Photovoltaics for Utility Scale Applications Applications (PVUSA) Project Pacific Gas Electric Company (PG&E) built the Kerman 500-kW photovoltaic power plant. Located near the end of a distribution feeder in a rural section of Fresno County, the plant was not built so much to demonstrate PV technology, but to evaluate its interaction with the local distribution grid and quantify available nontraditional grid-support benefits (those other than energy and capacity). As demand for new generation began to languish in the 1980s, and siting and permitting of power plants and transmission lines became more involved, utilities began considering smaller, distributed power sources. Potential benefits include shorter construction lead time, less capital outlay, and better utilization of existing assets. The results of a PG&E study in 1990/1991 of the benefits from a PV system to the distribution grid prompted the PVUSA Project to construct a plant at Kerman. Completed in 1993, the plant is believed to be the first one specifically built to evaluate the multiple benefits to the grid of a strategically sited plant. Each of nine discrete benefits were evaluated in detail by first establishing the technical impact, then translating the results into present economic value. Benefits span the entire system from distribution feeder to the generation fleet. This work breaks new ground in evaluation of distributed resources, and suggests that resource planning practices be expanded to account for these non-traditional benefits.

Innovation in Photovoltaic Science, Engineering, and Policy: A Potential Trillion-Dollar Global Industry for Sustainable Energy

NASA Astrophysics Data System (ADS)

Zheng, Cheng

The solar photovoltaic (PV) technology was an expensive niche energy source only for satellite applications, hallmarked by the Bell Lab's launch of the Telstar satellite with PV cells in 1962. Over the past decades, the accumulation of vast amount of effort across various disciplines in science, engineering, and policy has enabled the phenomenal growth of the solar PV industry into a global enterprise with about 140 gigawatt (GW) of cumulative installations by the end of 2013. Further cost reduction through innovation holds the promise in deploying terawatt (TW)-scale solar PV systems globally in both developed and developing countries, meeting growing energy demand and mitigating climate change. Chapter 1 presents a big picture view of the unsustainable path, heavily relying on fossil fuels, in the current global energy landscape. The main body of the dissertation examines the solar PV technology from a holistic and interdisciplinary perspective: from the basic research, to innovations in manufacturing and installing PV modules, to the driving energy policies. Chapter 2 offers a fundamental understanding of the PV technology and a review on recent scientific advances in improving PV efficiency (W/m 2). Chapter 3 reviews the state-of-the-art process flow in manufacturing commercial PV modules. In the context of pursuing further reduction in manufacturing cost (/m2), the thin Si film concept and its recent research effort are reviewed. Aiming to explore novel ways to produce high-quality seed crystals for thin Si film deposition, the key findings of the laser crystallization experiment is presented in Chapter 4. The fundamental thermophysics of nucleation and crystal growth is first reviewed, which highlights the importance of temperature evolution and heat transport in modelling the ultrafast laser crystallization process. Laser crystallization of a range of Si nanostructures are then carried out to study the nucleation and crystal growth behavior under some novel conditions, such as suspended narrow Si membranes and Si nanoparticles confined on top of oxide nanostructures. The cost of a PV module (/W) is determined by both its rated efficiency (W/m2) and its manufacturing cost (/m2). However, the same PV module with the same cost can lead to significantly different levelized cost of electricity (LCOE) in /kWh, depending on the location and configuration of the installed PV system. Chapter 5 starts with an overview of the geographic distribution of solar resources and retail electricity rates, which yield a range of grid parity points across the world. Then, energy yield simulations for different PV panel tilt configurations are carried out using the angle-and-wavelength-resolved solar irradiance data, to examine the effect of angular and spectral variations in the solar spectrum on system performance. Energy policies have been the driving forces for the phenomenal progress of the PV technology: the continuing reduction in cost and the rapid growth in deployment. Chapter 6 first reviews major policy instruments for PV, and then discusses about a few important policy lessons from the rapid development of the global PV industry during 2000-2013. Concerned with the mounting fiscal pressure from deployment incentives and focused on further cost reductions, an innovation-focused policy framework is proposed to revive the PV manufacturing sector and to pursue an innovation-driven global PV industry moving forward.

DOE and AID stand-alone photovoltaic activities

NASA Technical Reports Server (NTRS)

Bifano, W. J.; Ratajczak, A. F.

1983-01-01

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system activities sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, PV-powered medical refrigerators in six countries, PV system microprocessor control development activities and PV-hybrid system assessments. The AID project includes a large village system in Tunisia, a water pumping/grain grinding project in Upper Volta, five medical clinics in four countries, PV-powered remote earth station application. These PV activities and summarizes significant findings to data are reviewed.

Frequency Response Assessment and Enhancement of the U.S. Power Grids towards Extra-High Photovoltaic Generation Penetrations – an Industry Perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yong; You, Shutang; Tan, Jin

Nonsynchronous generations such as photovoltaics (PVs) are expected to undermine bulk power systems (BPSs)' frequency response at high penetration levels. Though the underlying mechanism has been relatively well understood, the accurate assessment and effective enhancement of the U.S. interconnections, frequency response under extra-high PV penetration conditions remains an issue. In this paper, the industry-provided full-detail interconnection models were further validated by synchrophasor frequency measurements and realistically-projected PV geographic distribution information were used to develop extra-high PV penetration scenarios and dynamic models for the three main U.S. interconnections, including Eastern Interconnection (EI), Western Electricity Coordinating Council (WECC), and Electric Reliability Councilmore » of Texas (ERCOT). Up to 65% instantaneous PV and 15% wind penetration were simulated and the frequency response change trend of each U.S. interconnection due to the increasing PV penetration level were examined. Most importantly, the practical solutions to address the declining frequency response were discussed. This paper will provide valuable guidance for policy makers, utility operators and academic researchers not only in the U.S. but also other countries in the world.« less

Frequency Response Assessment and Enhancement of the U.S. Power Grids towards Extra-High Photovoltaic Generation Penetrations – an Industry Perspective

DOE PAGES

Liu, Yong; You, Shutang; Tan, Jin; ...

2018-01-30

Nonsynchronous generations such as photovoltaics (PVs) are expected to undermine bulk power systems (BPSs)' frequency response at high penetration levels. Though the underlying mechanism has been relatively well understood, the accurate assessment and effective enhancement of the U.S. interconnections, frequency response under extra-high PV penetration conditions remains an issue. In this paper, the industry-provided full-detail interconnection models were further validated by synchrophasor frequency measurements and realistically-projected PV geographic distribution information were used to develop extra-high PV penetration scenarios and dynamic models for the three main U.S. interconnections, including Eastern Interconnection (EI), Western Electricity Coordinating Council (WECC), and Electric Reliability Councilmore » of Texas (ERCOT). Up to 65% instantaneous PV and 15% wind penetration were simulated and the frequency response change trend of each U.S. interconnection due to the increasing PV penetration level were examined. Most importantly, the practical solutions to address the declining frequency response were discussed. This paper will provide valuable guidance for policy makers, utility operators and academic researchers not only in the U.S. but also other countries in the world.« less

Performance test of a grid-tied PV system to power a split air conditioner system in Surabaya

NASA Astrophysics Data System (ADS)

Tarigan, E.

2017-11-01

Air conditioner for cooling air is one of the major needs for those who live in hot climate area such as Indonesia. This work presents the performance test of a grid-tied PV system to power air conditioner under a hot tropical climate in Surabaya, Indonesia. A 800 WP grid-tied photovoltaic (PV) system was used, and its performance was tested to power a 0.5 pk of split air conditioner system. It was found that about 3.5 kWh daily energy was consumed by the tested air conditioner system, and about 80% it could be supplied from the PV system. While the other 20% was supplied by the grid during periods of low solar irradiation, 440 Wh of energy was fed into the grid during operation out of office hours. By using the grid-tied PV system, the energy production by PV system did not need to match the consumption of the air conditioner. However, a larger capacity of PV system would mean that a higher percentage of the load would be covered by PV system.

Coordinated Collaboration between Heterogeneous Distributed Energy Resources

DOE PAGES

Abdollahy, Shahin; Lavrova, Olga; Mammoli, Andrea

2014-01-01

A power distribution feeder, where a heterogeneous set of distributed energy resources is deployed, is examined by simulation. The energy resources include PV, battery storage, natural gas GenSet, fuel cells, and active thermal storage for commercial buildings. The resource scenario considered is one that may exist in a not too distant future. Two cases of interaction between different resources are examined. One interaction involves a GenSet used to partially offset the duty cycle of a smoothing battery connected to a large PV system. The other example involves the coordination of twenty thermal storage devices, each associated with a commercial building.more » Storage devices are intended to provide maximum benefit to the building, but it is shown that this can have a deleterious effect on the overall system, unless the action of the individual storage devices is coordinated. A network based approach is also introduced to calculate some type of effectiveness metric to all available resources which take part in coordinated operation. The main finding is that it is possible to achieve synergy between DERs on a system; however this required a unified strategy to coordinate the action of all devices in a decentralized way.« less

Simulation, measurement, and emulation of photovoltaic modules using high frequency and high power density power electronic circuits

NASA Astrophysics Data System (ADS)

Erkaya, Yunus

The number of solar photovoltaic (PV) installations is growing exponentially, and to improve the energy yield and the efficiency of PV systems, it is necessary to have correct methods for simulation, measurement, and emulation. PV systems can be simulated using PV models for different configurations and technologies of PV modules. Additionally, different environmental conditions of solar irradiance, temperature, and partial shading can be incorporated in the model to accurately simulate PV systems for any given condition. The electrical measurement of PV systems both prior to and after making electrical connections is important for attaining high efficiency and reliability. Measuring PV modules using a current-voltage (I-V) curve tracer allows the installer to know whether the PV modules are 100% operational. The installed modules can be properly matched to maximize performance. Once installed, the whole system needs to be characterized similarly to detect mismatches, partial shading, or installation damage before energizing the system. This will prevent any reliability issues from the onset and ensure the system efficiency will remain high. A capacitive load is implemented in making I-V curve measurements with the goal of minimizing the curve tracer volume and cost. Additionally, the increase of measurement resolution and accuracy is possible via the use of accurate voltage and current measurement methods and accurate PV models to translate the curves to standard testing conditions. A move from mechanical relays to solid-state MOSFETs improved system reliability while significantly reducing device volume and costs. Finally, emulating PV modules is necessary for testing electrical components of a PV system. PV emulation simplifies and standardizes the tests allowing for different irradiance, temperature and partial shading levels to be easily tested. Proper emulation of PV modules requires an accurate and mathematically simple PV model that incorporates all known system variables so that any PV module can be emulated as the design requires. A non-synchronous buck converter is proposed for the emulation of a single, high-power PV module using traditional silicon devices. With the proof-of-concept working and improvements in efficiency, power density and steady-state errors made, dynamic tests were performed using an inverter connected to the PV emulator. In order to improve the dynamic characteristics, a synchronous buck converter topology is proposed along with the use of advanced GaNFET devices which resulted in very high power efficiency and improved dynamic response characteristics when emulating PV modules.

Uncertainties in the Value of Bill Savings from Behind-the-Meter, Residential Photovoltaic Systems: The Roles of Electricity Market Conditions, Retail Rate Design, and Net Metering

NASA Astrophysics Data System (ADS)

Darghouth, Naim Richard

Net metering has become a widespread policy mechanism in the U.S. for supporting customer adoption of distributed photovoltaics (PV), allowing customers with PV systems to reduce their electric bills by offsetting their consumption with PV generation, independent of the timing of the generation relative to consumption. Although net metering is one of the principal drivers for the residential PV market in the U.S., the academic literature on this policy has been sparse and this dissertation contributes to this emerging body of literature. This dissertation explores the linkages between the availability of net metering, wholesale electricity market conditions, retail rates, and the residential bill savings from behind-the-meter PV systems. First, I examine the value of the bill savings that customers receive under net metering and alternatives to net metering, and the associated role of retail rate design, based on current rates and a sample of approximately two hundred residential customers of California's two largest electric utilities. I find that the bill savings per kWh of PV electricity generated varies greatly, largely attributable to the increasing block structure of the California utilities' residential retail rates. I also find that net metering provides significantly greater bill savings than alternative compensation mechanisms based on avoided costs. However, retail electricity rates may shift as wholesale electricity market conditions change. I then investigate a potential change in market conditions -- increased solar PV penetrations -- on wholesale prices in the short-term based on the merit-order effect. This demonstrates the potential price effects of changes in market conditions, but also points to a number of methodological shortcomings of this method, motivating my usage of a long-term capacity investment and economic dispatch model to examine wholesale price effects of various wholesale market scenarios in the subsequent analysis. By developing three types of retail rates (a flat rate, a time-of-use rate, and real-time pricing) from these wholesale price profiles, I examine bill savings from PV generation for the ten wholesale market scenarios under net metering and an alternative to net metering where hourly excess PV generation is compensated at the wholesale price. Most generally, I challenge the common assertion that PV compensation is likely to stay constant (or rise) due to constant (or rising) retail rates, and find that future electricity market scenarios can drive substantial changes in residential retail rates and that these changes, in concert with variations in retail rate structures and PV compensation mechanisms, interact to place substantial uncertainty on the future value of bill savings from residential PV.

An Analysis of the Effects of Residential Photovoltaic Energy Systems on Home Sales Prices in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoen, Ben; Cappers, Peter; Wiser, Ryan

2011-04-19

An increasing number of homes in the U.S. have sold with photovoltaic (PV) energy systems installed at the time of sale, yet relatively little research exists that estimates the marginal impacts of those PV systems on home sale prices. A clearer understanding of these possible impacts might influence the decisions of homeowners considering the installation of a PV system, homebuyers considering the purchase of a home with PV already installed, and new home builders considering including PV as an optional or standard product on their homes. This research analyzes a large dataset of California homes that sold from 2000 throughmore » mid-2009 with PV installed. It finds strong evidence that homes with PV systems sold for a premium over comparable homes without PV systems during this time frame. Estimates for this premium expressed in dollars per watt of installed PV range, on average, from roughly $4 to $5.5/watt across a large number of hedonic and repeat sales model specifications and robustness tests. When expressed as a ratio of the sales price premium of PV to estimated annual energy cost savings associated with PV, an average ratio of 14:1 to 19:1 can be calculated; these results are consistent with those of the more-extensive existing literature on the impact of energy efficiency on sales prices. When the data are split among new and existing homes, however, PV system premiums are markedly affected. New homes with PV show premiums of $2.3-2.6/watt, while existing homes with PV show premiums of more than $6/watt. Reasons for this discrepancy are suggested, yet further research is warranted. A number of other areas where future research would be useful are also highlighted.« less

Status of DOE and AID stand-alone photovoltaic system field tests

NASA Astrophysics Data System (ADS)

Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

Status of DOE and AID stand-alone photovoltaic system field tests

NASA Technical Reports Server (NTRS)

Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

1984-01-01

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

Concentrated solar power plants impact on PV penetration level and grid flexibility under Egyptian climate

NASA Astrophysics Data System (ADS)

Moukhtar, Ibrahim; Elbaset, Adel A.; El Dein, Adel Z.; Qudaih, Yaser; Mitani, Yasunori

2018-05-01

Photovoltaic (PV) system integration in the electric grid has been increasing over the past decades. However, the impact of PV penetration on the electric grid, especially during the periods of higher and lower generation for the solar system at the middle of the day and during cloudy weather or at night respectively, limit the high penetration of solar PV system. In this research, a Concentrated Solar Power (CSP) with Thermal Energy Storage (TES) has been aggregated with PV system in order to accommodate the required electrical power during the higher and lower solar energy at all timescales. This paper analyzes the impacts of CSP on the grid-connected PV considering high penetration of PV system, particularly when no energy storages in the form of batteries are used. Two cases have been studied, the first when only PV system is integrated into the electric grid and the second when two types of solar energy (PV and CSP) are integrated. The System Advisor Model (SAM) software is used to simulate the output power of renewable energy. Simulation results show that the performance of CSP has a great impact on the penetration level of PV system and on the flexibility of the electric grid. The overall grid flexibility increases due to the ability of CSP to store and dispatch the generated power. In addition, CSP/TES itself has inherent flexibility. Therefore, CSP reduces the minimum generation constraint of the conventional generators that allows more penetration of the PV system.

Solar Photovoltaic DC Systems: Basics and Safety: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNutt, Peter F; Sekulic, William R; Dreifuerst, Gary

Solar Photovoltaic (PV) systems are common and growing with 42.4 GW installed capacity in U.S. (almost 15 GW added in 2016). This paper will help electrical workers, and emergency responders understand the basic operating principles and hazards of PV DC arrays. We briefly discuss the following aspects of solar photovoltaic (PV) DC systems: the effects of solar radiation and temperature on output power; PV module testing standards; common system configurations; a simple PV array sizing example; NEC guidelines and other safety features; DC array commissioning, periodic maintenance and testing; arc-flash hazard potential; how electrical workers and emergency responders can andmore » do work safely around PV arrays; do moonlight and artificial lighting pose a real danger; typical safe operating procedures; and other potential DC-system hazards to be aware of. We also present some statistics on PV DC array electrical incidents and injuries. Safe PV array operation is possible with a good understanding of PV DC arrays basics and having good safe operating procedures in place.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Speer, B.; Mendelsohn, M.; Cory, K.

Insuring solar photovoltaic (PV) systems poses certain challenges. Insurance premiums, which can represent a significant part of overall costs for PV developers, can affect market competition. The market for certain types of insurance products is limited. Historical loss data is lacking, and test data for the long-term viability of PV products under real-life conditions is limited. Insurers' knowledge about PV systems and the PV industry is uneven even as the industry introduces innovative contractual structures and business models. Interviews conducted for this report with PV project developers, insurance brokers, and underwriters suggest government actions aimed at better testing, data collection,more » and communication could facilitate the development of a market for PV insurance products. This report identifies actions by governments, national laboratories, and other stakeholders that could accelerate the development of insurance products in support PV systems. Such actions include: increasing understanding of the solar PV industry among insurance professionals; expanding the availability of PV historical loss data; evaluating the expansion of renewable energy business classification; developing module and component testing capabilities and services offered by federal labs; and, advancing industry standards for PV system installers.« less

Distribution Integration | Grid Modernization | NREL

Science.gov Websites

There is Strength: Measuring and Mitigating Solar PV Impacts in Southern California Using Power Factors distributed energy resources, such as PV, began more than a decade ago and has included numerous high-impact partnered with utilities to develop best practices for solar integration, to developing technical screening

Design and simulation of maximum power point tracking (MPPT) system on solar module system using constant voltage (CV) method

NASA Astrophysics Data System (ADS)

Bhatara, Sevty Satria; Iskandar, Reza Fauzi; Kirom, M. Ramdlan

2016-02-01

Solar energy is one of renewable energy resource where needs a photovoltaic module to convert it into electrical energy. One of the problems on solar energy conversion is the process of battery charging. To improve efficiency of energy conversion, PV system needs another control method on battery charging called maximum power point tracking (MPPT). This paper report the study on charging optimation using constant voltage (CV) method. This method has a function of determining output voltage of the PV system on maximal condition, so PV system will always produce a maximal energy. A model represented a PV system with and without MPPT was developed using Simulink. PV system simulation showed a different outcome energy when different solar radiation and numbers of solar module were applied in the model. On the simulation of solar radiation 1000 W/m2, PV system with MPPT produces 252.66 Watt energy and PV system without MPPT produces 252.66 Watt energy. The larger the solar radiation, the greater the energy of PV modules was produced.

Increased Throughput and Sensitivity of Synchrotron-Based Characterization for Photovoltaic Materials

DOE PAGES

Morishige, Ashley E.; Laine, Hannu S.; Looney, Erin E.; ...

2017-04-03

Optimizing photovoltaic (PV) devices requires characterization and optimization across several length scales, from centimeters to nanometers. Synchrotron-based micro-X-ray fluorescence spectromicroscopy (μ-XRF) is a valuable link in the PV-related material and device characterization suite. μ-XRF maps of elemental distributions in PV materials have high spatial resolution and excellent sensitivity and can be measured on absorber materials and full devices. Recently, we implemented on-the-fly data collection (flyscan) at Beamline 2-ID-D at the Advanced Photon Source at Argonne National Laboratory, eliminating a 300 ms per-pixel overhead time. This faster scanning enables high-sensitivity (~10 14 atoms/cm 2), large-area (10 000s of μm 2), high-spatialmore » resolution (<;200 nm scale) maps to be completed within a practical scanning time. We specifically show that when characterizing detrimental trace metal precipitate distributions in multicrystalline silicon wafers for PV, flyscans can increase the productivity of μ-XRF by an order of magnitude. Additionally, flyscan μ-XRF mapping enables relatively large-area correlative microscopy. As an example, we map the transition metal distribution in a 50 μm-diameter laser-fired contact of a silicon solar cell before and after lasing. As a result, while we focus on μ-XRF of mc-Si wafers for PV, our results apply broadly to synchrotron-based mapping of PV absorbers and devices.« less

A MPPT Algorithm Based PV System Connected to Single Phase Voltage Controlled Grid

NASA Astrophysics Data System (ADS)

Sreekanth, G.; Narender Reddy, N.; Durga Prasad, A.; Nagendrababu, V.

2012-10-01

Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV systemthat provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution.

RTDS implementation of an improved sliding mode based inverter controller for PV system.

PubMed

Islam, Gazi; Muyeen, S M; Al-Durra, Ahmed; Hasanien, Hany M

2016-05-01

This paper proposes a novel approach for testing dynamics and control aspects of a large scale photovoltaic (PV) system in real time along with resolving design hindrances of controller parameters using Real Time Digital Simulator (RTDS). In general, the harmonic profile of a fast controller has wide distribution due to the large bandwidth of the controller. The major contribution of this paper is that the proposed control strategy gives an improved voltage harmonic profile and distribute it more around the switching frequency along with fast transient response; filter design, thus, becomes easier. The implementation of a control strategy with high bandwidth in small time steps of Real Time Digital Simulator (RTDS) is not straight forward. This paper shows a good methodology for the practitioners to implement such control scheme in RTDS. As a part of the industrial process, the controller parameters are optimized using particle swarm optimization (PSO) technique to improve the low voltage ride through (LVRT) performance under network disturbance. The response surface methodology (RSM) is well adapted to build analytical models for recovery time (Rt), maximum percentage overshoot (MPOS), settling time (Ts), and steady state error (Ess) of the voltage profile immediate after inverter under disturbance. A systematic approach of controller parameter optimization is detailed. The transient performance of the PSO based optimization method applied to the proposed sliding mode controlled PV inverter is compared with the results from genetic algorithm (GA) based optimization technique. The reported real time implementation challenges and controller optimization procedure are applicable to other control applications in the field of renewable and distributed generation systems. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Affordable remote-area power supply in the Philippines

NASA Astrophysics Data System (ADS)

Heruela, C. S.

The feasibility of photovoltaic (PV) systems for electrifying remote areas of the Philippines is discussed. In particular, a technical description is given of those PV systems that are appropriate to the needs of remote, but populated, rural areas and have been developed as part of the Philippine-German Solar Energy Project. Details are provided of a financing scheme, piloted by the Project on an unelectrified island, to make PV systems affordable to rural users. An analysis is presented of the potential of large-scale applications of PV systems in developing countries such as the Philippines, and a description is provided of current efforts to promote the use of such technology. A storage battery is identified as an essential component of a PV system. As a consequence, the wide use of PV systems will have a very significant impact on the market for storage batteries in countries embarking on PV-utilization programmes. It is clear, therefore, that battery manufacturers should take an interest in future development in PV applications.

U.S. Residential Photovoltaic (PV) System Prices, Q4 2013 Benchmarks: Cash Purchase, Fair Market Value, and Prepaid Lease Transaction Prices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, C.; James, T. L.; Margolis, R.

The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in global PV module prices. This report provides a Q4 2013 update for residential PV systems, based on an objective methodology that closely approximates the book value of a PV system. Several cases are benchmarked to represent common variation in business models, labor rates, and module choice. We estimate a weighted-average cash purchase price of $3.29/W for modeled standard-efficiency, polycrystalline-silicon residential PV systems installed in the United States. This is a 46% declinemore » from the 2013-dollar-adjusted price reported in the Q4 2010 benchmark report. In addition, this report frames the cash purchase price in the context of key price metrics relevant to the continually evolving landscape of third-party-owned PV systems by benchmarking the minimum sustainable lease price and the fair market value of residential PV systems.« less

Three junction holographic micro-scale PV system

NASA Astrophysics Data System (ADS)

Wu, Yuechen; Vorndran, Shelby; Ayala Pelaez, Silvana; Kostuk, Raymond K.

2016-09-01

In this work a spectrum splitting micro-scale concentrating PV system is evaluated to increase the conversion efficiency of flat panel PV systems. In this approach, the dispersed spectrum splitting concentration systems is scaled down to a small size and structured in an array. The spectrum splitting configuration allows the use of separate single bandgap PV cells that increase spectral overlap with the incident solar spectrum. This results in an overall increase in the spectral conversion efficiency of the resulting system. In addition other benefits of the micro-scale PV system are retained such reduced PV cell material requirements, more versatile interconnect configurations, and lower heat rejection requirements that can lead to a lower cost system. The system proposed in this work consists of two cascaded off-axis holograms in combination with a micro lens array, and three types of PV cells. An aspherical lens design is made to minimize the dispersion so that higher concentration ratios can be achieved for a three-junction system. An analysis methodology is also developed to determine the optical efficiency of the resulting system, the characteristics of the dispersed spectrum, and the overall system conversion efficiency for a combination of three types of PV cells.

Solar San Diego: The Impact of Binomial Rate Structures on Real PV Systems; Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

VanGeet, O.; Brown, E.; Blair, T.

2008-05-01

There is confusion in the marketplace regarding the impact of solar photovoltaics (PV) on the user's actual electricity bill under California Net Energy Metering, particularly with binomial tariffs (those that include both demand and energy charges) and time-of-use (TOU) rate structures. The City of San Diego has extensive real-time electrical metering on most of its buildings and PV systems, with interval data for overall consumption and PV electrical production available for multiple years. This paper uses 2007 PV-system data from two city facilities to illustrate the impacts of binomial rate designs. The analysis will determine the energy and demand savingsmore » that the PV systems are achieving relative to the absence of systems. A financial analysis of PV-system performance under various rate structures is presented. The data revealed that actual demand and energy use benefits of binomial tariffs increase in summer months, when solar resources allow for maximized electricity production. In a binomial tariff system, varying on- and semi-peak times can result in approximately $1,100 change in demand charges per month over not having a PV system in place, an approximate 30% cost savings. The PV systems are also shown to have a 30%-50% reduction in facility energy charges in 2007.« less

Optimization of joint energy micro-grid with cold storage

NASA Astrophysics Data System (ADS)

Xu, Bin; Luo, Simin; Tian, Yan; Chen, Xianda; Xiong, Botao; Zhou, Bowen

2018-02-01

To accommodate distributed photovoltaic (PV) curtailment, to make full use of the joint energy micro-grid with cold storage, and to reduce the high operating costs, the economic dispatch of joint energy micro-grid load is particularly important. Considering the different prices during the peak and valley durations, an optimization model is established, which takes the minimum production costs and PV curtailment fluctuations as the objectives. Linear weighted sum method and genetic-taboo Particle Swarm Optimization (PSO) algorithm are used to solve the optimization model, to obtain optimal power supply output. Taking the garlic market in Henan as an example, the simulation results show that considering distributed PV and different prices in different time durations, the optimization strategies are able to reduce the operating costs and accommodate PV power efficiently.

Continuation Power Flow Analysis for PV Integration Studies at Distribution Feeders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jiyu; Zhu, Xiangqi; Lubkeman, David L.

2017-10-30

This paper presents a method for conducting continuation power flow simulation on high-solar penetration distribution feeders. A load disaggregation method is developed to disaggregate the daily feeder load profiles collected in substations down to each load node, where the electricity consumption of residential houses and commercial buildings are modeled using actual data collected from single family houses and commercial buildings. This allows the modeling of power flow and voltage profile along a distribution feeder on a continuing fashion for a 24- hour period at minute-by-minute resolution. By separating the feeder into load zones based on the distance between the loadmore » node and the feeder head, we studied the impact of PV penetration on distribution grid operation in different seasons and under different weather conditions for different PV placements.« less

Measurement of the Neutron Radius of 208Pb Through Parity-Violation in Electron Scattering

DOE PAGES

Abrahamyan, Sergey; Albataineh, Hisham; Aniol, Konrad; ...

2012-03-15

We report the first measurement of the parity-violating asymmetry A PV in the elastic scattering of polarized electrons from 208Pb. A PV is sensitive to the radius of the neutron distribution (R n). The result A PV = 0.656 ± 0.060 (stat) ± 0.013 (syst) corresponds to a difference between the radii of the neutron and proton distributions R n-R p = 0.33 -0.18 +0.16 fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.

Measurement of the neutron radius of 208Pb through parity violation in electron scattering.

PubMed

Abrahamyan, S; Ahmed, Z; Albataineh, H; Aniol, K; Armstrong, D S; Armstrong, W; Averett, T; Babineau, B; Barbieri, A; Bellini, V; Beminiwattha, R; Benesch, J; Benmokhtar, F; Bielarski, T; Boeglin, W; Camsonne, A; Canan, M; Carter, P; Cates, G D; Chen, C; Chen, J-P; Hen, O; Cusanno, F; Dalton, M M; De Leo, R; de Jager, K; Deconinck, W; Decowski, P; Deng, X; Deur, A; Dutta, D; Etile, A; Flay, D; Franklin, G B; Friend, M; Frullani, S; Fuchey, E; Garibaldi, F; Gasser, E; Gilman, R; Giusa, A; Glamazdin, A; Gomez, J; Grames, J; Gu, C; Hansen, O; Hansknecht, J; Higinbotham, D W; Holmes, R S; Holmstrom, T; Horowitz, C J; Hoskins, J; Huang, J; Hyde, C E; Itard, F; Jen, C-M; Jensen, E; Jin, G; Johnston, S; Kelleher, A; Kliakhandler, K; King, P M; Kowalski, S; Kumar, K S; Leacock, J; Leckey, J; Lee, J H; LeRose, J J; Lindgren, R; Liyanage, N; Lubinsky, N; Mammei, J; Mammoliti, F; Margaziotis, D J; Markowitz, P; McCreary, A; McNulty, D; Mercado, L; Meziani, Z-E; Michaels, R W; Mihovilovic, M; Muangma, N; Muñoz-Camacho, C; Nanda, S; Nelyubin, V; Nuruzzaman, N; Oh, Y; Palmer, A; Parno, D; Paschke, K D; Phillips, S K; Poelker, B; Pomatsalyuk, R; Posik, M; Puckett, A J R; Quinn, B; Rakhman, A; Reimer, P E; Riordan, S; Rogan, P; Ron, G; Russo, G; Saenboonruang, K; Saha, A; Sawatzky, B; Shahinyan, A; Silwal, R; Sirca, S; Slifer, K; Solvignon, P; Souder, P A; Sperduto, M L; Subedi, R; Suleiman, R; Sulkosky, V; Sutera, C M; Tobias, W A; Troth, W; Urciuoli, G M; Waidyawansa, B; Wang, D; Wexler, J; Wilson, R; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yim, V; Zana, L; Zhan, X; Zhang, J; Zhang, Y; Zheng, X; Zhu, P

2012-03-16

We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.

