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Sample records for small-scale wind power

  1. Power Spectra, Power Law Exponents, and Anisotropy of Solar Wind Turbulence at Small Scales

    NASA Technical Reports Server (NTRS)

    Podesta, J. J.; Roberts, D. A.; Goldstein, M. L.

    2006-01-01

    The Wind spacecraft provides simultaneous solar wind velocity and magnetic field measurements with 3- second time resolution, roughly an order of magnitude faster than previous measurements, enabling the small scale features of solar wind turbulence to be studied in unprecedented detail. Almost the entire inertial range can now be explored (the inertial range extends from approximately 1 to 10(exp 3) seconds in the spacecraft frame) although the dissipation range of the velocity fluctuations is still out of reach. Improved measurements of solar wind turbulence spectra at 1 AU in the ecliptic plane are presented including spectra of the energy and cross-helicity, the magnetic and kinetic energies, the Alfven ratio, the normalized cross-helicity, and the Elsasser ratio. Some recent observations and theoretical challenges are discussed including the observation that the velocity and magnetic field spectra often show different power law exponents with values close to 3/2 and 5/3, respectively; the energy (kinetic plus magnetic) and cross-helicity often have approximately equal power law exponents with values intermediate between 3/2 and 5/3; and the Alfven ratio, the ratio of the kinetic to magnetic energy spectra, is often a slowly increasing function of frequency increasing from around 0.4 to 1 for frequencies in the inertial range. Differences between high- and low-speed wind are also discussed. Comparisons with phenomenological turbulence theories show that important aspects of the physics are yet unexplained.

  2. Power Spectra, Power Law Exponents, and Anisotropy of Solar Wind Turbulence at Small Scales

    NASA Technical Reports Server (NTRS)

    Podesta, J. J.; Roberts, D. A.; Goldstein, M. L.

    2006-01-01

    The Wind spacecraft provides simultaneous solar wind velocity and magnetic field measurements with 3- second time resolution, roughly an order of magnitude faster than previous measurements, enabling the small scale features of solar wind turbulence to be studied in unprecedented detail. Almost the entire inertial range can now be explored (the inertial range extends from approximately 1 to 10(exp 3) seconds in the spacecraft frame) although the dissipation range of the velocity fluctuations is still out of reach. Improved measurements of solar wind turbulence spectra at 1 AU in the ecliptic plane are presented including spectra of the energy and cross-helicity, the magnetic and kinetic energies, the Alfven ratio, the normalized cross-helicity, and the Elsasser ratio. Some recent observations and theoretical challenges are discussed including the observation that the velocity and magnetic field spectra often show different power law exponents with values close to 3/2 and 5/3, respectively; the energy (kinetic plus magnetic) and cross-helicity often have approximately equal power law exponents with values intermediate between 3/2 and 5/3; and the Alfven ratio, the ratio of the kinetic to magnetic energy spectra, is often a slowly increasing function of frequency increasing from around 0.4 to 1 for frequencies in the inertial range. Differences between high- and low-speed wind are also discussed. Comparisons with phenomenological turbulence theories show that important aspects of the physics are yet unexplained.

  3. Investment Timing and Capacity Choice for Small-Scale Wind PowerUnder Uncertainty

    SciTech Connect

    Fleten, Stein-Erik; Maribu, Karl Magnus

    2004-11-28

    This paper presents a method for evaluation of investments in small-scale wind power under uncertainty. It is assumed that the price of electricity is uncertain and that an owner of a property with wind resources has a deferrable opportunity to invest in one wind power turbine within a capacity range. The model evaluates investment in a set of projects with different capacity. It is assumed that the owner substitutes own electricity load with electricity from the wind mill and sells excess electricity back to the grid on an hourly basis. The problem for the owner is to find the price levels at which it is optimal to invest, and in which capacity to invest. The results suggests it is optimal to wait for significantly higher prices than the net present value break-even. Optimal scale and timing depend on the expected price growth rate and the uncertainty in the future prices.

  4. Small-Scale Hydroelectric Power Demonstration Project

    SciTech Connect

    Gleeson, L.

    1991-12-01

    The US Department of Energy Field Office, Idaho, Small-Scale Hydroelectric Power Program was initiated in conjunction with the restoration of three power generating plants in Idaho Falls, Idaho, following damage caused by the Teton Dam failure on June 5, 1976. There were many parties interested in this project, including the state and environmental groups, with different concerns. This report was prepared by the developer and describes the design alternatives the applicant provided in an attempt to secure the Federal Energy Regulatory Commission license. Also included are correspondence between the related parties concerning the project, major design alternatives/project plan diagrams, the license, and energy and project economics.

  5. Some features of the small-scale solar wind fluctuations

    NASA Technical Reports Server (NTRS)

    Zastenker, G.; Eiges, P.; Avanov, L.; Astafyeva, N.; Zurbuchen, Th.; Bochsler, P.

    1995-01-01

    We have investigated small-scale variations of the solar wind ion flux measured with Faraday cups onboard the Prognoz-8 satellite. These measurements have a high time resolution of 1.24 seconds for intervals with a duration of several hours and as high as 0.02 seconds for some periods of about 1 hour duration. The main goal of this work is the determination of the quantitative features of fast ion flux fluctuations using mainly spectral analysis but also other methods. We also identify their association with interplanetary plasma parameters. Particularly, it is shown that the slope of the power spectra in the frequency range from 1E-4 to 6E-2 Hz is close to the classical Kolmogorov (-5/3) law. We also discuss some intervals with a very high level of the relative amplitude of flux fluctuations (10-20 percent) which were observed near the Earth's bow shock in the foreshock region. The use of the wavelet method for the long time series allows us to study the temporal evolution of power spectra.

  6. Some features of the small-scale solar wind fluctuations

    NASA Technical Reports Server (NTRS)

    Zastenker, G.; Eiges, P.; Avanov, L.; Astafyeva, N.; Zurbuchen, Th.; Bochsler, P.

    1995-01-01

    We have investigated small-scale variations of the solar wind ion flux measured with Faraday cups onboard the Prognoz-8 satellite. These measurements have a high time resolution of 1.24 seconds for intervals with a duration of several hours and as high as 0.02 seconds for some periods of about 1 hour duration. The main goal of this work is the determination of the quantitative features of fast ion flux fluctuations using mainly spectral analysis but also other methods. We also identify their association with interplanetary plasma parameters. Particularly, it is shown that the slope of the power spectra in the frequency range from 1E-4 to 6E-2 Hz is close to the classical Kolmogorov (-5/3) law. We also discuss some intervals with a very high level of the relative amplitude of flux fluctuations (10-20 percent) which were observed near the Earth's bow shock in the foreshock region. The use of the wavelet method for the long time series allows us to study the temporal evolution of power spectra.

  7. Small-scale flow structures in the solar wind turbulence

    NASA Astrophysics Data System (ADS)

    Wang, Tieyan; Fu, Huishan; Cao, Jinbin; He, Jiansen; Zhao, Jinsong; Zhang, Lei; Dunlop, Malcolm; Yang, Jian; Chen, Zuzheng; Lu, Haoyu

    2017-04-01

    Small-scale flow structures play a key role in balancing and dissipating turbulent kinetic energy. Significant progress has been made towards understanding the flow patterns in hydrodynamic (HD) turbulence. However, the geometry/topology of the turbulent, magnetized plasma flow remains not fully understood. By virtue of the multi-point plasma moments measured by the Magnetospheric Multiscale (MMS) mission, quantification of the velocity gradient, which carries geometrical information of the fluid elements, becomes available. Through analyzing the geometric invariants of the coarse-grained velocity gradient (R and Q), we have investigated the small-scale structure of the turbulent flow in the solar wind. Three main results that agree with theoretical/numerical and experimental results of homogeneous HD turbulence are reported: (1) The joint probability density function of the (R, Q) phase map exhibit a 'teardrop' shape; (2) The vorticity is aligned with the positive intermediate principal of the strain tensor; (3) The ratios of the mean eigenvalues of the stains tensor are around 3: 1: -4, implying sheet-like structures with viscous dissipation and dissipation production. Interestingly, dissimilarities from HD flows are found, featuring a population whose enstrophy is correlated with dissipation. Further investigation of the magnetic field patterns shows a dominance of quasi-2D structures, which is different from the velocity field. Implications of our work are discussed.

  8. Dynamic properties of small-scale solar wind plasma fluctuations.

    PubMed

    Riazantseva, M O; Budaev, V P; Zelenyi, L M; Zastenker, G N; Pavlos, G P; Safrankova, J; Nemecek, Z; Prech, L; Nemec, F

    2015-05-13

    The paper presents the latest results of the studies of small-scale fluctuations in a turbulent flow of solar wind (SW) using measurements with extremely high temporal resolution (up to 0.03 s) of the bright monitor of SW (BMSW) plasma spectrometer operating on astrophysical SPECTR-R spacecraft at distances up to 350,000 km from the Earth. The spectra of SW ion flux fluctuations in the range of scales between 0.03 and 100 s are systematically analysed. The difference of slopes in low- and high-frequency parts of spectra and the frequency of the break point between these two characteristic slopes was analysed for different conditions in the SW. The statistical properties of the SW ion flux fluctuations were thoroughly analysed on scales less than 10 s. A high level of intermittency is demonstrated. The extended self-similarity of SW ion flux turbulent flow is constantly observed. The approximation of non-Gaussian probability distribution function of ion flux fluctuations by the Tsallis statistics shows the non-extensive character of SW fluctuations. Statistical characteristics of ion flux fluctuations are compared with the predictions of a log-Poisson model. The log-Poisson parametrization of the structure function scaling has shown that well-defined filament-like plasma structures are, as a rule, observed in the turbulent SW flows.

  9. Small-scale wind disturbances observed by the MU radar during the passage of typhoon Kelly

    SciTech Connect

    Sato, Kaoru )

    1993-02-14

    This paper describes small-scale wind disturbances associated with Typhoon Kelly (October 1987) that were observed by the MU radar, one of the MST (mesosphere, stratosphere, and troposphere) radars, for about 60 hours with fine time and height resolution. To elucidate the background of small-scale disturbances, synoptic-scale variation in atmospheric stability related to the typhoon structure during the observation is examined. When the typhoon passed near the MU radar site, the structure was no longer axisymmetric. There is deep convection only in north-northeast side of the typhoon while convection behind it is suppressed by a synoptic-scale cold air mass moving eastward to the west of the typhoon. A change in atmospheric stability over the radar site as indicated by echo power profiles is likely due to the passage of the sharp transition zone of convection. Strong small-scale wind disturbances were observed around the typhoon passage. The statistical characteristics are different before (BT) and after (AT) the typhoon passage, especially in frequency spectra of vertical wind fluctuations. The spectra for BT are unique compared with earlier studies of vertical winds observed by VHF radars. Another difference is dominance of a horizontal wind component with a vertical wavelength of about 3 km, observed only in AT. Further analyses are made of characteristics and vertical momentum fluxes for dominant disturbances. Some disturbances are generated to remove the momentum of cyclonic wind rotation of the typhoon. Deep convection, topographic effects in strong winds, and strong vertical shear of horizontal winds around an inversion layer are possible sources of the disturbances. Two monochromatic disturbances lasting for more than 10 h in the lower stratosphere observed in BT and AT are identified as inertio-gravity waves, by obtaining wave parameters consistent with all observed quantities. Both of the inertio-gravity waves propagate energy away from the typhoon.

  10. Numerical study on small scale vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Parra-Santos, Teresa; Gallegos, Armando; Uzarraga, Cristóbal N.; Rodriguez, Miguel A.

    2016-03-01

    The performance of a Vertical Axis Wind Turbine (VAWT) is numerically analyzed. The set-up is Hdarrieus with three straight blades airfoils NACA attached to a rotating vertical shaft. The wind turbine has solidity equals to the unity operating with wind velocity of 7 m/s. Influence of pitch angle is tested to get design tendencies. 2D, transient, Navier Stokes equations are solved using the code Ansys-Fluent. Conservation equations were solved with a Third-Order MUSCL scheme using SIMPLE to couple pressure and velocity. More than six revolutions must be simulated to get the periodic behavior. Two models of turbulence have been contrasted Realizable k-epsilon and Transition SST concluding the last one show more realistic flow features. Pitch angles of 0º, -6º and -10º have been tested with Tip Speed Ratios ranging from 0.7 and 1.6. The no null pitch angles improve the performance of the wind turbine. Instantaneous and averaged power coefficients as well as detailed flow field around the airfoils are showed.

  11. A triboelectric wind turbine for small-scale energy harvesting

    NASA Astrophysics Data System (ADS)

    Perez, Matthias; Boisseau, Sebastien; Geisler, Matthias; Despesse, Ghislain; Reboud, Jean Luc

    2016-11-01

    This paper deals with a rotational energy harvester including a Horizontal Axis Wind Turbine (HAWT), a cylindrical stator covered by several electrodes, and thin Teflon dielectric membranes hung on the rotor. The sliding contact of the Teflon membranes on the stator provides simultaneously large capacitance variations and a polarization source for the electrostatic converter by exploiting triboelectric phenomena. 1μW has been harvested at 4m/s; 130μW at 10m/s and 550μW at 20m/s with a 40mmØ device. In order to validate the energy harvesting chain, the airflow energy harvester has been connected to a power management circuit implementing Synchronous Electric Charge Extraction (SECE) to supply a wireless sensor node with temperature and acceleration measurements, transmitted to a computer at 868MHz.

  12. An experimental study of potential residential and commercial applications of small-scale hybrid power systems

    NASA Astrophysics Data System (ADS)

    Acosta, Michael Anthony

    The research presented in this thesis provides an understanding of small-scale hybrid power systems. Experiments were conducted to identify potential applications of renewable energy in residential and commercial applications in the Rio Grande Valley of Texas. Solar and wind energy converted into electric energy was stored in batteries and inverted to power common household and commercial appliances. Several small to medium size hybrid power systems were setup and utilized to conduct numerous tests to study renewable energy prospects and feasibility for various applications. The experimental results obtained indicate that carefully constructed solar power systems can provide people living in isolated communities with sufficient energy to consistently meet their basic power needs.

  13. Torque Characteristics Simulation on Small Scale Combined Type Vertical Axis Wind Turbine

    NASA Astrophysics Data System (ADS)

    Feng, Fang; Li, Shengmao; Li, Yan; Xu, Dan

    The straight-bladed vertical axis wind turbine (SB-VAWT) receives more attentions recently for its goodness of simple design, low cost and good maintenance. However, its starting performance is poor. To increase its starting torque, Savonius rotor was combined on the SB-VAWT in this study because Savonius rotor has good starting torque coefficient. Based on the wind tunnel tests data, a small scaled combined type SB-VAWT (CSB-VAWT) which has 50W rated power output was designed. The starting torque coefficient, dynamic torque and power performance were analyzed. Both the starting and dynamic torque performance of the CSB-VAWT have been greatly improved according to the simulation results.

  14. Small-scale AFBC hot air gas turbine power cycle

    SciTech Connect

    Ashworth, R.A.; Keener, H.M.; Hall, A.W.

    1995-12-31

    The Energy and Environmental Research Corporation (EER), the Ohio Agricultural Research and Development Center (OARDC), the Will-Burt Company (W-B) and the US Department of Energy (DOE) have successfully developed and completed pilot plant tests on a small scale atmospheric fluidized bed combustion (AFBC) system. This system can be used to generate electricity, and/or hot water, steam. Following successful pilot plant operation, commercial demonstration will take place at Cedar Lane Farms (CLF), near Wooster, Ohio. The system demonstration will be completed by the end of 1995. The project is being funded through a cooperative effort between the DOE, EER, W-B, OARDC, CLF and the Ohio Coal Development Office (OCDO). The small scale AFBC, has no internal heat transfer surfaces in the fluid bed proper. Combining the combustor with a hot air gas turbine (HAGT) for electrical power generation, can give a relatively high overall system thermal efficiency. Using a novel method of recovering waste heat from the gas turbine, a gross heat rate of 13,500 Btu/kWhr ({approximately}25% efficiency) can be achieved for a small 1.5 MW{sub e} plant. A low technology industrial recuperation type gas turbine is used that operates with an inlet blade temperature of 1,450 F and a compression ratio of 3.9:1. The AFBC-HAGT technology can be used to generate power for remote rural communities to replace diesel generators, or can be used for small industrial co-generation applications.

  15. Performance of small-scale tidal power plants

    NASA Astrophysics Data System (ADS)

    Fay, J. A.; Smachlo, M. A.

    1983-12-01

    Small-scale tidal power plants - having electric power between 1 and 100 MW, approximately - possess several attractive economic and environmental benefits. The dynamical behavior of such systems is calculated in terms of dimensionless variables and parameters, so that the size of the system is inconsequential (except for one parameter related to the slope of the walls of the tidal basin). Two measures of system performance are defined: capacity factor (ratio of average to rated power) and effectiveness (ratio of average to ideal tidal power). It was found that improving both parameters is mutually incompatible so that an economic analysis will determine the optimum values of the system design and performance parameters. The effects of variation of tidal range and basin shape were determined. Using typical variable flow properties of low-head hydroturbines, a favorable design head could be determined from the analysis. It was found that the change in the area of the intertidal zone relative to the surface area of the tidal pond is greater for small, as compared to large, systems, possibly leading to proportionately greater environmental effects. A comparison of the performance of several tidal power plant designs with the methodology of this paper showed generally good agreement with the dimensionless performance parameters and only a modest difference among them over several orders of magnitude in size of power plant.

  16. Performance of small-scale tidal power plants

    SciTech Connect

    Fay, J.A.; Smachio, M.A.

    1983-11-01

    Small-scale tidal power plants--having electric power between 1 and 100 MW, approximately--possess several attractive economic and environmental benefits. The dynamical behavior of such systems is calculated in terms of dimensionless variables and parameters so that the size of the system is inconsequential (except for one parameter related to the slope of the walls of the tidal basin). Two measures of system performance are defined: capacity factor (ratio of average to rated power) and effectiveness (ratio of average to ideal tidal power). It was found that improving both parameters is mutually incompatible so that an economic analysis will determine the optimum values of the system design and performance parameters. The effects of variation of tidal range and basin shape were determined. Using typical variable flow properties of low-head hydroturbines, a favorable design head could be determined from the analysis. It was found that the change in the area of the intertidal zone relative to the surface area of the tidal pond is greater for small, as compared to large, systems, possibly leading to proportionately greater environmental effects. A comparison of the performance of several tidal power plant designs with the methodology of this paper showed generally good agreement with the dimensionless performance parameters and only a modest difference among them over several orders of magnitude in size of power plant.

  17. Small-Scale Geothermal Power Plant Field Verification Projects: Preprint

    SciTech Connect

    Kutscher, C.

    2001-07-03

    In the spring of 2000, the National Renewable Energy Laboratory issued a Request for Proposal for the construction of small-scale (300 kilowatt [kW] to 1 megawatt [MW]) geothermal power plants in the western United States. Five projects were selected for funding. Of these five, subcontracts have been completed for three, and preliminary design work is being conducted. The three projects currently under contract represent a variety of concepts and locations: a 1-MW evaporatively enhanced, air-cooled binary-cycle plant in Nevada; a 1-MW water-cooled Kalina-cycle plant in New Mexico; and a 750-kW low-temperature flash plant in Utah. All three also incorporate direct heating: onion dehydration, heating for a fish hatchery, and greenhouse heating, respectively. These projects are expected to begin operation between April 2002 and September 2003. In each case, detailed data on performance and costs will be taken over a 3-year period.

  18. Power spectrum for the small-scale Universe

    NASA Astrophysics Data System (ADS)

    Widrow, Lawrence M.; Elahi, Pascal J.; Thacker, Robert J.; Richardson, Mark; Scannapieco, Evan

    2009-08-01

    The first objects to arise in a cold dark matter (CDM) universe present a daunting challenge for models of structure formation. In the ultra small-scale limit, CDM structures form nearly simultaneously across a wide range of scales. Hierarchical clustering no longer provides a guiding principle for theoretical analyses and the computation time required to carry out credible simulations becomes prohibitively high. To gain insight into this problem, we perform high-resolution (N = 7203-15843) simulations of an Einstein-de Sitter cosmology where the initial power spectrum is P(k) ~ kn, with -2.5 <= n <= - 1. Self-similar scaling is established for n = -1 and -2 more convincingly than in previous, lower resolution simulations and for the first time, self-similar scaling is established for an n = -2.25 simulation. However, finite box-size effects induce departures from self-similar scaling in our n = -2.5 simulation. We compare our results with the predictions for the power spectrum from (one-loop) perturbation theory and demonstrate that the renormalization group approach suggested by McDonald improves perturbation theory's ability to predict the power spectrum in the quasi-linear regime. In the non-linear regime, our power spectra differ significantly from the widely used fitting formulae of Peacock & Dodds and Smith et al. and a new fitting formula is presented. Implications of our results for the stable clustering hypothesis versus halo model debate are discussed. Our power spectra are inconsistent with predictions of the stable clustering hypothesis in the high-k limit and lend credence to the halo model. Nevertheless, the fitting formula advocated in this paper is purely empirical and not derived from a specific formulation of the halo model.

  19. Small-scale Geothermal Power Plants Using Hot Spring Water

    NASA Astrophysics Data System (ADS)

    Tosha, T.; Osato, K.; Kiuchi, T.; Miida, H.; Okumura, T.; Nakashima, H.