Photovoltaic electricity generation: Value for residential and commercial sectors

NASA Astrophysics Data System (ADS)

Bhattacharjee, Ujjwal

The photovoltaic (PV) industry in the US has seen an upsurge in recent years, and PV holds great promise as a renewable technology with no greenhouse gas emissions with its use. We aim to assess the value of PV based electricity for users in the residential and commercial sectors focusing on the financial impacts it has, which may not be greatly recognized. Specifically, we pursue two goals. First, the emerging 'renewable portfolio standard (RPS)' adopted in several states in the country has been a driving force for large scale PV deployment, but financial incentives offered to PV in different RPS states differ considerably. We use life cycle cost model to estimate the cost of PV based electricity for thirty-two RPS states in the country. Results indicate that the levelized cost of PV electricity is high (40 to 60 Cents/kWh). When the contribution of the financial incentives (along with the cost of energy saved) is taken into account, the cost of PV based electricity is negative in some RPS states such as California, New Jersey, New York, while for most of the RPS states the cost of PV electricity continues to remain high. In addition, the states with negative or low cost of PV electricity have been driving the PV diffusion in the residential sector. Therefore, a need to adjust the financial incentive structure in different RPS states is recommended for homogenous development of the residential PV market in the country. Second, we assess the value of the PV in reducing the highest peak load demand in commercial buildings and hence the high value demand charge. The Time-of-Use (TOU) based electricity tariff is widely used by electric utilities in the commercial sector. Energy and peak load are two important facets of the TOU tariff regime. Tools are well established to estimate the energy contribution from a PV system (installed in a commercial building), but not power output on a short time interval. A joint conditional probability model has been developed that enables estimation of the PV contribution towards the peak load reduction for a given high building load. Results indicate a significant cost saving (15% to 40%) with application of the model. This will encourage commercial entities (building owners) to adopt PV as a distributed energy source. The tool would be useful for energy modelers and green building architects as it will enable them to estimate cost savings due to PV deployment in commercial buildings. Moreover, the model tested for three different commercial buildings indicates that school buildings show the best promise for PV deployment followed, respectively, by office buildings and manufacturing facilities. This will help PV incentive programs in the country to use resources effectively to enhance the diffusion of PV in the commercial sector.

MATLAB Simulation of Photovoltaic and Photovoltaic/Thermal Systems Performance

NASA Astrophysics Data System (ADS)

Nasir, Farah H. M.; Husaini, Yusnira

2018-03-01

The efficiency of the photovoltaic reduces when the photovoltaic cell temperature increased due to solar irradiance. One solution is come up with the cooling system photovoltaic system. This combination is forming the photovoltaic-thermal (PV/T) system. Not only will it generate electricity also heat at the same time. The aim of this research is to focus on the modeling and simulation of photovoltaic (PV) and photovoltaic-thermal (PV/T) electrical performance by using single-diode equivalent circuit model. Both PV and PV/T models are developed in Matlab/Simulink. By providing the cooling system in PV/T, the efficiency of the system can be increased by decreasing the PV cell temperature. The maximum thermal, electrical and total efficiency values of PV/T in the present research are 35.18%, 15.56% and 50.74% at solar irradiance of 400 W/m2, mass flow rate of 0.05kgs-1 and inlet temperature of 25 °C respectively has been obtained. The photovoltaic-thermal shows that the higher efficiency performance compared to the photovoltaic system.

Photovoltaic battery & charge controller market & applications survey. An evaluation of the photovoltaic system market for 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammond, R.L.; Turpin, J.F.; Corey, G.P.

1996-12-01

Under the sponsorship of the Department of Energy, Office of Utility Technologies, the Battery Analysis and Evaluation Department and the Photovoltaic System Assistance Center of Sandia National Laboratories (SNL) initiated a U.S. industry-wide PV Energy Storage System Survey. Arizona State University (ASU) was contracted by SNL in June 1995 to conduct the survey. The survey included three separate segments tailored to: (a) PV system integrators, (b) battery manufacturers, and (c) PV charge controller manufacturers. The overall purpose of the survey was to: (a) quantify the market for batteries shipped with (or for) PV systems in 1995, (b) quantify the PVmore » market segments by battery type and application for PV batteries, (c) characterize and quantify the charge controllers used in PV systems, (d) characterize the operating environment for energy storage components in PV systems, and (e) estimate the PV battery market for the year 2000. All three segments of the survey were mailed in January 1996. This report discusses the purpose, methodology, results, and conclusions of the survey.« less

Distributed solar radiation fast dynamic measurement for PV cells

NASA Astrophysics Data System (ADS)

Wan, Xuefen; Yang, Yi; Cui, Jian; Du, Xingjing; Zheng, Tao; Sardar, Muhammad Sohail

2017-10-01

To study the operating characteristics about PV cells, attention must be given to the dynamic behavior of the solar radiation. The dynamic behaviors of annual, monthly, daily and hourly averages of solar radiation have been studied in detail. But faster dynamic behaviors of solar radiation need more researches. The solar radiation random fluctuations in minute-long or second-long range, which lead to alternating radiation and cool down/warm up PV cell frequently, decrease conversion efficiency. Fast dynamic processes of solar radiation are mainly relevant to stochastic moving of clouds. Even in clear sky condition, the solar irradiations show a certain degree of fast variation. To evaluate operating characteristics of PV cells under fast dynamic irradiation, a solar radiation measuring array (SRMA) based on large active area photodiode, LoRa spread spectrum communication and nanoWatt MCU is proposed. This cross photodiodes structure tracks fast stochastic moving of clouds. To compensate response time of pyranometer and reduce system cost, the terminal nodes with low-cost fast-responded large active area photodiode are placed besides positions of tested PV cells. A central node, consists with pyranometer, large active area photodiode, wind detector and host computer, is placed in the center of the central topologies coordinate to scale temporal envelope of solar irradiation and get calibration information between pyranometer and large active area photodiodes. In our SRMA system, the terminal nodes are designed based on Microchip's nanoWatt XLP PIC16F1947. FDS-100 is adopted for large active area photodiode in terminal nodes and host computer. The output current and voltage of each PV cell are monitored by I/V measurement. AS62-T27/SX1278 LoRa communication modules are used for communicating between terminal nodes and host computer. Because the LoRa LPWAN (Low Power Wide Area Network) specification provides seamless interoperability among Smart Things without the need of complex local installations, configuring of our SRMA system is very easy. Lora also provides SRMA a means to overcome the short communication distance and weather signal propagation decline such as in ZigBee and WiFi. The host computer in SRMA system uses the low power single-board PC EMB-3870 which was produced by NORCO. Wind direction sensor SM5386B and wind-force sensor SM5387B are installed to host computer through RS-485 bus for wind reference data collection. And Davis 6450 solar radiation sensor, which is a precision instrument that detects radiation at wavelengths of 300 to 1100 nanometers, allow host computer to follow real-time solar radiation. A LoRa polling scheme is adopt for the communication between host computer and terminal nodes in SRMA. An experimental SRMA has been established. This system was tested in Ganyu, Jiangshu province from May to August, 2016. In the test, the distances between the nodes and the host computer were between 100m and 1900m. At work, SRMA system showed higher reliability. Terminal nodes could follow the instructions from host computer and collect solar radiation data of distributed PV cells effectively. And the host computer managed the SRAM and achieves reference parameters well. Communications between the host computer and terminal nodes were almost unaffected by the weather. In conclusion, the testing results show that SRMA could be a capable method for fast dynamic measuring about solar radiation and related PV cell operating characteristics.

An Economic Analysis of Residential Photovoltaic Systems with and without Energy Storage

NASA Astrophysics Data System (ADS)

Kizito, Rodney

Residential photovoltaic (PV) systems serve as a source of electricity generation that is separate from the traditional utilities. Investor investment into residential PV systems provides several financial benefits such as federal tax credit incentives for installation, net metering credit from excess generated electricity added back to the grid, and savings in price per kilowatt-hour (kWh) from the PV system generation versus the increasing conventional utility price per kWh. As much benefit as stand-alone PV systems present, the incorporation of energy storage yields even greater benefits. Energy storage (ES) is capable of storing unused PV provided energy from daytime periods of high solar supply but low consumption. This allows the investor to use the stored energy when the cost of conventional utility power is high, while also allowing for excess stored energy to be sold back to the grid. This paper aims to investigate the overall returns for investor's investing in solely PV and ES-based PV systems by using a return of investment (ROI) economic analysis. The analysis is carried out over three scenarios: (1) residence without a PV system or ES, (2) residence with just a PV system, and (3) residence with both a PV system and ES. Due to the variation in solar exposure across the regions of the United States, this paper performs an analysis for eight of the top solar market states separately, accounting for the specific solar generation capabilities of each state. A Microsoft Excel tool is provided for computation of the ROI in scenario 2 and 3. A benefit-cost ration (BCR) is used to depict the annual economic performance of the PV system (scenario 2) and PV + ES system (scenario 3). The tool allows the user to adjust the variables and parameters to satisfy the users' specific investment situation.

Application of Autonomous Smart Inverter Volt-VAR Function for Voltage Reduction Energy Savings and Power Quality in Electric Distribution Systems: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Nagarajan, Adarsh; Baggu, Murali

This paper evaluated the impact of smart inverter Volt-VAR function on voltage reduction energy saving and power quality in electric power distribution systems. A methodology to implement the voltage reduction optimization was developed by controlling the substation LTC and capacitor banks, and having smart inverters participate through their autonomous Volt-VAR control. In addition, a power quality scoring methodology was proposed and utilized to quantify the effect on power distribution system power quality. All of these methodologies were applied to a utility distribution system model to evaluate the voltage reduction energy saving and power quality under various PV penetrations and smartmore » inverter densities.« less

Stem Inc. SunShot Incubator Program Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butterfield, Karen

In this Energy Storage Control Algorithms project, Stem sought to develop tools and control algorithms to increase the value and reduce balance-of-system and grid integration costs associated with adding distributed solar generation to the grid. These advances fell under the headings SolarScope and SolarController. Stem sought to create initial market traction with a fully commercialized product for the solar industry to size storage systems (SolarScope) as well as a solar intermittency-mitigation framework for utilities (SolarController) in the course of the project. The company sought to align strategic growth plans and enable the rollout of the products to broader audiences inmore » multiple geographic regions by leveraging the major solar companies in the national market as partners. Both final products were both intended to be commercialized. They are: SolarScope: Analysis tool to identify viable PV + storage projects and thereby expedite the sales and interconnection processes. SolarScope combines customer load data, PV production estimates, utility rate tariff, and simulated storage into a simple user interface for PV developers. Developers can easily identify viable solar + storage sites without the need for complex and time consuming, site-by-site spreadsheet modeling. SolarContoller: Tool to autonomously dispatch distributed storage in order to mitigate voltage fluctuation and reduce curtailment. SolarController co-optimizes, in real time, storage dispatch for circuit stability and curtailment reduction, enabling higher penetrations of PV. SolarController is automated, not requiring utility dispatch or management, as Stem hardware senses grid voltage, frequency, customer load, PV production, and power factor. In the end the two products met with different outcomes. SolarScope was tested by potential users, and continues to be used as a foundational platform for partnership with key solar industry partners. SolarController, on the other hand, was successful in lab testing but was not commercialized due to a lack of marketability and lack of interested customer base. Together the development of these two products marked a material step forward for Stem; and a new milestone along the pathway of integration for the solar and storage industries. SolarScope is leading to real, out-of-the-lab project development in storage + solar for the commercial customer sector. Meanwhile SolarController has opened the eyes of regulators and utility executives alike to the potential of distributed solar and by doing so, has moved the conversation forward for the integration of distributed energy resources more broadly on the grid.« less

The impact of a large penetration of intermittent sources on the power system operation and planning

NASA Astrophysics Data System (ADS)

Ausin, Juan Carlos

This research investigated the impact on the power system of a large penetration of intermittent renewable sources, mainly wind and photovoltaic generation. Currently, electrical utilities deal with wind and PV plants as if they were sources of negative demand, that is to say, they have no control over the power output produced. In this way, the grid absorbs all the power fluctuation as if it were coming from a common load. With the level of wind penetration growing so quickly, there is growing concern amongst the utilities and the grid operators, as they will have to deal with a much higher level of fluctuation. In the same way, the potential cost reduction of PV technologies suggests that a similar development may be expected for solar production in the mid term. The first part of the research was focused on the issues that affect utility planning and reinforcement decision making. Although DG is located mainly on the distribution network, a large penetration may alter the flows, not only on the distribution lines, but also on the transmission system and through the transmission - distribution interfaces. The optimal capacity and production costs for the UK transmission network have been calculated for several combinations of load profiles and typical wind/PV output scenarios. A full economic analysis is developed, showing the benefits and disadvantages that a large penetration of these distributed generators may have on transmission system operator reinforcement strategies. Closely related to planning factors are institutional, revelatory, and economic considerations, such as transmission pricing, which may hamper the integration of renewable energy technologies into the electric utility industry. The second part of the research related to the impact of intermittent renewable energy technologies on the second by second, minute by minute, and half-hour by half-hour operations of power systems. If a large integration of these new generators partially replaces the conventional rotating machines the aggregate fluctuation starts to become an important factor, and should be taken into account for the calculation of the balancing requirements. Additional balancing requirements would increase the total balancing cost and this could stop the future development of the intermittent sources.

Model Predictive Control techniques with application to photovoltaic, DC Microgrid, and a multi-sourced hybrid energy system

NASA Astrophysics Data System (ADS)

Shadmand, Mohammad Bagher

Renewable energy sources continue to gain popularity. However, two major limitations exist that prevent widespread adoption: availability and variability of the electricity generated and the cost of the equipment. The focus of this dissertation is Model Predictive Control (MPC) for optimal sized photovoltaic (PV), DC Microgrid, and multi-sourced hybrid energy systems. The main considered applications are: maximum power point tracking (MPPT) by MPC, droop predictive control of DC microgrid, MPC of grid-interaction inverter, MPC of a capacitor-less VAR compensator based on matrix converter (MC). This dissertation firstly investigates a multi-objective optimization technique for a hybrid distribution system. The variability of a high-penetration PV scenario is also studied when incorporated into the microgrid concept. Emerging (PV) technologies have enabled the creation of contoured and conformal PV surfaces; the effect of using non-planar PV modules on variability is also analyzed. The proposed predictive control to achieve maximum power point for isolated and grid-tied PV systems speeds up the control loop since it predicts error before the switching signal is applied to the converter. The low conversion efficiency of PV cells means we want to ensure always operating at maximum possible power point to make the system economical. Thus the proposed MPPT technique can capture more energy compared to the conventional MPPT techniques from same amount of installed solar panel. Because of the MPPT requirement, the output voltage of the converter may vary. Therefore a droop control is needed to feed multiple arrays of photovoltaic systems to a DC bus in microgrid community. Development of a droop control technique by means of predictive control is another application of this dissertation. Reactive power, denoted as Volt Ampere Reactive (VAR), has several undesirable consequences on AC power system network such as reduction in power transfer capability and increase in transmission loss if not controlled appropriately. Inductive loads which operate with lagging power factor consume VARs, thus load compensation techniques by capacitor bank employment locally supply VARs needed by the load. Capacitors are highly unreliable components due to their failure modes and aging inherent. Approximately 60% of power electronic devices failure such as voltage-source inverter based static synchronous compensator (STATCOM) is due to the use of aluminum electrolytic DC capacitors. Therefore, a capacitor-less VAR compensation is desired. This dissertation also investigates a STATCOM capacitor-less reactive power compensation that uses only inductors combined with predictive controlled matrix converter.

Design, modeling, simulation and evaluation of a distributed energy system

NASA Astrophysics Data System (ADS)

Cultura, Ambrosio B., II

This dissertation presents the design, modeling, simulation and evaluation of distributed energy resources (DER) consisting of photovoltaics (PV), wind turbines, batteries, a PEM fuel cell and supercapacitors. The distributed energy resources installed at UMass Lowell consist of the following: 2.5kW PV, 44kWhr lead acid batteries and 1500W, 500W & 300W wind turbines, which were installed before year 2000. Recently added to that are the following: 10.56 kW PV array, 2.4 kW wind turbine, 29 kWhr Lead acid batteries, a 1.2 kW PEM fuel cell and 4-140F supercapacitors. Each newly added energy resource has been designed, modeled, simulated and evaluated before its integration into the existing PV/Wind grid-connected system. The Mathematical and Simulink model of each system was derived and validated by comparing the simulated and experimental results. The Simulated results of energy generated from a 10.56kW PV system are in good agreement with the experimental results. A detailed electrical model of a 2.4kW wind turbine system equipped with a permanent magnet generator, diode rectifier, boost converter and inverter is presented. The analysis of the results demonstrates the effectiveness of the constructed simulink model, and can be used to predict the performance of the wind turbine. It was observed that a PEM fuel cell has a very fast response to load changes. Moreover, the model has validated the actual operation of the PEM fuel cell, showing that the simulated results in Matlab Simulink are consistent with the experimental results. The equivalent mathematical equation, derived from an electrical model of the supercapacitor, is used to simulate its voltage response. The model is completely capable of simulating its voltage behavior, and can predict the charge time and discharge time of voltages on the supercapacitor. The bi-directional dc-dc converter was designed in order to connect the 48V battery bank storage to the 24V battery bank storage. This connection was needed in order to increase the reliability of the DER system. Furthermore, the new computer-based Data Acquisition (DAQ) system for the DER has been designed and installed. The DAQ system is an important component in PC-based measurement, which is used in acquiring and storing data. The design and installation of signal conditioning improve the accuracy, effectiveness and safety of measurements, because of capabilities such as amplifications, isolation, and filtering. A Labview program was the software used to interface and communicate between the DAQ devices and the personal computer. The overall simulink model of the DER system is presented in the last chapter. The simulink model is discussed, and the discussion explains the operation of a grid connected DER. This model can be used as the basis or future reference for designs and installations of DER projects. This model can also be used in converting the DER grid connected system into a Smart Grid system, and that will be the next potential research work to explore.

On-line monitoring system of PV array based on internet of things technology

NASA Astrophysics Data System (ADS)

Li, Y. F.; Lin, P. J.; Zhou, H. F.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.; Su, F. P.

2017-11-01

The Internet of Things (IoT) Technology is used to inspect photovoltaic (PV) array which can greatly improve the monitoring, performance and maintenance of the PV array. In order to efficiently realize the remote monitoring of PV operating environment, an on-line monitoring system of PV array based on IoT is designed in this paper. The system includes data acquisition, data gateway and PV monitoring centre (PVMC) website. Firstly, the DSP-TMS320F28335 is applied to collect indicators of PV array using sensors, then the data are transmitted to data gateway through ZigBee network. Secondly, the data gateway receives the data from data acquisition part, obtains geographic information via GPS module, and captures the scenes around PV array via USB camera, then uploads them to PVMC website. Finally, the PVMC website based on Laravel framework receives all data from data gateway and displays them with abundant charts. Moreover, a fault diagnosis approach for PV array based on Extreme Learning Machine (ELM) is applied in PVMC. Once fault occurs, a user alert can be sent via E-mail. The designed system enables users to browse the operating conditions of PV array on PVMC website, including electrical, environmental parameters and video. Experimental results show that the presented monitoring system can efficiently real-time monitor the PV array, and the fault diagnosis approach reaches a high accuracy of 97.5%.

DGIC Interconnection Insights | Distributed Generation Interconnection

Science.gov Websites

Power Association (SEPA), produced a webinar Utility Participation in the Roof Top Solar PV Market with ). These leaders are pioneering utility-owned rooftop solar programs to broaden the reach of solar PV utility hired solar PV developers who, representing CPS Energy, will install, own, and maintain solar

An Evaluation Method for PV Systems by using Limited Data Item

NASA Astrophysics Data System (ADS)

Oozeki, Takashi; Izawa, Toshiyasu; Otani, Kenji; Tsuzuku, Ken; Koike, Hisafumi; Kurokawa, Kosuke

Beside photovoltaic (PV) systems are recently expected to introduce around Japan, almost all of them have not been taken care after established since PV systems are called maintenance free. In fact, there are few troubles about PV operations behind owners of PV systems because characteristics of them cannot be identified completely such as the ideal output energy. Therefore, it is very important to evaluate the characteristics of them. For evaluating them, equipments of measuring are required, and they, especially Pyrheliometer, are expensive as much as owners of the PV system cannot equip usually. Consequently, An evaluation method which can reveal the performance of operation such as the performance ratio with a very few kinds of data is necessary. In this paper, proposed method can evaluate performance ratio, shading losses, inverter efficiency losses by using only system output data items. The adequacies of the method are indicated by comparing with actual data and field survey results. As a result, the method is intended to be checking tool of PV system performance.

Grid tied PV/battery system architecture and power management for fast electric vehicle charging

NASA Astrophysics Data System (ADS)

Badawy, Mohamed O.

The prospective spread of Electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) arises the need for fast charging rates. Higher charging rates requirements lead to high power demands, which cant be always supported by the grid. Thus, the use of on-site sources alongside the electrical grid for EVs charging is a rising area of interest. In this dissertation, a photovoltaic (PV) source is used to support the high power EVs charging. However, the PV output power has an intermittent nature that is dependable on the weather conditions. Thus, battery storage are combined with the PV in a grid tied system, providing a steady source for on-site EVs use in a renewable energy based fast charging station. Verily, renewable energy based fast charging stations should be cost effective, efficient, and reliable to increase the penetration of EVs in the automotive market. Thus, this Dissertation proposes a novel power flow management topology that aims on decreasing the running cost along with innovative hardware solutions and control structures for the developed architecture. The developed power flow management topology operates the hybrid system at the minimum operating cost while extending the battery lifetime. An optimization problem is formulated and two stages of optimization, i.e online and offline stages, are adopted to optimize the batteries state of charge (SOC) scheduling and continuously compensate for the forecasting errors. The proposed power flow management topology is validated and tested with two metering systems, i.e unified and dual metering systems. The results suggested that minimal power flow is anticipated from the battery storage to the grid in the dual metering system. Thus, the power electronic interfacing system is designed accordingly. Interconnecting bi-directional DC/DC converters are analyzed, and a cascaded buck boost (CBB) converter is chosen and tested under 80 kW power flow rates. The need to perform power factor correction (PFC) on the grid power while supplying the battery storage and the DC loads inspired a novel dual switch control structure for the CBB AC/DC converter used in this dissertation. Thus, The CBB operates at a discontinuous capacitor voltage mode (DCVM) and the control structure enables for a non-distorted input current at overlapping output voltage levels. The PFC concept is validated and tested for a single phase rectifier and a 3 phase extension of the proposed concept is presented. Lastly, the PV source used in this study is required to supply power to both, the grid system, and to the DC loads, i.e the battery storage and the EVs. Thus, the PV panels used are connected in series to reach a desirable high voltage on the DC bus output of the PV system. Consequently, a novel differential power processing architecture is proposed in this dissertation. The proposed architecture enables each PV element to operate at its local maximum power point (MPP) while processing only a small portion of its total generated power through the distributed integrated converters. This leads to higher energy capture at an increased conversion efficiency while overcoming the difficulties associated with unmatched MPPs of the PV elements.

Andy Walker | NREL

Science.gov Websites

efficiency and renewable energy projects. His patent on the Renewable Energy Optimization (REO) method of distribution function for time-series simulation Analytical and numerical optimization Project delivery with System Operations and Maintenance: 2nd Edition, 2016, NREL/Sandia/Sunspec Alliance SuNLaMP PV O&M

Photovoltaic power generation; Proceedings of the EC Contractors' Meeting, Hamburg, West Germany, July 12, 13, 1983

NASA Astrophysics Data System (ADS)

Palz, W.

Several operational examples of photovoltaic (PV) power generation systems in Europe are described. The systems include: a 300 kW power plant in Pellworm, West Germany; the Tremiti desalination plant in Tremiti, Italy; and the Kythnos PV power plant in Kythnos, Greece. Consideration is also given to a PV-powered swimming pool heating system in Chevretogne, Belgium; a rural electrification program using PV power plants in French Guyana; a solar-wind project on Terschelling Island, the Netherlands; and a PV power plant for hydrogen production and water pumping in Hoboken, Belgium. A 30-kW power station in Marchwood, England and the Nice airport survey and control system are also cited as examples of successful PV power generation systems.

On enhancing energy harvesting performance of the photovoltaic modules using an automatic cooling system and assessing its economic benefits of mitigating greenhouse effects on the environment

NASA Astrophysics Data System (ADS)

Wang, Jen-Cheng; Liao, Min-Sheng; Lee, Yeun-Chung; Liu, Cheng-Yue; Kuo, Kun-Chang; Chou, Cheng-Ying; Huang, Chen-Kang; Jiang, Joe-Air

2018-02-01

The performance of photovoltaic (PV) modules under outdoor operation is greatly affected by their location and environmental conditions. The temperature of a PV module gradually increases as it is exposed to solar irradiation, resulting in degradation of its electrical characteristics and power generation efficiency. This study adopts wireless sensor network (WSN) technology to develop an automatic water-cooling system for PV modules in order to improve their PV power generation efficiency. A temperature estimation method is developed to quickly and accurately estimate the PV module temperatures based on weather data provided from the WSN monitoring system. Further, an estimation method is also proposed for evaluation of the electrical characteristics and output power of the PV modules, which is performed remotely via a control platform. The automatic WSN-based water-cooling mechanism is designed to avoid the PV module temperature from reaching saturation. Equipping each PV module with the WSN-based cooling system, the ambient conditions are monitored automatically so that the temperature of the PV module is controlled by sprinkling water on the panel surface. The field-test experiment results show an increase in the energy harvested by the PV modules of approximately 17.75% when using the proposed WSN-based cooling system.

Photovoltaic Reliability Group activities in USA and Brazil (Presentation Recording)

NASA Astrophysics Data System (ADS)

Dhere, Neelkanth G.; Cruz, Leila R. O.

2015-09-01

Recently prices of photovoltaic (PV) systems have been reduced considerably and may continue to be reduced making them attractive. If these systems provide electricity over the stipulated warranty period, it would be possible attain socket parity within the next few years. Current photovoltaic module qualifications tests help in minimizing infant mortality but do not guarantee useful lifetime over the warranty period. The PV Module Quality Assurance Task Force (PVQAT) is trying to formulate accelerated tests that will be useful towards achieving the ultimate goal of assuring useful lifetime over the warranty period as well as to assure manufacturing quality. Unfortunately, assuring the manufacturing quality may require 24/7 presence. Alternatively, collecting data on the performance of fielded systems would assist in assuring manufacturing quality. Here PV systems installed by home-owners and small businesses can constitute as an important untapped source of data. The volunteer group, PV - Reliable, Safe and Sustainable Quality! (PVRessQ!) is providing valuable service to small PV system owners. Photovoltaic Reliability Group (PVRG) is initiating activities in USA and Brazil to assist home owners and small businesses in monitoring photovoltaic (PV) module performance and enforcing warranty. It will work in collaboration with small PV system owners, consumer protection agencies. Brazil is endowed with excellent solar irradiance making it attractive for installation of PV systems. Participating owners of small PV systems would instruct inverter manufacturers to copy the daily e-mails to PVRG and as necessary, will authorize the PVRG to carry out review of PV systems. The presentation will consist of overall activities of PVRG in USA and Brazil.

Duke Energy Photovoltaic Integration Study: Carolinas Service Areas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Shuai; Samaan, Nader A.; Meng, Da

2014-03-01

Solar energy collected using photovoltaic (PV) technology is a clean and renewable energy source that offers multiple benefits to the electric utility industry and its customers, such as cost predictability, reduced emissions, and loss reduction by distributed installations. Renewable energy goals established in North Carolina Senate Bill 3 (SB3), in combination with the state tax credit and decreases in the cost of energy from PV panels, have resulted in rapid solar power penetration within the Carolinas services areas of Duke Energy. Continued decreases in PV prices are expected to lead to greater PV penetration rates than currently required in SB3.more » Despite the potential benefits, significant penetration of PV energy is of concern to the utility industry because of its impact on operating reliability and integration cost to customers, and equally important, how any additional costs may be allocated to different customer groups. Some of these impacts might become limiting factors for PV energy, especially growing distributed generation installed at customer sites. Recognizing the importance of renewable energy developments for a sustainable energy future and economic growth, Duke Energy has commissioned this study to simulate the effects of high-PV penetration rates and to initiate the process of quantifying the impacts. The objective of the study is to inform resource plans, guide operation improvements, and drive infrastructure investments for a steady and smooth transition to a new energy mix that provides optimal values to customers. The study team consists of experts from Pacific Northwest National Laboratory (PNNL), Power Costs, Inc. (PCI), Clean Power Research (CPR), Alstom Grid, and Duke Energy. PNNL, PCI, and CPR performed the study on generation impacts; Duke Energy modeled the transmission cases; and distribution simulations were conducted by Alstom Grid. PNNL analyzed the results from each work stream and produced the report.« less

PV system field experience and reliability

NASA Astrophysics Data System (ADS)

Durand, Steven; Rosenthal, Andrew; Thomas, Mike

1997-02-01

Hybrid power systems consisting of battery inverters coupled with diesel, propane, or gasoline engine-driven electrical generators, and photovoltaic arrays are being used in many remote locations. The potential cost advantages of hybrid systems over simple engine-driven generator systems are causing hybrid systems to be considered for numerous applications including single-family residential, communications, and village power. This paper discusses the various design constraints of such systems and presents one technique for reducing hybrid system losses. The Southwest Technology Development Institute under contract to the National Renewable Energy Laboratory and Sandia National Laboratories has been installing data acquisition systems (DAS) on a number of small and large hybrid PV systems. These systems range from small residential systems (1 kW PV - 7 kW generator), to medium sized systems (10 kW PV - 20 kW generator), to larger systems (100 kW PV - 200 kW generator). Even larger systems are being installed with hundreds of kilowatts of PV modules, multiple wind machines, and larger diesel generators.

Photovoltaic Inverter Controllers Seeking AC Optimal Power Flow Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dall'Anese, Emiliano; Dhople, Sairaj V.; Giannakis, Georgios B.

This paper considers future distribution networks featuring inverter-interfaced photovoltaic (PV) systems, and addresses the synthesis of feedback controllers that seek real- and reactive-power inverter setpoints corresponding to AC optimal power flow (OPF) solutions. The objective is to bridge the temporal gap between long-term system optimization and real-time inverter control, and enable seamless PV-owner participation without compromising system efficiency and stability. The design of the controllers is grounded on a dual ..epsilon..-subgradient method, while semidefinite programming relaxations are advocated to bypass the non-convexity of AC OPF formulations. Global convergence of inverter output powers is analytically established for diminishing stepsize rules formore » cases where: i) computational limits dictate asynchronous updates of the controller signals, and ii) inverter reference inputs may be updated at a faster rate than the power-output settling time.« less

Non-Gaussian elliptic-flow fluctuations in PbPb collisions at $$\\sqrt{\\smash[b]{s_{_\\text{NN}}}} = 5.02$$ TeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sirunyan, Albert M; et al.

Event-by-event fluctuations in the elliptic-flow coefficientmore » $$v_2$$ are studied in PbPb collisions at $$\\sqrt{s_{_\\text{NN}}} = 5.02$$ TeV using the CMS detector at the CERN LHC. Elliptic-flow probability distributions $${p}(v_2)$$ for charged particles with transverse momentum 0.3$$< p_\\mathrm{T} <$$3.0 GeV and pseudorapidity $$| \\eta | <$$ 1.0 are determined for different collision centrality classes. The moments of the $${p}(v_2)$$ distributions are used to calculate the $$v_{2}$$ coefficients based on cumulant orders 2, 4, 6, and 8. A rank ordering of the higher-order cumulant results and nonzero standardized skewness values obtained for the $${p}(v_2)$$ distributions indicate non-Gaussian initial-state fluctuation behavior. Bessel-Gaussian and elliptic power fits to the flow distributions are studied to characterize the initial-state spatial anisotropy.« less

Highlights of recent balance of system research and evaluation

NASA Astrophysics Data System (ADS)

Thomas, M. G.; Stevens, J. W.

The cost of most photovoltaic (PV) systems is more a function of the balance of system (BOS) components than the collectors. The exception to this rule is the grid-tied system whose cost is related more directly to the collectors, and secondarily to the inverter/controls. In fact, recent procurements throughout the country document that collector costs for roof-mounted, utility-tied systems (Russell, PV Systems Workshop, 7/94) represent 60% to 70% of the system cost. This contrasts with the current market for packaged stand-alone all PV or PV-hybrid systems where collectors represent only 25% to 35% of the total. Not only are the BOS components the cost drivers in the current cost-effective PV system market place, they are also the least reliable components. This paper discusses the impact that BOS issues have on component performance, system performance, and system cost and reliability. We will also look at recent recommended changes in system design based upon performance evaluations of fielded PV systems.

Photovoltaic system derived data for determining the solar resource and for modeling the performance of other photovoltaic systems

DOE PAGES

Marion, Bill; Smith, Benjamin

2017-03-27

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. Here, a method was developed to back-solve for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the measured ac power of south-facing PV module/micro-inverter systems. The method was validated using one year of irradiance and PV performance measurements for five PV systems, each with a different tilt/azimuth orientation, and located in Golden, Colorado. Compared to using a measured global horizontal irradiance for PV performance model input,more » using the back-solved values of DNI and DHI only increased the range of mean bias deviations from measured values by 0.6% for the modeled annual averages of the global tilt irradiance and ac power for the five PV systems. Correcting for angle-of-incidence effects is an important feature of the method to prevent underestimating the solar resource and for modeling the performance of PV systems with more dissimilar PV module orientations. The results for the method were also shown more favorable than the results when using an existing power projection method for estimating the ac power.« less

Photovoltaic system derived data for determining the solar resource and for modeling the performance of other photovoltaic systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marion, Bill; Smith, Benjamin

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. Here, a method was developed to back-solve for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the measured ac power of south-facing PV module/micro-inverter systems. The method was validated using one year of irradiance and PV performance measurements for five PV systems, each with a different tilt/azimuth orientation, and located in Golden, Colorado. Compared to using a measured global horizontal irradiance for PV performance model input,more » using the back-solved values of DNI and DHI only increased the range of mean bias deviations from measured values by 0.6% for the modeled annual averages of the global tilt irradiance and ac power for the five PV systems. Correcting for angle-of-incidence effects is an important feature of the method to prevent underestimating the solar resource and for modeling the performance of PV systems with more dissimilar PV module orientations. The results for the method were also shown more favorable than the results when using an existing power projection method for estimating the ac power.« less

Simulation study of air and water cooled photovoltaic panel using ANSYS

NASA Astrophysics Data System (ADS)

Syafiqah, Z.; Amin, N. A. M.; Irwan, Y. M.; Majid, M. S. A.; Aziz, N. A.

2017-10-01

Demand for alternative energy is growing due to decrease of fossil fuels sources. One of the promising and popular renewable energy technology is a photovoltaic (PV) technology. During the actual operation of PV cells, only around 15% of solar irradiance is converted to electricity, while the rest is converted into heat. The electrical efficiency decreases with the increment in PV panel’s temperature. This electrical energy is referring to the open-circuit voltage (Voc), short-circuit current (Isc) and output power generate. This paper examines and discusses the PV panel with water and air cooling system. The air cooling system was installed at the back of PV panel while water cooling system at front surface. The analyses of both cooling systems were done by using ANSYS CFX and PSPICE software. The highest temperature of PV panel without cooling system is 66.3 °C. There is a decrement of 19.2% and 53.2% in temperature with the air and water cooling system applied to PV panel.

Climate, Air Quality, and Human Health Benefits of Various Solar Photovoltaic Development Scenarios in China in 2030

NASA Astrophysics Data System (ADS)

Yang, J.; Mauzerall, D. L.; Wagner, F.; Li, X.

2016-12-01

Solar photovoltaic (PV) technology can greatly reduce both air pollution and GHG emissions from the power sector. The Chinese government has plans to scale up solar PV installation between now and 2030. However, there is little analysis of how deployment strategies will influence the range of benefits. Here we conduct the first integrated assessment study that quantifies the climate, air quality, and related human health benefits of various solar PV development strategies in 2030 China. Our results indicate that both the location of PV deployment, which coal power plants are replaced, and the extent of inter-provincial transmission greatly influence the co-benefits. We compare CO2 and PM2.5 reductions from two PV installation scenarios both with the 2030 government target of 400 GW national installed capacity. First, we assume all solar PV is utilized within the province in which it is generated and that it can not exceed 30% of total provincial electricity generation. We find that deploying more solar PV in locations near load centers via distributed PV systems has larger benefits and could lead to approximately 20,500 (between 8000 - 32,400, high and low bounds) annual avoided premature deaths, 15% more than building utility-scale solar PV plants in the sunny, yet sparsely populated northwest. The difference occurs because in the northwest a lower population and cleaner air leads to smaller reductions in air pollution related premature mortalities. Also greater potential for PV curtailment exists in the west. In terms of CO2 reduction, deploying PV near load centers leads to 12% greater reductions in CO2 emissions from the power sector - approximately 5% of China's total CO2 emission in 2030. Second, we enable inter-provincial transmission of PV electricity within each of China's six regional grids which allows greater use of abundant sunlight in the northwest. Our results for 2030 show that by expanding to the regional grid, curtailment rates in the northwest would drop from 25% to 14%, and additional reductions of 30% SO2 and 25% NOxfrom the power sector would result. Thus our study demonstrates substantial air quality and climate co-benefits of developing solar PV in China. We also find that expanding inter-provincial electricity transmission would both reduce curtailment and increase air quality benefits.

Photovoltaic System Pricing Trends: Historical, Recent, and Near-Term Projections 2015 Edition

DOE Data Explorer

Feldman, David; Barbose, Galen; Margolis, Robert; Bolinger, Mark; Chung, Donald; Fu, Ran; Seel, Joachim; Davidson, Carolyn; Wiser, Ryan

2016-05-13

This is the fourth edition in an annual briefing prepared jointly by LBNL and NREL intended to provide a high-level overview of historical, recent, and projected near-term PV system pricing trends in the United States. The briefing draws on several ongoing research activities at the two labs, including LBNL's annual Tracking the Sun report series, NREL's bottom-up PV cost modeling, and NREL's synthesis of PV market data and projections. The briefing examines progress in PV price reductions to help DOE and other PV stakeholders manage the transition to a market-driven PV industry, and integrates different perspectives and methodologies for characterizing PV system pricing, in order to provide a broader perspective on underlying trends within the industry.

Tumor necrosis factor-α -308 G>A and interleukin-6 -174 G>C promoter polymorphisms and pemphigus.

PubMed

Mosaad, Youssef M; Fathy, Hanan; Fawzy, Zakaria; El-Saied, Moustafa Ahmed

2012-05-01

The objective of this study was to analyze the possible involvement of the tumor necrosis factor (TNF)-α -308 G>A and interleukin-6 (IL-6) -174 G>C polymorphisms in the susceptibility and/or disease profile of pemphigus in Egyptian patients. Detection of TNF-α -308 G>A by amplification refractory mutation system and IL-6 -174 G>C by restriction fragment length polymorphism was performed for 70 patients and 203 controls. No significant differences were observed in the distribution of TNF-α -308 in pemphigus patients and controls. However, GA+AA genotypes were more frequent in pemphigus vulgaris (PV) patients only versus controls (p(c) = 0.046). The frequency of the C allele and CC/GC genotypes of IL-6 -174 was significantly higher in pemphigus patients and those with the 2 major clinical forms (PV and pemphigus foliaceus [PF]) compared with controls (p < 0.05). Comparison of the distribution of TNF-α -308 and IL-6 -174 variants in relation to clinical type of pemphigus (PV versus PF), activity score, recurrence, and demographic data of patients revealed no significant associations. The IL-6 -174 CC genotype represents a marker of increased susceptibility to pemphigus in Egyptian patients and GG genotype can be considered a low-risk genotype; TNF-α -308 A-containing genotypes contribute to the susceptibility to PV only. Copyright © 2012 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

Zinc Bromide Flow Battery Installation for Islanding and Backup Power

DTIC Science & Technology

2016-09-18

ability to control the generation has become more difficult with the increase of renewable energy systems such as solar photovoltaics ( PV ) and wind... PV and Inverter Room Building 6311 Rooftop Solar PV 30kW 232kW STC PV Array B5-PS2T33 Pad Switchboard ZnBr Energy Storage System (ESS) PowerBoxEnergy...Agreement • 1.5 MW of Photovoltaic • PV Parking lot lights • 24 Solar Thermal systems including the Combat Training Tank (Pool) Energy/Water Efficiency

Measurement of the Width and Skewness of Elliptic Flow Fluctuations in PbPb Collisions at 5.02 TeV with CMS

NASA Astrophysics Data System (ADS)

Castle, James R.; CMS Collaboration

2017-11-01

Flow harmonic fluctuations are studied for PbPb collisions at √{sNN} = 5.02 TeV using the CMS detector at the LHC. Flow harmonic probability distributions p(v2) are obtained by unfolding smearing effects from observed azimuthal anisotropy distributions using particles of 0.3

Integrated application of combined cooling, heating and power poly-generation PV radiant panel system of zero energy buildings

NASA Astrophysics Data System (ADS)

Yin, Baoquan

2018-02-01

A new type of combined cooling, heating and power of photovoltaic radiant panel (PV/R) module was proposed, and applied in the zero energy buildings in this paper. The energy system of this building is composed of PV/R module, low temperature difference terminal, energy storage, multi-source heat pump, energy balance control system. Radiant panel is attached on the backside of the PV module for cooling the PV, which is called PV/R module. During the daytime, the PV module was cooled down with the radiant panel, as the temperature coefficient influence, the power efficiency was increased by 8% to 14%, the radiant panel solar heat collecting efficiency was about 45%. Through the nocturnal radiant cooling, the PV/R cooling capacity could be 50 W/m2. For the multifunction energy device, the system shows the versatility during the heating, cooling and power used of building utilization all year round.

Solar San Diego: The Impact of Binomial Rate Structures on Real PV-Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Geet, O.; Brown, E.; Blair, T.

2008-01-01

There is confusion in the marketplace regarding the impact of solar photovoltaics (PV) on the user's actual electricity bill under California Net Energy Metering, particularly with binomial tariffs (those that include both demand and energy charges) and time-of-use (TOU) rate structures. The City of San Diego has extensive real-time electrical metering on most of its buildings and PV systems, with interval data for overall consumption and PV electrical production available for multiple years. This paper uses 2007 PV-system data from two city facilities to illustrate the impacts of binomial rate designs. The analysis will determine the energy and demand savingsmore » that the PV systems are achieving relative to the absence of systems. A financial analysis of PV-system performance under various rates structures is presented. The data revealed that actual demand and energy use benefits of bionomial tariffs increase in summer months, when solar resources allow for maximized electricity production. In a binomial tariff system, varying on- and semi-peak times can result in approximately $1,100 change in demand charges per month over not having a PV system in place, an approximate 30% cost savings. The PV systems are also shown to have a 30%-50% reduction in facility energy charges in 2007. Future work will include combining demand and electricity charges and increasing the breadth of rate structures tested, including the impacts of non-coincident demand charges.« less

Numerical modeling of uncertainty and variability in the technology, manufacturing, and economics of crystalline silicon photovoltaics

NASA Astrophysics Data System (ADS)

Ristow, Alan H.

2008-10-01

Electricity generated from photovoltaics (PV) promises to satisfy the world's ever-growing thirst for energy without significant pollution and greenhouse gas emissions. At present, however, PV is several times too expensive to compete economically with conventional sources of electricity delivered via the power grid. To ensure long-term success, must achieve cost parity with electricity generated by conventional sources of electricity. This requires detailed understanding of the relationship between technology and economics as it pertains to PV devices and systems. The research tasks of this thesis focus on developing and using four types of models in concert to develop a complete picture of how solar cell technology and design choices affect the quantity and cost of energy produced by PV systems. It is shown in this thesis that high-efficiency solar cells can leverage balance-of-systems (BOS) costs to gain an economic advantage over solar cells with low efficiencies. This advantage is quantified and dubbed the "efficiency premium." Solar cell device models are linked to models of manufacturing cost and PV system performance to estimate both PV system cost and performance. These, in turn, are linked to a model of levelized electricity cost to estimate the per-kilowatt-hour cost of electricity produced by the PV system. A numerical PV module manufacturing cost model is developed to facilitate this analysis. The models and methods developed in this thesis are used to propose a roadmap to high-efficiency multicrystalline-silicon PV modules that achieve cost parity with electricity from the grid. The impact of PV system failures on the cost of electricity is also investigated; from this, a methodology is proposed for improving the reliability of PV inverters.

NATIONAL ASSESSMENT OF EMISSIONS REDUCTION IMPACT FROM ROOFTOP PV

EPA Science Inventory

This effort will determine the emissions impacts to the U.S. PV generated electricity when PV systems are installed on building rooftops and employed as demand-side power supplies. The national assessment will be based on data provided by existing rooftop PV systems that have be...

The Tucson Electric Power Solar Test Yard

NASA Astrophysics Data System (ADS)

Lonij, Vincent; Orsburn, Sean; Salhab, Anas; Kopp, Emily; Brooks, Adria; Jayadevan, Vijai; Greenberg, James; St. Germaine, Michael; Allen, Nate; Jones, Sarah; Hardesty, Garrett; Cronin, Alex

2011-10-01

In collaboration with Tucson Electric Power we studied the performance of twenty different grid-tied photovoltaic systems, consisting of over 600 PV modules in all. We added data acquisition hardware to monitor DC power from the modules, AC power from the inverters, PV module temperatures, and meteorological data such as the irradiance incident on the PV systems. We report measurements of PV system yields and efficiencies over periods of minutes, days, and years. We also report temperature and irradiance coefficients of efficiency and measurements of long-term degradation. We also use our data to validate models that predict the output from PV systems.

The AC photovoltaic module is here!

NASA Astrophysics Data System (ADS)

Strong, Steven J.; Wohlgemuth, John H.; Wills, Robert H.

1997-02-01

This paper describes the design, development, and performance results of a large-area photovoltaic module whose electrical output is ac power suitable for direct connection to the utility grid. The large-area ac PV module features a dedicated, integrally mounted, high-efficiency dc-to-ac power inverter with a nominal output of 250 watts (STC) at 120 Vac, 60 H, that is fully compatible with utility power. The module's output is connected directly to the building's conventional ac distribution system without need for any dc wiring, string combiners, dc ground-fault protection or additional power-conditioning equipment. With its advantages, the ac photovoltaic module promises to become a universal building block for use in all utility-interactive PV systems. This paper discusses AC Module design aspects and utility interface issues (including islanding).

Distribution System Pricing with Distributed Energy Resources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hledik, Ryan; Lazar, Jim; Schwartz, Lisa

Technological changes in the electric utility industry bring tremendous opportunities and significant challenges. Customers are installing clean sources of on-site generation such as rooftop solar photovoltaic (PV) systems. At the same time, smart appliances and control systems that can communicate with the grid are entering the retail market. Among the opportunities these changes create are a cleaner and more diverse power system, the ability to improve system reliability and system resilience, and the potential for lower total costs. Challenges include integrating these new resources in a way that maintains system reliability, provides an equitable sharing of system costs, and avoidsmore » unbalanced impacts on different groups of customers, including those who install distributed energy resources (DERs) and low-income households who may be the least able to afford the transition.« less

Simulation of Hawaiian Electric Companies Feeder Operations with Advanced Inverters and Analysis of Annual Photovoltaic Energy Curtailment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giraldez Miner, Julieta I.; Nagarajan, Adarsh; Gotseff, Peter

The Hawaiian Electric Companies achieved a consolidated Renewable Portfolio Standard (RPS) of approximately 26% at the end of 2016. This significant RPS performance was achieved using various renewable energy sources - biomass, geothermal, solar photovoltaic (PV) systems, hydro, wind, and biofuels - and customer-sited, grid-connected technologies (primarily private rooftop solar PV systems). The Hawaiian Electric Companies are preparing grid-modernization plans for the island grids. The plans outline specific near-term actions to accelerate the achievement of Hawai'i's 100% RPS by 2045. A key element of the Companies' grid-modernization strategy is to utilize new technologies - including storage and PV systems withmore » grid-supportive inverters - that will help to more than triple the amount of private rooftop solar PV systems. The Hawaiian Electric Companies collaborated with the Smart Inverter Technical Working Group Hawai'i (SITWG) to partner with the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to research the implementation of advanced inverter grid support functions (GSF). Together with the technical guidance from the Companies's planning engineers and stakeholder input from the SITWG members, NREL proposed a scope of work that explored different modes of voltage-regulation GSF to better understand the trade-offs of the grid benefits and curtailment impacts from the activation of selected advanced inverter grid support functions. The simulation results presented in this report examine the effectiveness in regulating voltage as well as the impact to the utility and the customers of various inverter-based grid support functions on two Hawaiian Electric distribution substations.« less

Quantifying Proportional Variability

PubMed Central

Heath, Joel P.; Borowski, Peter

2013-01-01

Real quantities can undergo such a wide variety of dynamics that the mean is often a meaningless reference point for measuring variability. Despite their widespread application, techniques like the Coefficient of Variation are not truly proportional and exhibit pathological properties. The non-parametric measure Proportional Variability (PV) [1] resolves these issues and provides a robust way to summarize and compare variation in quantities exhibiting diverse dynamical behaviour. Instead of being based on deviation from an average value, variation is simply quantified by comparing the numbers to each other, requiring no assumptions about central tendency or underlying statistical distributions. While PV has been introduced before and has already been applied in various contexts to population dynamics, here we present a deeper analysis of this new measure, derive analytical expressions for the PV of several general distributions and present new comparisons with the Coefficient of Variation, demonstrating cases in which PV is the more favorable measure. We show that PV provides an easily interpretable approach for measuring and comparing variation that can be generally applied throughout the sciences, from contexts ranging from stock market stability to climate variation. PMID:24386334

Photovoltaic Lifetime Project | Photovoltaic Research | NREL

Science.gov Websites

PV & Solar Resource Testing Accelerated Testing & Analysis Systems Engineering Project Sandia National Laboratories' PV Performance Modeling Collaborative website. Jinko Solar. PV systems mounted on the ground. Jinko Solar PV Lifetime installation at NREL. need-alt Light-induced degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmintier, Bryan S; Bugbee, Bruce; Gotseff, Peter

Capturing technical and economic impacts of solar photovoltaics (PV) and other distributed energy resources (DERs) on electric distribution systems can require high-time resolution (e.g. 1 minute), long-duration (e.g. 1 year) simulations. However, such simulations can be computationally prohibitive, particularly when including complex control schemes in quasi-steady-state time series (QSTS) simulation. Various approaches have been used in the literature to down select representative time segments (e.g. days), but typically these are best suited for lower time resolutions or consider only a single data stream (e.g. PV production) for selection. We present a statistical approach that combines stratified sampling and bootstrapping tomore » select representative days while also providing a simple method to reassemble annual results. We describe the approach in the context of a recent study with a utility partner. This approach enables much faster QSTS analysis by simulating only a subset of days, while maintaining accurate annual estimates.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbose, Galen; Wiser, Ryan; Bolinger, Mark

In the U.S., the increasing financial support for customer-sited photovoltaic (PV) systems provided through publicly-funded incentive programs has heightened concerns about the long-term performance of these systems. Given the barriers that customers face to ensuring that their PV systems perform well, and the responsibility that PV incentive programs bear to ensure that public funds are prudently spent, these programs should, and often do, play a critical role in addressing PV system performance. To provide a point of reference for assessing the current state of the art, and to inform program design efforts going forward, we examine the approaches to encouragingmore » PV system performance used by 32 prominent PV incentive programs in the U.S. We identify eight general strategies or groups of related strategies that these programs have used to address factors that affect performance, and describe key implementation details. Based on this review, we then offer recommendations for how PV incentive programs can be effectively designed to mitigate potential performance issues.« less

Estimation of the monthly average daily solar radiation using geographic information system and advanced case-based reasoning.

PubMed

Koo, Choongwan; Hong, Taehoon; Lee, Minhyun; Park, Hyo Seon

2013-05-07

The photovoltaic (PV) system is considered an unlimited source of clean energy, whose amount of electricity generation changes according to the monthly average daily solar radiation (MADSR). It is revealed that the MADSR distribution in South Korea has very diverse patterns due to the country's climatic and geographical characteristics. This study aimed to develop a MADSR estimation model for the location without the measured MADSR data, using an advanced case based reasoning (CBR) model, which is a hybrid methodology combining CBR with artificial neural network, multiregression analysis, and genetic algorithm. The average prediction accuracy of the advanced CBR model was very high at 95.69%, and the standard deviation of the prediction accuracy was 3.67%, showing a significant improvement in prediction accuracy and consistency. A case study was conducted to verify the proposed model. The proposed model could be useful for owner or construction manager in charge of determining whether or not to introduce the PV system and where to install it. Also, it would benefit contractors in a competitive bidding process to accurately estimate the electricity generation of the PV system in advance and to conduct an economic and environmental feasibility study from the life cycle perspective.

Fuzzy-PI-based centralised control of semi-isolated FP-SEPIC/ZETA BDC in a PV/battery hybrid system

NASA Astrophysics Data System (ADS)

Mahendran, Venmathi; Ramabadran, Ramaprabha

2016-11-01

Multiport converters with centralised controller have been most commonly used in stand-alone photovoltaic (PV)/battery hybrid system to supply the load smoothly without any disturbances. This study presents the performance analysis of four-port SEPIC/ZETA bidirectional converter (FP-SEPIC/ZETA BDC) using various types of centralised control schemes like Fuzzy tuned proportional integral controller (Fuzzy-PI), fuzzy logic controller (FLC) and conventional proportional integral (PI) controller. The proposed FP-SEPIC/ZETA BDC with various control strategy is derived for simultaneous power management of a PV source using distributed maximum power point tracking (DMPPT) algorithm, a rechargeable battery, and a load by means of centralised controller. The steady state and the dynamic response of the FP-SEPIC/ZETA BDC are analysed using three different types of controllers under line and load regulation. The Fuzzy-PI-based control scheme improves the dynamic response of the system when compared with the FLC and the conventional PI controller. The power balance between the ports is achieved by pseudorandom carrier modulation scheme. The response of the FP-SEPIC/ZETA BDC is also validated experimentally using hardware prototype model of 500 W system. The effectiveness of the control strategy is validated using simulation and experimental results.

Progressing Deployment of Solar Photovoltaic Installations in the United States

NASA Astrophysics Data System (ADS)

Kwan, Calvin Lee

2011-07-01

This dissertation evaluates the likelihood of solar PV playing a larger role in national and state level renewable energy portfolios. I examine the feasibility of large-scale solar PV arrays on college campuses, the financials associated with large-scale solar PV arrays and finally, the influence of environmental, economic, social and political variables on the distribution of residential solar PV arrays in the United States. Chapter two investigates the challenges and feasibility of college campuses adopting a net-zero energy policy. Using energy consumption data, local solar insolation data and projected campus growth, I present a method to identify the minimum sized solar PV array that is required for the City College campus of the Los Angeles Community College District to achieve net-zero energy status. I document how current energy demand can be reduced using strategic demand side management, with remaining energy demand being met using a solar PV array. Chapter three focuses on the financial feasibility of large-scale solar PV arrays, using the proposed City College campus array as an example. I document that even after demand side energy management initiatives and financial incentives, large-scale solar PV arrays continue to have ROIs greater than 25 years. I find that traditional financial evaluation methods are not suitable for environmental projects such as solar PV installations as externalities are not taken into account and therefore calls for development of alternative financial valuation methods. Chapter four investigates the influence of environmental, social, economic and political variables on the distribution of residential solar PV arrays across the United States using ZIP code level data from the 2000 US Census. Using data from the National Renewable Energy Laboratory's Open PV project, I document where residential solar PVs are currently located. A zero-inflated negative binomial model was run to evaluate the influence of selected variables. Using the same model, predicted residential solar PV shares were generated and illustrated using GIS software. The results of this model indicate that solar insolation, state energy deregulation and cost of electricity are statistically significant factors positively correlated with the adoption of residential solar PV arrays. With this information, policymakers at the towns and cities level can establish effective solar PV promoting policies and regulations for their respective locations.

A GUI Based Software for Sizing Stand Alone AC Coupled Hybrid PV-Diesel Power System under Malaysia Climate

NASA Astrophysics Data System (ADS)

Syafiqah Syahirah Mohamed, Nor; Amalina Banu Mohamat Adek, Noor; Hamid, Nurul Farhana Abd

2018-03-01

This paper presents the development of Graphical User Interface (GUI) software for sizing main component in AC coupled photovoltaic (PV) hybrid power system based on Malaysia climate. This software provides guideline for PV system integrator to design effectively the size of components and system configuration to match the system and load requirement with geographical condition. The concept of the proposed software is balancing the annual average renewable energy generation and load demand. In this study, the PV to diesel generator (DG) ratio is introduced by considering the hybrid system energy contribution. The GUI software is able to size the main components in the PV hybrid system to meet with the set target of energy contribution ratio. The rated powers of the components to be defined are PV array, grid-tie inverter, bi-directional inverter, battery storage and DG. GUI is used to perform all the system sizing procedures to make it user friendly interface as a sizing tool for AC coupled PV hybrid system. The GUI will be done by using Visual Studio 2015 based on the real data under Malaysia Climate.

A fault diagnosis system for PV power station based on global partitioned gradually approximation method

NASA Astrophysics Data System (ADS)

Wang, S.; Zhang, X. N.; Gao, D. D.; Liu, H. X.; Ye, J.; Li, L. R.

2016-08-01

As the solar photovoltaic (PV) power is applied extensively, more attentions are paid to the maintenance and fault diagnosis of PV power plants. Based on analysis of the structure of PV power station, the global partitioned gradually approximation method is proposed as a fault diagnosis algorithm to determine and locate the fault of PV panels. The PV array is divided into 16x16 blocks and numbered. On the basis of modularly processing of the PV array, the current values of each block are analyzed. The mean current value of each block is used for calculating the fault weigh factor. The fault threshold is defined to determine the fault, and the shade is considered to reduce the probability of misjudgments. A fault diagnosis system is designed and implemented with LabVIEW. And it has some functions including the data realtime display, online check, statistics, real-time prediction and fault diagnosis. Through the data from PV plants, the algorithm is verified. The results show that the fault diagnosis results are accurate, and the system works well. The validity and the possibility of the system are verified by the results as well. The developed system will be benefit for the maintenance and management of large scale PV array.

PVMaT 1998 overview

NASA Astrophysics Data System (ADS)

Mittchell, Richard L.; Symko-Davies, Martha; Thomas, Holly P.; Witt, C. Edwin

1999-03-01

The Photovoltaic Manufacturing Technology (PVMaT) Project is a government/industry research and development (R&D) partnership between the U.S. federal government (through the U.S. Department of Energy [DOE]) and members of the U.S. PV industry. The goals of PVMaT are to assist the U.S. PV industry improve module manufacturing processes and equipment; accelerate manufacturing cost reductions for PV modules, balance-of-systems components, and integrated systems; increase commercial product performance and reliability; and enhance investment opportunities for substantial scale-ups of U.S.-based PV manufacturing plant capacities. The approach for PVMaT has been to cost-share the R&D risk as industry explores new manufacturing options and ideas for improved PV modules and components, advances system and product integration, and develops new system designs. These activities will lead to overall reduced system life-cycle costs for reliable PV end-products. The 1994 PVMaT Product-Driven BOS and Systems activities, as well as Product-Driven Module Manufacturing R&D activities, are just being completed. Fourteen new subcontracts have just been awarded in the areas of PV System and Component Technology and Module Manufacturing Technology. Government funding, subcontractor cost-sharing, and a comparison of the relative efforts by PV technology throughout the PVMaT project are also discussed.

Intelligent control of PV system on the basis of the fuzzy recurrent neuronet*

NASA Astrophysics Data System (ADS)

Engel, E. A.; Kovalev, I. V.; Engel, N. E.

2016-04-01

This paper presents the fuzzy recurrent neuronet for PV system’s control. Based on the PV system’s state, the fuzzy recurrent neural net tracks the maximum power point under random perturbations. The validity and advantages of the proposed intelligent control of PV system are demonstrated by numerical simulations. The simulation results show that the proposed intelligent control of PV system achieves real-time control speed and competitive performance, as compared to a classical control scheme on the basis of the perturbation & observation algorithm.

Effects of Scandinavian hydro power on storage needs in a fully renewable European power system for various transmission capacity scenarios

NASA Astrophysics Data System (ADS)

Kies, Alexander; Nag, Kabitri; von Bremen, Lueder; Lorenz, Elke; Heinemann, Detlev

2015-04-01

The penetration of renewable energies in the European power system has increased in the last decades (23.5% share of renewables in the gross electricity consumption of the EU-28 in 2012) and is expected to increase further up to very high shares close to 100%. Planning and organizing this European energy transition towards sustainable power sources will be one of the major challenges of the 21st century. It is very likely that in a fully renewable European power system wind and photovoltaics (pv) will contribute the largest shares to the generation mix followed by hydro power. However, feed-in from wind and pv is due to the weather dependant nature of their resources fluctuating and non-controllable. To match generation and consumption several solutions and their combinations were proposed like very high backup-capacities of conventional power generation (e.g. fossile or nuclear), storages or the extension of the transmission grid. Apart from those options hydro power can be used to counterbalance fluctuating wind and pv generation to some extent. In this work we investigate the effects of hydro power from Norway and Sweden on residual storage needs in Europe depending on the overlaying grid scenario. High temporally and spatially resolved weather data with a spatial resolution of 7 x 7 km and a temporal resolution of 1 hour was used to model the feed-in from wind and pv for 34 investigated European countries for the years 2003-2012. Inflow into hydro storages and generation by run-of-river power plants were computed from ERA-Interim reanalysis runoff data at a spatial resolution of 0.75° x 0.75° and a daily temporal resolution. Power flows in a simplified transmission grid connecting the 34 European countries were modelled minimizing dissipation using a DC-flow approximation. Previous work has shown that hydro power, namely in Norway and Sweden, can reduce storage needs in a renewable European power system by a large extent. A 15% share of hydro power in Europe can reduce storage needs by up to 50% with respect to stored energy. This requires however large transmission capacities between the major hydro power producers in Scandinavia and the largest consumers of electrical energy in Western Europe. We show how Scandinavian hydro power can reduce storage needs in dependency of the transmission grid for two fully renewable scenarios: The first one has its wind and pv generation capacities distributed according to an empirically derived approach. The second scenario has an optimal spatial distribution to minimize storage needs distribution of wind and pv generation capacities across Europe. We show that in both cases hydro power together with a well developed transmission grid has the potential to contribute a large share to the solution of the generation-consumption mismatch problem. The work is part of the RESTORE 2050 project (BMBF) that investigates the requirements for cross-country grid extensions, usage of storage technologies and capacities and the development of new balancing technologies.

PV_LIB Toolbox v. 1.3

DOE Office of Scientific and Technical Information (OSTI.GOV)

2015-12-09

PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV system's plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms are documented in openly available literature with the appropriate references included in comments within the code.

Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Phillips, Brandon S.; Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H., Jr.

2015-01-01

To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of the space environment. It is critical to understand space environment interactions not only on the PV components, but also the array substrate materials, wiring harnesses, connectors, and protection circuitry (e.g. blocking diodes). Key elements of the space environment which must be accounted for in a PV system design include: Solar Photon Radiation, Charged Particle Radiation, Plasma, and Thermal Cycling. While solar photon radiation is central to generating power in PV systems, the complete spectrum includes short wavelength ultraviolet components, which photo-ionize materials, as well as long wavelength infrared which heat materials. High energy electron radiation has been demonstrated to significantly reduce the output power of III-V type PV cells; and proton radiation damages material surfaces - often impacting coverglasses and antireflective coatings. Plasma environments influence electrostatic charging of PV array materials, and must be understood to ensure that long duration arcs do not form and potentially destroy PV cells. Thermal cycling impacts all components on a PV array by inducing stresses due to thermal expansion and contraction. Given such demanding environments, and the complexity of structures and materials that form a PV array system, mission success can only be ensured through realistic testing in the laboratory. NASA's Marshall Space Flight Center has developed a broad space environment test capability to allow PV array designers and manufacturers to verify their system's integrity and avoid costly on-orbit failures. The Marshall Space Flight Center test capabilities are available to government, commercial, and university customers. Test solutions are tailored to meet the customer's needs, and can include performance assessments, such as flash testing in the case of PV cells.