    2013-12-01

    The installed capacity of the geothermal power plants has been summed up to be about 515MW in Japan. However, the electricity generated by the geothermal resources only contributes to 0.2% of the whole electricity supply. After the catastrophic earthquake and tsunami devastated the Pacific coast of north-eastern Japan on Friday, March 11, 2011, the Japanese government is encouraging the increase of the renewable energy supply including the geothermal. It needs, however, more than 10 years to construct the geothermal power plant with more than 10MW capacity since the commencement of the development. Adding the problem of the long lead time, high temperature fluid is mainly observed in the national parks and the high quality of the geothermal resources is limited. On the other hand hot springs are often found. The utilisation of the low temperature hot water becomes worthy of notice. The low temperature hot water is traditionally used for bathing and there are many hot springs in Japan. Some of the springs have enough temperature and enthalpy to turn the geothermal turbine but a new technology of the binary power generation makes the lower temp fluid to generate electricity. Large power generators with the binary technology are already installed in many geothermal fields in the world. In the recent days small-scale geothermal binary generators with several tens to hundreds kW capacity are developed, which are originally used by the waste heat energy in an iron factory and so on. The newly developed binary unit is compact suitable for the installation in a Japanese inn but there are the restrictions for the temperature of the hot water and the working fluid. The binary power unit using alternatives for chlorofluorocarbon as the working fluid is relatively free from the restriction. KOBELCO, a company of the Kobe Steel Group, designed and developed the binary power unit with an alternative for chlorofluorocarbon. The unit has a 70 MW class electric generator. Three

  20. Proceedings of a Topical Meeting On Small Scale Geothermal Power Plants and Geothermal Power Plant Projects

    SciTech Connect

    1986-02-12

    These proceedings describe the workshop of the Topical Meeting on Small Scale Geothermal Power Plants and Geothermal Power Plant Projects. The projects covered include binary power plants, rotary separator, screw expander power plants, modular wellhead power plants, inflow turbines, and the EPRI hybrid power system. Active projects versus geothermal power projects were described. In addition, a simple approach to estimating effects of fluid deliverability on geothermal power cost is described starting on page 119. (DJE-2005)

  1. Integrated bioenergy conversion concepts for small scale gasification power systems

    NASA Astrophysics Data System (ADS)

    Aldas, Rizaldo Elauria

    Thermal and biological gasification are promising technologies for addressing the emerging concerns in biomass-based renewable energy, environmental protection and waste management. However, technical barriers such as feedstock quality limitations, tars, and high NOx emissions from biogas fueled engines impact their full utilization and make them suffer at the small scale from the need to purify the raw gas for most downstream processes, including power generation other than direct boiler use. The two separate gasification technologies may be integrated to better address the issues of power generation and waste management and to complement some of each technologies' limitations. This research project investigated the technical feasibility of an integrated thermal and biological gasification concept for parameters critical to appropriately matching an anaerobic digester with a biomass gasifier. Specific studies investigated the thermal gasification characteristics of selected feedstocks in four fixed-bed gasification experiments: (1) updraft gasification of rice hull, (2) indirect-heated gasification of rice hull, (3) updraft gasification of Athel wood, and (4) downdraft gasification of Athel and Eucalyptus woods. The effects of tars and other components of producer gas on anaerobic digestion at mesophilic temperature of 36°C and the biodegradation potentials and soil carbon mineralization of gasification tars during short-term aerobic incubation at 27.5°C were also examined. Experiments brought out the ranges in performance and quality and quantity of gasification products under different operating conditions and showed that within the conditions considered in the study, these gasification products did not adversely impact the overall digester performance. Short-term aerobic incubation demonstrated variable impacts on carbon mineralization depending on tar and soil conditions. Although tars exhibited low biodegradation indices, degradation may be improved if the

  2. Energetic Ion Acceleration by Small-scale Solar Wind Flux Ropes

    NASA Astrophysics Data System (ADS)

    le Roux, J. A.; Webb, G. M.; Zank, G. P.; Khabarova, O.

    2015-09-01

    We consider different limits of our recently developed kinetic transport theory to investigate the potential of supersonic solar wind regions containing several small-scale flux ropes to explain the acceleration of suprathermal ions to power-law spectra as observations show. Particle acceleration is modeled in response to flux-rope activity involving contraction, merging (reconnection), and collisions in the limit where the particle gyoradius is smaller than the characteristic flux-rope scale length. The emphasis is mainly on the statistical variance in the electric fields induced by flux-rope dynamics rather than on the mean electric field induced by multiple flux ropes whose acceleration effects are discussed elsewhere. Our steady-state analytical solutions suggest that ion drift acceleration by flux ropes, irrespective of whether displaying incompressible or compressible behavior, can yield power laws asymptotically at higher energies whereas an exponential spectral rollover results asymptotically when field-aligned guiding center motion acceleration occur by reconnection electric fields from merging flux ropes. This implies that at sufficiently high particle energies, drift acceleration might dominate. We also expect compressive flux ropes to yield harder power-law spectra than incompressible flux ropes.

  3. SMALL SCALE FUEL CELL AND REFORMER SYSTEMS FOR REMOTE POWER

    SciTech Connect

    Dennis Witmer

    2003-12-01

    New developments in fuel cell technologies offer the promise of clean, reliable affordable power, resulting in reduced environmental impacts and reduced dependence on foreign oil. These developments are of particular interest to the people of Alaska, where many residents live in remote villages, with no roads or electrical grids and a very high cost of energy, where small residential power systems could replace diesel generators. Fuel cells require hydrogen for efficient electrical production, however. Hydrogen purchased through conventional compressed gas suppliers is very expensive and not a viable option for use in remote villages, so hydrogen production is a critical piece of making fuel cells work in these areas. While some have proposed generating hydrogen from renewable resources such as wind, this does not appear to be an economically viable alternative at this time. Hydrogen can also be produced from hydrocarbon feed stocks, in a process known as reforming. This program is interested in testing and evaluating currently available reformers using transportable fuels: methanol, propane, gasoline, and diesel fuels. Of these, diesel fuels are of most interest, since the existing energy infrastructure of rural Alaska is based primarily on diesel fuels, but this is also the most difficult fuel to reform, due to the propensity for coke formation, due to both the high vaporization temperature and to the high sulfur content in these fuels. There are several competing fuel cell technologies being developed in industry today. Prior work at UAF focused on the use of PEM fuel cells and diesel reformers, with significant barriers identified to their use for power in remote areas, including stack lifetime, system efficiency, and cost. Solid Oxide Fuel Cells have demonstrated better stack lifetime and efficiency in demonstrations elsewhere (though cost still remains an issue), and procuring a system for testing was pursued. The primary function of UAF in the fuel cell

  4. Large- and small-scale constraints on power spectra in Omega = 1 universes

    NASA Technical Reports Server (NTRS)

    Gelb, James M.; Gradwohl, Ben-Ami; Frieman, Joshua A.

    1993-01-01

    The CDM model of structure formation, normalized on large scales, leads to excessive pairwise velocity dispersions on small scales. In an attempt to circumvent this problem, we study three scenarios (all with Omega = 1) with more large-scale and less small-scale power than the standard CDM model: (1) cold dark matter with significantly reduced small-scale power (inspired by models with an admixture of cold and hot dark matter); (2) cold dark matter with a non-scale-invariant power spectrum; and (3) cold dark matter with coupling of dark matter to a long-range vector field. When normalized to COBE on large scales, such models do lead to reduced velocities on small scales and they produce fewer halos compared with CDM. However, models with sufficiently low small-scale velocities apparently fail to produce an adequate number of halos.

  5. Analyzing the dynamic response of rotating blades in small-scale wind turbines

    NASA Astrophysics Data System (ADS)

    Hsiung, Wan-Ying; Huang, Yu-Ting; Loh, Chin-Hsiung; Loh, Kenneth J.; Kamisky, Robert J.; Nip, Danny; van Dam, Cornelis

    2014-03-01

    The objective of this study was to validate modal analysis, system identification and damage detection of small-scale rotating wind turbine blades in the laboratory and in the field. Here, wind turbine blades were instrumented with accelerometers and strain gages, and data acquisition was achieved using a prototype wireless sensing system. In the first portion of this study conducted in the laboratory, sensors were installed onto metallic structural elements that were fabricated to be representative of an actual wind blade. In order to control the excitation (rotation of the wind blade), a motor was used to spin the blades at controlled angular velocities. The wind turbine was installed on a shaking table for testing under rotation of turbine blades. Data measured by the sensors were recorded while the blade was operated at different speeds. On the other hand, the second part of this study utilized a small-scale wind turbine system mounted on the rooftop of a building. The main difference, as compared to the lab tests, was that the field tests relied on actual wind excitations (as opposed to a controlled motor). The raw data from both tests were analyzed using signal processing and system identification techniques for deriving the model response of the blades. The multivariate singular spectrum analysis (MSSA) and covariance-driven stochastic subspace identification method (SSI-COV) were used to identify the dynamic characteristics of the system. Damage of one turbine blade (loose bolts connection) in the lab test was also conducted. The extracted modal properties for both undamaged and damage cases under different ambient or forced excitations (earthquake loading) were compared. These tests confirmed that dynamic characterization of rotating wind turbines was feasible, and the results will guide future monitoring studies planned for larger-scale systems.

  6. Development of a Small Scale BIGGT Power Plant

    DTIC Science & Technology

    1994-10-02

    cotton gin trash, SERDP 8 Western Regional Biomass Energy Program 16. PRICE CODE N/A 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19...by the Western Regional Biomass Energy Program. INTRODUCTION The most economically promising path for supplying electrical and thermal power to...we could never have completed an uneventful 24 hour run. ACKNOWLEDGEMENTS The U.S. Department of Energy’s Western Regional Biomass Energy Program

  7. Observations and analysis of small-scale magnetic flux ropes in the solar wind

    NASA Astrophysics Data System (ADS)

    Zheng, Jinlei; Hu, Qiang

    2016-11-01

    The small-scale magnetic flux ropes (of duration ranging from a few minutes to a few hours) in the solar wind have the typical topology of winding field lines around a central axis, which is similar to the large-scale flux ropes, i.e., magnetic clouds. However, accumulating evidence suggests that their plasma characteristics, origin, formation mechanism and evolution are different from those of large-scale flux ropes. The small-scale flux ropes are intensively studied in recent years, since they affect particle transport and energization, and are considered as the potential source of local acceleration. The Grad-Shafranov reconstruction technique is a tool to reconstruct the two and a half dimensional field structure based on in-situ measurements captured by an observing platform moving past it. In this study, we reconstruct the flux rope structures in two events using the Grad-Shafranov reconstruction approach. In one event, a twin flux rope structure at 1 AU occurring on 2002 February 1 and two following single flux rope structures are identified behind an interplanetary shock. In the other event, we reconstruct the flux rope structures occurring on 1998 March 25 and 26 at 1 AU in the ambient solar wind. The associated energetic particle signatures and the possible origin of these flux rope structures are discussed.

  8. A diagnostic model to estimate winds and small-scale drag from Mars Observer PMIRR data

    NASA Technical Reports Server (NTRS)

    Barnes, J. R.

    1993-01-01

    Theoretical and modeling studies indicate that small-scale drag due to breaking gravity waves is likely to be of considerable importance for the circulation in the middle atmospheric region (approximately 40-100 km altitude) on Mars. Recent earth-based spectroscopic observations have provided evidence for the existence of circulation features, in particular, a warm winter polar region, associated with gravity wave drag. Since the Mars Observer PMIRR experiment will obtain temperature profiles extending from the surface up to about 80 km altitude, it will be extensively sampling middle atmospheric regions in which gravity wave drag may play a dominant role. Estimating the drag then becomes crucial to the estimation of the atmospheric winds from the PMIRR-observed temperatures. An interative diagnostic model based upon one previously developed and tested with earth satellite temperature data will be applied to the PMIRR measurements to produce estimates of the small-scale zonal drag and three-dimensional wind fields in the Mars middle atmosphere. This model is based on the primitive equations, and can allow for time dependence (the time tendencies used may be based upon those computed in a Fast Fourier Mapping procedure). The small-scale zonal drag is estimated as the residual in the zonal momentum equation; the horizontal winds having first been estimated from the meridional momentum equation and the continuity equation. The scheme estimates the vertical motions from the thermodynamic equation, and thus needs estimates of the diabatic heating based upon the observed temperatures. The latter will be generated using a radiative model. It is hoped that the diagnostic scheme will be able to produce good estimates of the zonal gravity wave drag in the Mars middle atmosphere, estimates that can then be used in other diagnostic or assimilation efforts, as well as more theoretical studies.

  9. Detection of small-scale structures in the dissipation regime of solar-wind turbulence.

    PubMed

    Perri, S; Goldstein, M L; Dorelli, J C; Sahraoui, F

    2012-11-09

    Recent observations of the solar wind have pointed out the existence of a cascade of magnetic energy from the scale of the proton Larmor radius ρ(p) down to the electron Larmor radius ρ(e) scale. In this Letter we study the spatial properties of magnetic field fluctuations in the solar wind and find that at small scales the magnetic field does not resemble a sea of homogeneous fluctuations, but rather a two-dimensional plane containing thin current sheets and discontinuities with spatial sizes ranging from l >/~ ρ(p) down to ρ(e) and below. These isolated structures may be manifestations of intermittency that localize sites of turbulent dissipation. Studying the relationship between turbulent dissipation, reconnection, and intermittency is crucial for understanding the dynamics of laboratory and astrophysical plasmas.

  10. Small-scale hydroelectric power in the southeast: new impetus for an old energy source

    SciTech Connect

    Not Available

    1980-06-01

    The Southeastern conference, Small-Scale Hydroelectric Power: New Impetus for an Old Energy Source, was convened to provide a forum for state legislators and other interested persons to discuss the problems facing small-scale hydro developers, and to recommend appropriate solutions to resolve those problems. During the two-day meeting state legislators and their staffs, along with dam developers, utility and industry representatives, environmentalists and federal/state officials examined and discussed the problems impeding small-scale hydro development at the state level. Based upon the problem-oriented discussions, alternative policy options were recommended for consideration by the US Department of Energy, state legislatures and the staff of the National Conference of State Legislatures (NCSL). Emphasis was placed on the legal, institutional, environmental and economic barriers at the state level, as well as the federal delays associated with licensing small-scale hydro projects. Whereas other previously held conferences have emphasized the identification and technology of small-scale hydro as an alternative energy source, this conference stressed legislative resolution of the problems and delays in small-scale hydro licensing and development. Panel discussions and workshops are summarized. Papers on the environmental, economic, and legal aspects of small-scale hydropower development are presented. (LCL)

  11. Small scale hydroelectric power potential in Nevada: a preliminary reconnaissance survey

    SciTech Connect

    Cochran, G.F.; Fordham, J.W.; Richard, K.; Loux, R.

    1981-04-01

    This preliminary reconnaissance survey is intended to: develop a first estimate as to the potential number, location and characteristics of small-scale (50 kW to 15 MW) hydroelectric sites in Nevada; provide a compilation of various Federal and state laws and regulations, including tax and financing regulations, that affect small-scale hydroelectric development and provide information on sources of small-scale hydroelectric generation hardware and consultants/ contractors who do small scale hydroelectric work. The entire survey has been conducted in the office working with various available data bases. The site survey and site evaluation methods used are described, and data are tabulated on the flow, power potential, predicted capital expenditures required, etc. for 61 potential sites with measured flows and for 77 sites with derived flows. A map showing potential site locations is included. (LCL)

  12. Small-scale hydroelectric power in the Pacific Northwest: new impetus for an old energy source

    SciTech Connect

    Not Available

    1980-07-01

    Energy supply is one of the most important issues facing Northwestern legislators today. To meet the challenge, state legislatures must address the development of alternative energy sources. The Small-Scale Hydroelectric Power Policy Project of the National Conference of State Legislators (NCSL) was designed to assist state legislators in looking at the benefits of one alternative, small-scale hydro. Because of the need for state legislative support in the development of small-scale hydroelectric, NCSL, as part of its contract with the Department of Energy, conducted the following conference on small-scale hydro in the Pacific Northwest. The conference was designed to identify state obstacles to development and to explore options for change available to policymakers. A summary of the conference proceedings is presented.

  13. Small-scale structures in common-volume meteor wind measurements

    NASA Astrophysics Data System (ADS)

    Fraser, G. J.; Marsh, S. H.; Baggaley, W. J.; Bennett, R. G. T.; Lawrence, B. N.; McDonald, A. J.; Plank, G. E.

    2006-02-01

    Observational differences occur when different techniques are used for measuring mesospheric winds because the different instruments observe different physical quantities to infer the wind velocity, and have differing time and space resolution. The AMOR meteor wind radar near Christchurch, New Zealand [Marsh et al., 2000. Journal of Atmospheric and Solar-Terrestrial Physics 62,1129 1133.] has good resolution in time (˜0.1 s) and height (˜1 km) and a narrow beam centred in the geographic N S meridian. The meteor echoes randomly sample the atmosphere in a region extending over several hundred kilometres to the South of the radar. The volume of data obtained from the one instrument has made it possible to use correlations between measurements made from individual meteor trails to identify the contribution of atmospheric variability to the observational differences. Measurements of the meridional wind component made from May July 1997 inclusive show that a large part (20 30 m/s r.m.s.) of the atmospheric variation is due to inhomogeneities with small scales, of the order of 10 km and 1 h. There is also a component which has a random time phase over the observation interval but a spatial scale which is coherent over several hundred kilometres, consistent with the behaviour of gravity waves.

  14. Extreme small-scale wind episodes over the Barents Sea: When, where and why?

    NASA Astrophysics Data System (ADS)

    Kolstad, Erik W.

    2015-04-01

    The Barents Sea is mostly ice-free during winter and therefore prone to severe weather associated with marine cold air outbreaks, such as polar lows. With the increasing marine activity in the region, it is important to study the climatology and variability of episodes with strong winds, as well as to understand their causes. Explosive marine cyclogenesis is usually caused by a combination of several mechanisms: upper-level forcing, stratospheric dry intrusions, latent heat release, surface energy fluxes, low-level baroclinicity. An additional factor that has been linked to extremely strong surface winds, is low static stability in the lower atmosphere, which allows for downward transfer of high-momentum air. Here the most extreme small-scale wind episodes in a high-resolution (5 km) 35-year hindcast were analyzed from a dynamical perspective, and it was found that they were associated with unusually strong low-level baroclinicity and surface heat fluxes. And crucially, the 12 most severe episodes had stronger cold-air advection than 12 slightly less severe cases, suggesting that marine cold air outbreaks are the most important mechanism for extreme winds on small spatial scales over the Barents Sea. Observational data is sparse in the Arctic, so forecasters are often in need of simple indicators when evaluating the potential for strong winds. Polar low forecasters in northern Norway monitor the vertical difference between the SST and the temperature at 500 hPa, which is a simple and effective indicator of cold air outbreaks. Already 24 hours before the most intense storms' peak intensity, this difference was higher than normal, acting as a possible harbinger of extreme winds for experienced forecasters. As the quality and resolution of the forecast models increase with time, it is in data-sparse regions such as the Barents Sea that human experience still gives a vital edge.

  15. Small is different: RPC observations of a small scale comet interacting with the solar wind

    NASA Astrophysics Data System (ADS)

    Nilsson, Hans; Burch, James L.; Carr, Christopher M.; Eriksson, Anders I.; Glassmeier, Karl-Heinz; Henri, Pierre; Rosetta Plasma Consortium Team

    2016-10-01

    Rosetta followed comet 67P from low activity at more than 3 AU heliocentric distance to peak activity at perihelion and then out again. We study the evolution of the dynamic plasma environment using data from the Rosetta Plasma Consortium (RPC). Observations of cometary plasma began in August 2014, at a distance of 100 km from the comet nucleus and at 3.6 AU from the Sun. As the comet approached the Sun, outgassing from the comet increased, as did the density of the cometary plasma. Measurements showed a highly heterogeneous cold ion environment, permeated by the solar wind. The solar wind was deflected due to the mass loading from newly added cometary plasma, with no discernible slowing down. The magnetic field magnitude increased significantly above the background level, and strong low frequency waves were observed in the magnetic field, a.k.a. the "singing comet". Electron temperatures were high, leading to a frequently strongly negative spacecraft potential. In mid to late April 2015 the solar wind started to disappear from the observation region. This was associated with a solar wind deflection reaching nearly 180°, indicating that mass loading became efficient enough to form a solar wind-free region. Accelerated water ions, moving mainly in the anti-sunward direction, kept being observed also after the solar wind disappearance. Plasma boundaries began to form and a collisionopause was tentatively identified in the ion and electron data. At the time around perihelion, a diamagnetic cavity was also observed, at a surprisingly large distance from the comet. In late 2016 the solar wind re-appeared at the location of Rosetta, allowing for studies of asymmetry of the comet ion environment with respect to perihelion. A nightside excursion allowed us to get a glimpse of the electrodynamics of the innermost part of the plasma tail. Most of these phenomena are dependent on the small-scale physics of comet 67P, since for most of the Rosetta mission the solar wind

  16. Damage assessment of small-scale wind turbine blade using piezoelectric sensors

    NASA Astrophysics Data System (ADS)

    Rim, Mi-Sun; Kim, Sang-Woo; Kim, Eun-Ho; Lee, In

    2012-04-01

    Real-time structural health monitoring (SHM) systems are applied many fields. Recently, the interest about wind energy was increased by the demand of clean energy in the world and many researches were actively performed for applying SHM technology to wind turbine systems. Piezoelectric sensor is one kind of sensor which is widely used for SHM system to assess damage creation. In this paper, the small scale wind turbine blade was fabricated and health monitoring of the blade was performed using the piezoelectric sensor. The quasi-static bending test of the blade was carried out and the PVDF (Polyvinylidene fluoride) sensors, which are polymer type piezoelectric materials, were used for health monitoring. Two-cycle test was performed; the load was applied during 350 sec and removed at the first cycle, and load was applied again until the blade was broken completely at the second cycle. The voltage of PVDF sensors were measured during the quasi-static bending test in order to find out the moment when the damage occurrence started. The voltage of the sensor critically changed at the moment of damage occurred.

  17. Work done by the Wind on the Geostrophic Ocean Circulation: The Effect of Small Scales in the QuikSCAT Wind Stress Data.

    NASA Astrophysics Data System (ADS)

    Hughes, C. W.; Wilson, C.

    2007-12-01

    It has recently been noted that the effect of ocean currents on wind stress is visible in data from the QuickSCAT scatterometer. Duhaut and Straub suggested that this effect could have a significant impact on the work done on geostrophic currents by winds, reducing it by of order 20% in comparison to estimates which do not account for the effect of currents on wind stress. We calculate the work done, using a combination of wind stress (including the current effect) from scatterometer data, and currents from altimetry, drifter, and satellite gravity data. We find a global total of 0.76 TW, smaller than previous estimates, together with an estimate that the effect of currents should produce a reduction of 0.19 TW. This means that, if the data we are using are sufficiently well-sampled to resolve the correlations responsible for the current effect, calculations which do not account for the current effect would produce an estimate of 0.95 TW, a number which lies within the range of previous estimates. We test whether the sampling is sufficient by calculating the power based on a spatially smoothed version of the wind stress, which removes the effect of small-scale currents. This power is larger to approximately the expected degree in midlatitude regions, but not in the tropics, where something more complicated appears to be happening. The contribution of time-dependent terms to the average power produces a similar effect in regions dominated by mesoscale eddies.

  18. Transient flows of the solar wind associated with small-scale solar activity in solar minimum

    NASA Astrophysics Data System (ADS)

    Slemzin, Vladimir; Veselovsky, Igor; Kuzin, Sergey; Gburek, Szymon; Ulyanov, Artyom; Kirichenko, Alexey; Shugay, Yulia; Goryaev, Farid

    The data obtained by the modern high sensitive EUV-XUV telescopes and photometers such as CORONAS-Photon/TESIS and SPHINX, STEREO/EUVI, PROBA2/SWAP, SDO/AIA provide good possibilities for studying small-scale solar activity (SSA), which is supposed to play an important role in heating of the corona and producing transient flows of the solar wind. During the recent unusually weak solar minimum, a large number of SSA events, such as week solar flares, small CMEs and CME-like flows were observed and recorded in the databases of flares (STEREO, SWAP, SPHINX) and CMEs (LASCO, CACTUS). On the other hand, the solar wind data obtained in this period by ACE, Wind, STEREO contain signatures of transient ICME-like structures which have shorter duration (<10h), weaker magnetic field strength (<10 nT) and lower proton temperature than usual ICMEs. To verify the assumption that ICME-like transients may be associated with the SSA events we investigated the number of weak flares of C-class and lower detected by SPHINX in 2009 and STEREO/EUVI in 2010. The flares were classified on temperature and emission measure using the diagnostic means of SPHINX and Hinode/EIS and were confronted with the parameters of the solar wind (velocity, density, ion composition and temperature, magnetic field, pitch angle distribution of the suprathermal electrons). The outflows of plasma associated with the flares were identified by their coronal signatures - CMEs (only in few cases) and dimmings. It was found that the mean parameters of the solar wind projected to the source surface for the times of the studied flares were typical for the ICME-like transients. The results support the suggestion that weak flares can be indicators of sources of transient plasma flows contributing to the slow solar wind at solar minimum, although these flows may be too weak to be considered as separate CMEs and ICMEs. The research leading to these results has received funding from the European Union’s Seventh Programme

  19. Small Scale Electrical Power Generation from Heat Co-Produced in Geothermal Fluids: Mining Operation

    SciTech Connect

    Clark, Thomas M.; Erlach, Celeste

    2014-12-30

    Demonstrate the technical and economic feasibility of small scale power generation from low temperature co-produced fluids. Phase I is to Develop, Design and Test an economically feasible low temperature ORC solution to generate power from lower temperature co-produced geothermal fluids. Phase II &III are to fabricate, test and site a fully operational demonstrator unit on a gold mine working site and operate, remotely monitor and collect data per the DOE recommended data package for one year.

  20. A medium-power small-scale slotted CO2 waveguide laser with HF excitation

    NASA Astrophysics Data System (ADS)

    Vitruk, P. P.; Iatsenko, N. A.

    1989-03-01

    Experimental results are reported on the high-frequency capacitive discharge (HFCD) regime of a medium-power small-scale slotted waveguide CO2 laser. An output power of 100-200 W at an electrooptical efficiency of 5-6 percent was obtained using a CO2:N2:He = 1:1:3 mixture at a pressure of 8-12 torr at a low gas flowrate (0.2 liter/min).

  1. Achieving Full Dynamic Similarity with Small-Scale Wind Turbine Models

    NASA Astrophysics Data System (ADS)

    Miller, Mark; Kiefer, Janik; Westergaard, Carsten; Hultmark, Marcus

    2016-11-01

    Power and thrust data as a function of Reynolds number and Tip Speed Ratio are presented at conditions matching those of a full scale turbine. Such data has traditionally been very difficult to acquire due to the large length-scales of wind turbines, and the limited size of conventional wind tunnels. Ongoing work at Princeton University employs a novel, high-pressure wind tunnel (up to 220 atmospheres of static pressure) which uses air as the working fluid. This facility allows adjustment of the Reynolds number (via the fluid density) independent of the Tip Speed Ratio, up to a Reynolds number (based on chord and velocity at the tip) of over 3 million. Achieving dynamic similarity using this approach implies very high power and thrust loading, which results in mechanical loads greater than 200 times those experienced by a similarly sized model in a conventional wind tunnel. In order to accurately report the power coefficients, a series of tests were carried out on a specially designed model turbine drive-train using an external testing bench to replicate tunnel loading. An accurate map of the drive-train performance at various operating conditions was determined. Finally, subsequent corrections to the power coefficient are discussed in detail. Supported by: National Science Foundation Grant CBET-1435254 (program director Gregory Rorrer).

  2. Coronal hole boundaries evolution at small scales. II. XRT view. Can small-scale outflows at CHBs be a source of the slow solar wind

    NASA Astrophysics Data System (ADS)

    Subramanian, S.; Madjarska, M. S.; Doyle, J. G.

    2010-06-01

    Aims: We aim to further explore the small-scale evolution of coronal hole boundaries using X-ray high-resolution and high-cadence images. We intend to determine the fine structure and dynamics of the events causing changes of coronal hole boundaries and to explore the possibility that these events are the source of the slow solar wind. Methods: We developed an automated procedure for the identification of transient brightenings in images from the X-ray telescope on-board Hinode taken with an Al Poly filter in the equatorial coronal holes, polar coronal holes, and the quiet Sun with and without transient coronal holes. Results: We found that in comparison to the quiet Sun, the boundaries of coronal holes are abundant with brightening events including areas inside the coronal holes where closed magnetic field structures are present. The visual analysis of these brightenings revealed that around 70% of them in equatorial, polar and transient coronal holes and their boundaries show expanding loop structures and/or collimated outflows. In the quiet Sun only 30% of the brightenings show flows with most of them appearing to be contained in the solar corona by closed magnetic field lines. This strongly suggests that magnetic reconnection of co-spatial open and closed magnetic field lines creates the necessary conditions for plasma outflows to large distances. The ejected plasma always originates from pre-existing or newly emerging (at X-ray temperatures) bright points. Conclusions: The present study confirms our findings that the evolution of loop structures known as coronal bright points is associated with the small-scale changes of coronal hole boundaries. The loop structures show an expansion and eruption with the trapped plasma consequently escaping along the “quasi” open magnetic field lines. These ejections appear to be triggered by magnetic reconnection, e.g. the so-called interchange reconnection between the closed magnetic field lines (BPs) and the open

  3. Small scale aspects of warm dark matter: Power spectra and acoustic oscillations

    SciTech Connect

    Boyanovsky, Daniel; Wu Jun

    2011-02-15

    We provide a semianalytic derivation of approximate evolution equations for density perturbations of warm dark matter candidates that decoupled while relativistic with arbitrary distribution functions, their solutions at small scales, and a simple numerical implementation that yields their transfer functions and power spectra. Density perturbations evolve through three stages: radiation domination when the particle is relativistic and nonrelativistic and matter domination. An early integrated Sachs-Wolfe effect during the first stage leads to an enhancement of density perturbations and a plateau in the transfer function for k < or approx. k{sub fs}, the free-streaming wave vector. An effective fluid description emerges at small scales which includes the effects of free streaming in initial conditions and inhomogeneities. The transfer function features warm dark matter acoustic oscillations at scales k > or approx. 2k{sub fs}. A simple analytic interpolation of the power spectra between large and small scales and a numerical implementation valid for arbitrary distribution functions is provided. As an application we study the power spectra for two models of sterile neutrinos with m{approx}keV produced nonresonantly and compare our results to those obtained from Boltzmann codes.

  4. Wind Power

    NASA Image and Video Library

    2010-01-26

    This image of an area south of Olympus Mons shows a region where the wind has been an active agent in modifying the surface. Small linear dunes cover the surface in this image taken by NASA 2001 Mars Odyssey spacecraft.

  5. Legal obstacles and incentives to the development of small scale hydroelectric power in Kentucky

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level are examined. The introductory section examines the dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and concludes with an inquiry into the practical use of the doctrine by the FERC. Additional sections cover acquisition; liability; Department for Natural Resources and Environmental Protection; energy utilities; local regulations; incidental impacts; financial considerations; and sources of information. In Kentucky, many of the impacts have not been implemented with regard to small-scale hydroelectric energy, since in Kentucky most electricity is coal-generated and any hydroelectric power that does exist, is derived from TVA or the Army Corp of Engineer projects.

  6. Electricity's future: the shift to efficiency and small-scale power

    SciTech Connect

    Flavin, C.

    1984-01-01

    Because most countries have rigid, centralized utility systems, small-scale power generation has barely caught on outside the US. In many countries a single state utility or a few large private utilities have exclusive rights to generate power, and these bureaucracies have concentrated on large power plants. But rapid advances under way in a wide range of small-scale generating technologies may soon encourage changes worldwide. Research programs are widespread, and international developments are closely followed. Improved energy efficiency and load management should also be considered as alternatives to building new power plants. In most regions of the world inefficient appliances can be replaced, houses weatherized, and industrial equipment upgraded for a fraction of the cost of building a new generating plant. Efficiency can be promoted many ways, but some of the best include utility-sponsored information and financing programs, with a return allowed on the investment, just as a new power plant would receive. Electricity prices can be adjusted to encourage less power use at peak periods, thus avoiding the need to build additional plants. Many utilities have recently adopted efficiency programs at the insistence of government regulators, but most are just token efforts. 101 references.

  7. Small scale noise and wind tunnel tests of upper surface blowing nozzle flap concepts. Volume 1. Aerodynamic test results

    NASA Technical Reports Server (NTRS)

    Renselaer, D. J.; Nishida, R. S.; Wilkin, C. A.

    1975-01-01

    The results and analyses of aerodynamic and acoustic studies conducted on the small scale noise and wind tunnel tests of upper surface blowing nozzle flap concepts are presented. Various types of nozzle flap concepts were tested. These are an upper surface blowing concept with a multiple slot arrangement with seven slots (seven slotted nozzle), an upper surface blowing type with a large nozzle exit at approximately mid-chord location in conjunction with a powered trailing edge flap with multiple slots (split flow or partially slotted nozzle). In addition, aerodynamic tests were continued on a similar multi-slotted nozzle flap, but with 14 slots. All three types of nozzle flap concepts tested appear to be about equal in overall aerodynamic performance but with the split flow nozzle somewhat better than the other two nozzle flaps in the landing approach mode. All nozzle flaps can be deflected to a large angle to increase drag without significant loss in lift. The nozzle flap concepts appear to be viable aerodynamic drag modulation devices for landing.

  8. Legal obstacles and incentives to the development of small scale hydroelectric power in New Jersey

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level in New Jersey are described. The Federal government also exercises extensive regulatory authority in the area. The dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and an inquiry into the practical use of the doctrine by the FERC is discussed. New Jersey follows the riparian theory of water law. Following an extensive discussion of the New Jersey water law, New Jersey regulatory law and financial considerations regarding hydroelectric power development are discussed.

  9. SMALL-SCALE SOLAR WIND TURBULENCE DUE TO NONLINEAR ALFVÉN WAVES

    SciTech Connect

    Kumar, Sanjay; Moon, Y.-J.; Sharma, R. P.

    2015-10-10

    We present an evolution of wave localization and magnetic power spectra in solar wind plasma using kinetic Alfvén waves (AWs) and fast AWs. We use a two-fluid model to derive the dynamical equations of these wave modes and then numerically solve these nonlinear dynamical equations to analyze the power spectra and wave localization at different times. The ponderomotive force associated with the kinetic AW (or pump) is responsible for the wave localization, and these thin slabs (or sheets) become more chaotic as the system evolves with time until the modulational instability (or oscillating two-stream instability) saturates. From our numerical results, we notice a steepening of the spectra from the inertial range (k{sup −1.67}) to the dispersion range (k{sup −3.0}). The steepening of the spectra could be described as the energy transference from longer to smaller scales. The formation of complex magnetic thin slabs and the change of the spectral index may be considered to be the main reason for the charged particles acceleration in solar wind plasma.

  10. Small scale solar wind turbulence due to nonlinear Alfvén waves

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Sharma, R. P.; Moon, Y. J.

    2015-12-01

    In the work presented here, we study the evolution of wave localization and magnetic power spectrum using kinetic Alfven wave (AW) and fast AW in the solar wind plasma. We derived the dynamical equations for these wave modes using two-fluid model and then solved numerically to analyze power spectra as well as wave localization at different instants of time. The ponderomotive force associated with the pump is responsible for the wave localization and these localized structures become more chaotic as the system evolves with time until the modulational instability (or oscillating two-stream instability) mentioned here, saturates. We observe steepening of the spectra as we go from inertial range to the dispersion range i.e. nearly k-1.67 to k-3.0. The steepening of spectra may be described as the transfer of energy from longer scale to the smaller scale. The formation of complex magnetic filaments and change in the spectral index may be responsible for the charged particles acceleration in the solar wind plasma.

  11. SMALL-SCALE PRESSURE-BALANCED STRUCTURES DRIVEN BY OBLIQUE SLOW MODE WAVES MEASURED IN THE SOLAR WIND

    SciTech Connect

    Yao Shuo; He, J.-S.; Tu, C.-Y.; Wang, L.-H.; Marsch, E.

    2013-09-01

    Recently, small-scale pressure-balanced structures (PBSs) were identified in the solar wind, but their formation mechanism remains unclear. This work aims to reveal the dependence of the properties of small-scale PBSs on the background magnetic field (B{sub 0}) direction and thus to corroborate the in situ mechanism that forms them. We analyze the plasma and magnetic field data obtained by WIND in the quiet solar wind at 1 AU. First, we use a developed moving-average method to obtain B{sub 0}(s, t) for every temporal scale (s) at each time moment (t). By wavelet cross-coherence analysis, we obtain the correlation coefficients between the thermal pressure P{sub th} and the magnetic pressure P{sub B}, distributing against the temporal scale and the angle {theta}{sub xB} between B{sub 0}(s, t) and Geocentric Solar Ecliptic coordinates (GSE)-x. We note that the angle coverage of a PBS decreases with shorter temporal scale, but the occurrence of the PBSs is independent of {theta}{sub xB}. Suspecting that the isolated small PBSs are formed by compressive waves in situ, we continue this study by testing the wave modes forming a small-scale PBS with B{sub 0}(s, t) quasi-parallel to GSE-x. As a result, we identify that the cross-helicity and the compressibility attain values for a slow mode from theoretical calculations. The wave vector is derived from minimum variance analysis. Besides, the proton temperatures obey T < T{sub Parallel-To} derived from the velocity distribution functions, excluding a mirror mode, which is the other candidate for the formation of PBSs in situ. Thus, a small-scale PBS is shown to be driven by oblique, slow-mode waves in the solar wind.

  12. Wind work on the geostrophic ocean circulation: An observational study of the effect of small scales in the wind stress

    NASA Astrophysics Data System (ADS)

    Hughes, Chris W.; Wilson, Chris

    2008-02-01

    We use QuikSCAT scatterometer data, together with geostrophic surface currents calculated from a combination of satellite altimetry, gravity and drifter data, to investigate the rate of work done on the geostrophic circulation by wind stress. In particular, we test the suggestion that accounting for ocean currents in the calculation of stress from 10 m winds can result in a reduction of 20-35% in the wind work, compared with an approximate calculation in which currents are not accounted for. We calculate the predicted effect of accounting for ocean currents to be a reduction in power of about 0.19 TW, and find a total power input from observations which include this effect to be 0.76 TW, smaller than earlier estimates by about the right amount. By recalculating the power input using smoothed wind stresses or currents, we demonstrate that the effect of ocean currents is visible in the midlatitude data, and close to the predicted value. Proof that the data are adequate to resolve the effect in the tropics, however, is lacking, suggesting that additional processes may also be important in this region.

  13. Wind Power Now!

    ERIC Educational Resources Information Center

    Inglis, David Rittenhouse

    1975-01-01

    The government promotes and heavily subsidizes research in nuclear power plants. Federal development of wind power is slow in comparison even though much research with large wind-electric machines has already been conducted. Unless wind power programs are accelerated it will not become a major energy alternative to nuclear power. (MR)

  14. Wind Power Now!

    ERIC Educational Resources Information Center

    Inglis, David Rittenhouse

    1975-01-01

    The government promotes and heavily subsidizes research in nuclear power plants. Federal development of wind power is slow in comparison even though much research with large wind-electric machines has already been conducted. Unless wind power programs are accelerated it will not become a major energy alternative to nuclear power. (MR)

  15. Validation of a power-law noise model for simulating small-scale breast tissue

    NASA Astrophysics Data System (ADS)

    Reiser, I.; Edwards, A.; Nishikawa, R. M.

    2013-09-01

    We have validated a small-scale breast tissue model based on power-law noise. A set of 110 patient images served as truth. The statistical model parameters were determined by matching the radially averaged power-spectrum of the projected simulated tissue with that of the central tomosynthesis patient breast projections. Observer performance in a signal-known exactly detection task in simulated and actual breast backgrounds was compared. Observers included human readers, a pre-whitening observer model and a channelized Hotelling observer model. For all observers, good agreement between performance in the simulated and actual backgrounds was found, both in the tomosynthesis central projections and the reconstructed images. This tissue model can be used for breast x-ray imaging system optimization. The complete statistical description of the model is provided.

  16. Validation of a power-law noise model for simulating small-scale breast tissue

    PubMed Central

    Reiser, I.; Edwards, A.; Nishikawa, R. M.

    2013-01-01

    We have validated a small-scale breast tissue model based on power-law noise. A set of 110 patient images served as truth. The statistical model parameters were determined by matching the radially-averaged power-spectrum of the projected simulated tissue with that of the central tomosynthesis patient breast projections. Observer performance in a signal-known exactly detection task in simulated and actual breast backgrounds was compared. Observers included human readers, a pre-whitening observer model and a channelized Hotelling observer model. For all observers, good agreement between performance in the simulated and actual backgrounds was found, both in the tomosynthesis central projections and the reconstructed images. This tissue model can be used for breast x-ray imaging system optimization. The complete statistical description of the model is provided. PMID:23938858

  17. Legal obstacles and incentives to the development of small scale hydroelectric power in West Virginia

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric in West Virginia at the state level are described. The Federal government also exercises extensive regulatory authority in the area. The introductory section examines the dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and concludes with an inquiry into the practical use of the doctrine by FERC. The development of small-scale hydroelectric energy depends on the selection of a site which will produce sufficient water power capacity to make the project economically attractive to a developer. In West Virginia, the right to use the flowing waters of a stream, creek, or river is appurtenant to the ownership of the lands bordering the watercourse. The lands are known as riparian lands. The water rights are known as riparian rights. Thus, the first obstacle a developer faces involves the acquisition of riparian lands and the subsequent right to the use of the water. The water law in West Virginia is discussed in detail followed by discussions on direct and indirect regulations; continuing obligations; financial considerations; and interstate organizations.

  18. Legal obstacles and incentives to the development of small scale hydroelectric power in New York

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level are discussed. The Federal government also exercises extensive regulatory authority in the area, and the dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and an inquiry into the practical use of the doctrine by the FERC is examined. The first step the small scale hydroelectric developer must take is that of acquiring title to the real property comprising the development site. The real estate parcel must include the requisite interest in the land adjacent to the watercourse, access to the underlying streambed and where needed, the land necessary for an upstream impoundment area. Land acquisition may be effectuated by purchase, lease, or grant by the state. In addition to these methods, New York permits the use of the eminent domain power of the state for public utilities under certain circumstances.

  19. An investigation of rotor harmonic noise by the use of small scale wind tunnel models

    NASA Technical Reports Server (NTRS)

    Sternfeld, H., Jr.; Schaffer, E. G.

    1982-01-01

    Noise measurements of small scale helicopter rotor models were compared with noise measurements of full scale helicopters to determine what information about the full scale helicopters could be derived from noise measurements of small scale helicopter models. Comparisons were made of the discrete frequency (rotational) noise for 4 pairs of tests. Areas covered were tip speed effects, isolated rotor, tandem rotor, and main rotor/tail rotor interaction. Results show good comparison of noise trends with configuration and test condition changes, and good comparison of absolute noise measurements with the corrections used except for the isolated rotor case. Noise measurements of the isolated rotor show a great deal of scatter reflecting the fact that the rotor in hover is basically unstable.

  20. Customer adoption of small-scale on-site power generation

    SciTech Connect

    Siddiqui, Afzal S.; Marnay, Chris; Hamachi, Kristina S.; Rubio, F. Javier

    2001-04-01

    The electricity supply system is undergoing major regulatory and technological change with significant implications for the way in which the sector will operate (including its patterns of carbon emissions) and for the policies required to ensure socially and environmentally desirable outcomes. One such change stems from the rapid emergence of viable small-scale (i.e., smaller than 500 kW) generators that are potentially competitive with grid delivered electricity, especially in combined heat and power configurations. Such distributed energy resources (DER) may be grouped together with loads in microgrids. These clusters could operate semi-autonomously from the established power system, or macrogrid, matching power quality and reliability more closely to local end-use requirements. In order to establish a capability for analyzing the effect that microgrids may have on typical commercial customers, such as office buildings, restaurants, shopping malls, and grocery stores, an economic mod el of DER adoption is being developed at Berkeley Lab. This model endeavors to indicate the optimal quantity and type of small on-site generation technologies that customers could employ given their electricity requirements. For various regulatory schemes and general economic conditions, this analysis produces a simple operating schedule for any installed generators. Early results suggest that many commercial customers can benefit economically from on-site generation, even without considering potential combined heat and power and reliability benefits, even though they are unlikely to disconnect from the established power system.

  1. Performance and aerodynamic braking of a horizontal-axis wind turbine from small-scale wind tunnel tests

    SciTech Connect

    Cao, H.V.; Wentz, W.H. Jr.