Development of the Optimum Operation Scheduling Model of Domestic Electric Appliances for the Supply-Demand Adjustment in a Power System

NASA Astrophysics Data System (ADS)

Ikegami, Takashi; Iwafune, Yumiko; Ogimoto, Kazuhiko

The high penetration of variable renewable generation such as Photovoltaic (PV) systems will cause the issue of supply-demand imbalance in a whole power system. The activation of the residential power usage, storage and generation by sophisticated scheduling and control using the Home Energy Management System (HEMS) will be needed to balance power supply and demand in the near future. In order to evaluate the applicability of the HEMS as a distributed controller for local and system-wide supply-demand balances, we developed an optimum operation scheduling model of domestic electric appliances using the mixed integer linear programming. Applying this model to several houses with dynamic electricity prices reflecting the power balance of the total power system, it was found that the adequate changes in electricity prices bring about the shift of residential power usages to control the amount of the reverse power flow due to excess PV generation.

Theoretical and experimental investigations on the cooling capacity distributions at the stages in the thermally-coupled two-stage Stirling-type pulse tube cryocooler without external precooling

NASA Astrophysics Data System (ADS)

Tan, Jun; Dang, Haizheng

2017-03-01

The two-stage Stirling-type pulse tube cryocooler (SPTC) has advantages in simultaneously providing the cooling powers at two different temperatures, and the capacity in distributing these cooling capacities between the stages is significant to its practical applications. In this paper, a theoretical model of the thermally-coupled two-stage SPTC without external precooling is established based on the electric circuit analogy with considering real gas effects, and the simulations of both the cooling performances and PV power distribution between stages are conducted. The results indicate that the PV power is inversely proportional to the acoustic impedance of each stage, and the cooling capacity distribution is determined by the cold finger cooling efficiency and the PV power into each stage together. The design methods of the cold fingers to achieve both the desired PV power and the cooling capacity distribution between the stages are summarized. The two-stage SPTC is developed and tested based on the above theoretical investigations, and the experimental results show that it can simultaneously achieve 0.69 W at 30 K and 3.1 W at 85 K with an electric input power of 330 W and a reject temperature of 300 K. The consistency between the simulated and the experimental results is observed and the theoretical investigations are experimentally verified.

Comparative analyses of Xanthomonas and Xylella complete genomes.

PubMed

Moreira, Leandro M; De Souza, Robson F; Digiampietri, Luciano A; Da Silva, Ana C R; Setubal, João C

2005-01-01

Computational analyses of four bacterial genomes of the Xanthomonadaceae family reveal new unique genes that may be involved in adaptation, pathogenicity, and host specificity. The Xanthomonas genus presents 3636 unique genes distributed in 1470 families, while Xylella genus presents 1026 unique genes distributed in 375 families. Among Xanthomonas-specific genes, we highlight a large number of cell wall degrading enzymes, proteases, and iron receptors, a set of energy metabolism genes, second copy of the type II secretion system, type III secretion system, flagella and chemotactic machinery, and the xanthomonadin synthesis gene cluster. Important genes unique to the Xylella genus are an additional copy of a type IV pili gene cluster and the complete machinery of colicin V synthesis and secretion. Intersections of gene sets from both genera reveal a cluster of genes homologous to Salmonella's SPI-7 island in Xanthomonas axonopodis pv citri and Xylella fastidiosa 9a5c, which might be involved in host specificity. Each genome also presents important unique genes, such as an HMS cluster, the kdgT gene, and O-antigen in Xanthomonas axonopodis pv citri; a number of avrBS genes and a distinct O-antigen in Xanthomonas campestris pv campestris, a type I restriction-modification system and a nickase gene in Xylella fastidiosa 9a5c, and a type II restriction-modification system and two genes related to peptidoglycan biosynthesis in Xylella fastidiosa temecula 1. All these differences imply a considerable number of gene gains and losses during the divergence of the four lineages, and are associated with structural genome modifications that may have a direct relation with the mode of transmission, adaptation to specific environments and pathogenicity of each organism.

The Profitability of an Investment in Photovoltaics in South Carolina

NASA Astrophysics Data System (ADS)

Welsh, Thomas McClain

As renewable energy becomes more prevalent across the United States and the world, solar energy investment has also grown. There have been many studies done on photovoltaic (PV) systems in terms of energy payback and efficiency, but little research done to understand a PV system as a financial investment specific to South Carolina. This study aims to understand the return on investment that a PV system can achieve. More specifically whether PV systems in areas of South Carolina that uses Duke Energy achieve a favorable return on investment and what affects the profitability. This study uses the PVwatts calculator provided by NREL as well as an investment simulation to calculate the Internal Rate of Return (IRR) and Net Present Value on 1024 simulated 5kW PV arrays and evaluates their profitability. It then uses this information to apply it to real case studies for houses in South Carolina. This study found that shade has a significant impact on profitability of investment. At 30% shading, profitability drops near 0% IRR or below. Orientation impacts profitability significantly as well. Panels that are facing south, southeast, and southwest yielded the best return. While north, northeast and northwest orientations yielded very low or negative IRR. East and west facing panels can yield positive financial return, but this return is lower than panels orientated to the south. PV systems oriented towards the east or west must have optimal conditions to remain efficient. This study found that tilt had minimal impact on financially return. Incentives also significantly impacted profitability of investment. For a PV system to be profitable, federal, state, and Duke Energy incentives needed to be applied to the investment. When homes with PV systems are sold also has a great impact on profitability. Research has shown that there is a housing premium for homes with PV systems (Adomatis, 2015). This premium is highest when first installed and declines as the PV systems age. People also associate premiums with houses with PV systems even if the system is not adding much value to the home. This study has also found that the price of the PV system impacts investment. Premium grade panels had significantly less return compared to standard grade panels because prices per watt were higher.

The adoption of residential solar photovoltaic systems in the presence of a financial incentive: A case study of consumer experiences with the Renewable Energy Standard Offer Program in Ontario (Canada)

NASA Astrophysics Data System (ADS)

Adachi, Christopher William Junji

2009-12-01

Traditionally, high initial capital costs and lengthy payback periods have been identified as the most significant barriers that limit the diffusion of solar photovoltaic (PV) systems. In response, the Ontario Government, through the Ontario Power Authority (OPA), introduced the Renewable Energy Standard Offer Program (RESOP) in November, 2006. The RESOP offers owners of solar PV systems with a generation capacity under 10MW a 20 year contract to sell electricity back to the grid at a guaranteed rate of $0.42/kWh. While it is the intent of incentive programs such as the RESOP to begin to lower financial barriers in order to increase the uptake of solar PV systems, there is no guarantee that the level of participation will in fact rise. The "on-the-ground" manner in which consumers interact with such an incentive program ultimately determines its effectiveness. The purpose of this thesis is to analyze the relationship between the RESOP and solar PV system consumers. To act on this purpose, the experiences of current RESOP participants are presented, wherein the factors that are either hindering or promoting utilization of the RESOP and the adoption of solar PV systems are identified. This thesis was conducted in three phases--a literature review, preliminary key informant interviews, and primary RESOP participant interviews--with each phase informing the scope and design of the subsequent stage. First, a literature survey was completed to identify and to understand the potential drivers and barriers to the adoption of a solar PV system from the perspective of a consumer. Second, nine key informant interviews were completed to gain further understanding regarding the specific intricacies of the drivers and barriers in the case of Ontario, as well as the overall adoption system in the province. These interviews were conducted between July and September, 2008. Third, interviews with 24 RESOP participants were conducted; they constitute the primary data set. These interviews were conducted between November and December, 2008. Findings of this thesis suggest that the early adopters of solar PV systems have been motivated by their self-identified sustainability-oriented social attitudes, rather than the lowering of the financial barrier. Only six of 24 respondents noted that they would not have purchased a solar PV system in the absence of the RESOP. For nine of 24 respondents, the catalyst for the purchase of the solar PV systems was not the creation of the RESOP, but instead the presence of a community-based co-operative purchasing group (CBCPG) that had selected a vender and that provided a support service to help the consumer navigate the administrative processes associated with the RESOP. Regarding the functioning of the RESOP, interview respondents reported lengthy periods of time to secure electrical connection, hidden additional fees, and arduous administrative processes. Based on their experiences interacting with Local Distribution Companies, vendors, and the OPA, respondent evaluations of the overall adoption process ranged from extremely positive (some interviewees praised the RESOP for its ease of participation and utility), to extremely negative (other interviewees condemned the RESOP because of its administrative complexity and hidden costs and fees). A key finding from this research is that weaknesses in the administration and promotion of the RESOP have been mitigated by the presence of CBCPGs and third parties aiding consumers in the purchase, installation, administration, and connection of their solar PV system. Recommendations of this thesis include the creation of new and enhancement of existing CBCPGs, a simplification of the required administrative processes, and an increase in the rates of compensation.

Smoothing PV System’s Output by Tuning MPPT Control

NASA Astrophysics Data System (ADS)

Ina, Nobuhiko; Yanagawa, Shigeyuki; Kato, Takeyoshi; Suzuoki, Yasuo

A PV system’s output is not stable and fluctuates depending on a weather condition. Using a battery is one of the feasible ways to stabilize a PV system’s output, although it requires an additional cost and provides an additional waste of the used battery. In this paper, we propose tuning a characteristic of Maxiumum Power Point Tracking (MPPT) control for smoothing a short term change of PV system’s output during a sharp insolation fluctuation, as an approach without additional equipments. In our proposed method, when an insolation increases rapidly, the operation point of MPPT control changes to the new point where the maximum power is not generated with present insolation, so that the speed of PV system’s output increase is limited to a certain value, i. e. 1%/min. In order to evaluate the effect of our proposed method in terms of reducing the additional operation task of the electric power system, we evaluated the additional LFC capacity for a large-scale installation of PV systems. As a result, it was revealed that the additional LFC capacity is not required even if a PV system is installed by 5% of utility system, when our proposed method is applied to all PV systems.

Why silicon is and will remain the dominant photovoltaic material

NASA Astrophysics Data System (ADS)

Singh, Rajendra

2009-07-01

Rising demands of energy in emerging economies, coupled with the green house gas emissions related problems around the globe have provided a unique opportunity of exploiting the advantages offered by photovoltaic (PV) systems for green energy electricity generation. Similar to cell phones, power generated by PV systems can reach over two billion people worldwide who have no access to clean energy. Only silicon based PV devices meet the low-cost manufacturing criterion of clean energy conversion (abundance of raw material and no environmental health and safety issues). The use of larger size glass substrates and manufacturing techniques similar to the ones used by the liquid crystal display industry and the large scale manufacturing of amorphous silicon thin films based modules (~ GW per year manufacturing at a single location) can lead to installed PV system cost of $3/Wp. This will open a huge market for grid connected PV systems and related markets. With further research and development, this approach can provide $2/Wp installed PV system costs in the next few years. At this cost level, PV electricity generation is competitive with any other technology, and PV power generation can be a dominant electricity generation technology in the 21st century.

Photovoltaic-Thermal New Technology Demonstration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dean, Jesse; McNutt, Peter; Lisell, Lars

Photovoltaic-thermal (PV-T) hybrid solar systems offer increased electricity production by cooling the PV panel, and using the removed thermal energy to heat water - all in the same footprint as a standard PV system. GPG's assessment of the nation's first large-scale PV-T system installed at the Thomas P. O'Neill, Jr. Federal Building in Boston, MA, provided numerous lessons learned in system design, and identified a target market of locations with high utility costs and electric hot water backup.

Hawaiian Electric Advanced Inverter Test Plan - Result Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoke, Anderson; Nelson, Austin; Prabakar, Kumaraguru

This presentation is intended to share the results of lab testing of five PV inverters with the Hawaiian Electric Companies and other stakeholders and interested parties. The tests included baseline testing of advanced inverter grid support functions, as well as distribution circuit-level tests to examine the impact of the PV inverters on simulated distribution feeders using power hardware-in-the-loop (PHIL) techniques. hardware-in-the-loop (PHIL) techniques.

Photovoltaic roofing tile systems

NASA Astrophysics Data System (ADS)

Melchior, B.

The integration of photovoltaic (PV) systems in architecture is discussed. A PV-solar roofing tile system with polymer concrete base; PV-roofing tile with elastomer frame profiles and aluminum profile frames; contact technique; and solar cell modules measuring technique are described. Field tests at several places were conducted on the solar generator, electric current behavior, battery station, electric installation, power conditioner, solar measuring system with magnetic bubble memory technique, data transmission via telephone modems, and data processing system. The very favorable response to the PV-compact system proves the commercial possibilities of photovoltaic integration in architecture.

Application of Phasor Measurement Units for Protection of Distribution Networks with High Penetration of Photovoltaic Sources

NASA Astrophysics Data System (ADS)

Meskin, Matin

The rate of the integration of distributed generation (DG) units to the distribution level to meet the growth in demand increases as a reasonable replacement for costly network expansion. This integration brings many advantages to the consumers and power grids, as well as giving rise to more challenges in relation to protection and control. Recent research has brought to light the negative effects of DG units on short circuit currents and overcurrent (OC) protection systems in distribution networks. Change in the direction of fault current flow, increment or decrement of fault current magnitude, blindness of protection, feeder sympathy trip, nuisance trip of interrupting devices, and the disruption of coordination between protective devices are some potential impacts of DG unit integration. Among other types of DG units, the integration of renewable energy resources into the electric grid has seen a vast improvement in recent years. In particular, the interconnection of photovoltaic (PV) sources to the medium voltage (MV) distribution networks has experienced a rapid increase in the last decade. In this work, the effect of PV source on conventional OC relays in MV distribution networks is shown. It is indicated that the PV output fluctuation, due to changes in solar radiation, causes the magnitude and direction of the current to change haphazardly. These variations may result in the poor operation of OC relays as the main protective devices in the MV distribution networks. In other words, due to the bi-directional power flow characteristic and the fluctuation of current magnitude occurring in the presence of PV sources, a specific setting of OC relays is difficult to realize. Therefore, OC relays may operate in normal conditions. To improve the OC relay operation, a voltage-dependent-overcurrent protection is proposed. Although, this new method prevents the OC relay from maloperation, its ability to detect earth faults and high impedance faults is poor. Thus, a comprehensive protective system is suggested at the end of the dissertation. The proposed method is based on the application of the phasor measurement unit (PMU) and the differential protection method. All of the current magnitudes and angles are collected by PMU and are sent to the phasor data concentrator (PDC), where a differential protection algorithm is applied to these data. If any fault is detected, the trip will be sent back to the corresponding circuit breakers across the network. Higher selectivity, sensitivity, and faster operation in the differential protection are superior to those of other protection schemes. Differential protection operates as unit protection, which means that it operates only when there is a fault in the protection zone. It does not function for faults occurring out of zone. Therefore, no coordination is required between differential protections across the power system. Moreover, the misoperation of this protective scheme is less likely as compared to other protection methods.

A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions

PubMed Central

Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C.

2015-01-01

This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper. PMID:26230694

A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions.

PubMed

Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C

2015-07-29

This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper.

Energy Storage Requirements for Achieving 50% Penetration of Solar Photovoltaic Energy in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul; Margolis, Robert

2016-09-01

We estimate the storage required to enable PV penetration up to 50% in California (with renewable penetration over 66%), and we quantify the complex relationships among storage, PV penetration, grid flexibility, and PV costs due to increased curtailment. We find that the storage needed depends strongly on the amount of other flexibility resources deployed. With very low-cost PV (three cents per kilowatt-hour) and a highly flexible electric power system, about 19 gigawatts of energy storage could enable 50% PV penetration with a marginal net PV levelized cost of energy (LCOE) comparable to the variable costs of future combined-cycle gas generatorsmore » under carbon constraints. This system requires extensive use of flexible generation, transmission, demand response, and electrifying one quarter of the vehicle fleet in California with largely optimized charging. A less flexible system, or more expensive PV would require significantly greater amounts of storage. The amount of storage needed to support very large amounts of PV might fit within a least-cost framework driven by declining storage costs and reduced storage-duration needs due to high PV penetration.« less

Energy Storage Requirements for Achieving 50% Solar Photovoltaic Energy Penetration in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul; Margolis, Robert

2016-08-01

We estimate the storage required to enable PV penetration up to 50% in California (with renewable penetration over 66%), and we quantify the complex relationships among storage, PV penetration, grid flexibility, and PV costs due to increased curtailment. We find that the storage needed depends strongly on the amount of other flexibility resources deployed. With very low-cost PV (three cents per kilowatt-hour) and a highly flexible electric power system, about 19 gigawatts of energy storage could enable 50% PV penetration with a marginal net PV levelized cost of energy (LCOE) comparable to the variable costs of future combined-cycle gas generatorsmore » under carbon constraints. This system requires extensive use of flexible generation, transmission, demand response, and electrifying one quarter of the vehicle fleet in California with largely optimized charging. A less flexible system, or more expensive PV would require significantly greater amounts of storage. The amount of storage needed to support very large amounts of PV might fit within a least-cost framework driven by declining storage costs and reduced storage-duration needs due to high PV penetration.« less

Performance Analysis and Discussion on the Thermoelectric Element Footprint for PV-TE Maximum Power Generation

NASA Astrophysics Data System (ADS)

Li, Guiqiang; Zhao, Xudong; Jin, Yi; Chen, Xiao; Ji, Jie; Shittu, Samson

2018-06-01

Geometrical optimisation is a valuable way to improve the efficiency of a thermoelectric element (TE). In a hybrid photovoltaic-thermoelectric (PV-TE) system, the photovoltaic (PV) and thermoelectric (TE) components have a relatively complex relationship; their individual effects mean that geometrical optimisation of the TE element alone may not be sufficient to optimize the entire PV-TE hybrid system. In this paper, we introduce a parametric optimisation of the geometry of the thermoelectric element footprint for a PV-TE system. A uni-couple TE model was built for the PV-TE using the finite element method and temperature-dependent thermoelectric material properties. Two types of PV cells were investigated in this paper and the performance of PV-TE with different lengths of TE elements and different footprint areas was analysed. The outcome showed that no matter the TE element's length and the footprint areas, the maximum power output occurs when A n /A p = 1. This finding is useful, as it provides a reference whenever PV-TE optimisation is investigated.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbose, Galen; Wiser, Ryan; Bolinger, Mark

Increasing levels of financial support for customer-sited photovoltaic (PV) systems, provided through publicly-funded incentive programs, has heightened concerns about the long-term performance of these systems. Given the barriers that customers face to ensuring that their PV systems perform well, and the responsibility that PV incentive programs bear to ensure that public funds are prudently spent, these programs should, and often do, play a critical role in ensuring that PV systems receiving incentives perform well. To provide a point of reference for assessing the current state of the art, and to inform program design efforts going forward, we examine the approachesmore » to encouraging PV system performance used by 32 prominent PV incentive programs in the U.S. We identify eight general strategies or groups of related strategies that these programs have used to address performance issues, and highlight important differences in the implementation of these strategies among programs.« less

Do Photovoltaic Energy Systems Effect Residential Selling Prices? Results from a California Statewide Investigation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoen, Ben; Cappers, Pete; Wiser, Ryan

2011-04-12

An increasing number of homes in the U.S. have sold with photovoltaic (PV) energy systems installed at the time of sale, yet relatively little research exists that provides estimates of the marginal impacts of those PV systems on home sale prices. This research analyzes a large dataset of California homes that sold from 2000 through mid-2009 with PV installed. We find strong evidence that homes with PV systems sold for a premium over comparable homes without PV systems during this time frame. Estimates for this premium expressed in dollars per watt of installed PV range, from roughly $4 to $6.4/wattmore » across the full dataset, to approximately $2.3/watt for new homes, to more than $6/watt for existing homes. A number of ideas for further research are suggested.« less

PV systems photoelectric parameters determining for field conditions and real operation conditions

NASA Astrophysics Data System (ADS)

Shepovalova, Olga V.

2018-05-01

In this work, research experience and reference documentation have been generalized related to PV systems photoelectric parameters (PV array output parameters) determining. The basic method has been presented that makes it possible to determine photoelectric parameters with the state-of-the-art reliability and repeatability. This method provides an effective tool for PV systems comparison and evaluation of PV system parameters that the end-user will have in the course of its real operation for compliance with those stipulated in reference documentation. The method takes in consideration all parameters that may possibly affect photoelectric performance and that are supported by sufficiently valid procedures for their values testing. Test conditions, requirements for equipment subject to tests and test preparations have been established and the test procedure for fully equipped PV system in field tests and in real operation conditions has been described.

Photovoltaic central station step and touch potential considerations in grounding system design

NASA Technical Reports Server (NTRS)

Engmann, G.

1983-01-01

The probability of hazardous step and touch potentials is an important consideration in central station grounding system design. Steam turbine generating station grounding system design is based on accepted industry practices and there is extensive in-service experience with these grounding systems. A photovoltaic (PV) central station is a relatively new concept and there is limited experience with PV station grounding systems. The operation and physical configuration of a PV central station is very different from a steam electric station. A PV station bears some similarity to a substation and the PV station step and touch potentials might be addressed as they are in substation design. However, the PV central station is a generating station and it is appropriate to examine the effect that the differences and similarities of the two types of generating stations have on step and touch potential considerations.

Improving Photovoltaic Energy Production with Fiber-Optic Distributed Temperature Sensing

NASA Astrophysics Data System (ADS)

Hausner, M. B.; Berli, M.

2014-12-01

The efficiency of solar photovoltaic (PV) generators declines sharply with increased temperatures. Peak solar exposure often occurs at the same time as peak temperatures, but solar PV installations are typically designed based on solar angle. In temperate areas, the peak temperatures may not be high enough to induce significant efficiency losses. In some of the areas with the greatest potential for solar development, however, summer air temperatures regularly reach 45 °C and PV panel temperatures exceed the air temperatures. Here we present a preliminary model of a PV array intended to optimize solar production in a hot and arid environment. The model begins with the diurnal and seasonal cycles in the angle and elevation of the sun, but also includes a meteorology-driven energy balance to project the temperatures of the PV panels and supporting structure. The model will be calibrated and parameterized using a solar array at the Desert Research Institute's (DRI) Renewable Energy Deployment and Display (REDD) facility in Reno, Nevada, and validated with a similar array at DRI's Las Vegas campus. Optical fibers will be installed on the PV panels and structural supports and interrogated by a distributed temperature sensor (DTS) to record the spatial and temporal variations in temperature. Combining the simulated panel temperatures, the efficiency-temperature relationship for the panels, and the known solar cycles at a site will allow us to optimize the design of future PV collectors (i.e., the aspect and angle of panels) for given production goals.

Comparison and selection of off-grid PV systems

NASA Astrophysics Data System (ADS)

Izmailov, Andrey Yu.; Lobachevsky, Yakov P.; Shepovalova, Olga V.

2018-05-01

This work deals with comparison, evaluation and selection of PV systems of the same type based on their technical parameters either indicated in their technical specifications or calculated ones. Stand-alone and grid backed up photoelectric systems have been considered. General requirements for photoelectric system selection and evaluation have been presented that ensure system operability and required efficiency in operation conditions. Generic principles and definition of photoelectric systems characteristics have been considered. The described method is mainly targeted at PV engineering personnel and private customers purchasing PV systems. It can be also applied in the course of project contests, tenders, etc.

NREL Photovoltaic Program FY 1995 annual report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-06-01

This report summarizes the in-house and subcontracted R&D activities from Oct. 1994 through Sept. 1995; their objectives are to conduct basic, applied, and engineering research, manage subcontracted R&D projects, perform research complementary to subcontracted work, develop and maintain state-of-the-art measurement and device capabilities, develop PV manufacturing technology and modules, transfer results to industry, and evolve viable partnerships for PV systems and market development. The research activities are grouped into 5 sections: crystalline Si and advanced devices, thin-film PV, PV manufacturing, PV module and system performance and engineering, and PV applications and market development.

Photovoltaic (PV) Systems Comparison at Fort Hood

DTIC Science & Technology

2010-06-01

Monocrystalline PV panels • Energy Photovoltaics, EPV-42 Solar Modules: Thin film PV panels • OutBack Flexware PV Advanced Photovoltaic Combiner...energy for an administrative building – Compare the performance between two different PV technologies: thin film and crystalline PV panels • Demo Team...Center for Energy and Environment PV Technology • Monocrystalline silicon1 • Thin film2 1 “About Solar,” DBK Corporation, http://www.dbksolar.com

Sub-synchronous resonance damping using high penetration PV plant

NASA Astrophysics Data System (ADS)

Khayyatzadeh, M.; Kazemzadeh, R.

2017-02-01

The growing need to the clean and renewable energy has led to the fast development of transmission voltage-level photovoltaic (PV) plants all over the world. These large scale PV plants are going to be connected to power systems and one of the important subjects that should be investigated is the impact of these plants on the power system stability. Can large scale PV plants help to damp sub-synchronous resonance (SSR) and how? In this paper, this capability of a large scale PV plant is investigated. The IEEE Second Benchmark Model aggregated with a PV plant is utilized as the case study. A Wide Area Measurement System (WAMS) based conventional damping controller is designed and added to the main control loop of PV plant in order to damp the SSR and also investigation of the destructive effect of time delay in remote feedback signal. A new optimization algorithm called teaching-learning-based-optimization (TLBO) algorithm has been used for managing the optimization problems. Fast Furrier Transformer (FFT) analysis and also transient simulations of detailed nonlinear system are considered to investigate the performance of the controller. Robustness of the proposed system has been analyzed by facing the system with disturbances leading to significant changes in generator and power system operating point, fault duration time and PV plant generated power. All the simulations are carried out in MATLAB/SIMULINK environment.

An overview of photovoltaic applications in space

NASA Technical Reports Server (NTRS)

Wasel, Robert A.

1987-01-01

An overview is given of the uses of photovoltaic (PV) power in space. The contribution of PV systems on unmanned, low Earth orbit and inner planetary missions is noted. The development of PV technology along the two paths of high efficiency and high power is discussed. The importance of increasing the service life of PV systems is covered.

Researchers at NREL Find Fewer Failures of PV Panels and Different

Science.gov Websites

10, 2017 Overall failure rates for photovoltaic (PV) solar panels have fallen dramatically when Failures of PV Panels and Different Degradation Modes in Systems Installed after 2000 Researchers at NREL Find Fewer Failures of PV Panels and Different Degradation Modes in Systems Installed after 2000 April

Evaluating the Technical and Economic Performance of PV Plus Storage Power Plants: Report Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul L.; Margolis, Robert M.; Eichman, Joshua D.

The decreasing costs of both PV and energy storage technologies have raised interest in the creation of combined PV plus storage systems to provide dispatchable energy and reliable capacity. In this study, we examine the tradeoffs among various PV plus storage configurations and quantify the impact of configuration on system net value.

Evaluating the Technical and Economic Performance of PV Plus Storage Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul L.; Margolis, Robert M.; Eichman, Joshua D.

The decreasing costs of both PV and energy storage technologies have raised interest in the creation of combined PV plus storage systems to provide dispatchable energy and reliable capacity. In this study, we examine the tradeoffs among various PV plus storage configurations and quantify the impact of configuration on system net value.

New Best-Practices Guide for Photovoltaic System Operations and Maintenance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fact sheet summarizing technical report TP-7A40-67553. As solar photovoltaic (PV) systems have continued their transition from niche applications into large, mature markets in the United States, their potential as financial investments has risen accordingly. Mainstream investors, however, need to feel confident about the risk and return of solar photovoltaic (PV) systems before committing funds. A major influence on risk and return for PV is operations and maintenance (O&M) - but O&M practices and costs vary widely across the United States, making these variables difficult for investors to predict. To address this barrier to continued PV investment, the PV O&M Workingmore » Group has developed a new best-practices guide for PV O&M.« less

Photovoltaic performance models - A report card

NASA Technical Reports Server (NTRS)

Smith, J. H.; Reiter, L. R.

1985-01-01

Models for the analysis of photovoltaic (PV) systems' designs, implementation policies, and economic performance, have proliferated while keeping pace with rapid changes in basic PV technology and extensive empirical data compiled for such systems' performance. Attention is presently given to the results of a comparative assessment of ten well documented and widely used models, which range in complexity from first-order approximations of PV system performance to in-depth, circuit-level characterizations. The comparisons were made on the basis of the performance of their subsystem, as well as system, elements. The models fall into three categories in light of their degree of aggregation into subsystems: (1) simplified models for first-order calculation of system performance, with easily met input requirements but limited capability to address more than a small variety of design considerations; (2) models simulating PV systems in greater detail, encompassing types primarily intended for either concentrator-incorporating or flat plate collector PV systems; and (3) models not specifically designed for PV system performance modeling, but applicable to aspects of electrical system design. Models ignoring subsystem failure or degradation are noted to exclude operating and maintenance characteristics as well.

An Operating Method Using Prediction of Photovoltaic Power for a Photovoltaic-Diesel Hybrid Power Generation System

NASA Astrophysics Data System (ADS)

Yamamoto, Shigehiro; Sumi, Kazuyoshi; Nishikawa, Eiichi; Hashimoto, Takeshi

This paper describes a novel operating method using prediction of photovoltaic (PV) power for a photovoltaic-diesel hybrid power generation system. The system is composed of a PV array, a storage battery, a bi-directional inverter and a diesel engine generator (DG). The proposed method enables the system to save fuel consumption by using PV energy effectively, reducing charge and discharge energy of the storage battery, and avoiding low-load operation of the DG. The PV power is simply predicted from a theoretical equation of solar radiation and the observed PV energy for a constant time before the prediction. The amount of fuel consumption of the proposed method is compared with that of other methods by a simulation based on measurement data of the PV power at an actual PV generation system for one year. The simulation results indicate that the amount of fuel consumption of the proposed method is smaller than that of any other methods, and is close to that of the ideal operation of the DG.

MONITOR THE PHOTOVOLTAIC (PV) SYSTEM ON THE NCC ROOFTOP

EPA Science Inventory

This study will investigate the pollution emission reduction and demand-side management potential of a
100 kW PV system located on the roof of the National Computer Center (NCC). Standardized instrumentation to measure meteorological and PV system performance variables will b...

Photovoltaic performance and reliability workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroposki, B

1996-10-01

This proceedings is the compilation of papers presented at the ninth PV Performance and Reliability Workshop held at the Sheraton Denver West Hotel on September 4--6, 1996. This years workshop included presentations from 25 speakers and had over 100 attendees. All of the presentations that were given are included in this proceedings. Topics of the papers included: defining service lifetime and developing models for PV module lifetime; examining and determining failure and degradation mechanisms in PV modules; combining IEEE/IEC/UL testing procedures; AC module performance and reliability testing; inverter reliability/qualification testing; standardization of utility interconnect requirements for PV systems; need activitiesmore » to separate variables by testing individual components of PV systems (e.g. cells, modules, batteries, inverters,charge controllers) for individual reliability and then test them in actual system configurations; more results reported from field experience on modules, inverters, batteries, and charge controllers from field deployed PV systems; and system certification and standardized testing for stand-alone and grid-tied systems.« less

Commercialization of PV-powered pumping systems for use in utility PV service programs. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-03-01

The project described in this report was a commercialization effort focused on cost-effective remote water pumping systems for use in utility-based photovoltaic (PV) service programs. The project combined a commercialization strategy tailored specifically for electric utilities with the development of a PV-powered pumping system that operates conventional ac pumps rather than relying on the more expensive and less reliable PV pumps on the market. By combining these two attributes, a project goal was established of creating sustained utility purchases of 250 PV-powered water pumping systems per year. The results of each of these tasks are presented in two parts containedmore » in this Final Summary Report. The first part summarizes the results of the Photovoltaic Services Network (PSN) as a new business venture, while the second part summarizes the results of the Golden Photon system installations. Specifically, results and photographs from each of the system installations are presented in this latter part.« less

Biosafety of parenteral Brucella abortus RB51 vaccine in bison calves

USGS Publications Warehouse

Roffe, T.J.; Olsen, S.C.; Gidlewski, T.; Jensen, A.E.; Palmer, M.V.; Huber, R.