    1987-07-01

    Wind tunnel tests of three 20-inch diameter, zero-twist, zero-pitch wind turbine rotor models have been conducted in the WSU 7' x 10' wind tunnel to determine the performance of such rotors with NACA 23024 and NACA 64/sub 3/-621 airfoil sections. Aerodynamic braking characteristics of a 38 percent span, 30 percent chord, vented aileron configuration were measured on the NACA 23024 rotor. Surface flow patterns were observed using fluorescent mini-tufts attached to the suction side of the rotor blades. Experimental results with and without ailerons are compared to predictions using airfoil section data and a momentum performance code. Results of the performance studies show that the 64/sub 3/-621 rotor produces higher peak power than the 23024 rotor for a given rotor speed. Analytical studies, however, indicate that the 23024 should produce higher power. Transition strip experiments show that the 23024 rotor is much more sensitive to roughness than the 64/sub 3/-621 rotor. These trends agree with analytical predictions. Results of the aileron tests show that this aileron, when deflected, produces a braking torque at all tip-speed ratios. In free-wheeling coastdowns the rotor blade stopped, then rotated backward at a tip-speed ratio of -0.6. Results of the tuft studies indicate that substantial spanwise flow develops as blade stall occurs at low tip-speed ratios.

  2. Performance and aerodynamic braking of a horizontal-axis wind turbine from small-scale wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Cao, H. V.; Wentz, W. H., Jr.

    1987-01-01

    Wind tunnel tests of three 20" diameter, zero twist, zero pitch wind turbine rotor models were conducted in a 7' x 10' wind tunnel to determine the performance of such rotors with NACA 23024 and NACA 64 sub 3-621 airfoil sections. Aerodynamic braking characteristics of a 38% span, 30% chord, vented aileron configuration were measured on the NACA 23024 rotor. Surface flow patterns were observed using fluorescent mini-tufts attached to the suction side of the rotor blades. Experimental results with and without ailerons are compared to predictions using airfoil section data and a momentum performance code. Results of the performance studies show that the 64 sub 3-621 rotor produces higher peak power than the 23024 rotor for a given rotor speed. Analytical studies, however, indicate that the 23024 should produce higher power. Transition strip experiments show that the 23024 rotor is much more sensitive to roughness than the 64 sub 3-621 rotor. These trends agree with analytical predictions. Results of the aileron test show that this aileron, when deflected, produces a braking torque at all tip speed ratios. In free wheeling coastdowns the rotor blade stopped, then rotated backward at a tip speed ratio of -0.6.

  3. Wind power soars

    SciTech Connect

    Flavin, C.

    1996-12-31

    Opinions on the world market for wind power are presented in this paper. Some data for global wind power generating capacity are provided. European and other markets are discussed individually. Estimated potential for wind power is given for a number of countries. 3 figs.

  4. Legal obstacles and incentives to the development of small scale hydroelectric power in Connecticut

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric power in Connecticut are discussed. The Federal government also exercises extensive regulatory authority in the area and this dual system is examined from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and an inquiry into the practical use of the doctrine by the FERC. Connecticut follows the riparian theory of water law. Under this theory of the water law, private rights in rivers and streams are confined to the use of flowing water. A riparian proprietor does not own the water that flows by his estate. Licensing, permitting, and review procedures are discussed followed by discussion on public utilities regulation and indirect considerations.

  5. Legal obstacles and incentives to the development of small scale hydroelectric power in Ohio

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level is described. The Federal government also exercises extensive regulatory authority in the area. The introductory section examines the regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and concludes with an inquiry into the practical use of the doctrine by the FERC. A developer must obtain title or interest to a streambed from the proper riparian owners. Ohio provides assistance to an electric company in this undertaking by providing it with the power of eminent domain in the event it is unable to reach a purchase agreement with the riparian proprietors. The Ohio Water Law is discussed in detail, followed by discussions: Licensing, Permitting, and Review Procedures; Indirect Considerations; Ohio Public Utilities Commission; Ohio Department of Energy; Incidental Provision; and Financial Considerations.

  6. A study of large scale gust generation in a small scale atmospheric wind tunnel with applications to Micro Aerial Vehicles

    NASA Astrophysics Data System (ADS)

    Roadman, Jason Markos

    Modern technology operating in the atmospheric boundary layer can always benefit from more accurate wind tunnel testing. While scaled atmospheric boundary layer tunnels have been well developed, tunnels replicating portions of the atmospheric boundary layer turbulence at full scale are a comparatively new concept. Testing at full-scale Reynolds numbers with full-scale turbulence in an "atmospheric wind tunnel" is sought. Many programs could utilize such a tool including Micro Aerial Vehicle(MAV) development, the wind energy industry, fuel efficient vehicle design, and the study of bird and insect flight, to name just a few. The small scale of MAVs provide the somewhat unique capability of full scale Reynolds number testing in a wind tunnel. However, that same small scale creates interactions under real world flight conditions, atmospheric gusts for example, that lead to a need for testing under more complex flows than the standard uniform flow found in most wind tunnels. It is for these reasons that MAVs are used as the initial testing application for the atmospheric gust tunnel. An analytical model for both discrete gusts and a continuous spectrum of gusts is examined. Then, methods for generating gusts in agreement with that model are investigated. Previously used methods are reviewed and a gust generation apparatus is designed. Expected turbulence and gust characteristics of this apparatus are compared with atmospheric data. The construction of an active "gust generator" for a new atmospheric tunnel is reviewed and the turbulence it generates is measured utilizing single and cross hot wires. Results from this grid are compared to atmospheric turbulence and it is shown that various gust strengths can be produced corresponding to weather ranging from calm to quite gusty. An initial test is performed in the atmospheric wind tunnel whereby the effects of various turbulence conditions on transition and separation on the upper surface of a MAV wing is investigated

  7. Inflation that runs naturally: Gravitational waves and suppression of power at large and small scales

    NASA Astrophysics Data System (ADS)

    Minor, Quinn E.; Kaplinghat, Manoj

    2015-03-01

    We point out three correlated predictions of the axion monodromy inflation model: the large amplitude of gravitational waves, the suppression of power on horizon scales and on scales relevant for the formation of dwarf galaxies. While these predictions are likely generic to models with oscillations in the inflaton potential, the axion monodromy model naturally accommodates the required running spectral index through Planck-scale corrections to the inflaton potential. Applying this model to a combined data set of Planck, ACT, SPT, and WMAP low-ℓ polarization cosmic microwave background (CMB) data, we find a best-fit tensor-to-scalar ratio r0.05=0.07-0.04+0.05 due to gravitational waves, which may have been observed by the BICEP2 experiment. Despite the contribution of gravitational waves, the total power on large scales (CMB power spectrum at low multipoles) is lower than the standard Λ CDM cosmology with a power-law spectrum of initial perturbations and no gravitational waves, thus mitigating some of the tension on large scales. There is also a reduction in the matter power spectrum of 20-30% at scales corresponding to k =10 Mpc-1 , which are relevant for dwarf galaxy formation. This will alleviate some of the unsolved small-scale structure problems in the standard Λ CDM cosmology. The inferred matter power spectrum is also found to be consistent with recent Lyman-α forest data, which is in tension with the Planck-favored Λ CDM model with a power-law primordial power spectrum.

  8. Power spectrum of small-scale density irregularities in the interstellar medium

    NASA Technical Reports Server (NTRS)

    Armstrong, J. W.; Rickett, B. J.

    1981-01-01

    Observations of the interstellar scintillation of radiation from 17 pulsars are reported which are used to place limits on the power spectrum of small-scale electron density irregularities in the interstellar medium. Measurements made at 340, 408, and 450 MHz in the dispersion measure range 3-57/cu cm pc of the time-dependent radio frequency spectrum of interstellar scintillations were analyzed to determine the scintillation index and a scintillation frequency-correlation scale based on the autocorrelation function in radio frequency of the fluctuations in scintillation. The dispersion-measure dependence of the scintillation frequency correlation scale is found to be consistent with both Gaussian model interstellar medium spectra and power-law spectra with indices between 3.0 and 4, while the radio-frequency scaling of the frequency correlation scale is consistent with power law indices between 2.8 and 3.9. However comparison of the shape of the radio-frequency autocorrelation function with model calculations indicates power law models with indices greater than 3.6 are possible. Data are also consistent with a local three-dimensional density spectrum at a wave number of 10 to the -9th/m of 3 x 10 to the 28th to 3 x 10 to the 29th/cu m.

  9. Small scale wind tunnel model investigation of hybrid high lift systems combining upper surface blowing with the internally blown flap

    NASA Technical Reports Server (NTRS)

    Waites, W. L.; Chin, Y. T.

    1974-01-01

    A small-scale wind tunnel test of a two engine hybrid model with upper surface blowing on a simulated expandable duct internally blown flap was accomplished in a two phase program. The low wing Phase I model utilized 0.126c radius Jacobs/Hurkamp flaps and 0.337c radius Coanda flaps. The high wing Phase II model was utilized for continued studies on the Jacobs/Hurkamp flap. Principal study areas included: basic data both engines operative and with an engine out, control flap utilization, horizontal tail effectiveness, spoiler effectiveness, USB nacelle deflector study and USB/IBF pressure ratio effects.

  10. RAPID COMMUNICATION: Novel high performance small-scale thermoelectric power generation employing regenerative combustion systems

    NASA Astrophysics Data System (ADS)

    Weinberg, F. J.; Rowe, D. M.; Min, G.

    2002-07-01

    Hydrocarbon fuels have specific energy contents some two orders of magnitude greater than any electrical storage device. They therefore proffer an ideal source in the universal quest for compact, lightweight, long-lasting alternatives for batteries to power the ever-proliferating electronic devices. The motivation lies in the need to power, for example, equipment for infantry troops, for weather stations and buoys in polar regions which need to signal their readings intermittently to passing satellites, unattended over long periods, and many others. Fuel cells, converters based on miniaturized gas turbines, and other systems under intensive study, give rise to diverse practical difficulties. Thermoelectric devices are robust, durable and have no moving parts, but tend to be exceedingly inefficient. We propose regenerative combustion systems which mitigate this impediment and are likely to make high performance small-scale thermoelectric power generation applicable in practice. The efficiency of a thermoelectric generating system using preheat when operated between ambient and 1200 K is calculated to exceed the efficiency of the best present day thermoelectric conversion system by more than 20%.

  11. Wind power. [electricity generation

    NASA Technical Reports Server (NTRS)

    Savino, J. M.

    1975-01-01

    A historical background on windmill use, the nature of wind, wind conversion system technology and requirements, the economics of wind power and comparisons with alternative systems, data needs, technology development needs, and an implementation plan for wind energy are presented. Considerable progress took place during the 1950's. Most of the modern windmills feature a wind turbine electricity generator located directly at the top of their rotor towers.

  12. Wind power. [electricity generation

    NASA Technical Reports Server (NTRS)

    Savino, J. M.

    1975-01-01

    A historical background on windmill use, the nature of wind, wind conversion system technology and requirements, the economics of wind power and comparisons with alternative systems, data needs, technology development needs, and an implementation plan for wind energy are presented. Considerable progress took place during the 1950's. Most of the modern windmills feature a wind turbine electricity generator located directly at the top of their rotor towers.

  13. Wind Power Outlook 2004

    SciTech Connect

    anon.

    2004-01-01

    The brochure, expected to be updated annually, provides the American Wind Energy Association's (AWAE's) up-to-date assessment of the wind industry. It provides a summary of the state of wind power in the U.S., including the challenges and opportunities facing the industry. It provides summary information on the growth of the industry, policy-related factors such as the federal wind energy production tax credit status, comparisons with natural gas, and public views on wind energy.

  14. Wind power today

    SciTech Connect

    1998-04-01

    This publication highlights initiatives of the US DOE`s Wind Energy Program. 1997 yearly activities are also very briefly summarized. The first article describes a 6-megawatt wind power plant installed in Vermont. Another article summarizes technical advances in wind turbine technology, and describes next-generation utility and small wind turbines in the planning stages. A village power project in Alaska using three 50-kilowatt turbines is described. Very brief summaries of the Federal Wind Energy Program and the National Wind Technology Center are also included in the publication.

  15. Full Particle-In-Cell simulations on the solar wind interactions with a small-scale magnetic dipole

    NASA Astrophysics Data System (ADS)

    Usui, Hideyuki; Moritaka, Toseo; Matsumoto, Masaharu; Multi-scale PIC Simulation Team

    2013-04-01

    The Earth's magnetosphere which is caused by global interactions with the solar wind has been intensively investigated both by in-situ observations with satellites and global MHD simulations. Since the size of the Earth's magnetosphere is much larger than the ion inertia length in the solar wind, the formation of the magnetosphere and the associated macroscopic plasma phenomena can be examined in the MHD scale. However, as the magnetic dipole scale becomes comparable or smaller than the ion inertia length, plasma kinetics such as the finite Larmor radius effect and the electron-ion coupling cannot be ignored and will play important roles in the formation of a magnetosphere. In the current study, we have been investigating solar wind interactions with a small-scale magnetic dipole by means of a full particle-in-cell electromagnetic simulation. This study is motivated by one of the next-generation interplanetary flight systems which utilizes the momentum transfer of the solar wind to a spacecraft which creates an artificial small-scale magnetic dipole by a superconducting coil. In the simulation, we focus on a magnetic dipole whose size is less than the ion inertial length in the solar wind. In this situation, electron interaction becomes important in the process of the magnetosphere formation. The simulation result shows that the width of the boundary current layer as well as the spatial gradient of the local magnetic field compression found at the dayside can be characterized by the electron Larmor radius. At the boundary region where the magnetic fields are compressed, electrons basically stagnate and form a high density region while ions' trajectories are little affected because of large Larmor radius. However, owing to the electrostatic force induced by the difference of dynamics between electrons and ions, ions dynamics are also indirectly influenced by the presence of the small magnetosphere. In addition, IMF effect such as the formation of shock structure and

  16. Harvesting wind energy from the sea breeze in peri-urban coastal areas by means of small scale wind turbines - Case study: Viladecans, Llobregat Delta, northeast of Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Rojas, Jose I.; Cabrera, Barbara; Mazon, Jordi

    2016-04-01

    Wind speed data recorded during 18 years (1993-2010) in the Llobregat Delta (15 km south of Barcelona city; northeast of the Iberian Peninsula) were used to assess the wind energy generated by off-grid small scale wind turbines (the IT-PE-100 and the HP-600W) for the whole year and for the sea breeze period. The computations were made using QBlade, FAST and AeroDyn simulation tools and manufacturer power curves. Using manufacturer data, the HP-600W with hub-height 8 m would deliver 157 kWh during the whole year (78 kWh during the sea breeze period), with an average power of 18 W (37 W). In this work, the results of the simulations are compared with power and energy production data measured in an HP-600W turbine installed in situ from December 2014 to April 2016. Also, the measured power is compared to the power obtained by applying the measured wind in the period 2014-2016 to the manufacturer power curve and the power curve obtained with the simulations. The results of the computations agree with the experimental data, thus validating the proposed approach for wind resource estimation. The feasibility of using a vertical axis wind turbine for obtaining wind energy from the local, thermal wind regimes is also studied. This research confirms that the sea-breeze is an interesting wind energy resource for micro-generation in peri-urban coastal areas where large-scale wind farms cannot be implemented.

  17. Villacidro solar demo plant: Integration of small-scale CSP and biogas power plants in an industrial microgrid

    NASA Astrophysics Data System (ADS)

    Camerada, M.; Cau, G.; Cocco, D.; Damiano, A.; Demontis, V.; Melis, T.; Musio, M.

    2016-05-01

    The integration of small scale concentrating solar power (CSP) in an industrial district, in order to develop a microgrid fully supplied by renewable energy sources, is presented in this paper. The plant aims to assess in real operating conditions, the performance, the effectiveness and the reliability of small-scale concentrating solar power technologies in the field of distributed generation. In particular, the potentiality of small scale CSP with thermal storage to supply dispatchable electricity to an industrial microgrid will be investigated. The microgrid will be realized in the municipal waste treatment plant of the Industrial Consortium of Villacidro, in southern Sardinia (Italy), which already includes a biogas power plant. In order to achieve the microgrid instantaneous energy balance, the analysis of the time evolution of the waste treatment plant demand and of the generation in the existing power systems has been carried out. This has allowed the design of a suitable CSP plant with thermal storage and an electrochemical storage system for supporting the proposed microgrid. At the aim of obtaining the expected energy autonomy, a specific Energy Management Strategy, which takes into account the different dynamic performances and characteristics of the demand and the generation, has been designed. In this paper, the configuration of the proposed small scale concentrating solar power (CSP) and of its thermal energy storage, based on thermocline principle, is initially described. Finally, a simulation study of the entire power system, imposing scheduled profiles based on weather forecasts, is presented.

  18. Performance evaluation of an integrated small-scale SOFC-biomass gasification power generation system

    NASA Astrophysics Data System (ADS)

    Wongchanapai, Suranat; Iwai, Hiroshi; Saito, Motohiro; Yoshida, Hideo

    2012-10-01

    The combination of biomass gasification and high-temperature solid oxide fuel cells (SOFCs) offers great potential as a future sustainable power generation system. In order to provide insights into an integrated small-scale SOFC-biomass gasification power generation system, system simulation was performed under diverse operating conditions. A detailed anode-supported planar SOFC model under co-flow operation and a thermodynamic equilibrium for biomass gasification model were developed and verified by reliable experimental and simulation data. The other peripheral components include three gas-to-gas heat exchangers (HXs), heat recovery steam generator (HRSG), burner, fuel and air compressors. To determine safe operating conditions with high system efficiency, energy and exergy analysis was performed to investigate the influence through detailed sensitivity analysis of four key parameters, e.g. steam-to-biomass ratio (STBR), SOFC inlet stream temperatures, fuel utilization factor (Uf) and anode off-gas recycle ratio (AGR) on system performance. Due to the fact that SOFC stack is accounted for the most expensive part of the initial investment cost, the number of cells required for SOFC stack is economically optimized as well. Through the detailed sensitivity analysis, it shows that the increase of STBR positively affects SOFC while gasifier performance drops. The most preferable operating STBR is 1.5 when the highest system efficiencies and the smallest number of cells. The increase in SOFC inlet temperature shows negative impact on system and gasifier performances while SOFC efficiencies are slightly increased. The number of cells required for SOFC is reduced with the increase of SOFC inlet temperature. The system performance is optimized for Uf of 0.75 while SOFC and system efficiencies are the highest with the smallest number of cells. The result also shows the optimal anode off-gas recycle ratio of 0.6. Regarding with the increase of anode off-gas recycle ratio

  19. Homemade Electricity: An Introduction to Small-Scale Wind, Hydro, and Photovoltaic Systems.

    ERIC Educational Resources Information Center

    Smith, Diane

    This report consists of three parts. The first part provides advice (in the form of questions and answers) to prospective individual power producers who are considering investing in electricity-producing systems and in generating their own power. A list of Public Utilities Regulatory Policies Act (PURPA) regulations is included. This legislation…

  20. Wind Power Career Chat

    SciTech Connect

    L. Flowers

    2011-01-01

    This document will teach students about careers in the wind energy industry. Wind energy, both land-based and offshore, is expected to provide thousands of new jobs in the next several decades. Wind energy companies are growing rapidly to meet America's demand for clean, renewable, and domestic energy. These companies need skilled professionals. Wind power careers will require educated people from a variety of areas. Trained and qualified workers manufacture, construct, operate, and manage wind energy facilities. The nation will also need skilled researchers, scientists, and engineers to plan and develop the next generation of wind energy technologies.

  1. Wind powering America: Vermont

    SciTech Connect

    NREL

    2000-04-11

    Wind resources in the state of Vermont show great potential for wind energy development according to the wind resource assessment conducted by the state, its utilities, and NREL. This fact sheet provides a brief description of the resource assessment and a link to the resulting wind resource map produced by NREL. The fact sheet also provides a description of the state's net metering program, its financial incentives, and green power programs as well as a list of contacts for more information.

  2. Wind power generator

    SciTech Connect

    Ross, F.

    1980-08-26

    A wind power generator comprises element opposing the force of the wind pivotally mounted and extending radially from the pivot. A counterweight also mounts to the pivot and extends radially from the same. The wind opposing element also mounts to another pivot between a first and second portion thereof. A second weight aids the turning of the wind opposing element about the first pivot to create a rocking motion of the counterweight.

  3. The Spectrum of Wind Power Fluctuations

    NASA Astrophysics Data System (ADS)

    Bandi, Mahesh

    2016-11-01

    Wind is a variable energy source whose fluctuations threaten electrical grid stability and complicate dynamical load balancing. The power generated by a wind turbine fluctuates due to the variable wind speed that blows past the turbine. Indeed, the spectrum of wind power fluctuations is widely believed to reflect the Kolmogorov spectrum; both vary with frequency f as f - 5 / 3. This variability decreases when aggregate power fluctuations from geographically distributed wind farms are averaged at the grid via a mechanism known as geographic smoothing. Neither the f - 5 / 3 wind power fluctuation spectrum nor the mechanism of geographic smoothing are understood. In this work, we explain the wind power fluctuation spectrum from the turbine through grid scales. The f - 5 / 3 wind power fluctuation spectrum results from the largest length scales of atmospheric turbulence of order 200 km influencing the small scales where individual turbines operate. This long-range influence spatially couples geographically distributed wind farms and synchronizes farm outputs over a range of frequencies and decreases with increasing inter-farm distance. Consequently, aggregate grid-scale power fluctuations remain correlated, and are smoothed until they reach a limiting f - 7 / 3 spectrum. This work was funded by the Collective Interactions Unit, OIST Graduate University, Japan.

  4. Wind power prediction models

    NASA Technical Reports Server (NTRS)

    Levy, R.; Mcginness, H.

    1976-01-01

    Investigations were performed to predict the power available from the wind at the Goldstone, California, antenna site complex. The background for power prediction was derived from a statistical evaluation of available wind speed data records at this location and at nearby locations similarly situated within the Mojave desert. In addition to a model for power prediction over relatively long periods of time, an interim simulation model that produces sample wind speeds is described. The interim model furnishes uncorrelated sample speeds at hourly intervals that reproduce the statistical wind distribution at Goldstone. A stochastic simulation model to provide speed samples representative of both the statistical speed distributions and correlations is also discussed.