1999-01-01

Vaccination is considered among the primary management tools for reducing brucellosis prevalence in Greater Yellowstone Area (GYA) ungulates. Before their use, however, vaccine safety and efficacy must be demonstrated. Twenty-seven female bison (Bison bison) calves (approx 5 months old) were vaccinated with Brucella abortus Strain RB51 (1.5 x 1010 colony forming units [CFU], subcutaneously) as part of routine management. We assessed the persistence, pathology, shedding, and transmission associated with RB51 by serial necropsy, bacteriology, histopathology, and serology of 20 of these 27 vaccinated calves, and RB51 serology of 10 nonvaccinated, commingling adult females. With the exception of 1 calf, RB51 dot-blot titers at necropsy were <1:80. Strain RB51 was cultured from lymph nodes in 4 of 4 calves at 14 weeks postvaccination (PV), 4 of 4 calves at 18 weeks PV, 1 of 4 calves at 22 weeks PV, 3 of 4 at 26 weeks PV, and 0 of 4 calves at 30 weeks PV. No gross lesions were observed. Mild histologic changes occurred only in a few draining lymph nodes early in sampling. Adverse clinical effects were not observed in vaccinates. Swabs from nasopharynx, conjunctiva, rectum, and vagina were uniformly culture negative for RB51. Strain RB51 dot-blot assays of bison cows were negative at a 1:20 dilution at 26 weeks PV. Our results suggest that RB51 persists longer in bison calves than in domestic cattle and is systemically distributed within lymphatic tissues. However, bison apparently clear the RB51 vaccine strain without shedding, transmission, or significant adverse reactions.

Heterogeneous collaborative sensor network for electrical management of an automated house with PV energy.

PubMed

Castillo-Cagigal, Manuel; Matallanas, Eduardo; Gutiérrez, Alvaro; Monasterio-Huelin, Félix; Caamaño-Martín, Estefaná; Masa-Bote, Daniel; Jiménez-Leube, Javier

2011-01-01

In this paper we present a heterogeneous collaborative sensor network for electrical management in the residential sector. Improving demand-side management is very important in distributed energy generation applications. Sensing and control are the foundations of the "Smart Grid" which is the future of large-scale energy management. The system presented in this paper has been developed on a self-sufficient solar house called "MagicBox" equipped with grid connection, PV generation, lead-acid batteries, controllable appliances and smart metering. Therefore, there is a large number of energy variables to be monitored that allow us to precisely manage the energy performance of the house by means of collaborative sensors. The experimental results, performed on a real house, demonstrate the feasibility of the proposed collaborative system to reduce the consumption of electrical power and to increase energy efficiency.

State - Level Regulation's Effectiveness in Addressing Global Climate Change and Promoting Solar Energy Deployment

NASA Astrophysics Data System (ADS)

Peterman, Carla Joy

Paper 1, Local Solutions to Global Problems: Climate Change Policies and Regulatory Jurisdiction, considers the efficacy of various types of environmental regulations when they are applied locally to pollutants whose damages extend beyond the jurisdiction of the local regulators. Local regulations of a global pollutant may be ineffective if producers and consumers can avoid them by transacting outside the reach of the local regulator. In many cases, this may involve the physical relocation of the economic activity, a problem often referred to as "leakage." This paper highlights another way in which local policies can be circumvented: through the shuffling of who buys from whom. The paper maintains that the problems of reshuffling are exacerbated when the options for compliance with the regulations are more flexible. Numerical analyses is presented demonstrating that several proposed policies to limit greenhouse gas emissions from the California electricity sector may have very little effect on carbon emissions if they are applied only within that state. Paper 1 concludes that although local subsidies for energy efficiency, renewable electricity, and transportation biofuels constitute attempts to pick technology winners, they may be the only mechanisms that local jurisdictions, acting alone, have at their disposal to address climate change. Paper 2, Pass-Through of Solar PV Incentives to Consumers: The Early Years of California's Solar PV Incentives, examines the pass through of incentives to California solar PV system owners. The full post-subsidy price consumers pay for solar power is a key metric of the success of solar PV incentive programs and of overall PV market performance. This study examines the early years of California's most recent wave of distributed solar PV incentives (2000-2008) to determine the pass-through of incentives. Examination of this period is both intellectually and pragmatically important due to the high level of incentives provided and subsequent high cost to ratepayers; policymakers' expectations that price declines accrue to consumers; and market structure characteristics that might contribute to incomplete pass-through. This analysis shows that incentive passthrough in the California residential solar PV programs was incomplete. Consumer prices declined 54 cents for every additional dollar of incentive received. A large share of the incentive is captured by the solar PV contractor or other actors in the solar PV supply chain. The finding of incomplete pass-through is persistent across specifications. The analysis also identifies a lower degree of incentive pass-through for consumers in the highest income zip codes. Whether expectations of incentives' pass-through align with reality is critically important in the beginning years of emerging clean energy technology programs since this can affect the likelihood of future government investments and public support. Given the often-held policy assumption that consumer prices are declining in response to incentives, it is useful for policymakers to understand the circumstances under which such an assumption may not hold. Paper 3, Testing the Boundaries of the Solar Photovoltaic Learning System, tests how the choice of experience curves' geographic and technology assumptions affect solar PV experience curve results. Historically, solar PV experience curves have assumed one experience curve represents both module and non-module learning and that this learning happens at a global scale. These assumptions may be inaccurate for solar PV since the learning system, and technology and geographic boundaries, are likely different between PV modules and non-module components. Using 2004 to 2008 PV system price data from 13 states, and a longer time series of PV price data for California, some evidence is found that cumulative capacity at the state level is a better predictor of non-module costs than U.S. or global capacity. This paper explores, but is unable to significantly determine, how knowledge spillovers from neighboring states can influence a state's non-module costs. Given data limitations, and limitations to the two-factor experience model methodology itself, it is not possible to conclusively determine the correct geographic boundary for the non-module learning system. Throughout the paper ways in which the experience curve model and data can be augmented to achieve a better estimation are discussed. 2.

The geography of solar energy in the United States: Market definition, industry structure, and choice in solar PV adoption

DOE PAGES

O’Shaughnessy, Eric; Nemet, Gregory F.; Darghouth, Naïm

2018-01-30

The solar photovoltaic (PV) installation industry comprises thousands of firms around the world who collectively installed nearly 200 million panels in 2015. Spatial analysis of the emerging industry has received considerable attention from the literature, especially on the demand side concerning peer effects and adopter clustering. However this research area does not include similarly sophisticated spatial analysis on the supply side of the installation industry. The lack of understanding of the spatial structure of the PV installation industry leaves PV market research to rely on jurisdictional lines, such as counties, to define geographic PV markets. We develop an approach thatmore » uses the spatial distribution of installers' activity to define geographic boundaries for PV markets. Our method is useful for PV market research and applicable in the contexts of other industries. We use our approach to demonstrate that the PV industry in the United States is spatially heterogeneous. Despite the emergence of some national-scale PV installers, installers are largely local and installer communities are unique from one region to the next. The social implications of the spatial heterogeneity of the emerging PV industry involve improving understanding of issues such as market power, industry consolidation, and how much choice potential adopters have.« less

The geography of solar energy in the United States: Market definition, industry structure, and choice in solar PV adoption

DOE Office of Scientific and Technical Information (OSTI.GOV)

O’Shaughnessy, Eric; Nemet, Gregory F.; Darghouth, Naïm

The solar photovoltaic (PV) installation industry comprises thousands of firms around the world who collectively installed nearly 200 million panels in 2015. Spatial analysis of the emerging industry has received considerable attention from the literature, especially on the demand side concerning peer effects and adopter clustering. However this research area does not include similarly sophisticated spatial analysis on the supply side of the installation industry. The lack of understanding of the spatial structure of the PV installation industry leaves PV market research to rely on jurisdictional lines, such as counties, to define geographic PV markets. We develop an approach thatmore » uses the spatial distribution of installers' activity to define geographic boundaries for PV markets. Our method is useful for PV market research and applicable in the contexts of other industries. We use our approach to demonstrate that the PV industry in the United States is spatially heterogeneous. Despite the emergence of some national-scale PV installers, installers are largely local and installer communities are unique from one region to the next. The social implications of the spatial heterogeneity of the emerging PV industry involve improving understanding of issues such as market power, industry consolidation, and how much choice potential adopters have.« less

75 FR 61509 - Notice of Issuance of Final Determination Concerning Solar Photovoltaic Panel Systems

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-05

... solar photovoltaic (``PV'') panel systems contain both U.S. and foreign-origin raw materials and... of origin of the solar PV panel system described above for the purposes of U.S. government... transformation has occurred; however, no one factor is determinative. In this case, the solar PV systems are...

Design of A Grid Integrated PV System with MPPT Control and Voltage Oriented Controller using MATLAB/PLECES

NASA Astrophysics Data System (ADS)

Soreng, Bineeta; Behera, Pradyumna; Pradhan, Raseswari

2017-08-01

This paper presents model of a grid-integrated photovoltaic array with Maximum Power Point Tracker (MPPT) and voltage oriented controller. The MPPT of the PV array is usually an essential part of PV system as MPPT helps the operating point of the solar array to align its maximum power point. In this model, the MPPT along with a DC-DC converter lets a PV generator to produce continuous power, despite of the measurement conditions. The neutral-point-clamped converter (NPC) with a boost converter raises the voltage from the panels to the DC-link. An LCL-filter smoothens the current ripple caused by the PWM modulation of the grid-side inverter. In addition to the MPPT, the system has two more two controllers, such as voltage controller and a current controller. The voltage control has a PI controller to regulate the PV voltage to optimal level by controlling the amount of current injected into the boost stage. Here, the grid-side converter transfers the power from the DC-link into the grid and maintains the DC-link voltage. Three-phase PV inverters are used for off-grid or designed to create utility frequency AC. The PV system can be connected in series or parallel to get the desired output power. To justify the working of this model, the grid-integrated PV system has been designed in MATLAB/PLECS. The simulation shows the P-V curve of implemented PV Array consisting 4 X 20 modules, reactive, real power, grid voltage and current.

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

NASA Astrophysics Data System (ADS)

Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

2018-06-01

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

NASA Astrophysics Data System (ADS)

Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

2018-03-01

In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

The identification of conduction gaps after pulmonary vein isolation using a new electroanatomic mapping system.

PubMed

Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Tsujimura, Takuya; Matsuda, Yasuhiro; Okuno, Shota; Ohashi, Takuya; Tsuji, Aki; Mano, Toshiaki

2017-11-01

The reconnection of left atrial-pulmonary vein (LA-PV) conduction after the initial procedure of pulmonary vein (PV) isolation is not rare, and is one of the main cause of atrial fibrillation (AF) recurrence after PV isolation. We investigated feasibility of a new ultrahigh-resolution mapping system using a 64-pole small basket catheter for the identification of LA-PV conduction gaps. This prospective study included 31 consecutive patients (20 with persistent AF) undergoing a second ablation after a PV isolation procedure with LA-PV reconnected conduction at any of the 4 PVs. An LA-PV map was created using the mapping system, and ablation was performed at the estimated gap location. The propagation map identified 54 gaps from 39 ipsilateral PV pairs, requiring manual electrogram reannotation for 23 gaps (43%). Gaps at the anterior and carinal regions of left and right ipsilateral PVs required manual electrogram reannotation more frequently than the other regions. The voltage map could identify the gap only in 19 instances (35%). Electrophysiological properties of the gaps (multiple gaps in the same ipsilateral PVs, conduction time, velocity, width, and length) did not differ between those needing and not needing manual electrogram reannotation. During the gap ablation, either the activation sequence alteration or elimination of PV potentials was observed using a circular catheter placed in the PV, suggesting that all the identified gaps were correct. This new electroanatomic mapping system visualized all the LA-PV gaps in patients undergoing a second AF ablation. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Multi-state residential transaction estimates of solar photovoltaic system premiums

DOE PAGES

Hoen, Ben; Adomatis, Sandra; Jackson, Thomas; ...

2017-07-10

We report that as of the second quarter of 2016 more than 1.1 million solar photovoltaic (PV) homes exist in the US. Capturing the value these PV systems add to home sales is therefore important. Our study enhances the PV-home-valuation literature by analyzing 22,822 home sales, of which 3951 have PV, and which span eight states during 2002–2013. We also, for the first time, compare premiums with contributory value estimates derived from the present value of saved energy costs (income approach) and, separately, the replacement cost of systems at the time of sale (cost approach) to examine market signals. Wemore » find home buyers are consistently willing to pay PV home premiums across various states, housing and PV markets, and home types; average premiums equate to approximately $4/W or $15,000 for an average-sized 3.6-kW PV system. We find that a replacement cost net of state and federal incentives is a better proxy for premiums than gross installed costs, and that the income approach is a good signal if it accounts for tiered volumetric retail rates. Finally, other results include detailed premium analyses for PV home sub-populations.« less

Multi-state residential transaction estimates of solar photovoltaic system premiums

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoen, Ben; Adomatis, Sandra; Jackson, Thomas

We report that as of the second quarter of 2016 more than 1.1 million solar photovoltaic (PV) homes exist in the US. Capturing the value these PV systems add to home sales is therefore important. Our study enhances the PV-home-valuation literature by analyzing 22,822 home sales, of which 3951 have PV, and which span eight states during 2002–2013. We also, for the first time, compare premiums with contributory value estimates derived from the present value of saved energy costs (income approach) and, separately, the replacement cost of systems at the time of sale (cost approach) to examine market signals. Wemore » find home buyers are consistently willing to pay PV home premiums across various states, housing and PV markets, and home types; average premiums equate to approximately $4/W or $15,000 for an average-sized 3.6-kW PV system. We find that a replacement cost net of state and federal incentives is a better proxy for premiums than gross installed costs, and that the income approach is a good signal if it accounts for tiered volumetric retail rates. Finally, other results include detailed premium analyses for PV home sub-populations.« less

Network Reduction Algorithm for Developing Distribution Feeders for Real-Time Simulators: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagarajan, Adarsh; Nelson, Austin; Prabakar, Kumaraguru

As advanced grid-support functions (AGF) become more widely used in grid-connected photovoltaic (PV) inverters, utilities are increasingly interested in their impacts when implemented in the field. These effects can be understood by modeling feeders in real-time systems and testing PV inverters using power hardware-in-the-loop (PHIL) techniques. This paper presents a novel feeder model reduction algorithm using a Monte Carlo method that enables large feeders to be solved and operated on real-time computing platforms. Two Hawaiian Electric feeder models in Synergi Electric's load flow software were converted to reduced order models in OpenDSS, and subsequently implemented in the OPAL-RT real-time digitalmore » testing platform. Smart PV inverters were added to the real-time model with AGF responses modeled after characterizing commercially available hardware inverters. Finally, hardware inverters were tested in conjunction with the real-time model using PHIL techniques so that the effects of AGFs on the choice feeders could be analyzed.« less

Apparatus and method for mounting photovoltaic power generating systems on buildings

DOEpatents

Russell, Miles Clayton [Lincoln, MA

2008-10-14

Rectangular PV modules (6) are mounted on a building roof (4) by mounting stands that are distributed in rows and columns. Each stand comprises a base plate (10) that rests on the building roof (4) and first and second brackets (12, 14) of different height attached to opposite ends of the base plate (10). Each bracket (12, 14) has dual members for supporting two different PV modules (6), and each PV module (6) has a mounting pin (84) adjacent to each of its four corners. Each module (6) is supported by attachment of two of its mounting pins (84) to different first brackets (12), whereby the modules (6) and their supporting stands are able to resist uplift forces resulting from high velocity winds without the base plates (10) being physically attached to the supporting roof structure (4). Preferably the second brackets (14) have a telescoping construction that permits their effective height to vary from less than to substantially the same as that of the first brackets (12).

Experiences Integrating Transmission and Distribution Simulations for DERs with the Integrated Grid Modeling System (IGMS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmintier, Bryan; Hale, Elaine; Hodge, Bri-Mathias

2016-08-11

This paper discusses the development of, approaches for, experiences with, and some results from a large-scale, high-performance-computer-based (HPC-based) co-simulation of electric power transmission and distribution systems using the Integrated Grid Modeling System (IGMS). IGMS was developed at the National Renewable Energy Laboratory (NREL) as a novel Independent System Operator (ISO)-to-appliance scale electric power system modeling platform that combines off-the-shelf tools to simultaneously model 100s to 1000s of distribution systems in co-simulation with detailed ISO markets, transmission power flows, and AGC-level reserve deployment. Lessons learned from the co-simulation architecture development are shared, along with a case study that explores the reactivemore » power impacts of PV inverter voltage support on the bulk power system.« less

The ontogenetic development of neurons containing calcium-binding proteins in the septum of the guinea pig: Late onset of parvalbumin immunoreactivity versus calbindin and calretinin.

PubMed

Hermanowicz-Sobieraj, Beata; Robak, Anna

2017-01-01

The study describes the immunoreactivity of calbindin (CB), calretinin (CR) and parvalbumin (PV), their distribution pattern and the co-distribution of CB and CR as well as CB and PV in the septum of the guinea pig during development. Immunohistochemistry was conducted on embryonic (E40, E50, E60), newborn (P0) and postnatal (P5, P10, P20, P40, P100) guinea pig brains. The presence of both CB and CR was detected at E40, while PV began to be observed at E60. Immunoreactivity for CB was constant throughout ontogeny. In contrast to CR immunoreactivity, PV immunoreactivity was higher in the postnatal stages than in the prenatal and newborn stages. Double immunostaining showed that CB co-localized with CR from E40 onwards, while with PV from P5 onwards, suggesting that CB co-operates with these proteins in the guinea pig septum during different periods of ontogeny. Our results also indicate that among the studied CaBPs, CB exhibited the highest immunoreactivity during both embryonic and postnatal development. Copyright © 2016 Elsevier B.V. All rights reserved.

Detection of poliovirus infection in children with acute gastroenteritis in Chiang Mai, Thailand.

PubMed

Kumthip, Kattareeya; Khamrin, Pattara; Maneekarn, Niwat

2017-05-01

Poliovirus (PV) is typically transmitted by the fecal-oral route, which means that the risk of infection and virus distribution could be achieved by exposure to the virus contaminated in food and water. The aim of this study was to determine the occurrence of PV strains by detecting the virus in pediatric patients who admitted to the hospitals with diarrhea in Chiang Mai, Thailand during 2010-2015. By applying a reverse transcription-polymerase chain reaction and nucleotide sequencing analysis of 1,300 stool specimens collected from pediatric patients, PVs were detected at 0.61% (8 out of 1,300 specimens). Among eight PV positive samples, mixed infection with norovirus or human bocavirus was detected in one each out of eight cases. All PV strains detected in this study were characterized further by phylogenetic analysis of 343 bp of the 5' UTR and 315 bp of the partial VP1 sequences. The results revealed that eight PV strains detected in the present study two of each were PV1 and PV2, and four were PV3 serotypes of the Sabin vaccine strains. The data demonstrated the presence of PV1, PV2, and PV3 Sabin vaccine strains in children with acute gastroenteritis in Chiang Mai, Thailand. J. Med. Virol. 89:775-781, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Performance analysis of ‘Perturb and Observe’ and ‘Incremental Conductance’ MPPT algorithms for PV system

NASA Astrophysics Data System (ADS)

Lodhi, Ehtisham; Lodhi, Zeeshan; Noman Shafqat, Rana; Chen, Fieda

2017-07-01

Photovoltaic (PV) system usually employed The Maximum power point tracking (MPPT) techniques for increasing its efficiency. The performance of the PV system perhaps boosts by controlling at its apex point of power, in this way maximal power can be given to load. The proficiency of a PV system usually depends upon irradiance, temperature and array architecture. PV array shows a non-linear style for V-I curve and maximal power point on V-P curve also varies with changing environmental conditions. MPPT methods grantees that a PV module is regulated at reference voltage and to produce entire usage of the maximal output power. This paper gives analysis between two widely employed Perturb and Observe (P&O) and Incremental Conductance (INC) MPPT techniques. Their performance is evaluated and compared through theoretical analysis and digital simulation on the basis of response time and efficiency under varying irradiance and temperature condition using Matlab/Simulink.

The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

NASA Astrophysics Data System (ADS)

Bjørk, R.; Nielsen, K. K.

2015-10-01

The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have the same temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si), copper indium gallium (di)selenide (CIGS) and cadmium telluride (CdTe) cells. The degradation of PV performance with temperature is shown to dominate the increase in power produced by the TEG, due to the low efficiency of the TEG. For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and has a lower efficiency than the PV alone, whereas for an a-Si cell the total system performance may be slightly increased by the TEG.

Modeling and control of hybrid wind/photovoltaic/fuel cell distributed generation systems

NASA Astrophysics Data System (ADS)

Wang, Caisheng

Due to ever increasing energy consumption, rising public awareness of environmental protection, and steady progress in power deregulation, alternative (i.e., renewable and fuel cell based) distributed generation (DG) systems have attracted increased interest. Wind and photovoltaic (PV) power generation are two of the most promising renewable energy technologies. Fuel cell (FC) systems also show great potential in DG applications of the future due to their fast technology development and many merits they have, such as high efficiency, zero or low emission (of pollutant gases) and flexible modular structure. The modeling and control of a hybrid wind/PV/FC DG system is addressed in this dissertation. Different energy sources in the system are integrated through an AC bus. Dynamic models for the main system components, namely, wind energy conversion system (WECS), PV energy conversion system (PVECS), fuel cell, electrolyzer, power electronic interfacing circuits, battery, hydrogen storage tank, gas compressor and gas pressure regulator, are developed. Two types of fuel cells have been modeled in this dissertation: proton exchange membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC). Power control of a grid-connected FC system as well as load mitigation control of a stand-alone FC system are investigated. The pitch angle control for WECS, the maximum power point tracking (MPPT) control for PVECS, and the control for electrolyzer and power electronic devices, are also addressed in the dissertation. Based on the dynamic component models, a simulation model for the proposed hybrid energy system has been developed using MATLAB/Simulink. The overall power management strategy for coordinating the power flows among the different energy sources is presented in the dissertation. Simulation studies have been carried out to verify the system performance under different scenarios using a practical load profile and real weather data. The results show that the overall power management strategy is effective and the power flows among the different energy sources and the load demand is balanced successfully. The DG's impacts on the existing power system are also investigated in this dissertation. Analytical methods for finding optimal sites to deploy DG sources in power systems are presented and verified with simulation studies.

High-Efficiency Photovoltaic System Using Partially-Connected DC-DC Converter

NASA Astrophysics Data System (ADS)

Uno, Masatoshi; Kukita, Akio; Tanaka, Koji

Power conversion electronics for photovoltaic (PV) systems are desired to operate as efficiently as possible to exploit the power generated by PV modules. This paper proposes a novel PV system in which a dc-dc converter is partially connected to series-connected PV modules. The proposed system achieves high power-conversion efficiency by reducing the passing power and input/output voltages of the converter. The theoretical operating principle was experimentally validated. Resultant efficiency performances of the proposed and conventional systems demonstrated that the proposed system was more efficient in terms of power conversion though the identical converter was used for the both systems.

Stabilized PV system

DOEpatents

Dinwoodie, Thomas L.

2002-12-17

A stabilized PV system comprises an array of photovoltaic (PV) assemblies mounted to a support surface. Each PV assembly comprises a PV module and a support assembly securing the PV module to a position overlying the support surface. The array of modules is circumscribed by a continuous, belt-like perimeter assembly. Cross strapping, extending above, below or through the array, or some combination of above, below and through the array, secures a first position along the perimeter assembly to at least a second position along the perimeter assembly thereby stabilizing the array against wind uplift forces. The first and second positions may be on opposite sides on the array.

Genome-Wide Identification, Phylogeny, and Expression Analysis of ARF Genes Involved in Vegetative Organs Development in Switchgrass.

PubMed

Wang, Jianli; Wu, Zhenying; Shen, Zhongbao; Bai, Zetao; Zhong, Peng; Ma, Lichao; Pan, Duofeng; Zhang, Ruibo; Li, Daoming; Zhang, Hailing; Fu, Chunxiang; Han, Guiqing; Guo, Changhong

2018-01-01

Auxin response factors (ARFs) have been reported to play vital roles during plant growth and development. In order to reveal specific functions related to vegetative organs in grasses, an in-depth study of the ARF gene family was carried out in switchgrass ( Panicum virgatum L.), a warm-season C4 perennial grass that is mostly used as bioenergy and animal feedstock. A total of 47 putative ARF genes ( PvARFs ) were identified in the switchgrass genome (2n = 4x = 36), 42 of which were anchored to the seven pairs of chromosomes and found to be unevenly distributed. Sixteen PvARFs were predicted to be potential targets of small RNAs (microRNA160 and 167). Phylogenetically speaking, PvARFs were divided into seven distinct subgroups based on the phylogeny, exon/intron arrangement, and conserved motif distribution. Moreover, 15 pairs of PvARFs have different temporal-spatial expression profiles in vegetative organs (2nd, 3rd, and 4th internode and leaves), which implies that different PvARFs have specific functions in switchgrass growth and development. In addition, at least 14 pairs of PvARFs respond to naphthylacetic acid (NAA) treatment, which might be helpful for us to study on auxin response in switchgrass. The comprehensive analysis, described here, will facilitate the future functional analysis of ARF genes in grasses.

Feasibility Study of Residential Grid-Connected Solar Photovoltaic Systems in the State of Indiana

NASA Astrophysics Data System (ADS)

Al-Odeh, Mahmoud

This study aims to measure the financial viability of installing and using a residential grid-connected PV system in the State of Indiana while predicting its performance in eighteen geographical locations within the state over the system's expected lifetime. The null hypothesis of the study is that installing a PV system for a single family residence in the State of Indiana will not pay for itself within 25 years. Using a systematic approach consisting of six steps, data regarding the use of renewable energy in the State of Indiana was collected from the website of the US Department of Energy to perform feasibility analysis of the installation and use of a standard-sized residential PV system. The researcher was not able to reject the null hypothesis that installing a PV system for a single family residence in the State of Indiana will not pay for itself within 25 years. This study found that the standard PV system does not produce a positive project balance and does not pay for itself within 25 years (the life time of the system) assuming the average cost of a system. The government incentive programs are not enough to offset the cost of installing the system against the cost of the electricity that would not be purchased from the utility company. It can be concluded that the cost of solar PV is higher than the market valuation of the power it produces; thus, solar PV did not compete on the cost basis with the traditional competitive energy sources. Reducing the capital cost will make the standard PV system economically viable in Indiana. The study found that the capital cost for the system should be reduced by 15% - 56%.

Development of an Efficient Entire-Capsid-Coding-Region Amplification Method for Direct Detection of Poliovirus from Stool Extracts

PubMed Central

Kilpatrick, David R.; Nakamura, Tomofumi; Burns, Cara C.; Bukbuk, David; Oderinde, Soji B.; Oberste, M. Steven; Kew, Olen M.; Pallansch, Mark A.; Shimizu, Hiroyuki

2014-01-01

Laboratory diagnosis has played a critical role in the Global Polio Eradication Initiative since 1988, by isolating and identifying poliovirus (PV) from stool specimens by using cell culture as a highly sensitive system to detect PV. In the present study, we aimed to develop a molecular method to detect PV directly from stool extracts, with a high efficiency comparable to that of cell culture. We developed a method to efficiently amplify the entire capsid coding region of human enteroviruses (EVs) including PV. cDNAs of the entire capsid coding region (3.9 kb) were obtained from as few as 50 copies of PV genomes. PV was detected from the cDNAs with an improved PV-specific real-time reverse transcription-PCR system and nucleotide sequence analysis of the VP1 coding region. For assay validation, we analyzed 84 stool extracts that were positive for PV in cell culture and detected PV genomes from 100% of the extracts (84/84 samples) with this method in combination with a PV-specific extraction method. PV could be detected in 2/4 stool extract samples that were negative for PV in cell culture. In PV-positive samples, EV species C viruses were also detected with high frequency (27% [23/86 samples]). This method would be useful for direct detection of PV from stool extracts without using cell culture. PMID:25339406

Final Technical Report: Increasing Prediction Accuracy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, Bruce Hardison; Hansen, Clifford; Stein, Joshua

2015-12-01

PV performance models are used to quantify the value of PV plants in a given location. They combine the performance characteristics of the system, the measured or predicted irradiance and weather at a site, and the system configuration and design into a prediction of the amount of energy that will be produced by a PV system. These predictions must be as accurate as possible in order for finance charges to be minimized. Higher accuracy equals lower project risk. The Increasing Prediction Accuracy project at Sandia focuses on quantifying and reducing uncertainties in PV system performance models.

Market assessment of photovoltaic power systems for agricultural applications in the Philippines

NASA Technical Reports Server (NTRS)

Cabraal, R. A.; Delasanta, D.; Burrill, G.

1981-01-01

The market potential in the Philippines for stand alone photovoltaic (P/V) systems in agriculture was assessed. Applications include: irrigation, postharvest operation, food and fiber processing and storage, and livestock and fisheries operations. Power and energy use profiles for many applications as well as assessments of business, government and financial climate for P/V sales are described. Many characteristics of the Philippine agriculture and energy sector favorably influence the use of P/V systems. However, serious and significant barriers prevent achieving the technically feasible, cost competitive market for P/V systems in the agricultural sector. The reason for the small market is the limited availability capital for financing P/V systems. It is suggested that innovative financing schemes and promotional campaigns should be devised.

Market assessment of photovoltaic power systems for agricultural applications in the Philippines

NASA Astrophysics Data System (ADS)

Cabraal, R. A.; Delasanta, D.; Burrill, G.

1981-04-01

The market potential in the Philippines for stand alone photovoltaic (P/V) systems in agriculture was assessed. Applications include: irrigation, postharvest operation, food and fiber processing and storage, and livestock and fisheries operations. Power and energy use profiles for many applications as well as assessments of business, government and financial climate for P/V sales are described. Many characteristics of the Philippine agriculture and energy sector favorably influence the use of P/V systems. However, serious and significant barriers prevent achieving the technically feasible, cost competitive market for P/V systems in the agricultural sector. The reason for the small market is the limited availability capital for financing P/V systems. It is suggested that innovative financing schemes and promotional campaigns should be devised.

Mean-variance portfolio analysis data for optimizing community-based photovoltaic investment.

PubMed

Shakouri, Mahmoud; Lee, Hyun Woo

2016-03-01

The amount of electricity generated by Photovoltaic (PV) systems is affected by factors such as shading, building orientation and roof slope. To increase electricity generation and reduce volatility in generation of PV systems, a portfolio of PV systems can be made which takes advantages of the potential synergy among neighboring buildings. This paper contains data supporting the research article entitled: PACPIM: new decision-support model of optimized portfolio analysis for community-based photovoltaic investment [1]. We present a set of data relating to physical properties of 24 houses in Oregon, USA, along with simulated hourly electricity data for the installed PV systems. The developed Matlab code to construct optimized portfolios is also provided in . The application of these files can be generalized to variety of communities interested in investing on PV systems.

NREL Photovoltaic Program. FY 1994 annual report, October 1, 1993--September 30, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-06-01

This report summarizes the in-house and subcontracted research and development activities under the National renewable Energy Laboratory (NREL) Photovoltaics (PV) program for fiscal year 1994. Research is organized under the following areas; PV program management; crystalline silicon and advanced devices; thin-film PV technologies; PV manufacturing; PV module and system performance and engineering; and PV applications and markets.

Estimation of PV energy production based on satellite data

NASA Astrophysics Data System (ADS)

Mazurek, G.

2015-09-01

Photovoltaic (PV) technology is an attractive source of power for systems without connection to power grid. Because of seasonal variations of solar radiation, design of such a power system requires careful analysis in order to provide required reliability. In this paper we present results of three-year measurements of experimental PV system located in Poland and based on polycrystalline silicon module. Irradiation values calculated from results of ground measurements have been compared with data from solar radiation databases employ calculations from of satellite observations. Good convergence level of both data sources has been shown, especially during summer. When satellite data from the same time period is available, yearly and monthly production of PV energy can be calculated with 2% and 5% accuracy, respectively. However, monthly production during winter seems to be overestimated, especially in January. Results of this work may be helpful in forecasting performance of similar PV systems in Central Europe and allow to make more precise forecasts of PV system performance than based only on tables with long time averaged values.