  5. Enabling Wind Power Nationwide

    SciTech Connect

    Jose, Zayas; Michael, Derby; Patrick, Gilman; Ananthan, Shreyas; Lantz, Eric; Cotrell, Jason; Beck, Fredic; Tusing, Richard

    2015-05-01

    Leveraging this experience, the U.S. Department of Energy’s (DOE’s) Wind and Water Power Technologies Office has evaluated the potential for wind power to generate electricity in all 50 states. This report analyzes and quantifies the geographic expansion that could be enabled by accessing higher above ground heights for wind turbines and considers the means by which this new potential could be responsibly developed.

  6. Wind structure and small-scale wind variability in the stratosphere and mesosphere during the November 1980 Energy Budget Campaign

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.; Carlson, M.; Rees, D.; Offermann, D.; Philbrick, C. R.; Widdel, H. U.

    1982-01-01

    Rocket observations made from two sites in northern Scandinavia between November 6 and December 1, 1980, as part of the Energy Budget Campaign are discussed. It was found that significant vertical and temporal changes in the wind structure were present and that they coincided with different geomagnetic conditions, that is, quiet and enhanced. Before November 16, the meridional wind component above 60 km was found to be positive (southerly), whereas the magnitude of the zonal wind component increased with altitude. After November 16 the meridional component became negative (northerly), and the magnitude of the zonal wind component was observed to decrease with altitude. Time sections of the perturbations of the zonal wind reveal the presence of vertically propagating waves, suggesting gravity wave activity. The waves are found to increase in wavelength from 3-4 km near 40 km to more than 12 km near 80 km. The observational techniques made use of chaff foil, chemical trails, inflatable spheres, and parachutes.

  7. Wind structure and small-scale wind variability in the stratosphere and mesosphere during the November 1980 Energy Budget Campaign

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.; Carlson, M.; Rees, D.; Offermann, D.; Philbrick, C. R.; Widdel, H. U.

    1982-01-01

    Rocket observations made from two sites in northern Scandinavia between November 6 and December 1, 1980, as part of the Energy Budget Campaign are discussed. It was found that significant vertical and temporal changes in the wind structure were present and that they coincided with different geomagnetic conditions, that is, quiet and enhanced. Before November 16, the meridional wind component above 60 km was found to be positive (southerly), whereas the magnitude of the zonal wind component increased with altitude. After November 16 the meridional component became negative (northerly), and the magnitude of the zonal wind component was observed to decrease with altitude. Time sections of the perturbations of the zonal wind reveal the presence of vertically propagating waves, suggesting gravity wave activity. The waves are found to increase in wavelength from 3-4 km near 40 km to more than 12 km near 80 km. The observational techniques made use of chaff foil, chemical trails, inflatable spheres, and parachutes.

  8. Wind power in Jamaica

    SciTech Connect

    Chen, A.A.; Daniel, A.R.; Daniel, S.T. ); Gray, C.R. )

    1990-01-01

    Parameters to evaluate the potential for using wind energy to generate electricity in Jamaica were obtained. These include the average wind power scaled to a height of 20 m at existing weather stations and temporary anemometer sites, the variation in annual and monthly wind power, and the frequency distribution of wind speed and wind energy available. Four small commercial turbines were assumed to be operating at some of the sites, and the estimated energy captured by them, the time they operated above their cut-in speed and their capacity factors were also determined. Diurnal variations of wind speed and prevailing wind directions are discussed and a map showing wind power at various sites was produced. Two stations with long-term averages, Manley and Morant Point, gave results which warranted further investigation. Results from some temporary stations are also encouraging. Mean wind speeds at two other sites in the Caribbean are given for comparison. A method for estimating the power exponent for scaling the wind speed from climatic data is described in Appendix 2.

  9. Dynamic simulation of a solar-driven carbon dioxide transcritical power system for small scale combined heat and power production

    SciTech Connect

    Chen, Y.; Lundqvist, Per; Pridasawas, Wimolsiri

    2010-07-15

    Carbon dioxide is an environmental benign natural working fluid and has been proposed as a working media for a solar-driven power system. In the current work, the dynamic performance of a small scale solar-driven carbon dioxide power system is analyzed by dynamic simulation tool TRNSYS 16 and Engineering Equation Solver (EES) using co-solving technique. Both daily performance and yearly performance of the proposed system have been simulated. Different system operating parameters, which will influence the system performance, have been discussed. Under the Swedish climatic condition, the maximum daily power production is about 12 kW h and the maximum monthly power production is about 215 kW h with the proposed system working conditions. Besides the power being produced, the system can also produce about 10 times much thermal energy, which can be used for space heating, domestic hot water supply or driving absorption chillers. The simulation results show that the proposed system is a promising and environmental benign alternative for conventional low-grade heat source utilization system. (author)

  10. PROBING THE INFLATON: SMALL-SCALE POWER SPECTRUM CONSTRAINTS FROM MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND ENERGY SPECTRUM

    SciTech Connect

    Chluba, Jens; Erickcek, Adrienne L.; Ben-Dayan, Ido

    2012-10-20

    In the early universe, energy stored in small-scale density perturbations is quickly dissipated by Silk damping, a process that inevitably generates {mu}- and y-type spectral distortions of the cosmic microwave background (CMB). These spectral distortions depend on the shape and amplitude of the primordial power spectrum at wavenumbers k {approx}< 10{sup 4} Mpc{sup -1}. Here, we study constraints on the primordial power spectrum derived from COBE/FIRAS and forecasted for PIXIE. We show that measurements of {mu} and y impose strong bounds on the integrated small-scale power, and we demonstrate how to compute these constraints using k-space window functions that account for the effects of thermalization and dissipation physics. We show that COBE/FIRAS places a robust upper limit on the amplitude of the small-scale power spectrum. This limit is about three orders of magnitude stronger than the one derived from primordial black holes in the same scale range. Furthermore, this limit could be improved by another three orders of magnitude with PIXIE, potentially opening up a new window to early universe physics. To illustrate the power of these constraints, we consider several generic models for the small-scale power spectrum predicted by different inflation scenarios, including running-mass inflation models and inflation scenarios with episodes of particle production. PIXIE could place very tight constraints on these scenarios, potentially even ruling out running-mass inflation models if no distortion is detected. We also show that inflation models with sub-Planckian field excursion that generate detectable tensor perturbations should simultaneously produce a large CMB spectral distortion, a link that could potentially be established with PIXIE.

  11. Gravitational wave signature in B-modes and the power in ΛCDM models on large and small scales

    NASA Astrophysics Data System (ADS)

    Minor, Quinn Eliot; Kaplinghat, Manoj

    2015-01-01

    The cosmic microwave background (CMB) angular power spectrum has a drop in power at low multipoles (large scales), which is in tension with the standard ΛCDM + power-law spectrum model. This deficit is exacerbated if there is a significant tensor contribution to the CMB power spectrum, as recently suggested by the BICEP2 results. We show that this deficit appears naturally in the axion monodromy inflation model, where the inflaton potential contains a gentle oscillation, thus generating an oscillating power spectrum with a suppression of power at large scales while still achieving enough e-foldings to solve the horizon problem. Using a combined data set of Planck, ACT, and SPT temperature data along with WMAP polarization data, we find a best-fit tensor-to-scalar ratio r=0.07^{+0.06}_{-0.03} in this model. The BICEP2 result r 0.2 is disfavored by the data at the 99% confidence level. We show further that this oscillating power spectrum will also suppress power on small-scales, alleviating the too-big-to-fail in dwarf galaxies. Conversely, if a large-field inflation model such as axion monodromy is responsible for the deficit of power at large and small scales, then the imprint of gravitational waves on the CMB should be observable by B-mode polarization experiments in the future.

  12. Modeling the effect of small-scale magnetic turbulence on the X-ray properties of Pulsar Wind Nebulae

    NASA Astrophysics Data System (ADS)

    Bucciantini, N.; Bandiera, R.; Olmi, B.; Del Zanna, L.

    2017-10-01

    Pulsar Wind Nebulae (PWNe) constitute an ideal astrophysical environment to test our current understanding of relativistic plasma processes. It is well known that magnetic fields play a crucial role in their dynamics and emission properties. At present, one of the main issues concerns the level of magnetic turbulence present in these systems, which in the absence of space resolved X-ray polarization measures cannot be directly constrained. In this work, we investigate, for the first time using simulated synchrotron maps, the effect of a small-scale fluctuating component of the magnetic field on the emission properties in X-ray. We illustrate how to include the effects of a turbulent component in standard emission models for PWNe and which consequences are expected in terms of net emissivity and depolarization, showing that the X-ray surface brightness maps can provide already some rough constraints. We then apply our analysis to the Crab and Vela nebulae and by comparing our model with Chandra and Vela data, we found that the typical energies in the turbulent component of the magnetic field are about 1.5-3 times the one in the ordered field.

  13. Legal obstacles and incentives to the development of small scale hydroelectric power in Pennsylvania

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level are discussed. The Federal government also exercises extensive regulatory authority in the area, and the dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and an inquiry into the practical use of the doctrine by the FERC is examined. In Pennsylvania, there are 3 methods by which rights in water may be acquired: riparian ownership, prescription, and condemnation. These are discussed.

  14. Small-scale gravity waves in ER-2 MMS/MTP wind and temperature measurements during CRYSTAL-FACE

    NASA Astrophysics Data System (ADS)

    Wang, L.; Alexander, M. J.; Bui, T. P.; Mahoney, M. J.

    2005-11-01

    ER-2 MMS and MTP wind and temperature measurements during the CRYSTAL-FACE campaign in July 2002 were analyzed to retrieve information on small scale gravity waves (GWs) at aircraft's flight level. For a given flight segment, the S-transform was used to search for and identify small horizontal scale GW events, and to estimate the apparent horizontal wavelengths of the events. The horizontal propagation directions of the events were determined using the Stokes parameters method combined with the cross S-transform analysis. The MTP temperature gradient method was used to determine the vertical wavelengths of the events. GW momentum fluxes were calculated from the cross S-transform. Other wave parameters such as intrinsic frequencies were calculated using the GW dispersion relation. More than 100 GW events were identified. They were generally short horizontal scale and high frequency waves with λz of ~5 km and λh generally shorter than 20 km. Their intrinsic propagation directions were predominantly toward the east, whereas their ground-based propagation directions were primarily toward the west. Among the events, ~20% of them had very short horizontal wavelength (<10 km), very high intrinsic frequency (ω/N≥0.8), and relatively small momentum fluxes, and thus they were likely trapped in the lower stratosphere. The averaged magnitude of vertical flux of horizontal momentum was ~0.026 kg m-1 s-2, and the maximum magnitude was ~0.13 kg m-1 s-2. Using the estimated GW parameters and the background winds and stabilities from the NCAR/NCEP reanalysis data, we were able to trace the sources of the events using a simple reverse ray-tracing. More than 70% of the events were traced back to convective sources in the troposphere, and the sources were generally located upstream to the events. Finally, a probability density function of GW cooling rates was obtained in this study, which may be used in cirrus cloud models.

  15. Small-Scale Gravity Waves in ER-2 MMS/MTP Wind and Temperature Measurements during CRYSTAL-FACE

    NASA Technical Reports Server (NTRS)

    Wang, L.; Alexander, M. J.; Bui, T. P.; Mahoney, M. J.

    2006-01-01

    Lower stratospheric wind and temperature measurements made from NASA's high-altitude ER-2 research aircraft during the CRYSTAL-FACE campaign in July 2002 were analyzed to retrieve information on small scale gravity waves (GWs) at the aircraft's flight level (typically approximately 20 km altitude). For a given flight segment, the S-transform (a Gaussian wavelet transform) was used to search for and identify small horizontal scale GW events, and to estimate their apparent horizontal wavelengths. The horizontal propagation directions of the events were determined using the Stokes parameter method combined with the cross S-transform analysis. The vertical temperature gradient was used to determine the vertical wavelengths of the events. GW momentum fluxes were calculated from the cross S-transform. Other wave parameters such as intrinsic frequencies were calculated using the GW dispersion relation. More than 100GW events were identified. They were generally high frequency waves with vertical wavelength of approximately 5 km and horizontal wavelength generally shorter than 20 km. Their intrinsic propagation directions were predominantly toward the east, whereas their ground-based propagation directions were primarily toward the west. Among the events, approximately 20% of them had very short horizontal wavelength, very high intrinsic frequency, and relatively small momentum fluxes, and thus they were likely trapped in the lower stratosphere. Using the estimated GW parameters and the background winds and stabilities from the NCAR/NCEP reanalysis data, we were able to trace the sources of the events using a simple reverse ray-tracing. More than 70% of the events were traced back to convective sources in the troposphere, and the sources were generally located upstream of the locations of the events observed at the aircraft level. Finally, a probability density function of the reversible cooling rate due to GWs was obtained in this study, which may be useful for cirrus

  16. Small-Scale Gravity Waves in ER-2 MMS/MTP Wind and Temperature Measurements during CRYSTAL-FACE

    NASA Technical Reports Server (NTRS)

    Wang, L.; Alexander, M. J.; Bui, T. P.; Mahoney, M. J.

    2006-01-01

    Lower stratospheric wind and temperature measurements made from NASA's high-altitude ER-2 research aircraft during the CRYSTAL-FACE campaign in July 2002 were analyzed to retrieve information on small scale gravity waves (GWs) at the aircraft's flight level (typically approximately 20 km altitude). For a given flight segment, the S-transform (a Gaussian wavelet transform) was used to search for and identify small horizontal scale GW events, and to estimate their apparent horizontal wavelengths. The horizontal propagation directions of the events were determined using the Stokes parameter method combined with the cross S-transform analysis. The vertical temperature gradient was used to determine the vertical wavelengths of the events. GW momentum fluxes were calculated from the cross S-transform. Other wave parameters such as intrinsic frequencies were calculated using the GW dispersion relation. More than 100GW events were identified. They were generally high frequency waves with vertical wavelength of approximately 5 km and horizontal wavelength generally shorter than 20 km. Their intrinsic propagation directions were predominantly toward the east, whereas their ground-based propagation directions were primarily toward the west. Among the events, approximately 20% of them had very short horizontal wavelength, very high intrinsic frequency, and relatively small momentum fluxes, and thus they were likely trapped in the lower stratosphere. Using the estimated GW parameters and the background winds and stabilities from the NCAR/NCEP reanalysis data, we were able to trace the sources of the events using a simple reverse ray-tracing. More than 70% of the events were traced back to convective sources in the troposphere, and the sources were generally located upstream of the locations of the events observed at the aircraft level. Finally, a probability density function of the reversible cooling rate due to GWs was obtained in this study, which may be useful for cirrus

  17. Excitation of small-scale waves in the F region of the ionosphere by powerful HF radio waves

    NASA Astrophysics Data System (ADS)

    Blagoveshchenskaya, N. F.; Chernyshev, M. Y.; Kornienko, V. A.

    1998-01-01

    Ionospheric small-scale waves in the F region, initiated by heating facilities in Nizhniy Novgorod, have been studied by the method of field-aligned scattering of diagnostic HF radio signals. Experimental data have been obtained on the radio path Kiev-N. Novgorod-St. Petersburg during heating campaigns with heater radiated power ERP = 20 MW and 100 MW. Observations of scattered HF signals have been made by a Doppler spectrum device with high temporal resolution. Analysis of the experimental data shows a relation between the heater power level and the parameters of ionospheric small-scale oscillations falling within the range of Pc 3-4 magnetic pulsations. It is found that the periods of wave processes in the F region of the ionosphere, induced by the heating facility, decrease with increasing heating power. The level of heating power also has an impact on the horizontal east-west component of the electric field E, the vertical component of the Doppler velocity Vd and the amplitude of the vertical displacements M of the heated region. Typical magnitudes of these parameters are the following: E = 1.25 mVm, Vd = 6 ms, M = 600-1500 m for ERP = 20 MW and E = 2.5-4.5 mVm, Vd = 11-25 ms, M = 1000-5000 m for ERP = 100 MW. The results obtained confirm the hypothesis of excitation of the Alfvén resonator by powerful HF radio waves which leads to the generation of magnetic field oscillations in the heated region giving rise to artificial Pc 3-4 magnetic pulsations and ionospheric small-scale wave processes. In this situation an increase of the heater power would lead to a growth of the electric field of hydromagnetic waves propagating in the ionosphere as well as the amplitude of the vertical displacements of the heated region.

  18. Small-Scale Hydroelectric Power Demonstration Project. Pennsylvania Hydroelectric Development Corporation Flat Rock Dam: Project summary report

    SciTech Connect

    Gleeson, L.

    1991-12-01

    The US Department of Energy Field Office, Idaho, Small-Scale Hydroelectric Power Program was initiated in conjunction with the restoration of three power generating plants in Idaho Falls, Idaho, following damage caused by the Teton Dam failure on June 5, 1976. There were many parties interested in this project, including the state and environmental groups, with different concerns. This report was prepared by the developer and describes the design alternatives the applicant provided in an attempt to secure the Federal Energy Regulatory Commission license. Also included are correspondence between the related parties concerning the project, major design alternatives/project plan diagrams, the license, and energy and project economics.

  19. Legal obstacles and incentives to the development of small scale hydroelectric power in Vermont

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level in Vermont are discussed. The dual regulatory system involving state and Federal governments is discussed followed by discussions on property interests; direct regulation by the Public Service Board; indirect regulation; and financial considerations. An initial step required of any developer is that of real property acquisition. Ordinarily this involves acquiring the stream bed, land along the stream banks, and land needed for the impoundment reservoir. Ownership of land along the stream banks places the developer in the position of a riparian owner. This status is important in that only riparian owners are entitled to a reasonable use of the flowing water. In addition to acquisition by sale, lease, or gift, Vermont law allows certain developers to acquire property via eminent domain. Some general rules which have evolved as riparian law and applied in Vermont are discussed.

  20. Legal obstacles and incentives to the development of small scale hydroelectric power in Indiana

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy in Indiana are examined. The Federal government also exercises extensive regulatory authority in the area. An examination is made of the Federal-state relationships with the aim of creating a more orderly understanding of the vagaries of the system. The introductory chapter examines the dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and concludes with an inquiry into the practical use of the doctrine by the FERC. The Indiana water law; direct and indirect regulations; the Public Service Commission of Indiana; and financial considerations are examined.

  1. Legal obstacles and incentives to the development of small-scale hydroelectric power in Rhode Island

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level are discussed. The Federal government also exercises extensive regulatory authority in the area, and the dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and an inquiry into the practical use of the doctrine by the FERC is examined. In Rhode Island, any private rights in the flowing waters of a river or stream depend upon ownership of the abutting land. It appears Rhode Island follows the reasonable use theory of riparian law. The Department of Environmental Management is the most significant administrative agency with regard to dam construction, alteration, and operation in the state of Rhode Island.

  2. High-z objects and cold dark matter cosmogonies - Constraints on the primordial power spectrum on small scales

    NASA Technical Reports Server (NTRS)

    Kashlinsky, A.

    1993-01-01

    Modified cold dark matter (CDM) models were recently suggested to account for large-scale optical data, which fix the power spectrum on large scales, and the COBE results, which would then fix the bias parameter, b. We point out that all such models have deficit of small-scale power where density fluctuations are presently nonlinear, and should then lead to late epochs of collapse of scales M between 10 exp 9 - 10 exp 10 solar masses and (1-5) x 10 exp 14 solar masses. We compute the probabilities and comoving space densities of various scale objects at high redshifts according to the CDM models and compare these with observations of high-z QSOs, high-z galaxies and the protocluster-size object found recently by Uson et al. (1992) at z = 3.4. We show that the modified CDM models are inconsistent with the observational data on these objects. We thus suggest that in order to account for the high-z objects, as well as the large-scale and COBE data, one needs a power spectrum with more power on small scales than CDM models allow and an open universe.

  3. High-z objects and cold dark matter cosmogonies - Constraints on the primordial power spectrum on small scales

    NASA Technical Reports Server (NTRS)

    Kashlinsky, A.

    1993-01-01

    Modified cold dark matter (CDM) models were recently suggested to account for large-scale optical data, which fix the power spectrum on large scales, and the COBE results, which would then fix the bias parameter, b. We point out that all such models have deficit of small-scale power where density fluctuations are presently nonlinear, and should then lead to late epochs of collapse of scales M between 10 exp 9 - 10 exp 10 solar masses and (1-5) x 10 exp 14 solar masses. We compute the probabilities and comoving space densities of various scale objects at high redshifts according to the CDM models and compare these with observations of high-z QSOs, high-z galaxies and the protocluster-size object found recently by Uson et al. (1992) at z = 3.4. We show that the modified CDM models are inconsistent with the observational data on these objects. We thus suggest that in order to account for the high-z objects, as well as the large-scale and COBE data, one needs a power spectrum with more power on small scales than CDM models allow and an open universe.

  4. Legal obstacles and incentives to the development of small scale hydroelectric power in Delaware

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level are discussed. The Federal government also exercises extensive regulatory authority in the area, and the dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and an inquiry into the practical use of the doctrine by the FERC is examined. In Delaware, a watercourse is not to be confused with surface water. Each gives rise to certain riparian rights, but the law makes certain distinctions between the two. The presence of both surface waters and watercourses give rise to private and public rights related to the presence of the water. Some of these rights are vested in riparian owners. Recent Delaware case law has described the riparian owner as one who owns land on the bank of a river, or who is owner of land along, bordering upon, bounded by, fronting upon, abutting, or adjacent and contiguous to and in contact with a river. But, ownership of the bank does not give the riparian ownership of the water. Some law cases are cited to discuss the laws in Delaware.

  5. Legal obstacles and incentives to the development of small scale hydroelectric power in New Hampshire

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level are described. The Federal government also exercises extensive regulatory authority in the area and the dual regulatory system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and an inquiry into the practical use of the doctrine by the FERC is examined. The first step any developer must take is that of acquiring the real estate parcel. The step involves acquisition in some manner of both river banks, the river bed, and where necessary the land needed for the upstream impoundment area. The developer must acquire the river banks to be considered a riparian owner. Classification as a riparian is important for only a use of water by a riparian owner is deemed a reasonable use and hence legal. Apart from acquisition by sale, lease, or gift, New Hampshire law permits a number of other methods. In part use of these methods will depend on whether the developer is the state, a municipality, a private corporation, or a public utility. Provided the developer avails himself of the five (5) megawatts exemption, his main regulatory agency will be the Water Resources Board. However, the state is not free from the problems of legal uncertainty inherent in determinations of reasonableness.