Georgetown University Photovoltaic Higher Education National Exemplar Facility (PHENEF)

NASA Technical Reports Server (NTRS)

Marshall, N.

1984-01-01

Several photographs of this facility using photovoltaic (PV) cells are shown. An outline is given of the systems requirements, system design and wiring topology, a simplified block design, module electrical characteristics, PV module and PV module matching.

International PV QA Task Force's Proposed Comparative Rating System for PV Modules: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wohlgemuth, J.; Kurtz, S.

The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests aremore » being developed for each of the selected climate zones.« less

Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

DOE PAGES

Liu, Yong; Zhu, Lin; Zhan, Lingwei; ...

2015-06-23

Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructedmore » solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.« less

Performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX

NASA Astrophysics Data System (ADS)

Syafiqah, Z.; Amin, N. A. M.; Irwan, Y. M.; Irwanto, M.; Leow, W. Z.; Amelia, A. R.

2017-09-01

A research has been conducted to find the optimum combination for DC fan air cooling system of photovoltaic (PV) panel. During normal operation of PV panel, it is estimated that only 15 % of solar radiation is converted into electrical energy. Meanwhile, the rest of the solar radiation is converted into heat energy which affects the performance of the PV panel. Therefore, the aim of this research is to investigate the performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX. The effect of airflow configuration of DC fan has been investigated. This is to analyze whether the airflow circulation of DC fan cause a change towards the maximum temperature of PV panel. Besides, the impact of varying number of DC fans attached at the back of PV panel is evaluated. The result of airflow circulation of DC fan has been discussed. Meanwhile, with the increment number of DC fans, the PV panel temperature drops significantly. As a conclusion, the optimum number of DC fans is two with the combination of inlet airflow.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grocholski, Brent; Catalli, Krystle; Shim, Sang-Heon

The discovery of a phase transition in Mg-silicate perovskite (Pv) to postperovskite (pPv) at lowermost mantle pressure-temperature (P - T) conditions may provide an explanation for the discontinuous increase in shear wave velocity found in some regions at a depth range of 200 to 400 km above the core-mantle boundary, hereafter the D{double_prime} discontinuity. However, recent studies on binary and ternary systems showed that reasonable contents of Fe{sup 2+} and Al for pyrolite increase the thickness (width of the mixed phase region) of the Pv - pPv boundary (400-600 km) to much larger than the D{double_prime} discontinuity ({le} 70 km).more » These results challenge the assignment of the D{double_prime} discontinuity to the Pv - pPv boundary in pyrolite (homogenized mantle composition). Furthermore, the mineralogy and composition of rocks that can host a detectable Pv {yields} pPv boundary are still unknown. Here we report in situ measurements of the depths and thicknesses of the Pv {yields} pPv transition in multiphase systems (San Carlos olivine, pyrolitic, and midocean ridge basaltic compositions) at the P - T conditions of the lowermost mantle, searching for candidate rocks with a sharp Pv - pPv discontinuity. Whereas the pyrolitic mantle may not have a seismologically detectable Pv {yields} pPv transition due to the effect of Al, harzburgitic compositions have detectable transitions due to low Al content. In contrast, Al-rich basaltic compositions may have a detectable Pv - pPv boundary due to their distinct mineralogy. Therefore, the observation of the D{prime} discontinuity may be related to the Pv {yields} pPv transition in the differentiated oceanic lithosphere materials transported to the lowermost mantle by subducting slabs.« less

Plug and Play PV Systems for American Homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoepfner, Christian

2016-12-22

The core objectives of the Plug & Play PV Systems Project were to develop a PV system that can be installed on a residential rooftop for less than $1.50/W in 2020, and in less than 10 hours (from point of purchase to commissioning). The Fraunhofer CSE team’s approach to this challenge involved a holistic approach to system design – hardware and software – that make Plug & Play PV systems: • Quick, easy, and safe to install • Easy to demonstrate as code compliant • Permitted, inspected, and interconnected via an electronic process Throughout the three years of work duringmore » this Department of Energy SunShot funded project, the team engaged in a substantive way with inspectional services departments and utilities, manufacturers, installers, and distributors. We received iterative feedback on the system design and on ideas for how such systems can be commercialized. This ultimately led us to conceiving of Plug & Play PV Systems as a framework, with a variety of components compatible with the Plug & Play PV approach, including string or microinverters, conventional modules or emerging lightweight modules. The framework enables a broad group of manufacturers to participate in taking Plug & Play PV Systems to market, and increases the market size for such systems. Key aspects of the development effort centered on the system hardware and associated engineering work, the development of a Plug & Play PV Server to enable the electronic permitting, inspection and interconnection process, understanding the details of code compliance and, on occasion, supporting applications for modifications to the code to allow lightweight modules, for example. We have published a number of papers on our testing and assessment of novel technologies (e.g., adhered lightweight modules) and on the electronic architecture.« less

2014 NREL Photovoltaic Reliability Workshops | Photovoltaic Research | NREL

Science.gov Websites

Curves and Visual Inspection of PV Modules Deployed at TEP Solar Test Yard-Peter McNutt, NREL Data Determining PV System's Degradation Rate and the Impact of Data Filters-Wilson Zexu Zhang, REC Solar Pte. Ltd " Test in Qualifying Solar PV Inverters-Dutch Uselton, Lennox IND System Reliability for Utility PV

Ranking and characterization of established BMI and lipid associated loci as candidates for gene-environment interactions

PubMed Central

Luan, Jian'an; Mihailov, Evelin; Metspalu, Andres; Forouhi, Nita G.; Magnusson, Patrik K. E.; Pedersen, Nancy L.; Hallmans, Göran; Chu, Audrey Y.; Justice, Anne E.; Graff, Mariaelisa; Rose, Lynda M.; Langenberg, Claudia; Cupples, L. Adrienne; Ridker, Paul M.; Ong, Ken K.; Loos, Ruth J. F.; Chasman, Daniel I.; Ingelsson, Erik; Kilpeläinen, Tuomas O.; Scott, Robert A.; Mägi, Reedik

2017-01-01

Phenotypic variance heterogeneity across genotypes at a single nucleotide polymorphism (SNP) may reflect underlying gene-environment (G×E) or gene-gene interactions. We modeled variance heterogeneity for blood lipids and BMI in up to 44,211 participants and investigated relationships between variance effects (Pv), G×E interaction effects (with smoking and physical activity), and marginal genetic effects (Pm). Correlations between Pv and Pm were stronger for SNPs with established marginal effects (Spearman’s ρ = 0.401 for triglycerides, and ρ = 0.236 for BMI) compared to all SNPs. When Pv and Pm were compared for all pruned SNPs, only BMI was statistically significant (Spearman’s ρ = 0.010). Overall, SNPs with established marginal effects were overrepresented in the nominally significant part of the Pv distribution (Pbinomial <0.05). SNPs from the top 1% of the Pm distribution for BMI had more significant Pv values (PMann–Whitney = 1.46×10−5), and the odds ratio of SNPs with nominally significant (<0.05) Pm and Pv was 1.33 (95% CI: 1.12, 1.57) for BMI. Moreover, BMI SNPs with nominally significant G×E interaction P-values (Pint<0.05) were enriched with nominally significant Pv values (Pbinomial = 8.63×10−9 and 8.52×10−7 for SNP × smoking and SNP × physical activity, respectively). We conclude that some loci with strong marginal effects may be good candidates for G×E, and variance-based prioritization can be used to identify them. PMID:28614350

Integrated Building Energy Systems Design Considering Storage Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stadler, Michael; Marnay, Chris; Siddiqui, Afzal

The addition of storage technologies such as flow batteries, conventional batteries, and heat storage can improve the economic, as well as environmental attraction of micro-generation systems (e.g., PV or fuel cells with or without CHP) and contribute to enhanced demand response. The interactions among PV, solar thermal, and storage systems can be complex, depending on the tariff structure, load profile, etc. In order to examine the impact of storage technologies on demand response and CO2 emissions, a microgrid's distributed energy resources (DER) adoption problem is formulated as a mixed-integer linear program that can pursue two strategies as its objective function.more » These two strategies are minimization of its annual energy costs or of its CO2 emissions. The problem is solved for a given test year at representative customer sites, e.g., nursing homes, to obtain not only the optimal investment portfolio, but also the optimal hourly operating schedules for the selected technologies. This paper focuses on analysis of storage technologies in micro-generation optimization on a building level, with example applications in New York State and California. It shows results from a two-year research projectperformed for the U.S. Department of Energy and ongoing work. Contrary to established expectations, our results indicate that PV and electric storage adoption compete rather than supplement each other considering the tariff structure and costs of electricity supply. The work shows that high electricity tariffs during on-peak hours are a significant driver for the adoption of electric storage technologies. To satisfy the site's objective of minimizing energy costs, the batteries have to be charged by grid power during off-peak hours instead of PV during on-peak hours. In contrast, we also show a CO2 minimization strategy where the common assumption that batteries can be charged by PV can be fulfilled at extraordinarily high energy costs for the site.« less

Conjunction of Photovoltaic and Thermophotovoltaic Power Production in Spacecraft Power Systems

DTIC Science & Technology

2015-09-01

photovoltaic ( PV ) arrays, which draw electrical energy from the most prominent power source in our solar system, the Sun. These arrays are large, and pose...freemaps/1000px/dni/SolarGIS- Solar -map-DNI-World- map-en.png By contrast, spacecraft PV power production systems are not so limited. With the...operating parameters for a given solar cell, and PMax is generally the described Pout from which the PV cell’s efficiency is calculated. A PV cell’s

PV Module Reliability Workshop | Photovoltaic Research | NREL

Science.gov Websites

-year old PV system in Quebec, Canada-Alex Bradley, Tanya Dhir, Yves Poissant Solar panel design factors PV Module Reliability Workshop PV Module Reliability Workshop Tuesday, February 24, 2015 Chair : Michael Kempe The 2015 PV Module Reliability Workshop (PVMRW) continued in the tradition of this annual

A Smart Power Electronic Multiconverter for the Residential Sector.

PubMed

Guerrero-Martinez, Miguel Angel; Milanes-Montero, Maria Isabel; Barrero-Gonzalez, Fermin; Miñambres-Marcos, Victor Manuel; Romero-Cadaval, Enrique; Gonzalez-Romera, Eva

2017-05-26

The future of the grid includes distributed generation and smart grid technologies. Demand Side Management (DSM) systems will also be essential to achieve a high level of reliability and robustness in power systems. To do that, expanding the Advanced Metering Infrastructure (AMI) and Energy Management Systems (EMS) are necessary. The trend direction is towards the creation of energy resource hubs, such as the smart community concept. This paper presents a smart multiconverter system for residential/housing sector with a Hybrid Energy Storage System (HESS) consisting of supercapacitor and battery, and with local photovoltaic (PV) energy source integration. The device works as a distributed energy unit located in each house of the community, receiving active power set-points provided by a smart community EMS. This central EMS is responsible for managing the active energy flows between the electricity grid, renewable energy sources, storage equipment and loads existing in the community. The proposed multiconverter is responsible for complying with the reference active power set-points with proper power quality; guaranteeing that the local PV modules operate with a Maximum Power Point Tracking (MPPT) algorithm; and extending the lifetime of the battery thanks to a cooperative operation of the HESS. A simulation model has been developed in order to show the detailed operation of the system. Finally, a prototype of the multiconverter platform has been implemented and some experimental tests have been carried out to validate it.

A Smart Power Electronic Multiconverter for the Residential Sector

PubMed Central

Guerrero-Martinez, Miguel Angel; Milanes-Montero, Maria Isabel; Barrero-Gonzalez, Fermin; Miñambres-Marcos, Victor Manuel; Romero-Cadaval, Enrique; Gonzalez-Romera, Eva

2017-01-01

The future of the grid includes distributed generation and smart grid technologies. Demand Side Management (DSM) systems will also be essential to achieve a high level of reliability and robustness in power systems. To do that, expanding the Advanced Metering Infrastructure (AMI) and Energy Management Systems (EMS) are necessary. The trend direction is towards the creation of energy resource hubs, such as the smart community concept. This paper presents a smart multiconverter system for residential/housing sector with a Hybrid Energy Storage System (HESS) consisting of supercapacitor and battery, and with local photovoltaic (PV) energy source integration. The device works as a distributed energy unit located in each house of the community, receiving active power set-points provided by a smart community EMS. This central EMS is responsible for managing the active energy flows between the electricity grid, renewable energy sources, storage equipment and loads existing in the community. The proposed multiconverter is responsible for complying with the reference active power set-points with proper power quality; guaranteeing that the local PV modules operate with a Maximum Power Point Tracking (MPPT) algorithm; and extending the lifetime of the battery thanks to a cooperative operation of the HESS. A simulation model has been developed in order to show the detailed operation of the system. Finally, a prototype of the multiconverter platform has been implemented and some experimental tests have been carried out to validate it. PMID:28587131

Integrating Renewable Energy into the Transmission and Distribution System of the U. S. Virgin Islands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burman, K.; Olis, D.; Gevorgian, V.

2011-09-01

This report focuses on the economic and technical feasibility of integrating renewable energy technologies into the U.S. Virgin Islands transmission and distribution systems. The report includes three main areas of analysis: 1) the economics of deploying utility-scale renewable energy technologies on St. Thomas/St. John and St. Croix; 2) potential sites for installing roof- and ground-mount PV systems and wind turbines and the impact renewable generation will have on the electrical subtransmission and distribution infrastructure, and 3) the feasibility of a 100- to 200-megawatt power interconnection of the Puerto Rico Electric Power Authority (PREPA), Virgin Islands Water and Power Authority (WAPA),more » and British Virgin Islands (BVI) grids via a submarine cable system.« less

Control Strategies for the DAB Based PV Interface System

PubMed Central

El-Helw, Hadi M.; Al-Hasheem, Mohamed; Marei, Mostafa I.

2016-01-01

This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system. PMID:27560138

New Report Shines Light on Installed Costs and Deployment Barriers for

Science.gov Websites

Laboratory (NREL) are making available the most detailed component and system-level cost breakdowns to date previously unknown soft costs for the first time. The report, titled "Installed Cost Benchmarks and interest in pairing distributed PV with storage, but there's a lack of publicly available cost data and

Architecturally sensitive retrofitting of PV to a residential block in Greece to reduce its carbon footprint

NASA Astrophysics Data System (ADS)

Panopoulou, Ismini

Photovoltaic power is a unique energy source, with wide distribution potential, which can be integrated within the fabric of individual buildings, transforming the power generation in a less large-scale and regionally located issue. As a result, photovoltaic power is a free, clean and silent electrical supply that can be introduced into cities and residential areas. Over the past years, grid-connected, distributed photovoltaic power systems have become an explosively growing sector worldwide. This trend is expected to be continued in the future and solar systems may become a common building element of building construction. In Greece, where the main focus of the project is concentrated, the extended sunshine and the incentives of the new Renewable Energy Sources law of 2006, give a different perspective in photovoltaic investments. In the case study of Vera Water Residence complex in Athens, the viability of an architecturally sensitive retrofitting of PV was examined, from both financial and environmental aspects. The project was concentrated in one of the complex's buildings which was modelled in TAS simulator in order for the annual heating and cooling loads to be estimated. A closer to the reality estimation of electricity demand was made through the annual electricity bills of the building. The proposed building integrated photovoltaic system was designed in terms of following and respecting the aesthetics of the existing architecture of the complex while being as efficient as possible. The annual energy output and C02 emissions reductions were then calculated through RETScreen software analysis according to the location of the project and the characteristics of the PV system. Finally, an economic analysis has been included to the study, considering the installation cost, the annual savings and the embodied energy of the system, in order for the payback period of the investment to be determined. Finally, a small sensitivity analysis concerning the effect of different factors influencing the feasibility of the PV investment was carried out and as it was expected it had significant effect on the initially calculated the payback period value. The expected future increase of fuel prices and the reduction of the investment's initial cost due to government grants, added to the prospect of new future tax incentive and subsidies, have made the prospect of the project more attractive while significantly reducing the payback period.

Design and construction evaluation of a photovoltaic DC LED lighting system

NASA Astrophysics Data System (ADS)

Bhamidipati, Jyotsna

2008-08-01

The market demand for commercialization of Photovoltaic (PV) systems depends a lot on the reliability, efficiency and performance of various components within the system. PV panels produce DC power when exposed to sunlight, and an inverter converts this to AC power in a typical solar powered building. Though, PV lighting has existed for a long time it hasn't been very effective, as incandescent light sources were commonly used which are inefficient. Today fluorescent fixtures are mostly used with PV's due to its high efficacy. Light-emitting diodes present a new vision to energy efficiency in lighting design with their low energy consumption. Current research predicts improved efficiencies of LED light fixtures and their commercial use is a few years away. LEDs which operate on DC voltages when coupled with photovoltaics can be a simple PV lighting application and a sustainable solution with potential for payback. This research evaluates the design and construction of a photovoltaic DC LED lighting system for a solar house at Pennsylvania State University. A detailed cost and payback analysis of a PV DC LED lighting system is presented in this research. PV output simulations for the solar house are presented. Results presented in this research indicate that the Solid state lighting market is evolving rapidly and that LED's are a choice in stand-alone photovoltaic DC lighting systems. The efficiency and the cost-effectiveness of such systems would however improve in the coming years with research and development now focused on PV systems and on Solid state lighting technologies.

The Evolving Market Structure of the U.S. Residential Solar PV Installation

Science.gov Websites

Solar PV Installation Industry, 2000-2016 The Evolving Market Structure of the U.S. Residential Solar PV residential solar photovoltaic (PV) system and that the residential PV installation industry has become more concentrated over time. From 2000 to 2016, the U.S. residential solar photovoltaic (PV) installation industry

ENVI-PV: An Interactive Web Client for Multi-Criteria Life Cycle Assessment of Photovoltaic Systems Worldwide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perez-Lopez, Paula; Gschwind, Benoit; Blanc, Philippe

Solar photovoltaics (PV) is the second largest source of new capacity among renewable energies. The worldwide capacity encompassed 135 GW in 2013 and is estimated to increase to 1721 GW in 2030 and 4674 GW in 2050, according to a prospective high-renewable scenario. To achieve this production level while minimizing environmental impacts, decision makers must have access to environmental performance data that reflect their high spatial variability accurately. We propose ENVI-PV (http://viewer.webservice-energy.org/project_iea), a new interactive tool that provides maps and screening level data, based on weighted average supply chains, for the environmental performance of common PV technologies. Environmental impacts ofmore » PV systems are evaluated according to a life cycle assessment approach. ENVI-PV was developed using a state-of-the-art interoperable and open standard Web Service framework from the Open Geospatial Consortium (OGC). It combines the latest life cycle inventories, published in 2015 by the International Energy Agency (IEA) under the Photovoltaic Power Systems Program (PVPS) Task 12, and some inventories previously published from Ecoinvent v2.2 database with solar irradiation estimates computed from the worldwide NASA SSE database. ENVI-PV is the first tool to propose a worldwide coverage of environmental performance of PV systems using a multi-criteria assessment. The user can compare the PV environmental performance to the environmental footprint of country electricity mixes. ENVI-PV is designed as an environmental interactive tool to generate PV technological options and evaluate their performance in different spatial and techno-economic contexts. Its potential applications are illustrated in this paper with several examples.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbose, Galen; Wiser, Ryan; Bolinger, Mark

Some stakeholders continue to voice concerns about the performance of customer-sited photovoltaic (PV) systems, particularly because these systems typically receive financial support through ratepayer- or publicly-funded programs. Although much remains to be understood about the extent and specific causes of poor PV system performance, several studies of the larger programs and markets have shed some light on the issue. An evaluation of the California Energy Commission (CEC)'s Emerging Renewables Program, for example, found that 7% of systems, in a sample of 95, had lower-than-expected power output due to shading or soiling (KEMA 2005). About 3% of a larger sample ofmore » 140 systems were not operating at all or were operating well below expected output, due to failed equipment, faulty installation workmanship, and/or a lack of basic maintenance. In a recent evaluation of the other statewide PV incentive program in California, the Self-Generation Incentive Program, 9 of 52 projects sampled were found to have annual capacity factors less than 14.5%, although reasons for these low capacity factors generally were not identified (Itron 2005). Studies of PV systems in Germany and Japan, the two largest PV markets worldwide, have also revealed some performance problems associated with issues such as shading, equipment and installation defects, inverter failure, and deviations from module manufacturers' specifications (Otani et al. 2004, Jahn & Nasse 2004). Although owners of PV systems have an inherent incentive to ensure that their systems perform well, many homeowners and building operators may lack the necessary information and expertise to carry out this task effectively. Given this barrier, and the responsibility of PV incentive programs to ensure that public funds are prudently spent, these programs should (and often do) play a critical role in promoting PV system performance. Performance-based incentives (PBIs), which are based on actual energy production rather than the rated capacity of the modules or system, are often suggested as one possible strategy. Somewhat less recognized are the many other program design options also available, each with its particular advantages and disadvantages. To provide a point of reference for assessing the current state of the art, and to inform program design efforts going forward, we examine the approaches to encouraging PV system performance - including, but not limited to, PBIs - used by 32 prominent PV incentive programs in the U.S. (see Table 1).1 We focus specifically on programs that offer an explicit subsidy payment for customer-sited PV installations. PV support programs that offer other forms of financial support or that function primarily as a mechanism for purchasing renewable energy credits (RECs) through energy production-based payments are outside the scope of our review.2 The information presented herein is derived primarily from publicly available sources, including program websites and guidebooks, programs evaluations, and conference papers, as well as from a limited number of personal communications with program staff. The remainder of this report is organized as follows. The next section presents a simple conceptual framework for understanding the issues that affect PV system performance and provides an overview of the eight general strategies to encourage performance used among the programs reviewed in this report. The subsequent eight sections discuss in greater detail each of these program design strategies and describe how they have been implemented among the programs surveyed. Based on this review, we then offer a series of recommendations for how PV incentive programs can effectively promote PV system performance.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deline, Chris; Dann, Geoff

Recent increases in photovoltaic (PV) systems on Department of the Navy (DON) land and potential siting near airfields prompted Commander, Naval Installations Command to fund the Naval Facilities Engineering Command to evaluate the impact of electromagnetic interference (EMI) from PV systems on airfield electronic equipment. Naval Facilities Engineering and Expeditionary Warfare Center tasked Department of Energy National Renewable Energy laboratory (NREL) to conduct the assessment. PV systems often include high-speed switching semiconductor circuits to convert the voltage produced by the PV arrays to the voltage needed by the end user. Switching circuits inherently produce electromagnetic radiation at harmonics of themore » switching frequency. In this report, existing literature is summarized and tests to measure emissions and mitigation methods are discussed. The literature shows that the emissions from typical PV systems are low strength and unlikely to cause interference to most airfield electronic systems. With diligent procurement and siting of PV systems, including specifications for FCC Part 15 Class A compliant equipment and a 250-foot setback from communication equipment, NREL anticipates little to no EMI impact on nearby communications or telemetry equipment.« less

Keeping the Future Bright: Department of Defense (DOD) Sustainable Energy Strategy for Installations

DTIC Science & Technology

2016-04-04

solar photovoltaic ( PV ) energy from a novelty to a mainstream energy source represents another one of the biggest clean energy stories of the past...still slightly more expensive to install than utility-scale PV , distributed solar installation costs decreased in half since 2008, and this power source...capacity will increase in the coming years (See Figure 3)6 Figure 3: Solar PV (Utility Scale) Utility-Scale Median Sy5tem Price —12 10 6 Ibid. Ibid. 9 up

Integration, Validation, and Application of a PV Snow Coverage Model in SAM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, Janine M.; Ryberg, David Severin

2017-08-01

Due to the increasing deployment of PV systems in snowy climates, there is significant interest in a method capable of estimating PV losses resulting from snow coverage that has been verified for a variety of system designs and locations. Many independent snow coverage models have been developed over the last 15 years; however, there has been very little effort verifying these models beyond the system designs and locations on which they were based. Moreover, major PV modeling software products have not yet incorporated any of these models into their workflows. In response to this deficiency, we have integrated the methodologymore » of the snow model developed in the paper by Marion et al. (2013) into the National Renewable Energy Laboratory's (NREL) System Advisor Model (SAM). In this work, we describe how the snow model is implemented in SAM and we discuss our demonstration of the model's effectiveness at reducing error in annual estimations for three PV arrays. Next, we use this new functionality in conjunction with a long term historical data set to estimate average snow losses across the United States for two typical PV system designs. The open availability of the snow loss estimation capability in SAM to the PV modeling community, coupled with our results of the nationwide study, will better equip the industry to accurately estimate PV energy production in areas affected by snowfall.« less

Recent advances in the PV-CSP hybrid solar power technology

NASA Astrophysics Data System (ADS)

Ju, Xing; Xu, Chao; Han, Xue; Zhang, Hui; Wei, Gaosheng; Chen, Lin

2017-06-01

Photovoltaic - Concentrated Solar Power (PV-CSP) hybrid technology is considered to be an important future research trend in solar energy engineering. The development of the PV-CSP hybrid technology accelerates in recent years with the rapid maturation of photovoltaics (PV) and concentrated solar power (CSP). This paper presents the recent advances on PV-CSP technology, including different technologies based on new dispatch strategies, Organic Rankine Cycles, spectral beam filters and so on. The research status and the hybrid system performance of the recent researches are summarized, aimed to provide an extended recognition on the PV-CSP hybrid technology. The advantages and limitations of the hybrid system are concluded according to the researches reviewed.

Design of energy storage system to improve inertial response for large scale PV generation

DOE PAGES

Wang, Xiaoyu; Yue, Meng

2016-07-01

With high-penetration levels of renewable generating sources being integrated into the existing electric power grid, conventional generators are being replaced and grid inertial response is deteriorating. This technical challenge is more severe with photovoltaic (PV) generation than with wind generation because PV generation systems cannot provide inertial response unless special countermeasures are adopted. To enhance the inertial response, this paper proposes to use battery energy storage systems (BESS) as the remediation approach to accommodate the degrading inertial response when high penetrations of PV generation are integrated into the existing power grid. A sample power system was adopted and simulated usingmore » PSS/E software. Here, impacts of different penetration levels of PV generation on the system inertial response were investigated and then BESS was incorporated to improve the frequency dynamics.« less

Life cycle cost analysis of a stand-alone PV system in rural Kenya

NASA Astrophysics Data System (ADS)

Daly, Emma

The purpose of this quantitative research study was to determine the economic feasibility of a stand-alone PV system to electrify a rural area in Kenya. The research conducted involved a comprehensive review of all the relevant literature associated with the study. Methodologies were extrapolated from this extensive literature to develop a model for the complete design and economic analysis of a stand-alone PV system. A women's center in rural Kenya was used as a worked example to demonstrate the workings of the model. The results suggest that electrifying the center using a stand-alone PV system is an economically viable option which is encouraging for the surrounding area. This model can be used as a business model to determine the economic feasibility of a stand-alone PV system in alternative sites in Kenya.

Mean-variance portfolio analysis data for optimizing community-based photovoltaic investment

PubMed Central

Shakouri, Mahmoud; Lee, Hyun Woo

2016-01-01

The amount of electricity generated by Photovoltaic (PV) systems is affected by factors such as shading, building orientation and roof slope. To increase electricity generation and reduce volatility in generation of PV systems, a portfolio of PV systems can be made which takes advantages of the potential synergy among neighboring buildings. This paper contains data supporting the research article entitled: PACPIM: new decision-support model of optimized portfolio analysis for community-based photovoltaic investment [1]. We present a set of data relating to physical properties of 24 houses in Oregon, USA, along with simulated hourly electricity data for the installed PV systems. The developed Matlab code to construct optimized portfolios is also provided in Supplementary materials. The application of these files can be generalized to variety of communities interested in investing on PV systems. PMID:26937458

Photovoltaic Performance and Reliability Workshop summary

NASA Astrophysics Data System (ADS)

Kroposki, Benjamin

1997-02-01

The objective of the Photovoltaic Performance and Reliability Workshop was to provide a forum where the entire photovoltaic (PV) community (manufacturers, researchers, system designers, and customers) could get together and discuss technical issues relating to PV. The workshop included presentations from twenty-five speakers and had more than one hundred attendees. This workshop also included several open sessions in which the audience and speakers could discuss technical subjects in depth. Several major topics were discussed including: PV characterization and measurements, service lifetimes for PV devices, degradation and failure mechanisms for PV devices, standardization of testing procedures, AC module performance and reliability testing, inverter performance and reliability testing, standardization of utility interconnect requirements, experience from field deployed systems, and system certification.

Realworld maximum power point tracking simulation of PV system based on Fuzzy Logic control

NASA Astrophysics Data System (ADS)

Othman, Ahmed M.; El-arini, Mahdi M. M.; Ghitas, Ahmed; Fathy, Ahmed

2012-12-01

In the recent years, the solar energy becomes one of the most important alternative sources of electric energy, so it is important to improve the efficiency and reliability of the photovoltaic (PV) systems. Maximum power point tracking (MPPT) plays an important role in photovoltaic power systems because it maximize the power output from a PV system for a given set of conditions, and therefore maximize their array efficiency. This paper presents a maximum power point tracker (MPPT) using Fuzzy Logic theory for a PV system. The work is focused on the well known Perturb and Observe (P&O) algorithm and is compared to a designed fuzzy logic controller (FLC). The simulation work dealing with MPPT controller; a DC/DC Ćuk converter feeding a load is achieved. The results showed that the proposed Fuzzy Logic MPPT in the PV system is valid.

Research on comprehensive decision-making of PV power station connecting system

NASA Astrophysics Data System (ADS)

Zhou, Erxiong; Xin, Chaoshan; Ma, Botao; Cheng, Kai

2018-04-01

In allusion to the incomplete indexes system and not making decision on the subjectivity and objectivity of PV power station connecting system, based on the combination of improved Analytic Hierarchy Process (AHP), Criteria Importance Through Intercriteria Correlation (CRITIC) as well as grey correlation degree analysis (GCDA) is comprehensively proposed to select the appropriate system connecting scheme of PV power station. Firstly, indexes of PV power station connecting system are divided the recursion order hierarchy and calculated subjective weight by the improved AHP. Then, CRITIC is adopted to determine the objective weight of each index through the comparison intensity and conflict between indexes. The last the improved GCDA is applied to screen the optimal scheme, so as to, from the subjective and objective angle, select the connecting system. Comprehensive decision of Xinjiang PV power station is conducted and reasonable analysis results are attained. The research results might provide scientific basis for investment decision.

Modeling of a VMJ PV array under Gaussian high intensity laser power beam condition

NASA Astrophysics Data System (ADS)

Eom, Jeongsook; Kim, Gunzung; Park, Yongwan

2018-02-01

The high intensity laser power beaming (HILPB) system is one of the most promising systems in the long-rang wireless power transfer field. The vertical multi-junction photovoltaic (VMJ PV) array converts the HILPB into electricity to power the load or charges a battery. The output power of a VMJ PV array depends mainly on irradiance values of each VMJ PV cells. For simulating an entire VMJ PV array, the irradiance profile of the Gaussian HILPB and the irradiance level of the VMJ PV cell are mathematically modeled first. The VMJ PV array is modeled as a network with dimension m*n, where m represents the number of VMJ PV cells in a column, and n represents the number of VMJ PV cells in a row. In order to validate the results obtained in modeling and simulation, a laboratory setup was developed using 55 VMJ PV array. By using the output power model of VMJ PV array, we can establish an optimal power transmission path by the receiver based on the received signal strength. When the laser beam from multiple transmitters aimed at a VMJ PV array at the same time, the received power is the sum of all energy at a VMJ PV array. The transmitter sends its power characteristics as optically coded laser pulses and powers as HILPB. Using the attenuated power model and output power model of VMJ PV array, the receiver can estimate the maximum receivable powers from the transmitters and select optimal transmitters.

Development of an efficient entire-capsid-coding-region amplification method for direct detection of poliovirus from stool extracts.