  6. Legal obstacles and incentives to the development of small-scale hydroelectric power in Virginia

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy in Virginia are described. The state regulatory system does not comprise final authority; the Federal government also exercises extensive regulatory authority in the area. This dual system is a function of the federalist nature of our government. The introductory section examines the dual system from the standpoint of the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and inquires into the practical use of the doctrine by the FERC. The use of a natural-surface watercourse in Virginia is governed generally by the doctrine of riparian rights. Riparian rights is a system of water rights based on ownership of land bordering on a natural stream or watercourse. For land to be considered riparian to a stream, that land must be located on the watershed of that portion of the stream. The theory of riparian rights followed in Virginia is one of reasonable use. Under the reasonable-use doctrine, each riparian owner has an equal right to the reasonable use of the water running naturally through or by his land for any useful purpose. The water must continue to run after such use without material diminution or alteration and without pollution.

  7. Legal obstacles and incentives to the development of small scale hydroelectric power in Maryland

    SciTech Connect

    None,

    1980-05-01

    The legal and institutional obstacles to the development of small-scale hydroelectric energy at the state level in Maryland are described. The Federal government also exercises extensive regulatory authority in the area. The dual regulatory system is examined with the aim of creating a more orderly understanding of the vagaries of the system, focusing on the appropriate legal doctrine, the law of pre-emption, application of the law to the case of hydroelectric development, and an inquiry into the practical use of the doctrine by the FERC. In Maryland, by common law rule, title to all navigable waters and to the soil below the high-water mark of those waters is vested in the state as successor to the Lord Proprietary who had received it by grant from the Crown. Rights to non-navigable water, public trust doctrine, and eminent domain are also discussed. Direct and indirect regulations, continuing obligations, loan programs, and regional organizations are described in additional sections.

  8. Wind power freshens water

    SciTech Connect

    Pavlor, V.; Sidorov, V.

    1981-01-01

    A wind-powered lighthouse water-freshening installation was installed at lighthouse locations along the Caspian Sea's coast and at one of the collective farms in the Moldavian SSR. From sea water containing up to 36 grams of salts per liter, fresh water with up to 1 gram per liter was produced. Output was 60 liters per hour.

  9. Case studies of the legal and institutional obstacles and incentives to the development of small-scale hydroelectric power: Bull Run, Portland, Oregon

    SciTech Connect

    1980-05-01

    The National Conference of State Legislatures' Small-Scale Hydroelectric Policy Project is designed to assist selected state legislatures in looking at the benefits that a state can derive from the development of small-scale hydro, and in carrying out a review of state laws and regulations that affect the development of the state's small-scale hydro resources. The successful completion of the project should help establish state statutes and regulations that are consistent with the efficient development of small-scale hydro. As part of the project's work with state legislatures, seven case studies of small-scale hydro sites were conducted to provide a general analysis and overview of the significant problems and opportunities for the development of this energy resource. The case study approach was selected to expose the actual difficulties and advantages involved in developing a specific site. Such an examination of real development efforts will clearly reveal the important aspects about small-scale hydro development which could be improved by statutory or regulatory revision. Moreover, the case study format enables the formulation of generalized opportunities for promoting small-scale hydro based on specific development experiences. The case study for small-scale hydro power development at the City of Portland's water reserve in the Bull Run Forest is presented with information included on the Bull Run hydro power potential, current water usage, hydro power regulations and plant licensing, technical and economic aspects of Bull Run project, and the environmental impact. (LCL)

  10. Wind power machine

    SciTech Connect

    Denehi, D.

    1992-07-28

    This patent describes wind powered apparatus for producing electricity. It comprises: an endless chain trained over and movable in a continuous path about two substantially spaced-apart sprockets, a plurality of sails fixedly attached to the chain, guide means positioned adjacent the chain and operable, a rotary electrical generator; means connecting at least one of the sprockets to the generator to rotate the latter in response to movement of the chain by wind acting upon the sail flaps when in the first, open position thereof.

  11. The effects of the small-scale behaviour of dark matter power spectrum on CMB spectral distortion

    NASA Astrophysics Data System (ADS)

    Sarkar, Abir; Sethi, Shiv. K.; Das, Subinoy

    2017-07-01

    After numerous astronomical and experimental searches, the precise particle nature of dark matter is still unknown. The standard Weakly Interacting Massive Particle(WIMP) dark matter, despite successfully explaining the large-scale features of the universe, has long-standing small-scale issues. The spectral distortion in the Cosmic Microwave Background(CMB) caused by Silk damping in the pre-recombination era allows one to access information on a range of small scales 0.3 Mpc < k < 104 Mpc-1, whose dynamics can be precisely described using linear theory. In this paper, we investigate the possibility of using the Silk damping induced CMB spectral distortion as a probe of the small-scale power. We consider four suggested alternative dark matter candidates—Warm Dark Matter (WDM), Late Forming Dark Matter (LFDM), Ultra Light Axion (ULA) dark matter and Charged Decaying Dark Matter (CHDM); the matter power in all these models deviate significantly from the ΛCDM model at small scales. We compute the spectral distortion of CMB for these alternative models and compare our results with the ΛCDM model. We show that the main impact of alternative models is to alter the sub-horizon evolution of the Newtonian potential which affects the late-time behaviour of spectral distortion of CMB. The y-parameter diminishes by a few percent as compared to the ΛCDM model for a range of parameters of these models: LFDM for formation redshift zf = 105 (7%); WDM for mass mwdm = 1 keV (2%); CHDM for decay redshift zdecay = 105 (5%); ULA for mass ma = 10-24 eV (3%). This effect from the pre-recombination era can be masked by orders of magnitude higher y-distortions generated by late-time sources, e.g. the Epoch of Reionization and tSZ from the cluster of galaxies. We also briefly discuss the detectability of this deviation in light of the upcoming CMB experiment PIXIE, which might have the sensitivity to detect this signal from the pre-recombination phase.

  12. Remote sensing for wind power potential: a prospector's handbook

    SciTech Connect

    Wade, J.E.; Maule, P.A.; Bodvarsson, G.; Rosenfeld, C.L.; Woolley, S.G.; McClenahan, M.R.

    1983-02-01

    Remote sensing can aid in identifying and locating indicators of wind power potential from the terrestrial, marine, and atmospheric environments (i.e.: wind-deformed trees, white caps, and areas of thermal flux). It is not considered as a tool for determining wind power potential. A wide variety of remotely sensed evidence is described in terms of the scale at which evidence of wind power can be identified, and the appropriate remote sensors for finding such evidence. Remote sensing can be used for regional area prospecting using small-scale imagery. The information from such small-scale imagery is most often qualitative, and if it is transitory, examination of a number of images to verify presistence of the feature may be required. However, this evidence will allow rapid screening of a large area. Medium-scale imagery provides a better picture of the evidence obtained from small-scale imagery. At this level it is best to use existing imagery. Criteria relating to land use, accessibility, and proximity of candidate sites to nearby transmission lines can also be effectively evaluated from medium-scale imagery. Large-scale imagery provides the most quantitative evidence of the strength of wind. Wind-deformed trees can be identified at a large number of sites using only a few hours in locally chartered aircraft. A handheld 35mm camera can adequately document any evidence of wind. Three case studies that employ remote sensing prospecting techniques are described. Based on remotely sensed evidence, the wind power potential in three geographically and climatically diverse areas of the United States is estimated, and the estimates are compared to actual wind data in those regions. In addition, the cost of each survey is discussed. The results indicate that remote sensing for wind power potential is a quick, cost effective, and fairly reliable method for screening large areas for wind power potential.

  13. Electricity's Future: The Shift to Efficiency and Small-Scale Power. Worldwatch Paper 61.

    ERIC Educational Resources Information Center

    Flavin, Christopher

    Electricity, which has largely supplanted oil as the most controversial energy issue of the 1980s, is at the center of some of the world's bitterest economic and environmental controversies. Soaring costs, high interest rates, and environmental damage caused by large power plants have wreaked havoc on the once booming electricity industry.…

  14. Development of a New Generation of Small Scale Biomass-Fueled Electric Generating Power Plants.

    DTIC Science & Technology

    1995-08-01

    Product Gases. Energy from Biomass and Wastes X, Washington, DC, April 7-10, 1986. 2. Newby, R.A., and R.L. Bannister. Hot Gas Cleaning System for Coal ... Gasification Processes, Journal of Engineering for Gas Turbines and Power, April, 1994, Vol. 116, pp. 338. 3. Craig, J.D. Development of a Small

  15. Small-Scale Low Cost Solid Oxide Fuel Cell Power Systems

    SciTech Connect

    S. D. Vora

    2008-02-01

    Progress in tasks seeking greater cell power density and lower cost through new cell designs, new cell materials and lower operating temperature is summarized. The design of the program required Proof-of-Concept unit of residential capacity scale is reviewed along with a summary of results from its successful test. Attachment 1 summarizes the status of cell development. Attachment 2 summarizes the status of generator design, and Attachment 3 of BOP design.

  16. Effect of operating and sampling conditions on the exhaust gas composition of small-scale power generators.

    PubMed

    Smits, Marianne; Vanpachtenbeke, Floris; Horemans, Benjamin; De Wael, Karolien; Hauchecorne, Birger; Van Langenhove, Herman; Demeestere, Kristof; Lenaerts, Silvia

    2012-01-01

    Small stationary diesel engines, like in generator sets, have limited emission control measures and are therefore responsible for 44% of the particulate matter (PM) emissions in the United States. The diesel exhaust composition depends on operating conditions of the combustion engine. Furthermore, the measurements are influenced by the used sampling method. This study examines the effect of engine loading and exhaust gas dilution on the composition of small-scale power generators. These generators are used in different operating conditions than road-transport vehicles, resulting in different emission characteristics. Experimental data were obtained for gaseous volatile organic compounds (VOC) and PM mass concentration, elemental composition and nitrate content. The exhaust composition depends on load condition because of its effect on fuel consumption, engine wear and combustion temperature. Higher load conditions result in lower PM concentration and sharper edged particles with larger aerodynamic diameters. A positive correlation with load condition was found for K, Ca, Sr, Mn, Cu, Zn and Pb adsorbed on PM, elements that originate from lubricating oil or engine corrosion. The nitrate concentration decreases at higher load conditions, due to enhanced nitrate dissociation to gaseous NO at higher engine temperatures. Dilution on the other hand decreases PM and nitrate concentration and increases gaseous VOC and adsorbed metal content. In conclusion, these data show that operating and sampling conditions have a major effect on the exhaust gas composition of small-scale diesel generators. Therefore, care must be taken when designing new experiments or comparing literature results.

  17. Effect of Operating and Sampling Conditions on the Exhaust Gas Composition of Small-Scale Power Generators

    PubMed Central

    Smits, Marianne; Vanpachtenbeke, Floris; Horemans, Benjamin; De Wael, Karolien; Hauchecorne, Birger; Van Langenhove, Herman; Demeestere, Kristof; Lenaerts, Silvia

    2012-01-01

    Small stationary diesel engines, like in generator sets, have limited emission control measures and are therefore responsible for 44% of the particulate matter (PM) emissions in the United States. The diesel exhaust composition depends on operating conditions of the combustion engine. Furthermore, the measurements are influenced by the used sampling method. This study examines the effect of engine loading and exhaust gas dilution on the composition of small-scale power generators. These generators are used in different operating conditions than road-transport vehicles, resulting in different emission characteristics. Experimental data were obtained for gaseous volatile organic compounds (VOC) and PM mass concentration, elemental composition and nitrate content. The exhaust composition depends on load condition because of its effect on fuel consumption, engine wear and combustion temperature. Higher load conditions result in lower PM concentration and sharper edged particles with larger aerodynamic diameters. A positive correlation with load condition was found for K, Ca, Sr, Mn, Cu, Zn and Pb adsorbed on PM, elements that originate from lubricating oil or engine corrosion. The nitrate concentration decreases at higher load conditions, due to enhanced nitrate dissociation to gaseous NO at higher engine temperatures. Dilution on the other hand decreases PM and nitrate concentration and increases gaseous VOC and adsorbed metal content. In conclusion, these data show that operating and sampling conditions have a major effect on the exhaust gas composition of small-scale diesel generators. Therefore, care must be taken when designing new experiments or comparing literature results. PMID:22442670

  18. Small-Scale Low Cost Solid Oxide Fuel Cell Power Systems

    SciTech Connect

    S.D. Vora

    2003-02-28

    Tasks carried out during the first six months of the program are summarized. Development of seal-less cells with increased power density at lower operating temperature (800 C) was started. This required a new cell design and investigation of new cell materials. Conceptual design of the generator and balance of plant (BOP) for a residential system was initiated. Attachment 1 describes the progress in cell development and Attachments 2 and 3 deal with status of the generator and BOP design. Overall progress during the first six months and plans for future work are summarized in Attachment 4.

  19. Simulation and Evaluation of Small Scale Solar Power Tower Performance under Malaysia Weather Conditions

    NASA Astrophysics Data System (ADS)

    Gamil, A. M.; Gilani, S. I.; Al-Kayiem, H. H.

    2013-06-01

    Solar energy is the most available, clean, and inexpensive source of energy among the other renewable sources of energy. Malaysia is an encouraging location for the development of solar energy systems due to abundant sunshine (10 hours daily with average solar energy received between 1400 and 1900 kWh/m2). In this paper the design of heliostat field of 3 dual-axis heliostat units located in Ipoh, Malaysia is introduced. A mathematical model was developed to estimate the sun position and calculate the cosine losses in the field. The study includes calculating the incident solar power to a fixed target on the tower by analysing the tower height and ground distance between the heliostat and the tower base. The cosine efficiency was found for each heliostat according to the sun movement. TRNSYS software was used to simulate the cosine efficiencies and field hourly incident solar power input to the fixed target. The results show the heliostat field parameters and the total incident solar input to the receiver.

  20. Tension between the power spectrum of density perturbations measured on large and small scales

    NASA Astrophysics Data System (ADS)

    Battye, Richard A.; Charnock, Tom; Moss, Adam

    2015-05-01

    There is a tension between measurements of the amplitude of the power spectrum of density perturbations inferred using the cosmic microwave background (CMB) and directly measured by large-scale structure (LSS) on smaller scales. We show that this tension exists, and is robust, for a range of LSS indicators including clusters, lensing and redshift space distortions and using CMB data from either Planck or WMAP +SPT /ACT . One obvious way to try to reconcile this is the inclusion of a massive neutrino which could be either active or sterile. Using Planck and a combination of all the LSS data we find that (i) for an active neutrino ∑mν=(0.357 ±0.099 ) eV and (ii) for a sterile neutrino msterileeff=(0.67 ±0.18 ) eV and Δ Neff=0.32 ±0.20 . This is, however, at the expense of a degraded fit to Planck temperature data, and we quantify the residual tension at 2.5 σ and 1.6 σ for massive and sterile neutrinos, respectively. We also consider alternative explanations including a lower redshift for reionization that would be in conflict with polarization measurements made by WMAP and ad hoc modifications to the primordial power spectrum.

  1. Linear perturbation theory for tidal streams and the small-scale CDM power spectrum

    NASA Astrophysics Data System (ADS)

    Bovy, Jo; Erkal, Denis; Sanders, Jason L.

    2017-04-01

    Tidal streams in the Milky Way are sensitive probes of the population of low-mass dark matter subhaloes predicted in cold dark matter (CDM) simulations. We present a new calculus for computing the effect of subhalo fly-bys on cold streams based on the action-angle representation of streams. The heart of this calculus is a line-of-parallel-angle approach that calculates the perturbed distribution function of a stream segment by undoing the effect of all relevant impacts. This approach allows one to compute the perturbed stream density and track in any coordinate system in minutes for realizations of the subhalo distribution down to 105 M⊙, accounting for the stream's internal dispersion and overlapping impacts. We study the statistical properties of density and track fluctuations with large suites of simulations of the effect of subhalo fly-bys. The one-dimensional density and track power spectra along the stream trace the subhalo mass function, with higher mass subhaloes producing power only on large scales, while lower mass subhaloes cause structure on smaller scales. We also find significant density and track bispectra that are observationally accessible. We further demonstrate that different projections of the track all reflect the same pattern of perturbations, facilitating their observational measurement. We apply this formalism to data for the Pal 5 stream and make a first rigorous determination of 10^{+11}_{-6} dark matter subhaloes with masses between 106.5 and 109 M⊙ within 20 kpc from the Galactic centre [corresponding to 1.4^{+1.6}_{-0.9} times the number predicted by CDM-only simulations or to fsub(r < 20 kpc) ≈ 0.2 per cent] assuming that the Pal 5 stream is 5 Gyr old. Improved data will allow measurements of the subhalo mass function down to 105 M⊙, thus definitively testing whether dark matter is clumpy on the smallest scales relevant for galaxy formation.

  2. Wind Powering America Webinar Series (Postcard), Wind Powering America (WPA)

    SciTech Connect

    Not Available

    2012-02-01

    Wind Powering America offers a free monthly webinar series that provides expert information on today?s key wind energy topics. This postcard is an outreach tool that provides a brief description of the webinars as well as the URL.

  3. On the use of a small-scale two-phase thermosiphon to cool high-power electronics

    NASA Astrophysics Data System (ADS)

    Schrage, D. S.

    1990-01-01

    An experimental and analytical investigation of the steady-state thermal-hydraulic operating characteristics of a small-scale two-phase thermosiphon cooling actual power electronics are presented. Boiling heat transfer coefficients and circulation mass velocities were measured while varying heat load and pressure. Both a plain and augmented riser structure, utilizing micro-fins and reentrant cavities, were simultaneously tested. The boiling heat transfer coefficients increased with both increasing heat load and pressure. The mass velocity increased with increasing pressure while both increasing and then decreasing with increasing heat load. The reentrant cavity enhancement factor, a ratio of the augmented-to-plain riser nucleate boiling heat transfer coefficients, ranged from 1 to 1.4. High-speed photography revealed bubbly, slug, churn, wispy-annular and annular flow patterns. The experimental mass velocity and heat transfer coefficient data were compared to an analytical model with average absolute deviations of 16.3 and 26.3 percent, respectively.

  4. Wind Powering America Podcasts, Wind Powering America (WPA)

    SciTech Connect

    Not Available

    2012-04-01

    Wind Powering America and the National Association of Farm Broadcasters produce a series of radio interviews featuring experts discussing wind energy topics. The interviews are aimed at a rural stakeholder audience and are available as podcasts. On the Wind Powering America website, you can access past interviews on topics such as: Keys to Local Wind Energy Development Success, What to Know about Installing a Wind Energy System on Your Farm, and Wind Energy Development Can Revitalize Rural America. This postcard is a marketing piece that stakeholders can provide to interested parties; it will guide them to this online resource for podcast episodes.

  5. Wind Power for Municipal Utilities

    SciTech Connect

    Not Available

    2002-10-01

    Wind Power for Municipal Utilities is a trifold brochure that strives to educate municipal utility owners and operators about the benefits of investing in wind power development. It provides examples of municipal utilities that have successful wind energy projects and supportive statements from industry members.

  6. Developing a hybrid solar/wind powered irrigation system for crops in the Great Plains

    USDA-ARS?s Scientific Manuscript database

    Some small scale irrigation systems (< 2 ha) powered by wind or solar do not require subsidies, but this paper discusses ways to achieve an economical renewable energy powered center pivot irrigation system for crops in the Great Plains. By adding a solar-photovoltaic (PV) array together with a wind...

  7. Development of a small-scale power system with meso-scale vortex combustor and thermo-electric device

    NASA Astrophysics Data System (ADS)

    Shimokuri, D.; Hara, T.; Matsumoto, R.

    2015-10-01

    A small-scale vortex combustion power system has been developed using a thermo-electric device (TED). The system consisted of a heat medium, TED, and cooling plates. A vortex combustion chamber (7 mm inner diameter and 27 mm long) was fabricated inside the heat medium (40  ×  40  ×  20 mm and 52 g of duralumin). It was found that a stable propane/air flame could be established in the narrow 7 mm channel even for the large heat input conditions of 213 ~ 355 W. With a couple of TEDs, the maximum of 8.1 W (9.8 V  ×  0.83 A) could be successfully obtained for 355 W heat input, which corresponded to the energy conversion rate of 2.4%. The results of the gas and the combustor wall temperature measurements showed that the heat transfer from the burned gas to combustor wall was significantly enhanced by the vortex flow, which contributed to the relatively high efficiency energy conversion on the vortex combustion power system.

  8. Wind tunnel study of the power output spectrum in a micro wind farm

    NASA Astrophysics Data System (ADS)

    Bossuyt, Juliaan; Howland, Michael F.; Meneveau, Charles; Meyers, Johan

    2016-09-01

    Instrumented small-scale porous disk models are used to study the spectrum of a surrogate for the power output in a micro wind farm with 100 models of wind turbines. The power spectra of individual porous disk models in the first row of the wind farm show the expected -5/3 power law at higher frequencies. Downstream models measure an increased variance due to wake effects. Conversely, the power spectrum of the sum of the power over the entire wind farm shows a peak at the turbine-to-turbine travel frequency between the model turbines, and a near -5/3 power law region at a much wider range of lower frequencies, confirming previous LES results. Comparison with the spectrum that would result when assuming that the signals are uncorrelated, highlights the strong effects of correlations and anti-correlations in the fluctuations at various frequencies.

  9. The effects of the small-scale DM power on the cosmological neutral hydrogen (HI) distribution at high redshifts

    NASA Astrophysics Data System (ADS)

    Sarkar, Abir; Mondal, Rajesh; Das, Subinoy; Sethi, Shiv. K.; Bharadwaj, Somnath; Marsh, David J. E.

    2016-04-01

    The particle nature of dark matter remains a mystery. In this paper, we consider two dark matter models—Late Forming Dark Matter (LFDM) and Ultra-Light Axion (ULA) models—where the matter power spectra show novel effects on small scales. The high redshift universe offers a powerful probe of their parameters. In particular, we study two cosmological observables: the neutral hydrogen (HI) redshifted 21-cm signal from the epoch of reionization, and the evolution of the collapsed fraction of HI in the redshift range 2 < z < 5. We model the theoretical predictions of the models using CDM-like N-body simulations with modified initial conditions, and generate reionization fields using an excursion set model. The N-body approximation is valid on the length and halo mass scales studied. We show that LFDM and ULA models predict an increase in the HI power spectrum from the epoch of reionization by a factor between 2-10 for a range of scales 0.1 < k < 4 Mpc-1. Assuming a fiducial model where a neutral hydrogen fraction bar xHI = 0.5 must be achieved by z = 8, the reionization process allows us to put approximate bounds on the redshift of dark matter formation zf > 4 × 105 (for LFDM) and the axion mass ma > 2.6 × 10-23 eV (for ULA). The comparison of the collapsed mass fraction inferred from damped Lyman-α observations to the theoretical predictions of our models lead to the weaker bounds: zf > 2 × 105 and ma > 10-23 eV. These bounds are consistent with other constraints in the literature using different observables; we briefly discuss how these bounds compare with possible constraints from the observation of luminosity function of galaxies at high redshifts. In the case of ULAs, these constraints are also consistent with a solution to the cusp-core problem of CDM.

  10. Wind Power Generation Design Considerations.

    DTIC Science & Technology

    1984-12-01

    sites. have low starting torques, operate at high tip-to- wind speeds, and generate high power output per turbine weight. 5 The Savonius rotor operates...DISTRIBUTION 4 I o ....................................... . . . e . * * TABLES Number Page I Wind Turbine Characteristics II 0- 2 Maximum Economic Life II 3...Ratio of Blade Tip Speed to Wind Speed 10 4 Interference with Microwave and TV Reception by Wind Turbines 13 5 Typical Flow Patterns Over Two

  11. Power from the Wind

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2004-01-01

    Wind energy is the fastest-growing renewable energy source in the world. Over the last 20 years, the wind industry has done a very good job of engineering machines, improving materials, and economies of production, and making this energy source a reality. Like all renewable energy forms, wind energy's successful application is site specific. Also,…

  12. Power from the Wind

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2004-01-01

    Wind energy is the fastest-growing renewable energy source in the world. Over the last 20 years, the wind industry has done a very good job of engineering machines, improving materials, and economies of production, and making this energy source a reality. Like all renewable energy forms, wind energy's successful application is site specific. Also,…

  13. Wind power outlook 2006

    SciTech Connect

    anon.

    2006-04-15

    This annual brochure provides the American Wind Energy Association's up-to-date assessment of the wind industry in the United States. This 2006 general assessment shows positive signs of growth, use and acceptance of wind energy as a vital component of the U.S. energy mix.

  14. Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

    DTIC Science & Technology

    2016-08-01

    EW-201251) Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology...To) 09/30/2016 9/1912012 to 9/30/2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Conversion of Low Quality Waste Heat to Electric Power with...unlimited 13. SUPPLEMENTARY NOTES None 14. ABSTRACT An Organic Rankine Cycle generator (ORC) converts low-grade waste heat ( °C) into electric power

  15. The effects of the small-scale DM power on the cosmological neutral hydrogen (HI) distribution at high redshifts

    SciTech Connect

    Sarkar, Abir; Sethi, Shiv K.; Mondal, Rajesh; Bharadwaj, Somnath; Das, Subinoy; Marsh, David J.E. E-mail: rm@phy.iitkgp.ernet.in E-mail: sethi@rri.res.in E-mail: david.marsh@kcl.ac.uk

    2016-04-01

    The particle nature of dark matter remains a mystery. In this paper, we consider two dark matter models—Late Forming Dark Matter (LFDM) and Ultra-Light Axion (ULA) models—where the matter power spectra show novel effects on small scales. The high redshift universe offers a powerful probe of their parameters. In particular, we study two cosmological observables: the neutral hydrogen (HI) redshifted 21-cm signal from the epoch of reionization, and the evolution of the collapsed fraction of HI in the redshift range 2 < z < 5. We model the theoretical predictions of the models using CDM-like N-body simulations with modified initial conditions, and generate reionization fields using an excursion set model. The N-body approximation is valid on the length and halo mass scales studied. We show that LFDM and ULA models predict an increase in the HI power spectrum from the epoch of reionization by a factor between 2–10 for a range of scales 0.1 < k < 4 Mpc{sup −1}. Assuming a fiducial model where a neutral hydrogen fraction x-bar {sub HI} = 0.5 must be achieved by z = 8, the reionization process allows us to put approximate bounds on the redshift of dark matter formation z{sub f} > 4 × 10{sup 5} (for LFDM) and the axion mass m{sub a} > 2.6 × 10{sup −23} eV (for ULA). The comparison of the collapsed mass fraction inferred from damped Lyman-α observations to the theoretical predictions of our models lead to the weaker bounds: z{sub f} > 2 × 10{sup 5} and m{sub a} > 10{sup −23} eV. These bounds are consistent with other constraints in the literature using different observables; we briefly discuss how these bounds compare with possible constraints from the observation of luminosity function of galaxies at high redshifts. In the case of ULAs, these constraints are also consistent with a solution to the cusp-core problem of CDM.

  16. BIOMASS-FUELED, SMALL-SCALE, INTEGRATED-GASIFIER, GAS-TURBINE POWER PLANT: PROGRESS REPORT ON THE PHASE 2 DEVELOPMENT

    EPA Science Inventory

    The paper reports the latest efforts to complete development of Phase 2 of a three-phase effort to develop a family of small-scale (1 to 20 MWe) biomass-fueled power plants. The concept envisioned is an air-blown pressurized fluidized-bed gasifier followed by a dry hot gas clean...

  17. BIOMASS-FUELED, SMALL-SCALE, INTEGRATED-GASIFIER, GAS-TURBINE POWER PLANT: PROGRESS REPORT ON THE PHASE 2 DEVELOPMENT

    EPA Science Inventory

    The paper reports the latest efforts to complete development of Phase 2 of a three-phase effort to develop a family of small-scale (1 to 20 MWe) biomass-fueled power plants. The concept envisioned is an air-blown pressurized fluidized-bed gasifier followed by a dry hot gas clean...

  18. Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

    DTIC Science & Technology

    2016-06-01

    FINAL REPORT Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator...Economics: Total System Benefit - ORC Electric Output plus Cooling Load Reduction (45 kW...MWh Megawatt hours NEC National Electric Code NESHAP National Emissions Standard for Hazardous Air Pollutants v Acronym Definition NFPA

  19. SMALL-SCALE MAGNETIC ISLANDS IN THE SOLAR WIND AND THEIR ROLE IN PARTICLE ACCELERATION. I. DYNAMICS OF MAGNETIC ISLANDS NEAR THE HELIOSPHERIC CURRENT SHEET

    SciTech Connect

    Khabarova, O.; Zank, G. P.; Li, G.; Roux, J. A. le; Webb, G. M.; Dosch, A.; Malandraki, O. E.

    2015-08-01

    Increases of ion fluxes in the keV–MeV range are sometimes observed near the heliospheric current sheet (HCS) during periods when other sources are absent. These resemble solar energetic particle events, but the events are weaker and apparently local. Conventional explanations based on either shock acceleration of charged particles or particle acceleration due to magnetic reconnection at interplanetary current sheets (CSs) are not persuasive. We suggest instead that recurrent magnetic reconnection occurs at the HCS and smaller CSs in the solar wind, a consequence of which is particle energization by the dynamically evolving secondary CSs and magnetic islands. The effectiveness of the trapping and acceleration process associated with magnetic islands depends in part on the topology of the HCS. We show that the HCS possesses ripples superimposed on the large-scale flat or wavy structure. We conjecture that the ripples can efficiently confine plasma and provide tokamak-like conditions that are favorable for the appearance of small-scale magnetic islands that merge and/or contract. Particles trapped in the vicinity of merging islands and experiencing multiple small-scale reconnection events are accelerated by the induced electric field and experience first-order Fermi acceleration in contracting magnetic islands according to the transport theory of Zank et al. We present multi-spacecraft observations of magnetic island merging and particle energization in the absence of other sources, providing support for theory and simulations that show particle energization by reconnection related processes of magnetic island merging and contraction.

  20. Wind and solar powered turbine

    NASA Technical Reports Server (NTRS)

    Wells, I. D.; Koh, J. L.; Holmes, M. (Inventor)

    1984-01-01

    A power generating station having a generator driven by solar heat assisted ambient wind is described. A first plurality of radially extendng air passages direct ambient wind to a radial flow wind turbine disposed in a centrally located opening in a substantially disc-shaped structure. A solar radiation collecting surface having black bodies is disposed above the fist plurality of air passages and in communication with a second plurality of radial air passages. A cover plate enclosing the second plurality of radial air passages is transparent so as to permit solar radiation to effectively reach the black bodies. The second plurality of air passages direct ambient wind and thermal updrafts generated by the black bodies to an axial flow turbine. The rotating shaft of the turbines drive the generator. The solar and wind drien power generating system operates in electrical cogeneration mode with a fuel powered prime mover.

  1. Application of MC1 to Wind Cave National Park: Lessons from a small-scale study: Chapter 8

    USGS Publications Warehouse

    King, David A.; Bachelet, Dominique M.; Symstad, Amy

    2015-01-01

    MC1 was designed for application to large regions that include a wide range in elevation and topography, thereby encompassing a broad range in climates and vegetation types. The authors applied the dynamic global vegetation model MC1 to Wind Cave National Park (WCNP) in the southern Black Hills of South Dakota, USA, on the ecotone between ponderosa pine forest to the northwest and mixed-grass prairie to the southeast. They calibrated MC1 to simulate adequate fire effects in the warmer southeastern parts of the park to ensure grasslands there, while allowing forests to grow to the northwest, and then simulated future vegetation with climate projections from three GCMs. The results suggest that fire frequency, as affected by climate and/or human intervention, may be more important than the direct effects of climate in determining the distribution of ponderosa pine in the Black Hills region, both historically and in the future.

  2. Limits to Wind Power Utilization.

    ERIC Educational Resources Information Center

    Gustavson, M. R.

    1979-01-01

    Discusses noneconomic factors limiting the total power that can be extracted from the wind. These factors are examined with a macroscopic approach. Some general conclusions are also reached regarding the sites that would have to be utilized and the usable wind energy potentials. (HM)

  3. Limits to Wind Power Utilization.

    ERIC Educational Resources Information Center

    Gustavson, M. R.

    1979-01-01

    Discusses noneconomic factors limiting the total power that can be extracted from the wind. These factors are examined with a macroscopic approach. Some general conclusions are also reached regarding the sites that would have to be utilized and the usable wind energy potentials. (HM)

  4. Small Scale Organic Techniques

    ERIC Educational Resources Information Center

    Horak, V.; Crist, DeLanson R.

    1975-01-01

    Discusses the advantages of using small scale experimentation in the undergraduate organic chemistry laboratory. Describes small scale filtration techniques as an example of a semi-micro method applied to small quantities of material. (MLH)

  5. Starting to Explore Wind Power

    ERIC Educational Resources Information Center

    Hare, Jonathan

    2008-01-01

    Described is a simple, cheap and versatile homemade windmill and electrical generator suitable for a school class to use to explore many aspects and practicalities of using wind to generate electrical power. (Contains 8 figures.)

  6. Wind Power Charged Aerosol Generator

    SciTech Connect

    Marks, A.M.

    1980-07-01

    This describes experimental results on a Charged Aerosol Wind/Electric Power Generator, using Induction Electric Charging with a water jet issuing under water pressure from a small diameter (25-100 ..mu..m) orifice.

  7. Starting to Explore Wind Power

    ERIC Educational Resources Information Center

    Hare, Jonathan

    2008-01-01

    Described is a simple, cheap and versatile homemade windmill and electrical generator suitable for a school class to use to explore many aspects and practicalities of using wind to generate electrical power. (Contains 8 figures.)

  8. Integrated Wind Power Planning Tool

    NASA Astrophysics Data System (ADS)

    Rosgaard, Martin; Giebel, Gregor; Skov Nielsen, Torben; Hahmann, Andrea; Sørensen, Poul; Madsen, Henrik

    2013-04-01

    This poster presents the current state of the public service obligation (PSO) funded project PSO 10464, with the title "Integrated Wind Power Planning Tool". The goal is to integrate a mesoscale numerical weather prediction (NWP) model with purely statistical tools in order to assess wind power fluctuations, with focus on long term power system planning for future wind farms as well as short term forecasting for existing wind farms. Currently, wind power fluctuation models are either purely statistical or integrated with NWP models of limited resolution. Using the state-of-the-art mesoscale NWP model Weather Research & Forecasting model (WRF) the forecast error is sought quantified in dependence of the time scale involved. This task constitutes a preparative study for later implementation of features accounting for NWP forecast errors in the DTU Wind Energy maintained Corwind code - a long term wind power planning tool. Within the framework of PSO 10464 research related to operational short term wind power prediction will be carried out, including a comparison of forecast quality at different mesoscale NWP model resolutions and development of a statistical wind power prediction tool taking input from WRF. The short term prediction part of the project is carried out in collaboration with ENFOR A/S; a Danish company that specialises in forecasting and optimisation for the energy sector. The integrated prediction model will allow for the description of the expected variability in wind power production in the coming hours to days, accounting for its spatio-temporal dependencies, and depending on the prevailing weather conditions defined by the WRF output. The output from the integrated short term prediction tool constitutes scenario forecasts for the coming period, which can then be fed into any type of system model or decision making problem to be solved. The high resolution of the WRF results loaded into the integrated prediction model will ensure a high accuracy

  9. 2008 Wind Energy Projects, Wind Powering America (Poster)

    SciTech Connect

    Not Available

    2009-01-01

    The Wind Powering America program produces a poster at the end of every calendar year that depicts new U.S. wind energy projects. The 2008 poster includes the following projects: Stetson Wind Farm in Maine; Dutch Hill Wind Farm in New York; Grand Ridge Wind Energy Center in Illinois; Hooper Bay, Alaska; Forestburg, South Dakota; Elbow Creek Wind Project in Texas; Glacier Wind Farm in Montana; Wray, Colorado; Smoky Hills Wind Farm in Kansas; Forbes Park Wind Project in Massachusetts; Spanish Fork, Utah; Goodland Wind Farm in Indiana; and the Tatanka Wind Energy Project on the border of North Dakota and South Dakota.

  10. Philippines: Small-scale renewable energy update

    SciTech Connect

    1997-12-01

    This paper gives an overview of the application of small scale renewable energy sources in the Philippines. Sources looked at include solar, biomass, micro-hydroelectric, mini-hydroelectric, wind, mini-geothermal, and hybrid. A small power utilities group is being spun off the major utility, to provide a structure for developing rural electrification programs. In some instances, private companies have stepped forward, avoiding what is perceived as overwhelming beaurocracy, and installed systems with private financing. The paper provides information on survey work which has been done on resources, and the status of cooperative programs to develop renewable systems in the nation.

  11. Index for Wind Power Variability

    SciTech Connect

    Kiviluoma, Juha; Holttinen, Hannele; Cutululis, Nicolaos Antonio; Litong-Palima, Marisciel; Scharff, Richard; Milligan, Michael; Weir, David Edward

    2014-11-13

    Variability of large scale wind power generation is dependent on several factors: characteristics of installed wind power plants, size of the area where the plants are installed, geographic dispersion within that area and its weather regime(s). Variability can be described by ramps in power generation, i.e. changes from time period to time period. Given enough data points, it can be described with a probability density function. This approach focuses on two dimensions of variability: duration of the ramp and probability distribution. This paper proposes an index based on these two dimensions to enable comparisons and characterizations of variability under different conditions. The index is tested with real, large scale wind power generation data from several countries. Considerations while forming an index are discussed, as well as the main results regarding what the drivers of variability experienced for different data.

  12. Developing wind and/or solar powered crop irrigation systems for the Great Plains

    USDA-ARS?s Scientific Manuscript database

    Some small scale, off-grid irrigation systems (less than 2.5 ha) that are powered by wind or solar energy are cost effective, but this paper discusses ways to achieve an economical renewable energy powered center pivot irrigation system for crops in the Great Plains. It was found that partitioning t...

  13. Analytical and Experimental Investigation of Ejector-Powered Engine Simulators for Wind Tunnel Models

    DTIC Science & Technology

    1977-01-01

    installed in a wind tunnel model and will generate inlet and exhaust stream conditions which simulate conditions produced by turbine engines does not exist...requirements, have substantially reduced the emphasis for small-scale turbine engine development for wind tunnel models, at least in the forseeable...investigations of ejector-powered engine simulators (EPES) applicable to wind tunnel models of turbine engine aircraft are being conducted at the

  14. Long-Term Wind Power Variability

    SciTech Connect

    Wan, Y. H.

    2012-01-01

    The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.

  15. Power Quality Aspects in a Wind Power Plant: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Chacon, J.; Romanowitz, H.

    2006-01-01

    Although many operational aspects affect wind power plant operation, this paper focuses on power quality. Because a wind power plant is connected to the grid, it is very important to understand the sources of disturbances that affect the power quality.

  16. Integrated Wind Power Planning Tool

    NASA Astrophysics Data System (ADS)

    Rosgaard, M. H.; Giebel, G.; Nielsen, T. S.; Hahmann, A.; Sørensen, P.; Madsen, H.

    2012-04-01

    This poster presents the current state of the public service obligation (PSO) funded project PSO 10464, with the working title "Integrated Wind Power Planning Tool". The project commenced October 1, 2011, and the goal is to integrate a numerical weather prediction (NWP) model with purely statistical tools in order to assess wind power fluctuations, with focus on long term power system planning for future wind farms as well as short term forecasting for existing wind farms. Currently, wind power fluctuation models are either purely statistical or integrated with NWP models of limited resolution. With regard to the latter, one such simulation tool has been developed at the Wind Energy Division, Risø DTU, intended for long term power system planning. As part of the PSO project the inferior NWP model used at present will be replaced by the state-of-the-art Weather Research & Forecasting (WRF) model. Furthermore, the integrated simulation tool will be improved so it can handle simultaneously 10-50 times more turbines than the present ~ 300, as well as additional atmospheric parameters will be included in the model. The WRF data will also be input for a statistical short term prediction model to be developed in collaboration with ENFOR A/S; a danish company that specialises in forecasting and optimisation for the energy sector. This integrated prediction model will allow for the description of the expected variability in wind power production in the coming hours to days, accounting for its spatio-temporal dependencies, and depending on the prevailing weather conditions defined by the WRF output. The output from the integrated prediction tool constitute scenario forecasts for the coming period, which can then be fed into any type of system model or decision making problem to be solved. The high resolution of the WRF results loaded into the integrated prediction model will ensure a high accuracy data basis is available for use in the decision making process of the Danish

  17. Wind turbine sound power measurements.

    PubMed

    Keith, Stephen E; Feder, Katya; Voicescu, Sonia A; Soukhovtsev, Victor; Denning, Allison; Tsang, Jason; Broner, Norm; Richarz, Werner; van den Berg, Frits

    2016-03-01

    This paper provides experimental validation of the sound power level data obtained from manufacturers for the ten wind turbine models examined in Health Canada's Community Noise and Health Study (CNHS). Within measurement uncertainty, the wind turbine sound power levels measured using IEC 61400-11 [(2002). (International Electrotechnical Commission, Geneva)] were consistent with the sound power level data provided by manufacturers. Based on measurements, the sound power level data were also extended to 16 Hz for calculation of C-weighted levels. The C-weighted levels were 11.5 dB higher than the A-weighted levels (standard deviation 1.7 dB). The simple relationship between A- and C- weighted levels suggests that there is unlikely to be any statistically significant difference between analysis based on either C- or A-weighted data.

  18. Offshore Wind Power Integration in severely fluctuating Wind Conditions

    NASA Astrophysics Data System (ADS)

    von Bremen, L.

    2010-09-01

    Strong power fluctuations from offshore wind farms that are induced by wind speed fluctuations pose a severe problem to the save integration of offshore wind power into the power supply system. Experience at the first large-scale offshore wind farm Horns Rev showed that spatial smoothing of power fluctuations within a single wind farm is significantly smaller than onshore results suggest when distributed wind farms of 160 MW altogether are connected to a single point of common-coupling. Wind power gradients larger than 10% of the rated capacity within 5 minutes require large amount of regulation power that is very expensive for the grid operator. It must be noted that a wind speed change of only 0.5m/s result in a wind power change of 10% (within the range of 9-11 m/s where the wind power curve is steepest). Hence, it is very important for the grid operator to know if strong fluctuations are likely or not. Observed weather conditions at the German wind energy research platform FINO1 in the German bight are used to quantify wind fluctuations. With a standard power curve these wind fluctuations are transfered to wind power. The aim is to predict the probability of exceedence of certain wind power gradients that occur in a time interval of e.g. 12 hours. During 2006 and 2009 the distribution of wind power fluctuations looks very similar giving hope that distinct atmospheric processes can be determined that act as a trigger. Most often high wind power fluctuations occur in a range of wind speeds between 9-12 m/s as can be expected from the shape of the wind power curve. A cluster analysis of the 500 hPa geopotential height to detect predominant weather regimes shows that high fluctuations are more likely in north-western flow. It is shown that most often high fluctuations occur in non-stable atmospheric stratification. The description of stratification by means of the vertical gradient of the virtual potential temperature is chosen to be indicative for convection, i

  19. Wind driven power generating apparatus

    SciTech Connect

    Andruszkiw, W.; Andrushkiw, R.