PubMed

Arita, Minetaro; Kilpatrick, David R; Nakamura, Tomofumi; Burns, Cara C; Bukbuk, David; Oderinde, Soji B; Oberste, M Steven; Kew, Olen M; Pallansch, Mark A; Shimizu, Hiroyuki

2015-01-01

Laboratory diagnosis has played a critical role in the Global Polio Eradication Initiative since 1988, by isolating and identifying poliovirus (PV) from stool specimens by using cell culture as a highly sensitive system to detect PV. In the present study, we aimed to develop a molecular method to detect PV directly from stool extracts, with a high efficiency comparable to that of cell culture. We developed a method to efficiently amplify the entire capsid coding region of human enteroviruses (EVs) including PV. cDNAs of the entire capsid coding region (3.9 kb) were obtained from as few as 50 copies of PV genomes. PV was detected from the cDNAs with an improved PV-specific real-time reverse transcription-PCR system and nucleotide sequence analysis of the VP1 coding region. For assay validation, we analyzed 84 stool extracts that were positive for PV in cell culture and detected PV genomes from 100% of the extracts (84/84 samples) with this method in combination with a PV-specific extraction method. PV could be detected in 2/4 stool extract samples that were negative for PV in cell culture. In PV-positive samples, EV species C viruses were also detected with high frequency (27% [23/86 samples]). This method would be useful for direct detection of PV from stool extracts without using cell culture. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The impact of short-term stochastic variability in solar irradiance on optimal microgrid design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schittekatte, Tim; Stadler, Michael; Cardoso, Gonçalo

2016-07-01

This paper proposes a new methodology to capture the impact of fast moving clouds on utility power demand charges observed in microgrids with photovoltaic (PV) arrays, generators, and electrochemical energy storage. It consists of a statistical approach to introduce sub-hourly events in the hourly economic accounting process. The methodology is implemented in the Distributed Energy Resources Customer Adoption Model (DER-CAM), a state of the art mixed integer linear model used to optimally size DER in decentralized energy systems. Results suggest that previous iterations of DER-CAM could undersize battery capacities. The improved model depicts more accurately the economic value of PVmore » as well as the synergistic benefits of pairing PV with storage.« less

Coordination of International Standards with Implementation of the IECRE Conformity Assessment System to Provide Multiple Certification Offerings for PV Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, George; Haring, Adrian; Spooner, Ted

To help address the industry's needs for assuring the value and reducing the risk of investments in PV power plants; the International Electrotechnical Commission (IEC) has established a new conformity assessment system for renewable energy (IECRE). There are presently important efforts underway to define the requirements for various types of PV system certificates, and publication of the international standards upon which these certifications will be based. This paper presents a detailed analysis of the interrelationship of these activities and the timing for initiation of IECRE PV system certifications.

78 FR 17650 - Combined Notice of Filings #2

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-22

...: Spectrum Nevada Solar, LLC. Description: Application and Initial Baseline Tariff Filing to be effective 4... Service Agreement CA PV Energy, LLC at 1670 Champagne Ave to be effective 3/16/2013. Filed Date: 3/15/13...: Southern California Edison Company. Description: GIA and Distribution Service Agreement CA PV Energy, LLC...

DGIC Interconnection Insights | Distributed Generation Interconnection

Science.gov Websites

Center and Energy Analysis Group. NREL researchers examined PV project data from more than 30,000 solar permission to operate. "This report represents the first data-driven evaluation of how PV deployment additional insights on the research effort and report findings, check out STAT Chat (the "Solar

Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H., Jr.; Phillips, Brandon S.

2015-01-01

CubeSats, Communication Satellites, and Outer Planet Science Satellites all share one thing in common: Mission success depends on maintaining power in the harsh space environment. For a vast majority of satellites, spacecraft power is sourced by a photovoltaic (PV) array system. Built around PV cells, the array systems also include wiring, substrates, connectors, and protection diodes. Each of these components must function properly throughout the mission in order for power production to remain at nominal levels. Failure of even one component can lead to a crippling loss of power. To help ensure PV array systems do not suffer failures on-orbit due to the space environment, NASA's Marshall Space Flight Center (MSFC) has developed a wide ranging test and evaluation capability. Key elements of this capability include: Testing: a. Ultraviolet (UV) Exposure b. Charged Particle Radiation (Electron and Proton) c. Thermal Cycling d. Plasma and Beam Environments Evaluation: a. Electrostatic Discharge (ESD) Screening b. Optical Inspection and easurement c. PV Power Output including Large Area Pulsed Solar Simulator (LAPSS) measurements This paper will describe the elements of the space environment which particularly impact PV array systems. MSFC test capabilities will be described to show how the relevant space environments can be applied to PV array systems in the laboratory. A discussion of MSFC evaluation capabilities will also be provided. The sample evaluation capabilities offer test engineers a means to quantify the effects of the space environment on their PV array system or component. Finally, examples will be shown of the effects of the space environment on actual PV array materials tested at MSFC.

The impact of retail electricity tariff evolution on solar photovoltaic deployment

DOE PAGES

Gagnon, Pieter; Cole, Wesley J.; Frew, Bethany; ...

2017-11-10

Here, this analysis explores the impact that the evolution of retail electricity tariffs can have on the deployment of solar photovoltaics. It suggests that ignoring the evolution of tariffs resulted in up to a 36% higher prediction of the capacity of distributed PV in 2050, compared to scenarios that represented tariff evolution. Critically, the evolution of tariffs had a negligible impact on the total generation from PV $-$ both utility-scale and distributed $-$ in the scenarios that were examined.

The impact of retail electricity tariff evolution on solar photovoltaic deployment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gagnon, Pieter; Cole, Wesley J.; Frew, Bethany

Here, this analysis explores the impact that the evolution of retail electricity tariffs can have on the deployment of solar photovoltaics. It suggests that ignoring the evolution of tariffs resulted in up to a 36% higher prediction of the capacity of distributed PV in 2050, compared to scenarios that represented tariff evolution. Critically, the evolution of tariffs had a negligible impact on the total generation from PV $-$ both utility-scale and distributed $-$ in the scenarios that were examined.

A probabilistic approach to photovoltaic generator performance prediction

NASA Astrophysics Data System (ADS)

Khallat, M. A.; Rahman, S.

1986-09-01

A method for predicting the performance of a photovoltaic (PV) generator based on long term climatological data and expected cell performance is described. The equations for cell model formulation are provided. Use of the statistical model for characterizing the insolation level is discussed. The insolation data is fitted to appropriate probability distribution functions (Weibull, beta, normal). The probability distribution functions are utilized to evaluate the capacity factors of PV panels or arrays. An example is presented revealing the applicability of the procedure.

Heterogeneous Collaborative Sensor Network for Electrical Management of an Automated House with PV Energy

PubMed Central

Castillo-Cagigal, Manuel; Matallanas, Eduardo; Gutiérrez, Álvaro; Monasterio-Huelin, Félix; Caamaño-Martín, Estefaná; Masa-Bote, Daniel; Jiménez-Leube, Javier

2011-01-01

In this paper we present a heterogeneous collaborative sensor network for electrical management in the residential sector. Improving demand-side management is very important in distributed energy generation applications. Sensing and control are the foundations of the “Smart Grid” which is the future of large-scale energy management. The system presented in this paper has been developed on a self-sufficient solar house called “MagicBox” equipped with grid connection, PV generation, lead-acid batteries, controllable appliances and smart metering. Therefore, there is a large number of energy variables to be monitored that allow us to precisely manage the energy performance of the house by means of collaborative sensors. The experimental results, performed on a real house, demonstrate the feasibility of the proposed collaborative system to reduce the consumption of electrical power and to increase energy efficiency. PMID:22247680

Systems Engineering | Photovoltaic Research | NREL

Science.gov Websites

Research Other Reliability & Engineering pages: Real-Time PV & Solar Resource Testing Accelerated community toward developing comprehensive PV standards. Each year, NREL researchers, along with solar Engineering Systems Engineering We provide engineering testing and evaluation of photovoltaic (PV

Detection and location of fouling on photovoltaic panels using a drone-mounted infrared thermography system

NASA Astrophysics Data System (ADS)

Zhang, Peng; Zhang, Lifu; Wu, Taixia; Zhang, Hongming; Sun, Xuejian

2017-01-01

Due to weathering and external forces, solar panels are subject to fouling and defects after a certain amount of time in service. These fouling and defects have direct adverse consequences such as low-power efficiency. Because solar power plants usually have large-scale photovoltaic (PV) panels, fast detection and location of fouling and defects across large PV areas are imperative. A drone-mounted infrared thermography system was designed and developed, and its ability to detect rapid fouling on large-scale PV panel systems was investigated. The infrared images were preprocessed using the K neighbor mean filter, and the single PV module on each image was recognized and extracted. Combining the local and global detection method, suspicious sites were located precisely. The results showed the flexible drone-mounted infrared thermography system to have a strong ability to detect the presence and determine the position of PV fouling. Drone-mounted infrared thermography also has good technical feasibility and practical value in the detection of PV fouling detection.

Solar photovoltaic charging of lithium-ion batteries

NASA Astrophysics Data System (ADS)

Gibson, Thomas L.; Kelly, Nelson A.

Solar photovoltaic (PV) charging of batteries was tested by using high efficiency crystalline and amorphous silicon PV modules to recharge lithium-ion battery modules. This testing was performed as a proof of concept for solar PV charging of batteries for electrically powered vehicles. The iron phosphate type lithium-ion batteries were safely charged to their maximum capacity and the thermal hazards associated with overcharging were avoided by the self-regulating design of the solar charging system. The solar energy to battery charge conversion efficiency reached 14.5%, including a PV system efficiency of nearly 15%, and a battery charging efficiency of approximately 100%. This high system efficiency was achieved by directly charging the battery from the PV system with no intervening electronics, and matching the PV maximum power point voltage to the battery charging voltage at the desired maximum state of charge for the battery. It is envisioned that individual homeowners could charge electric and extended-range electric vehicles from residential, roof-mounted solar arrays, and thus power their daily commuting with clean, renewable solar energy.

Solar electric state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bumke, D.

The booming sales of photovoltaic (PV) equipment in California is described. Three types of markets appear to exist. These are: (1) people who want to electrify a remote home and avoid the large expense of a utility hook-up; (2) suburban renegades who are reluctant to depend on the grid; and (3) the marijuana farmers of northern California who do not want public exposure. Several PV systems and homes are described and illustrated. Various options of electrical systems (ac generators versus electronic inverters) are discussed and the merits of each system are pointed out. Expenses involved in PV systems are describedmore » and various voltage and battery options (12, 24, 36, or 48 volts) are discussed. Specific use of ac or dc for particular appliances is considered in detail. It is estimated that in California more than 500 homes are being powered by over 130,000 watts of PV power. It is predicted that the use of PV's will double in the next year. Sources of information on PV's (catalogs and books) are given. (MJJ)« less

Reconciling Consumer and Utility Objectives in the Residential Solar PV Market

NASA Astrophysics Data System (ADS)

Arnold, Michael R.

Today's energy market is facing large-scale changes that will affect all market players. Near the top of that list is the rapid deployment of residential solar photovoltaic (PV) systems. Yet that growing trend will be influenced multiple competing interests between various stakeholders, namely the utility, consumers and technology provides. This study provides a series of analyses---utility-side, consumer-side, and combined analyses---to understand and evaluate the effect of increases in residential solar PV market penetration. Three urban regions have been selected as study locations---Chicago, Phoenix, Seattle---with simulated load data and solar insolation data at each locality. Various time-of-use pricing schedules are investigated, and the effect of net metering is evaluated to determine the optimal capacity of solar PV and battery storage in a typical residential home. The net residential load profile is scaled to assess system-wide technical and economic figures of merit for the utility with an emphasis on intraday load profiles, ramp rates and electricity sales with increasing solar PV penetration. The combined analysis evaluates the least-cost solar PV system for the consumer and models the associated system-wide effects on the electric grid. Utility revenue was found to drop by 1.2% for every percent PV penetration increase, net metering on a monthly or annual basis improved the cost-effectiveness of solar PV but not battery storage, the removal of net metering policy and usage of an improved the cost-effectiveness of battery storage and increases in solar PV penetration reduced the system load factor. As expected, Phoenix had the most favorable economic scenario for residential solar PV, primarily due to high solar insolation. The study location---solar insolation and load profile---was also found to affect the time of year at which the largest net negative system load was realized.

ANN based Real-Time Estimation of Power Generation of Different PV Module Types

NASA Astrophysics Data System (ADS)

Syafaruddin; Karatepe, Engin; Hiyama, Takashi

Distributed generation is expected to become more important in the future generation system. Utilities need to find solutions that help manage resources more efficiently. Effective smart grid solutions have been experienced by using real-time data to help refine and pinpoint inefficiencies for maintaining secure and reliable operating conditions. This paper proposes the application of Artificial Neural Network (ANN) for the real-time estimation of the maximum power generation of PV modules of different technologies. An intelligent technique is necessary required in this case due to the relationship between the maximum power of PV modules and the open circuit voltage and temperature is nonlinear and can't be easily expressed by an analytical expression for each technology. The proposed ANN method is using input signals of open circuit voltage and cell temperature instead of irradiance and ambient temperature to determine the estimated maximum power generation of PV modules. It is important for the utility to have the capability to perform this estimation for optimal operating points and diagnostic purposes that may be an early indicator of a need for maintenance and optimal energy management. The proposed method is accurately verified through a developed real-time simulator on the daily basis of irradiance and cell temperature changes.

Experimental grid connected PV system power analysis

NASA Astrophysics Data System (ADS)

Semaoui, Smail; Abdeladim, Kamel; Arab, Amar Hadj; Boulahchich, Saliha; Amrouche, Said Ould; Yassaa, Noureddine

2018-05-01

Almost 80 % of Algerian territory is appropriate for the exploitation of solar energy. The Algerian energetic strategy provides a substantial injection of PV electricity to the national grid. Currently, about 344 MWp of PV arrays which corresponds approximately to 2,34 km2 of module surfaces, are connected on electricity grid over the national territory. The Algerian Northern regions are characterized by strong pollution and high humidity. These phenomena affect the energetic productivity of PV generator. The objective of our study is to analyze experimental grid connected PV system power in coastal locations. Hence, experiments have been conducted on three identical PV systems to determine the electrical performances. Transformer-less inverters are the most attractive for the ground-based photovoltaic (PV) system due to their efficiencies, reduced cost and weight. Besides, the absence of the galvanic isolation generates problems of capacitive leakage current on the AC side and the degradation of the insulation resistance on the DC side of the inverter. In this work, experimental study of the behavior of single-phase inverters without transformers is presented. The main objective of this work is to study the degradation of the insulation resistance at the input of the inverter, and the capacitive leakage current at the output of the inverter. This study was achieved at the CDER on a rainy day of 15/03/2017, on the first PV plant connected to the low voltage network in Algeria. This investigation can help forecasting the PV array energetic production by taking into account natural conditions.

A Best Practice for Developing Availability Guarantee Language in Photovoltaic (PV) O&M Agreements.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Balfour, John

This document outlines the foundation for developing language that can be utilized in an Equipment Availability Guarantee, typically included in an O&M services agreement between a PV system or plant owner and an O&M services provider, or operator. Many of the current PV O&M service agreement Availability Guarantees are based on contracts used for traditional power generation, which create challenges for owners and operators due to the variable nature of grid-tied photovoltaic generating technologies. This report documents language used in early PV availability guarantees and presents best practices and equations that can be used to more openly communicate how themore » reliability of the PV system and plant equipment can be expressed in an availability guarantee. This work will improve the bankability of PV systems by providing greater transparency into the equipment reliability state to all parties involved in an O&M services contract.« less

Practical design considerations for photovoltaic power station

NASA Astrophysics Data System (ADS)

Swanson, T. D.

Aspects of photovoltaic (PV) technology are discussed along with generic PV design considerations, taking into account the resource sunlight, PV modules and their reliability, questions of PV system design, the support structure subsystem, and a power conditioning unit subsystem. A description is presented of two recent projects which demonstrate the translation of an idea into actual working PV systems. A privately financed project in Denton, Maryland, went on line in early December, 1982, and began providing power to the local utility grid. It represents the first intermediate size, grid-connected, privately financed power station in the U.S. Based on firm quotes, the actual cost of this system is about $13/W peak. The other project, called the PV Breeder, is an energy independent facility which utilizes solar power to make new solar cells. It is also the first large industrial structure completely powered by the sun.

Using GIS data and satellite derived irradiance to optimize siting of PV installations in Switzerland

NASA Astrophysics Data System (ADS)

Kahl, Annelen; Nguyen, Viet-Anh; Bartlett, Stuart; Sossan, Fabrizio; Lehning, Michael

2016-04-01

For a successful distribution strategy of PV installations, it does not suffice to choose the locations with highest annual total irradiance. Attention needs to be given to spatial correlation patterns of insolation to avoid large system-wide variations, which can cause extended deficits in supply or might even damage the electrical network. One alternative goal instead is to seek configurations that provide the smoothest energy production, with the most reliable and predictable supply. Our work investigates several scenarios, each pursuing a different strategy for a future renewable Switzerland without nuclear power. Based on an estimate for necessary installed capacity for solar power [Bartlett, 2015] we first use heuristics to pre-select realistic placements for PV installations. Then we apply optimization methods to find a subset of locations that provides the best possible combined electricity production. For the first part of the selection process, we use a DEM to exclude high elevation zones which would be difficult to access and which are prone to natural hazards. Then we use land surface cover information to find all zones with potential roof area, deemed suitable for installation of solar panels. The optimization employs Principal Component Analysis of satellite derived irradiance data (Surface Incoming Shortwave Radiation (SIS), based on Meteosat Second Generation sensors) to incorporate a spatial aspect into the selection process that does not simply maximize annual total production but rather provides the most robust supply, by combining regions with anti-correlated cloud cover patterns. Depending on the initial assumptions and constraints, the resulting distribution schemes for PV installations vary with respect to required surface area, annual total and lowest short-term production, and illustrate how important it is to clearly define priorities and policies for a future renewable Switzerland.

Cost-Reduction Roadmap for Residential Solar Photovoltaics (PV), 2017-2030

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Jeffrey J.; Ardani, Kristen B.; Margolis, Robert M.

The installed cost of solar photovoltaics (PV) has fallen rapidly in recent years and is expected to continue declining in the future. In this report, we focus on the potential for continued PV cost reductions in the residential market. From 2010 to 2017, the levelized cost of energy (LCOE) for residential PV declined from 52 cents per kilowatt-hour (cents/kWh) to 16 cents/kWh (Fu et al. 2017). The U.S. Department of Energy's (DOE's) Solar Energy Technologies Office (SETO) recently set new LCOE targets for 2030, including a target of 5 cents/kWh for residential PV. We present a roadmap for achieving themore » SETO 2030 residential PV target. Because the 2030 target likely will not be achieved under business-as-usual trends (NREL 2017), we examine two key market segments that demonstrate significant opportunities for cost savings and market growth: installing PV at the time of roof replacement and installing PV as part of the new home construction process. Within both market segments, we identify four key cost-reduction opportunities: market maturation, business model integration, product innovation, and economies of scale. To assess the potential impact of these cost reductions, we compare modeled residential PV system prices in 2030 to the National Renewable Energy Laboratory's (NREL's) quarter one 2017 (Q1 2017) residential PV system price benchmark (Fu et al. 2017). We use a bottom-up accounting framework to model all component and project-development costs incurred when installing a PV system. The result is a granular accounting for 11 direct and indirect costs associated with installing a residential PV system in 2030. All four modeled pathways demonstrate significant installed-system price savings over the Q1 2017 benchmark, with the visionary pathways yielding the greatest price benefits. The largest modeled cost savings are in the supply chain, sales and marketing, overhead, and installation labor cost categories. When we translate these installed-system costs into LCOE, we find that the less-aggressive pathways achieve significant cost reductions, but may not achieve the 2030 LCOE target. On the other hand, both visionary pathways could get very close to (for roof replacement) or achieve (for new construction) the 2030 target. Our analysis has two key implications. First, because installed-system soft cost reductions account for about 65 percent of the LCOE reductions in 2030 for both visionary pathways, residential PV stakeholders may need to emphasize these soft cost reductions to achieve the 2030 target. Second, capturing these savings will likely require considerable innovation in the technologies and business practices employed by the PV industry.« less

Fault Analysis in Solar Photovoltaic Arrays

NASA Astrophysics Data System (ADS)

Zhao, Ye

Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to increase reliability, efficiency and safety in PV systems. Conventional fault protection methods usually add fuses or circuit breakers in series with PV components. But these protection devices are only able to clear faults and isolate faulty circuits if they carry a large fault current. However, this research shows that faults in PV arrays may not be cleared by fuses under some fault scenarios, due to the current-limiting nature and non-linear output characteristics of PV arrays. First, this thesis introduces new simulation and analytic models that are suitable for fault analysis in PV arrays. Based on the simulation environment, this thesis studies a variety of typical faults in PV arrays, such as ground faults, line-line faults, and mismatch faults. The effect of a maximum power point tracker on fault current is discussed and shown to, at times, prevent the fault current protection devices to trip. A small-scale experimental PV benchmark system has been developed in Northeastern University to further validate the simulation conclusions. Additionally, this thesis examines two types of unique faults found in a PV array that have not been studied in the literature. One is a fault that occurs under low irradiance condition. The other is a fault evolution in a PV array during night-to-day transition. Our simulation and experimental results show that overcurrent protection devices are unable to clear the fault under "low irradiance" and "night-to-day transition". However, the overcurrent protection devices may work properly when the same PV fault occurs in daylight. As a result, a fault under "low irradiance" and "night-to-day transition" might be hidden in the PV array and become a potential hazard for system efficiency and reliability.

Mitigating Short-Term Variations of Photovoltaic Generation Using Energy Storage with VOLTTRON

NASA Astrophysics Data System (ADS)

Morrissey, Kevin

A smart-building communications system performs smoothing on photovoltaic (PV) power generation using a battery energy storage system (BESS). The system runs using VOLTTRON(TM), a multi-agent python-based software platform dedicated to power systems. The VOLTTRON(TM) system designed for this project runs synergistically with the larger University of Washington VOLTTRON(TM) environment, which is designed to operate UW device communications and databases as well as to perform real-time operations for research. One such research algorithm that operates simultaneously with this PV Smoothing System is an energy cost optimization system which optimizes net demand and associated cost throughout a day using the BESS. The PV Smoothing System features an active low-pass filter with an adaptable time constant, as well as adjustable limitations on the output power and accumulated battery energy of the BESS contribution. The system was analyzed using 26 days of PV generation at 1-second resolution. PV smoothing was studied with unconstrained BESS contribution as well as under a broad range of BESS constraints analogous to variable-sized storage. It was determined that a large inverter output power was more important for PV smoothing than a large battery energy capacity. Two methods of selecting the time constant in real time, static and adaptive, are studied for their impact on system performance. It was found that both systems provide a high level of PV smoothing performance, within 8% of the ideal case where the best time constant is known ahead of time. The system was run in real time using VOLTTRON(TM) with BESS limitations of 5 kW/6.5 kWh and an adaptive update period of 7 days. The system behaved as expected given the BESS parameters and time constant selection methods, providing smoothing on the PV generation and updating the time constant periodically using the adaptive time constant selection method.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbose, Galen L.; Darghouth, Naïm R.; Millstein, Dev

Now in its eighth edition, Lawrence Berkeley National Laboratory (LBNL)’s Tracking the Sun report series is dedicated to summarizing trends in the installed price of grid-connected solar photovoltaic (PV) systems in the United States. The present report focuses on residential and nonresidential systems installed through year-end 2014, with preliminary trends for the first half of 2015. As noted in the text box below, this year’s report incorporates a number of important changes and enhancements. Among those changes, this year's report focuses solely on residential and nonresidential PV systems; data on utility-scale PV are reported in LBNL’s companion Utility-Scale Solar reportmore » series. Installed pricing trends presented within this report derive primarily from project-level data reported to state agencies and utilities that administer PV incentive programs, solar renewable energy credit (SREC) registration systems, or interconnection processes. In total, data were collected for roughly 400,000 individual PV systems, representing 81% of all U.S. residential and non-residential PV capacity installed through 2014 and 62% of capacity installed in 2014, though a smaller subset of this data were used in analysis.« less

Leasing Into the Sun: A Mixed Method Analysis of Transactions of Homes with Third Party Owned Solar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoen, Ben; Rand, Joseph; Adomatis, Sandra

This analysis is the first to examine if homes with third-party owned (TPO) PV systems are unique in the marketplace as compared to non-PV or non-TPO PV homes. This is of growing importance as the number of homes with TPO systems is nearly a half of a million in the US currently and is growing. A hedonic pricing model analysis of 20,106 homes that sold in California between 2011 and 2013 is conducted, as well as a paired sales analysis of 18 pairs of TPO PV and non-PV homes in San Diego spanning 2012 and 2013. The hedonic model examinedmore » 2,914 non-TPO PV home sales and 113 TPO PV sales and fails to uncover statistically significant premiums for TPO PV homes nor for those with pre-paid leases as compared to non-PV homes. Similarly, the paired sales analysis does not find evidence of an impact to value for the TPO homes when comparing to non-PV homes. Analyses of non-TPO PV sales both here and previously have found larger and statistically significant premiums. Collection of a larger dataset that covers the present period is recommended for future analyses so that smaller, more nuanced and recent effects can be discovered.« less

Electricity Bill Savings from Residential Photovoltaic Systems: Sensitivities to Changes in Future Electricity Market Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darghouth, Naim; Barbose, Galen; Wiser, Ryan

2013-01-09

Customer-sited photovoltaic (PV) systems in the United States are often compensated at the customer’s underlying retail electricity rate through net metering. Calculations of the customer economics of PV, meanwhile, often assume that retail rate structures and PV compensation mechanisms will not change and that retail electricity prices will increase (or remain constant) over time, thereby also increasing (or keeping constant) the value of bill savings from PV. Given the multitude of potential changes to retail rates and PV compensation mechanisms in the future, however, understanding how such changes might impact the value of bill savings from PV is critical formore » policymakers, regulators, utilities, the solar industry, and potential PV owners, i.e., any stakeholder interested in understanding uncertainties in and potential changes to the long-term customer economics of PV. This scoping study investigates the impact of, and interactions among, three key sources of uncertainty in the future value of bill savings from customer-sited PV, focusing in particular on residential customers. These three sources of uncertainty are: changes to electricity market conditions that would affect retail electricity prices, changes to the types of retail rate structures available to residential customers with PV, and shifts away from standard net-metering toward other compensation mechanisms for residential PV.« less

Immunoreactivities of calbindin-D28k, calretinin and parvalbumin in the somatosensory cortex of rodents during normal aging

PubMed Central

Ahn, Ji Hyeon; Hong, Seongkweon; Park, Joon Ha; Kim, In Hye; Cho, Jeong Hwi; Lee, Tae-Kyeong; Lee, Jae-Chul; Chen, Bai Hui; Shin, Bich-Na; Bae, Eun Joo; Jeon, Yong Hwan; Kim, Young-Myeong; Won, Moo-Ho; Choi, Soo Young

2017-01-01

Calbindin-D28k (CB), calretinin (CR) and parvalbumin (PV), which regulate cytosolic free Ca2+ concentrations in neurons, are chemically expressed in γ-aminobutyric acid (GABA)ergic neurons that regulate the degree of glutamatergic excitation and output of projection neurons. The present study investigated age-associated differences in CB, CR and PV immunoreactivities in the somatosensory cortex in three species (mice, rats and gerbils) of young (1 month), adult (6 months) and aged (24 months) rodents, using immunohistochemistry and western blotting. Abundant CB-immunoreactive neurons were distributed in layers II and III, and age-associated alterations in their number were different according to the species. CR-immunoreactive neurons were not abundant in all layers; however, the number of CR-immunoreactive neurons was the highest in all adult species. Many PV-immunoreactive neurons were identified in all layers, particularly in layers II and III, and they increased in all layers with age in all species. The present study demonstrated that the distribution pattern of CB-, CR- and PV-containing neurons in the somatosensory cortex were apparently altered in number with normal aging, and that CB and CR exhibited a tendency to decrease in aged rodents, whereas PV tended to increase with age. These results indicate that CB, CR and PV are markedly altered in the somatosensory cortex, and this change may be associated with normal aging. These findings may aid the elucidation of the mechanisms of aging and geriatric disease. PMID:28944879

High-resolution global irradiance monitoring from photovoltaic systems

NASA Astrophysics Data System (ADS)

Buchmann, Tina; Pfeilsticker, Klaus; Siegmund, Alexander; Meilinger, Stefanie; Mayer, Bernhard; Pinitz, Sven; Steinbrecht, Wolfgang

2016-04-01

Reliable and regional differentiated power forecasts are required to guarantee an efficient and economic energy transition towards renewable energies. Amongst other renewable energy technologies, e.g. wind mills, photovoltaic systems are an essential component of this transition being cost-efficient and simply to install. Reliable power forecasts are however required for a grid integration of photovoltaic systems, which among other data requires high-resolution spatio-temporal global irradiance data. Hence the generation of robust reviewed global irradiance data is an essential contribution for the energy transition. To achieve this goal our studies introduce a novel method which makes use of photovoltaic power generation in order to infer global irradiance. The method allows to determine high-resolution temporal global irradiance data (one data point every 15 minutes at each location) from power data of operated photovoltaic systems. Due to the multitude of installed photovoltaic systems (in Germany) the detailed spatial coverage is much better than for example only using global irradiance data from conventional pyranometer networks (e.g. from the German Weather Service). Our designated method is composed of two components: a forward component, i.e. to conclude from predicted global irradiance to photovoltaic (PV) power, and a backward component, i.e. from PV power with suitable calibration to global irradiance. The forward process is modelled by using the radiation transport model libRadtran (B. Mayer and A. Kylling (1)) for clear skies to obtain the characteristics (orientation, size, temperature dependence, …) of individual PV systems. For PV systems in the vicinity of a meteorological station, these data are validated against calibrated pyranometer readings. The forward-modelled global irradiance is used to determine the power efficiency for each photovoltaic system using non-linear optimisation techniques. The backward component uses the power efficiency and meteorological parameters (e.g. from the model COSMO-DE) to calculate global irradiance by means of the generated power of individual photovoltaic systems. For the year 2012, our method is tested for PV systems in the Allgäu region (south Germany), the distribution area of the system operator "AllgäuNetz GmbH & Co". The test region includes 215 online-monitored photovoltaic systems and one pyranometer station located at the DWD (Deutscher WetterDienst) weather station Hohenpeißenberg (operated by the German Weather Service). The present talk provides an introduction to the newly developed method along with first results for clear sky scenarios. (1) B. Mayer and A. Kylling (2005): Technical note: The libRadtran software package for radiative transfer calculations - description and examples of use. In: Chemistry and Physics Chemistry and Physics. Page: 1855 - 1877

Frequency Control Using On line Learning Method for Island Smart Grid with EVs and PVs

DTIC Science & Technology

2014-07-06

deviation from PVs are modeled as the power disturbance for the system . A. Case 1: active power disturbance without EVs constraints In this case, there are...IEEE Transactions on, vol. 3, no. 1, pp. 565–577, 2012. [7] M. Datta and T. Senjyu, “Fuzzy control of distributed pv inverters /energy storage systems ...this linearity assumption. In island smart grid with photovoltaics ( PVs ) and EVs, system state parameters and operating conditions are changing

Numerical modelling of phase-change material used for PV panels cooling

NASA Astrophysics Data System (ADS)

Sellami, Assia; Elotmani, Rabie; Kandoussi, Khalid; Eljouad, Mohamed; Hajjaji, Abdelowahed; Boutaous, M'Hamed

2017-12-01

Passive cooling of a PV solar panel using phase-change material (PCM) may play an important role in increasing efficiency of PV cells. Because it does not need a maintenance and does not release greenhouses gases, PCM seems to be a good way to decrease the among of overheating of PV cell. The aims of this paper describes a detailed multiphysical issue in order to understand the effect of PCM (RT25) in keeping PV cell temperature close to ambient. The study is focused on modeling the heat and mass transfer in a PCM domain by modifying the buoyancy term in momentum equation. Due to a phase-change and free convection, transient incompressible flow is taken into account to explain the dynamic variations of the velocity profile and viscosity distribution. With standard condition of irradiation and heat flux on both sides of the PV panel, a melt front has been tracked by the energy equation, which gives a good argument for the temperature evolution during phase-change.

An Analysis of the Malassezia Species Distribution in the Skin of Patients with Pityriasis Versicolor in Chengdu, China

PubMed Central

Xie, Zhen; Ran, Yuping; Zhang, Hao; Zhang, Min; Wan, Huiying; Li, Conghui

2014-01-01

Pityriasis versicolor (PV) is a common clinical problem associated with Malassezia species (Malassezia spp.). Controversies remain regarding the specific species involved in the development of PV. This study analyzed the difference in Malassezia spp. distribution in lesional and nonlesional skin in Chinese PV patients. A paired design was applied. Lesional and nonlesional scales from 24 cases were collected; real-time fluorescence quantitative PCR was used to detect 10 different Malassezia spp. In lesional skin, the highest detection rates were for M. globosa (95.8%), M. restricta (91.7%), and M. sympodialis (50.0%). In nonlesional skin, the highest detection rates were for M. globosa (87.5%), M. restricta (79.2%), and M. dermatis (33.3%). A significant difference in the detection rate was only found for M. sympodialis (50.8% versus 20.8%, P = 0.04). Compared with nonlesional skin, the amount of M. globosa, M. restricta, and M. sympodialis in lesional skin was significantly higher (3.8 ± 1.3,  2.5 ± 1.1, and 3.2 ± 1.6 times higher, resp.). The results of this study do not indicate that M. globosa and M. restricta are directly correlated with PV development; however, M. sympodialis is more likely related to PV development in Chinese individuals. PMID:25177714

An analysis of the Malassezia species distribution in the skin of patients with pityriasis versicolor in Chengdu, China.

PubMed

Xie, Zhen; Ran, Yuping; Zhang, Hao; Zhang, Min; Wan, Huiying; Li, Conghui

2014-01-01

Pityriasis versicolor (PV) is a common clinical problem associated with Malassezia species (Malassezia spp.). Controversies remain regarding the specific species involved in the development of PV. This study analyzed the difference in Malassezia spp. distribution in lesional and nonlesional skin in Chinese PV patients. A paired design was applied. Lesional and nonlesional scales from 24 cases were collected; real-time fluorescence quantitative PCR was used to detect 10 different Malassezia spp. In lesional skin, the highest detection rates were for M. globosa (95.8%), M. restricta (91.7%), and M. sympodialis (50.0%). In nonlesional skin, the highest detection rates were for M. globosa (87.5%), M. restricta (79.2%), and M. dermatis (33.3%). A significant difference in the detection rate was only found for M. sympodialis (50.8% versus 20.8%, P = 0.04). Compared with nonlesional skin, the amount of M. globosa, M. restricta, and M. sympodialis in lesional skin was significantly higher (3.8 ± 1.3,  2.5 ± 1.1, and 3.2 ± 1.6 times higher, resp.). The results of this study do not indicate that M. globosa and M. restricta are directly correlated with PV development; however, M. sympodialis is more likely related to PV development in Chinese individuals.

Solar photovoltaic systems in the development of Papua New Guinea

NASA Astrophysics Data System (ADS)

Kinnell, G. H.

Geographic and demographic features of Papua New Guinea are summarized, together with current applications of photovoltaic (PV) systems. The PV systems displace the increasing costs of generating power from diesel and kerosene powered units. PV systems power air navigation aids for the extensive air transport used in the absence of a road system. Remote television and visual aid education is possible with PV modules. A total of 50 kW of PV power is presently implemented, with the bulk dedicated to microwave repeater stations, navigation aids, and radio and lighting supplies. A village pumping installation is in operation, as are office lighting and ventilation, house lighting, and construction camp lighting. Another 350 kW is planned for the next 10 yr to run medical supply refrigeration, and further growth is seen for coupling with government-developed village lighting kits that feature industrial reflectors.

Life Cycle Assessment of Solar Photovoltaic Microgrid Systems in Off-Grid Communities.

PubMed

Bilich, Andrew; Langham, Kevin; Geyer, Roland; Goyal, Love; Hansen, James; Krishnan, Anjana; Bergesen, Joseph; Sinha, Parikhit

2017-01-17

Access to a reliable source of electricity creates significant benefits for developing communities. Smaller versions of electricity grids, known as microgrids, have been developed as a solution to energy access problems. Using attributional life cycle assessment, this project evaluates the environmental and energy impacts of three photovoltiac (PV) microgrids compared to other energy options for a model village in Kenya. When normalized per kilowatt hour of electricity consumed, PV microgrids, particularly PV-battery systems, have lower impacts than other energy access solutions in climate change, particulate matter, photochemical oxidants, and terrestrial acidification. When compared to small-scale diesel generators, PV-battery systems save 94-99% in the above categories. When compared to the marginal electricity grid in Kenya, PV-battery systems save 80-88%. Contribution analysis suggests that electricity and primary metal use during component, particularly battery, manufacturing are the largest contributors to overall PV-battery microgrid impacts. Accordingly, additional savings could be seen from changing battery manufacturing location and ensuring end of life recycling. Overall, this project highlights the potential for PV microgrids to be feasible, adaptable, long-term energy access solutions, with health and environmental advantages compared to traditional electrification options.

Accelerated Testing and Analysis | Photovoltaic Research | NREL

Science.gov Websites

& Engineering pages: Real-Time PV & Solar Resource Testing Systems Engineering Systems PV standards. Each year, NCPV researchers, along with solar companies and other national lab Accelerated Testing and Analysis Accelerated Testing and Analysis PV Research Other Reliability

Integration, Validation, and Application of a PV Snow Coverage Model in SAM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryberg, David; Freeman, Janine

2015-09-01

Due to the increasing deployment of PV systems in snowy climates, there is significant interest in a method capable of estimating PV losses resulting from snow coverage that has been verified for a wide variety of system designs and locations. A scattering of independent snow coverage models have been developed over the last 15 years; however, there has been very little effort spent on verifying these models beyond the system design and location on which they were based. Moreover, none of the major PV modeling software products have incorporated any of these models into their workflow. In response to thismore » deficiency, we have integrated the methodology of the snow model developed in the paper by Marion et al. [1] into the National Renewable Energy Laboratory's (NREL) System Advisor Model (SAM). In this work we describe how the snow model is implemented in SAM and discuss our demonstration of the model's effectiveness at reducing error in annual estimations for two PV arrays. Following this, we use this new functionality in conjunction with a long term historical dataset to estimate average snow losses across the United States for a typical PV system design. The open availability of the snow loss estimation capability in SAM to the PV modeling community, coupled with our results of the nation-wide study, will better equip the industry to accurately estimate PV energy production in areas affected by snowfall.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.

This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system ismore » based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.« less

Final Report: Towards an Emergent Model of Technology Adoption for Accelerating the Diffusion of Residential Solar PV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rai, Varun

This project sought to enable electric utilities in Texas to accelerate diffusion of residential solar photovoltaic (PV) by systematically identifying and targeting existing barriers to PV adoption. A core goal of the project was to develop an integrated research framework that combines survey research, econometric modeling, financial modeling, and implementation and evaluation of pilot projects to study the PV diffusion system. This project considered PV diffusion as an emergent system, with attention to the interactions between the constituent parts of the PV socio-technical system including: economics of individual decision-making; peer and social influences; behavioral responses; and information and transaction costs.more » We also conducted two pilot projects, which have yielded new insights into behavioral and informational aspects of PV adoption. Finally, this project has produced robust and generalizable results that will provide deeper insights into the technology-diffusion process that will be applicable for the design of utility programs for other technologies such as home-energy management systems and plug-in electric vehicles. When we started this project in 2013 there was little systematic research on characterizing the decision-making process of households interested in adopting PV. This project was designed to fill that research gap by analyzing the PV adoption process from the consumers' decision-making perspective and with the objective to systematically identifying and addressing the barriers that consumers face in the adoption of PV. The two key components of that decision-making process are consumers' evaluation of: (i) uncertainties and non-monetary costs associated with the technology and (ii) the direct monetary cost-benefit. This project used an integrated approach to study both the non-monetary and the monetary components of the consumer decision-making process.« less

Hybrid photovoltaic/thermal (PV/T) solar systems simulation with Simulink/Matlab

DOE Office of Scientific and Technical Information (OSTI.GOV)

da Silva, R.M.; Fernandes, J.L.M.

The purpose of this work consists in thermodynamic modeling of hybrid photovoltaic-thermal (PV/T) solar systems, pursuing a modular strategy approach provided by Simulink/Matlab. PV/T solar systems are a recently emerging solar technology that allows for the simultaneous conversion of solar energy into both electricity and heat. This type of technology present some interesting advantages over the conventional ''side-by-side'' thermal and PV solar systems, such as higher combined electrical/thermal energy outputs per unit area, and a more uniform and aesthetical pleasant roof area. Despite the fact that early research on PV/T systems can be traced back to the seventies, only recentlymore » it has gained a renewed impetus. In this work, parametric studies and annual transient simulations of PV/T systems are undertaken in Simulink/Matlab. The obtained results show an average annual solar fraction of 67%, and a global overall efficiency of 24% (i.e. 15% thermal and 9% electrical), for a typical four-person single-family residence in Lisbon, with p-Si cells, and a collector area of 6 m{sup 2}. A sensitivity analysis performed on the PV/T collector suggests that the most important variable that should be addressed to improve thermal performance is the photovoltaic (PV) module emittance. Based on those results, some additional improvements are proposed, such as the use of vacuum, or a noble gas at low-pressure, to allow for the removal of PV cells encapsulation without air oxidation and degradation, and thus reducing the PV module emittance. Preliminary results show that this option allows for an 8% increase on optical thermal efficiency, and a substantial reduction of thermal losses, suggesting the possibility of working at higher fluid temperatures. The higher working temperatures negative effect in electrical efficiency was negligible, due to compensation by improved optical properties. The simulation results are compared with experimental data obtained from other authors and perform reasonably well. The Simulink modeling platform has been mainly used worldwide on simulation of control systems, digital signal processing and electric circuits, but there are very few examples of application to solar energy systems modeling. This work uses the modular environment of Simulink/Matlab to model individual PV/T system components, and to assemble the entire installation layout. The results show that the modular approach strategy provided by Matlab/Simulink environment is applicable to solar systems modeling, providing good code scalability, faster developing time, and simpler integration with external computational tools, when compared with traditional imperative-oriented programming languages. (author)« less

PV technology and success of solar electricity in Vietnam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dung, T.Q.

1997-12-31

Since 1990 the PV Technology and the Solar electricity have been strongly developed in Vietnam. The PV experts of Solarlab have studied and set up an appropriate PV Technology responding to local Market needs. It has not only stood well but has been also transferred to Mali Republic and Lao P.D.R. The PV off grid systems of Solarlab demonstrate good efficiency and low prices. Over 60 solar stations and villages have been built to provide solar lighting for about 3000 families along the country in remote, mountainous areas and islands. 400 families are using stand-alone Solar Home Systems. The Solarmore » electricity has been chosen for Rural Electrification and National Telecommunication Network in remote and mountainous regions. Many International projects in cooperation with FONDEM-France, SELF USA and Governmental PV projects have been realized by Solarlab. The experiences of maintenance, management and finance about PV development in Vietnam are also mentioned.« less

NREL Report Shows Utility-Scale Solar PV System Cost Fell Nearly 30% Last

Science.gov Websites

Year | NREL | News | NREL Report Shows Utility-Scale Solar PV System Cost Fell Nearly 30% Last Year News Release: NREL Report Shows Utility-Scale Solar PV System Cost Fell Nearly 30% Last Year September 12, 2017 Record-low costs enabled by decline in module and inverter prices The installed cost of

Valuing the Resilience Provided by Solar and Battery Energy Storage Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLaren, Joyce A; Mullendore, Seth; Laws, Nicholas D

This paper explores the impact of valuing resilience on the economics of photovoltaics (PV) and storage systems for commercial buildings. The analysis presented here illustrates that accounting for the cost of grid power outages can change the breakeven point for PV and storage system investment, and increase the size of systems designed to deliver the greatest economic benefit over time. In other words, valuing resilience can make PV and storage systems economical in cases where they would not be otherwise. As storage costs decrease, and outages occur more frequently, PV and storage are likely to play a larger role inmore » building design and management considerations.« less

Mathematical modeling of photovoltaic thermal PV/T system with v-groove collector

NASA Astrophysics Data System (ADS)

Zohri, M.; Fudholi, A.; Ruslan, M. H.; Sopian, K.

2017-07-01

The use of v-groove in solar collector has a higher thermal efficiency in references. Dropping the working heat of photovoltaic panel was able to raise the electrical efficiency performance. Electrical and thermal efficiency were produced by photovoltaic thermal (PV/T) system concurrently. Mathematical modeling based on steady-state thermal analysis of PV/T system with v-groove was conducted. With matrix inversion method, the energy balance equations are explained by means of the investigative method. The comparison results show that in the PV/T system with the V-groove collector is higher temperature, thermal and electrical efficiency than other collectors.

Building Integrated Photovoltaic Module-Based on Aluminum Substrate With Forced Water Cooling.

PubMed

Pang, Wei; Zhang, Yongzhe; Cui, Yanan; Yu, Hongwen; Liu, Yu; Yan, Hui

2018-04-01

The increase of operating temperature on a photovoltaic (PV) cell degrades its electrical efficiency. This paper is organized to describe our latest design of an aluminum substrate-based photovoltaic/thermal (PV/T) system. The electrical efficiency of the proposed PV/T can be increased by ∼ 20% in comparison with a conventional glass substrate-based PV. The work will benefit hybrid utilization of solar energy in development of building integrated photovoltaic systems.

Using Residential Solar PV Quote Data to Analyze the Relationship Between Installer Pricing and Firm Size

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Margolis, Robert

2017-05-18

We use residential solar photovoltaic (PV) quote data to study the role of firm size in PV installer pricing. We find that large installers (those that installed more than 1,000 PV systems in any year from 2013 to 2015) quote higher prices for customer-owned systems, on average, than do other installers. The results suggest that low prices are not the primary value proposition of large installers.

Using Residential Solar PV Quote Data to Analyze the Relationship Between Installer Pricing and Firm Size

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Margolis, Robert

2017-05-19

We use residential solar photovoltaic (PV) quote data to study the role of firm size in PV installer pricing. We find that large installers (those that installed more than 1,000 PV systems in any year from 2013 to 2015) quote higher prices for customer-owned systems, on average, than do other installers. The results suggest that low prices are not the primary value proposition of large installers.

Design and Analysis of Photovoltaic (PV) Power Plant at Different Locations in Malaysia

NASA Astrophysics Data System (ADS)

Islam, M. A.; Hasanuzzaman, M.; Rahim, N. A.

2018-05-01

Power generation from sun oriented vitality through a photovoltaic (PV) system is ended up prevalent over the world due to clean innovation. Geographical location of Malaysia is very favorable for PV power generation system. The Malaysian government has also taken different steps to increase the use of solar energy especially by emphasizing on building integrated PV (BIPV) system. Comparative study on the feasibility of BIPV installation at the different location of Malaysia is rarely found. On the other hand, solar cell temperature has a negative impact on the electricity generation. So in this study cost effectiveness and initial investment cost of building integrated grid connected solar PV power plant in different regions of Malaysia have been carried. The effect of PV solar cell temperature on the payback period (PBP) is also investigated. Highest PBP is 12.38 years at Selangor and lowest PBP is 9.70 years at Sabah (Kota Kinabalu). Solar cell temperature significantly increases the PBP of PV plant and highest 14.64% and lowest 13.20% raise of PBP are encountered at Penang and Sarawak respectively.

A three-dimensional model-based partial volume correction strategy for gated cardiac mouse PET imaging

NASA Astrophysics Data System (ADS)

Dumouchel, Tyler; Thorn, Stephanie; Kordos, Myra; DaSilva, Jean; Beanlands, Rob S. B.; deKemp, Robert A.

2012-07-01

Quantification in cardiac mouse positron emission tomography (PET) imaging is limited by the imaging spatial resolution. Spillover of left ventricle (LV) myocardial activity into adjacent organs results in partial volume (PV) losses leading to underestimation of myocardial activity. A PV correction method was developed to restore accuracy of the activity distribution for FDG mouse imaging. The PV correction model was based on convolving an LV image estimate with a 3D point spread function. The LV model was described regionally by a five-parameter profile including myocardial, background and blood activities which were separated into three compartments by the endocardial radius and myocardium wall thickness. The PV correction was tested with digital simulations and a physical 3D mouse LV phantom. In vivo cardiac FDG mouse PET imaging was also performed. Following imaging, the mice were sacrificed and the tracer biodistribution in the LV and liver tissue was measured using a gamma-counter. The PV correction algorithm improved recovery from 50% to within 5% of the truth for the simulated and measured phantom data and image uniformity by 5-13%. The PV correction algorithm improved the mean myocardial LV recovery from 0.56 (0.54) to 1.13 (1.10) without (with) scatter and attenuation corrections. The mean image uniformity was improved from 26% (26%) to 17% (16%) without (with) scatter and attenuation corrections applied. Scatter and attenuation corrections were not observed to significantly impact PV-corrected myocardial recovery or image uniformity. Image-based PV correction algorithm can increase the accuracy of PET image activity and improve the uniformity of the activity distribution in normal mice. The algorithm may be applied using different tracers, in transgenic models that affect myocardial uptake, or in different species provided there is sufficient image quality and similar contrast between the myocardium and surrounding structures.

Analysis on Dissemination Conditions of Photovoltaics in Japan by Using Energy System Model MARKAL

NASA Astrophysics Data System (ADS)

Endo, Eiichi; Ichinohe, Masayuki

The national target for PV capacity in Japan is 4. 82, GW in 2010, and several PV Roadmaps until 2030 are also described. To achieve the target, several support programs, such as subsidization to capital cost, Green Credit by the Green Power Certification System, buy-back under the Renewable Portfolio Standard low, have been already introduced. Carbon tax is still under consideration, but there are several analyses about possible carbon tax. The purpose of this paper is to analyze PV system sales price and subsidy through buy-back which make photovoltaics cost-competitive with other energy technologies and make the target for PV capacity achievable by 2030 in Japan under an expected carbon tax. For the analysis energy system of Japan is modeled by using MARKAL. Based on the results of analysis, under 6000, JPY/t-C carbon tax, photovoltaics needs subsidy for a while even if we taking both fuel savings and Green Credit into account. For attaining the national target for PV capacity in 2010, photovoltaics needs more expensive buy-back than that in present, but after 2010 necessary buy-back decreases gradually. If 120, JPY/W PV system sales price is attained by 2030, photovoltaics becomes cost-competitive without any supports. Subsidy through buy-back becomes almost unnecessary in 2030, if we can reduce it less than 170, JPY/W. The total necessary buy-back meets peak in 2025. It is much more than ongoing subsidy to capital cost of PV systems, but annual revenue from the assumed carbon tax can finance the annual total necessary buy-back. This means if photovoltaics can attain the targeted PV system sales price, we should support it for a while by spending carbon tax revenue effectively and efficiently.

Environmental and Economic Performance of Commercial-scale Solar Photovoltaic Systems: A Field Study of Complex Energy Systems at the Desert Research Institute (DRI)

NASA Astrophysics Data System (ADS)

Liu, X.

2014-12-01

Solar photovoltaic (PV) systems are being aggressively deployed at residential, commercial, and utility scales to complement power generation from conventional sources. This is motivated both by the desire to reduce carbon footprints and by policy-driven financial incentives. Although several life cycle analyses (LCA) have investigated environmental impacts and energy payback times of solar PV systems, most results are based on hypothetical systems rather than actual, deployed systems that can provide measured performance data. Over the past five years, Desert Research Institute (DRI) in Nevada has installed eight solar PV systems of scales from 3 to 1000 kW, the sum of which supply approximately 40% of the total power use at DRI's Reno and Las Vegas campuses. The goal of this work is to explore greenhouse gas (GHG) impacts and examine the economic performance of DRI's PV systems by developing and applying a comprehensive LCA and techno-economic (TEA) model. This model is built using data appropriate for each type of panel used in the DRI systems. Power output is modeled using the National Renewable Energy Laboratory (NREL) model PVWatts. The performance of PVWatts is verified by the actual measurements from DRI's PV systems. Several environmental and economic metrics are quantified for the DRI systems, including life cycle GHG emissions and energy return. GHG results are compared with Nevada grid-based electricity. Initial results indicate that DRI's solar-derived electricity offers clear GHG benefits compared to conventional grid electricity. DRI's eight systems have GHG intensity values of 29-56 gCO2e/kWh, as compared to the GHG intensity of 212 gCO2e/kWh of national average grid power. The major source of impacts (82-92% of the total) is the upstream life cycle burden of manufacturing PV panels, which are made of either mono-crystalline or multi-crystalline silicon. Given the same type of PV panel, GHG intensity decreases as the scale of the system increases. Energy payback times of DRI's solar PV systems range from 0.5 to 1.5 years. The cost payback time for the DRI PV systems and the cost per ton of CO2 avoided by replacing Nevada-specific electrical power will be determined. The sensitivity of these environmental and economic impacts with respect to specific model parameters is being investigated.

IGMS: An Integrated ISO-to-Appliance Scale Grid Modeling System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmintier, Bryan; Hale, Elaine; Hansen, Timothy M.

This paper describes the Integrated Grid Modeling System (IGMS), a novel electric power system modeling platform for integrated transmission-distribution analysis that co-simulates off-the-shelf tools on high performance computing (HPC) platforms to offer unprecedented resolution from ISO markets down to appliances and other end uses. Specifically, the system simultaneously models hundreds or thousands of distribution systems in co-simulation with detailed Independent System Operator (ISO) markets and AGC-level reserve deployment. IGMS uses a new MPI-based hierarchical co-simulation framework to connect existing sub-domain models. Our initial efforts integrate opensource tools for wholesale markets (FESTIV), bulk AC power flow (MATPOWER), and full-featured distribution systemsmore » including physics-based end-use and distributed generation models (many instances of GridLAB-D[TM]). The modular IGMS framework enables tool substitution and additions for multi-domain analyses. This paper describes the IGMS tool, characterizes its performance, and demonstrates the impacts of the coupled simulations for analyzing high-penetration solar PV and price responsive load scenarios.« less

Sizing and modelling of photovoltaic water pumping system

NASA Astrophysics Data System (ADS)

Al-Badi, A.; Yousef, H.; Al Mahmoudi, T.; Al-Shammaki, M.; Al-Abri, A.; Al-Hinai, A.

2018-05-01

With the decline in price of the photovoltaics (PVs) their use as a power source for water pumping is the most attractive solution instead of using diesel generators or electric motors driven by a grid system. In this paper, a method to design a PV pumping system is presented and discussed, which is then used to calculate the required size of the PV for an existing farm. Furthermore, the amount of carbon dioxide emissions saved by the use of PV water pumping system instead of using diesel-fuelled generators or electrical motor connected to the grid network is calculated. In addition, an experimental set-up is developed for the PV water pumping system using both DC and AC motors with batteries. The experimental tests are used to validate the developed MATLAB model. This research work demonstrates that using the PV water pumping system is not only improving the living conditions in rural areas but it is also protecting the environment and can be a cost-effective application in remote locations.

Analysis of Aurora's Performance Simulation Engine for Three Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, Janine; Simon, Joseph

2015-07-07

Aurora Solar Inc. is building a cloud-based optimization platform to automate the design, engineering, and permit generation process of solar photovoltaic (PV) installations. They requested that the National Renewable Energy Laboratory (NREL) validate the performance of the PV system performance simulation engine of Aurora Solar’s solar design platform, Aurora. In previous work, NREL performed a validation of multiple other PV modeling tools 1, so this study builds upon that work by examining all of the same fixed-tilt systems with available module datasheets that NREL selected and used in the aforementioned study. Aurora Solar set up these three operating PV systemsmore » in their modeling platform using NREL-provided system specifications and concurrent weather data. NREL then verified the setup of these systems, ran the simulations, and compared the Aurora-predicted performance data to measured performance data for those three systems, as well as to performance data predicted by other PV modeling tools.« less

Terrestrial photovoltaic collector technology trends

NASA Technical Reports Server (NTRS)

Shimada, K.; Costogue, E.

1984-01-01

Following the path of space PV collector development in its early stages, terrestrial PV technologies based upon single-crystal silicon have matured rapidly. Currently, terrestrial PV cells with efficiencies approaching space cell efficiencies are being fabricated into modules at a fraction of the space PV module cost. New materials, including CuInSe2 and amorphous silicon, are being developed for lowering the cost, and multijunction materials for achieving higher efficiency. Large grid-interactive, tracking flat-plate power systems and concentrator PV systems totaling about 10 MW, are already in operation. Collector technology development both flat-plate and concentrator, will continue under an extensive government and private industry partnership.

Inverter testing at Sandia National Laboratories

NASA Astrophysics Data System (ADS)

Ginn, Jerry W.; Bonn, Russell H.; Sittler, Greg

1997-02-01

Inverters are key building blocks of photovoltaic (PV) systems that produce ac power. The balance of systems (BOS) portion of a PV system can account for up to 50% of the system cost, and its reliable operation is essential for a successful PV system. As part of its BOS program, Sandia National Laboratories (SNL) maintains a laboratory wherein accurate electrical measurements of power systems can be made under a variety of conditions. This paper outlines the work that is done in that laboratory.

Influence of Distributed Residential Energy Storage on Voltage in Rural Distribution Network and Capacity Configuration

NASA Astrophysics Data System (ADS)

Liu, Lu; Tong, Yibin; Zhao, Zhigang; Zhang, Xuefen

2018-03-01

Large-scale access of distributed residential photovoltaic (PV) in rural areas has solved the voltage problem to a certain extent. However, due to the intermittency of PV and the particularity of rural residents’ power load, the problem of low voltage in the evening peak remains to be resolved. This paper proposes to solve the problem by accessing residential energy storage. Firstly, the influence of access location and capacity of energy storage on voltage distribution in rural distribution network is analyzed. Secondly, the relation between the storage capacity and load capacity is deduced for four typical load and energy storage cases when the voltage deviation meets the demand. Finally, the optimal storage position and capacity are obtained by using PSO and power flow simulation.

Using Measured Plane-of-Array Data Directly in Photovoltaic Modeling: Methodology and Validation: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, Janine; Freestate, David; Riley, Cameron

2016-11-01

Measured plane-of-array (POA) irradiance may provide a lower-cost alternative to standard irradiance component data for photovoltaic (PV) system performance modeling without loss of accuracy. Previous work has shown that transposition models typically used by PV models to calculate POA irradiance from horizontal data introduce error into the POA irradiance estimates, and that measured POA data can correlate better to measured performance data. However, popular PV modeling tools historically have not directly used input POA data. This paper introduces a new capability in NREL's System Advisor Model (SAM) to directly use POA data in PV modeling, and compares SAM results frommore » both POA irradiance and irradiance components inputs against measured performance data for eight operating PV systems.« less

Using Measured Plane-of-Array Data Directly in Photovoltaic Modeling: Methodology and Validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, Janine; Freestate, David; Hobbs, William

2016-11-21

Measured plane-of-array (POA) irradiance may provide a lower-cost alternative to standard irradiance component data for photovoltaic (PV) system performance modeling without loss of accuracy. Previous work has shown that transposition models typically used by PV models to calculate POA irradiance from horizontal data introduce error into the POA irradiance estimates, and that measured POA data can correlate better to measured performance data. However, popular PV modeling tools historically have not directly used input POA data. This paper introduces a new capability in NREL's System Advisor Model (SAM) to directly use POA data in PV modeling, and compares SAM results frommore » both POA irradiance and irradiance components inputs against measured performance data for eight operating PV systems.« less

Using Measured Plane-of-Array Data Directly in Photovoltaic Modeling: Methodology and Validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, Janine; Freestate, David; Hobbs, William

2016-06-05

Measured plane-of-array (POA) irradiance may provide a lower-cost alternative to standard irradiance component data for photovoltaic (PV) system performance modeling without loss of accuracy. Previous work has shown that transposition models typically used by PV models to calculate POA irradiance from horizontal data introduce error into the POA irradiance estimates, and that measured POA data can correlate better to measured performance data. However, popular PV modeling tools historically have not directly used input POA data. This paper introduces a new capability in NREL's System Advisor Model (SAM) to directly use POA data in PV modeling, and compares SAM results frommore » both POA irradiance and irradiance components inputs against measured performance data for eight operating PV systems.« less

Droop Control of Solar PV, Grid and Critical Load using Suppressing DC Current Injection Technique without Battery Storage

NASA Astrophysics Data System (ADS)

Dama Mr., Jayachandra; (Mrs. , Lini Mathew, Dr.; Srikanth Mr., G.

2017-08-01

This paper presents design of a sustainable solar Photo voltaic system for an Indian cities based residential/community house, integrated with grid, supporting it as supplementary sources, to meet energy demand of domestic loads. The role of renewable energy sources in Distributed Generation (DG) is increasingly being recognized as a supplement and an alternative to large conventional central power supply. Though centralized economic system that solely depends on cities is hampered due to energy deficiency, the use of solar energy in cities is never been tried widely due to technical inconvenience and high installation cost. To mitigate these problems, this paper proposes an optimized design of grid-tied PV system without storage which is suitable for Indian origin as it requires less installallation cost and supplies residential loads when the grid power is unavailable. The energy requirement is mainly fulfilled from PV energy module for critical load of a city located residential house and supplemented by grid/DG for base and peak load. The system has been developed for maximum daily household demand of 50kWp and can be scaled to any higher value as per requirement of individual/community building ranging from 50kWp to 60kWp as per the requirement. A simplified control system model has been developed to optimize and control flow of power from these sources. The simulation work, using MATLAB Simulink software for proposed energy management, has resulted in an optimal yield leading efficient power flow control of proposed system.

Golden Rays - May 2017 | Solar Research | NREL

Science.gov Websites

, the energy reported by micro-inverters on existing PV systems can be used to back-solve for the solar future PV systems, the results matched those based on solar resource measurements from top-of-the-line the solar resource using data from 100 PV systems in five metropolitan areas. More Than 200 Attend

Investigation of the photovoltaic cell/ thermoelectric element hybrid system performance

NASA Astrophysics Data System (ADS)

Cotfas, D. T.; Cotfas, P. A.; Machidon, O. M.; Ciobanu, D.

2016-06-01

The PV/TEG hybrid system, consisting of the photovoltaic cells and thermoelectric element, is presented in the paper. The dependence of the PV/TEG hybrid system parameters on the illumination levels and the temperature is analysed. The maxim power values of the photovoltaic cell, of the thermoelectric element and of the PV/TEG system are calculated and a comparison between them is presented and analysed. An economic analysis is also presented.

Emissions from photovoltaic life cycles.

PubMed

Fthenakis, Vasilis M; Kim, Hyung Chul; Alsema, Erik

2008-03-15

Photovoltaic (PV) technologies have shown remarkable progress recently in terms of annual production capacity and life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004-2006, this study presents the life-cycle greenhouse gas emissions, criteria pollutant emissions, and heavy metal emissions from four types of major commercial PV systems: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. Life-cycle emissions were determined by employing average electricity mixtures in Europe and the United States during the materials and module production for each PV system. Among the current vintage of PV technologies, thin-film cadmium telluride (CdTe) PV emits the least amount of harmful air emissions as it requires the least amount of energy during the module production. However, the differences in the emissions between different PV technologies are very small in comparison to the emissions from conventional energy technologies that PV could displace. As a part of prospective analysis, the effect of PV breeder was investigated. Overall, all PV technologies generate far less life-cycle air emissions per GWh than conventional fossil-fuel-based electricity generation technologies. At least 89% of air emissions associated with electricity generation could be prevented if electricity from photovoltaics displaces electricity from the grid.