    1986-10-14

    A vertically adjustable wind driven power generating apparatus comprised of, in combination, a well in which is vertically movably mounted a wind driven power generating apparatus comprised of: (i) a wind driven power generating means comprised of a tubular housing having rotatably mounted therein a horizontally extending shaft. The shaft has a centrally disposed bevel gear fixedly attached thereto and helical vanes disposed longitudinally on both sides of the bevel gear; (ii) means for vertical movement of the tubular housing within the well comprised of (a) a hollow vertical support column having a circular cross section and having one end thereof attached to the bottom of the tubular housing and (b) a vertically extending hollow tubular member having a hollow interior fixedly mounted at its bottom end in the floor of the well and being open at its other end, the tubular member adapted to telescopically receive the vertical support column in its open end; (iii) vertical movement control means comprised of (a) downward movement control means comprising an inverted wing system generating inverse-lift mounted on the tubular housing, and (b) upward movement control means comprising a cylinder having an axially movable piston therein; (iv) power transmission means comprising a vertically extending power transmitting shaft that drives a power generator.

  20. Wind Power Utilization Guide.

    DTIC Science & Technology

    1981-09-01

    turbines, by John C. Yeoman. Dec 1978. 158 Table 7.4 also shows the power conditioning system and the tower height chosen for the installation. Next, the...Intersociety Energy Conversion Engineering Conference, Washington, D.C., Sep 22-26, 1969, pp 606-613. 173 , -.V ..-- - , 1 Smeaton , J. (1757). "An...Contact: John Harold or 2398 Fourth Street Tom Cummins Berkeley, CA 94710 Telephone: 415-848-2710 Aerowatt, S.A. Contact: Robert Dodge or c/o Automatic

  1. Wind for Schools: A Wind Powering America Project

    ERIC Educational Resources Information Center

    US Department of Energy, 2007

    2007-01-01

    The U.S. Department of Energy's (DOE's) Wind Powering America program (based at the National Renewable Energy Laboratory) sponsors the Wind for Schools Project to raise awareness in rural America about the benefits of wind energy while simultaneously educating college seniors regarding wind energy applications. The three primary project goals of…

  2. Wind Fins: Novel Lower-Cost Wind Power System

    SciTech Connect

    David C. Morris; Dr. Will D. Swearingen

    2007-10-08

    This project evaluated the technical feasibility of converting energy from the wind with a novel “wind fin” approach. This patent-pending technology has three major components: (1) a mast, (2) a vertical, hinged wind structure or fin, and (3) a power takeoff system. The wing structure responds to the wind with an oscillating motion, generating power. The overall project goal was to determine the basic technical feasibility of the wind fin technology. Specific objectives were the following: (1) to determine the wind energy-conversion performance of the wind fin and the degree to which its performance could be enhanced through basic design improvements; (2) to determine how best to design the wind fin system to survive extreme winds; (3) to determine the cost-effectiveness of the best wind fin designs compared to state-of-the-art wind turbines; and (4) to develop conclusions about the overall technical feasibility of the wind fin system. Project work involved extensive computer modeling, wind-tunnel testing with small models, and testing of bench-scale models in a wind tunnel and outdoors in the wind. This project determined that the wind fin approach is technically feasible and likely to be commercially viable. Project results suggest that this new technology has the potential to harvest wind energy at approximately half the system cost of wind turbines in the 10kW range. Overall, the project demonstrated that the wind fin technology has the potential to increase the economic viability of small wind-power generation. In addition, it has the potential to eliminate lethality to birds and bats, overcome public objections to the aesthetics of wind-power machines, and significantly expand wind-power’s contribution to the national energy supply.

  3. Wind Powering America Initiative (Fact Sheet)

    SciTech Connect

    Not Available

    2011-01-01

    The U.S. Department of Energy's Wind Powering America initiative engages in technology market acceptance, barrier reduction, and technology deployment support activities. This fact sheet outlines ways in which the Wind Powering America team works to reduce barriers to appropriate wind energy deployment, primarily by focusing on six program areas: workforce development, communications and outreach, stakeholder analysis and resource assessment, wind technology technical support, wind power for Native Americans, and federal sector support and collaboration.

  4. Spectrum of Wind Power Fluctuations

    NASA Astrophysics Data System (ADS)

    Bandi, M. M.

    2017-01-01

    Wind power fluctuations for an individual turbine and plant have been widely reported to follow the Kolmogorov spectrum of atmospheric turbulence; both vary with a fluctuation time scale τ as τ2 /3. Yet, this scaling has not been explained through turbulence theory. Using turbines as probes of turbulence, we show the τ2 /3 scaling results from a large scale influence of atmospheric turbulence. Owing to this long-range influence spanning 100s of kilometers, when power from geographically distributed wind plants is summed into aggregate power at the grid, fluctuations average (geographic smoothing) and their scaling steepens from τ2 /3→τ4 /3, beyond which further smoothing is not possible. Our analysis demonstrates grids have already reached this τ4 /3 spectral limit to geographic smoothing.

  5. Primer on Wind Power for Utility Applications

    SciTech Connect

    Wan, Y.

    2005-12-01

    The wind industry still faces many market barriers, some of which stem from utilities' lack of experience with the technology. Utility system operators and planners need to understand the effects of fluctuating wind power on system regulation and stability. Without high-frequency wind power data and realistic wind power plant models to analyze the problem, utilities often rely on conservative assumptions and worst-case scenarios to make engineering decisions. To remedy the situation, the National Renewable Energy Laboratory (NREL) has undertaken a project to record long-term, high-resolution (1-hertz [Hz]) wind power output data from large wind power plants in various regions. The objective is to systematically collect actual wind power data from large commercial wind power plants so that wind power fluctuations, their frequency distribution, the effects of spatial diversity, and the ancillary services of large commercial wind power plants can be analyzed. It also aims to provide the industry with nonproprietary wind power data in different wind regimes for system planning and operating impact studies. This report will summarize the results of data analysis performed at NREL and discuss the wind power characteristics related to power system operation and planning.

  6. Wind wheel electric power generator

    SciTech Connect

    Kaufman, J.W.

    1980-03-04

    Wind wheel electric power generator apparatus is disclosed as including a housing rotatably mounted upon a vertically disposed support column. Primary and auxiliary funnel-type, venturi ducts are fixedly mounted upon the housing for capturing wind currents and for conducting the same to a bladed wheel adapted to be operatively connected with generator apparatus. Additional air flows are also conducted onto the bladed wheel, all of the air flows positively effecting rotation of the wheel in a cumulative manner. The auxiliary ducts are disposed at an acute angle with respect to the longitudinal axis of the housing, and this feature , together with the rotatability of the housing and the ducts, permits capture of wind currents within a variable directional range.

  7. Wind wheel electric power generator

    NASA Technical Reports Server (NTRS)

    Kaufman, J. W. (Inventor)

    1980-01-01

    Wind wheel electric power generator apparatus includes a housing rotatably mounted upon a vertical support column. Primary and auxiliary funnel-type, venturi ducts are fixed onto the housing for capturing wind currents and conducting to a bladed wheel adapted to be operatively connected with the generator apparatus. Additional air flows are also conducted onto the bladed wheel; all of the air flows positively effecting rotation of the wheel in a cumulative manner. The auxiliary ducts are disposed at an acute angle with respect to the longitudinal axis of the housing, and this feature, together with the rotatability of the housing and the ducts, permits capture of wind currents within a variable directional range.

  8. Success Stories (Postcard), Wind Powering America (WPA)

    SciTech Connect

    Not Available

    2012-02-01

    Wind Powering America shares best practices and lessons learned on the Wind Powering America website. This postcard is an outreach tool that provides a brief description of the success stories as well as the URL.

  9. Wind for Schools: A Wind Powering America Project (Alaska) (Brochure)

    SciTech Connect

    Not Available

    2010-02-01

    This brochure provides an overview of Wind Powering America's Wind for Schools Project, including a description of the project, the participants, funding sources, the basic configurations, and how interested parties can become involved.

  10. Wind for Schools: A Wind Powering America Project (Brochure)

    SciTech Connect

    Baring-Gould, I.

    2009-08-01

    This brochure provides an overview of Wind Powering America's Wind for Schools Project, including a description of the project, the participants, funding sources, the basic configurations, and how interested parties can become involved.

  11. Wind for Schools: A Wind Powering America Project

    SciTech Connect

    Not Available

    2007-12-01

    This brochure serves as an introduction to Wind Powering America's Wind for Schools Project, including a description of the project, the participants, funding sources, and the basic configurations of the project.

  12. PSS Controller for Wind Power Generation Systems

    NASA Astrophysics Data System (ADS)

    Domínguez-García, J. L.; Gomis-Bellmunt, O.; Bianchi, F.; Sumper, A.

    2012-10-01

    Small signal stability analysis for power systems with wind farm interaction is presented. Power systems oscillation modes can be excited by disturbance or fault in the grid. Variable speed wind turbines can be regulated to reduce these oscillations, stabilising the power system. A power system stabiliser (PSS) control loop for wind power is designed in order to increase the damping of the oscillation modes. The proposed power system stabiliser controller is evaluated by small signal analysis.

  13. Power Quality Aspects in a Wind Power Plant

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Chacon, J.; Romanowitz, H.

    2006-01-01

    Like conventional power plants, wind power plants must provide the power quality required to ensure the stability and reliability of the power system it is connected to and to satisfy the customers connected to the same grid. When wind energy development began, wind power plants were very small, ranging in size from under one megawatt to tens megawatts with less than 100 turbines in each plant. Thus, the impact of wind power plant on the grid was very small, and any disturbance within or created by the plant was considered to be in the noise level. In the past 30 years, the size of wind turbines and the size of wind power plants have increased significantly. Notably, in Tehachapi, California, the amount of wind power generation has surpassed the infrastructure for which it was designed. At the same time, the lack of rules, standards, and regulations during early wind development has proven to be an increasing threat to the stability and power quality of the grid connected to a wind power plant. Fortunately, many new wind power plants are equipped with state of the art technology, which enables them to provide good service while producing clean power for the grid. The advances in power electronics have allowed many power system applications to become more flexible and to accomplish smoother regulation. Applications such as reactive power compensation, static transfer switches, energy storage, and variable-speed generations are commonly found in modern wind power plants. Although many operational aspects affect wind power plant operation, this paper, focuses on power quality. Because a wind power plant is connected to the grid, it is very important to understand the sources of disturbances that affect the power quality. In general, the voltage and frequency must be kept as stable as possible. The voltage and current distortions created by harmonics will also be discussed in this paper as will self-excitation, which may occur in a wind power plant due to loss of line.

  14. Wind Power Plant SCADA and Controls

    SciTech Connect

    Badrzadeh, Babak; Castillo, Nestor; Bradt, M.; Janakiraman, R.; Kennedy, R.; Klein, S.; Smith, Travis M; Vargas, L.

    2011-01-01

    Modern Wind Power Plants (WPPs) contain a variety of intelligent electronic devices (IEDs), Supervisory Control and Data Acquisition (SCADA) and communication systems. This paper discusses the issues related to a typical WPP's SCADA and Control. Presentation topics are: (1) Wind Turbine Controls; (2) Wind Plant SCADA, OEM SCADA Solutions, Third-Party SCADA Solutions; (3) Wind Plant Control; and (4) Security and Reliability Compliance.

  15. Engineering innovation to reduce wind power COE

    SciTech Connect

    Ammerman, Curtt Nelson

    2011-01-10

    There are enough wind resources in the US to provide 10 times the electric power we currently use, however wind power only accounts for 2% of our total electricity production. One of the main limitations to wind use is cost. Wind power currently costs 5-to-8 cents per kilowatt-hour, which is more than twice the cost of electricity generated by burning coal. Our Intelligent Wind Turbine LDRD Project is applying LANL's leading-edge engineering expertise in modeling and simulation, experimental validation, and advanced sensing technologies to challenges faced in the design and operation of modern wind turbines.

  16. Blowing in the Wind: A Review of Wind Power Technology

    ERIC Educational Resources Information Center

    Harris, Frank

    2014-01-01

    The use of wind as a replenishable energy resource has come back into favour in recent decades. It is much promoted as a viable, clean energy option that will help towards reducing CO[subscript 2] emissions in the UK. This article examines the history of wind power and considers the development of wind turbines, together with their economic,…

  17. Blowing in the Wind: A Review of Wind Power Technology

    ERIC Educational Resources Information Center

    Harris, Frank

    2014-01-01

    The use of wind as a replenishable energy resource has come back into favour in recent decades. It is much promoted as a viable, clean energy option that will help towards reducing CO[subscript 2] emissions in the UK. This article examines the history of wind power and considers the development of wind turbines, together with their economic,…

  18. Optimizing modes of a small-scale combined-cycle power plant with atmospheric-pressure gasifier

    NASA Astrophysics Data System (ADS)

    Donskoi, I. G.; Marinchenko, A. Yu.; Kler, A. M.; Ryzhkov, A. F.

    2015-09-01

    The scheme of an integrated coal gasification combined-cycle power plant with small capacity is proposed. Using the built mathematical model a feasibility study of this unit was performed, taking into account the kinetics of physical and chemical transformations in the fuel bed. The estimates of technical and economic efficiency of the plant have been obtained and compared with the alternative options.

  19. Exposure to electric power generator noise among small scale business operators in selected communities in Ibadan, Nigeria.

    PubMed

    Ana, Godson R E E; Luqman, Yesufu A; Shendell, Derek G; Owoaje, Eme T

    2014-11-01

    Inadequate and erratic power supplies mean small businesses use electric generators for alternative power. The authors' goal in the study described here was to assess noise from electric generators and impacts in the commercial areas of Agbowo and Ajibode in Ibadan, Nigeria. Noise levels (A-weighted decibels [dBA]) were measured over 12 weeks, three times a day, during the 2010 dry season using a sound level meter. A questionnaire was administered (515 respondents; 304 in Agbowo, 211 in Ajibode) and audiometric measurements were conducted on 40% of respondents. Mean noise levels varied by source (104 ± 7.7 dBA [diesel], 94.0 ± 6.3 dBA [petrol]) and were highest midday (90.6 ± 5.3 dBA [Agbowo], 70.9 ± 6.2 dBA [Ajibode]). Mean noise levels in Agbowo (78.5 ± 3.9 dBA) and Ajibode (65.7 ± 4.4 dBA) exceeded World Health Organization guidelines (65 dBA) for outdoor commercial environments. Working and living in Agbowo was significantly associated with current evidence of hearing impairment (odds ratio: 6.8, 95% confidence interval: 3.4-13.7). Reducing exposure to noise from electric power generators serving urban small businesses and homes is warranted.

  20. Small-Scale Hydroelectric Power Demonstration Project: reactivation of the Elk Rapids Hydroelectric Facility. Final technical and construction cost report

    SciTech Connect

    Not Available

    1985-05-01

    The Elk Rapids powerhouse dam is located on the Elk River channel in the Village of Elk Rapids, Michigan. Together with a small spillway structure located approximately 500 ft south of the dam, it constitutes the outlet to Lake Michigan for Elk Lake, Skegemog Lake, Torch Lake, Lake Bellaire, Clam Lake, and several smaller lakes. Power has been generated at the Elk Rapids site since the late nineteenth century, but the history of the present facility goes back to 1916 with the construction of the existing powerhouse dam by the Elk Rapids Iron Works Company. The facility was designed to contain four vertical-shaft generating units; however, only a single 270 hp Leffel type K unit was installed in 1916. In 1929, two additional Leffel units, rated 525 hp, were installed, and in 1930 a third 525 hp Leffel unit was added completely utilizing the capacity of the powerhouse and bringing the combined turbine capacity to 1845 hp.

  1. Wind turbine maximum power tracking device

    SciTech Connect

    Wertheim, M. M.; Herbermann, R. J.

    1985-06-25

    A method and apparatus for controlling the level of power transferred through a stand-alone wind power generating system utilizing a wind turbine whose output is converted to electrical power by means of an induction generator are disclosed. In the disclosed system, the velocity of the wind incident upon the blade of the turbine is sensed by a velocity sensor. This information is then used to vary the excitation frequency applied to the generator to adjust the shaft speed of the turbine in proportion to the change in wind velocity. The excitation frequency is adjusted in accordance with a control algorithm so that the power output of the system is equal to a maximum fraction of available wind power at wind velocities below a pre-determined power/velocity point.

  2. Wind power error estimation in resource assessments.

    PubMed

    Rodríguez, Osvaldo; Del Río, Jesús A; Jaramillo, Oscar A; Martínez, Manuel

    2015-01-01

    Estimating the power output is one of the elements that determine the techno-economic feasibility of a renewable project. At present, there is a need to develop reliable methods that achieve this goal, thereby contributing to wind power penetration. In this study, we propose a method for wind power error estimation based on the wind speed measurement error, probability density function, and wind turbine power curves. This method uses the actual wind speed data without prior statistical treatment based on 28 wind turbine power curves, which were fitted by Lagrange's method, to calculate the estimate wind power output and the corresponding error propagation. We found that wind speed percentage errors of 10% were propagated into the power output estimates, thereby yielding an error of 5%. The proposed error propagation complements the traditional power resource assessments. The wind power estimation error also allows us to estimate intervals for the power production leveled cost or the investment time return. The implementation of this method increases the reliability of techno-economic resource assessment studies.

  3. Wind Power Error Estimation in Resource Assessments

    PubMed Central

    Rodríguez, Osvaldo; del Río, Jesús A.; Jaramillo, Oscar A.; Martínez, Manuel

    2015-01-01

    Estimating the power output is one of the elements that determine the techno-economic feasibility of a renewable project. At present, there is a need to develop reliable methods that achieve this goal, thereby contributing to wind power penetration. In this study, we propose a method for wind power error estimation based on the wind speed measurement error, probability density function, and wind turbine power curves. This method uses the actual wind speed data without prior statistical treatment based on 28 wind turbine power curves, which were fitted by Lagrange's method, to calculate the estimate wind power output and the corresponding error propagation. We found that wind speed percentage errors of 10% were propagated into the power output estimates, thereby yielding an error of 5%. The proposed error propagation complements the traditional power resource assessments. The wind power estimation error also allows us to estimate intervals for the power production leveled cost or the investment time return. The implementation of this method increases the reliability of techno-economic resource assessment studies. PMID:26000444

  4. A survey on wind power ramp forecasting.

    SciTech Connect

    Ferreira, C.; Gama, J.; Matias, L.; Botterud, A.; Wang, J.

    2011-02-23

    The increasing use of wind power as a source of electricity poses new challenges with regard to both power production and load balance in the electricity grid. This new source of energy is volatile and highly variable. The only way to integrate such power into the grid is to develop reliable and accurate wind power forecasting systems. Electricity generated from wind power can be highly variable at several different timescales: sub-hourly, hourly, daily, and seasonally. Wind energy, like other electricity sources, must be scheduled. Although wind power forecasting methods are used, the ability to predict wind plant output remains relatively low for short-term operation. Because instantaneous electrical generation and consumption must remain in balance to maintain grid stability, wind power's variability can present substantial challenges when large amounts of wind power are incorporated into a grid system. A critical issue is ramp events, which are sudden and large changes (increases or decreases) in wind power. This report presents an overview of current ramp definitions and state-of-the-art approaches in ramp event forecasting.

  5. Wind power generation and dispatch in competitive power markets

    NASA Astrophysics Data System (ADS)

    Abreu, Lisias

    Wind energy is currently the fastest growing type of renewable energy. The main motivation is led by more strict emission constraints and higher fuel prices. In addition, recent developments in wind turbine technology and financial incentives have made wind energy technically and economically viable almost anywhere. In restructured power systems, reliable and economical operation of power systems are the two main objectives for the ISO. The ability to control the output of wind turbines is limited and the capacity of a wind farm changes according to wind speeds. Since this type of generation has no production costs, all production is taken by the system. Although, insufficient operational planning of power systems considering wind generation could result in higher system operation costs and off-peak transmission congestions. In addition, a GENCO can participate in short-term power markets in restructured power systems. The goal of a GENCO is to sell energy in such a way that would maximize its profitability. However, due to market price fluctuations and wind forecasting errors, it is essential for the wind GENCO to keep its financial risk at an acceptable level when constituting market bidding strategies. This dissertation discusses assumptions, functions, and methodologies that optimize short-term operations of power systems considering wind energy, and that optimize bidding strategies for wind producers in short-term markets. This dissertation also discusses uncertainties associated with electricity market environment and wind power forecasting that can expose market participants to a significant risk level when managing the tradeoff between profitability and risk.

  6. High Voltage Power Transmission for Wind Energy

    NASA Astrophysics Data System (ADS)

    Kim, Young il

    The high wind speeds and wide available area at sea have recently increased the interests on offshore wind farms in the U.S.A. As offshore wind farms become larger and are placed further from the shore, the power transmission to the onshore grid becomes a key feature. Power transmission of the offshore wind farm, in which good wind conditions and a larger installation area than an onshore site are available, requires the use of submarine cable systems. Therefore, an underground power cable system requires unique design and installation challenges not found in the overhead power cable environment. This paper presents analysis about the benefit and drawbacks of three different transmission solutions: HVAC, LCC/VSC HVDC in the grid connecting offshore wind farms and also analyzed the electrical characteristics of underground cables. In particular, loss of HV (High Voltage) subsea power of the transmission cables was evaluated by the Brakelmann's theory, taking into account the distributions of current and temperature.

  7. Evaluation of Global Wind Power and Interconnected Wind Farms

    NASA Astrophysics Data System (ADS)

    Archer, C. L.; Jacobson, M. Z.

    2005-12-01

    The world wind power potential is evaluated in this study. Wind speeds are calculated at 80 m, the hub height of modern, 77-m diameter, 1500 W turbines. Since relatively few observations are available at 80 m, the Least Square extrapolation technique is utilized to obtain estimates of wind speeds at 80 m given observed wind speeds at 10 m (widely available) and a network of sounding stations. Globally, about 13% of all reporting stations experience annual mean wind speeds >= 6.9 m/s at 80 m (i.e., wind power class 3 or greater) and can therefore be considered suitable for low-cost wind power generation. This estimate is believed to be conservative. Of all continents, North America has the largest number of stations in class >= 3 (453). Areas with great potential are found in Northern Europe along the North Sea, the southern tip of the South American continent, the island of Tasmania in Australia, the Great Lakes region, and the northeastern and northwestern coasts of North America. Assuming that statistics generated from all stations analyzed here are representative of the global distribution of winds, global wind power generated at locations with mean annual wind speeds >= 6.9 m/s at 80 m is found to be approximately 72 TW (54,000 Mtoe) for the year 2000. Even if only 20% of this power could be captured, it could satisfy 100% of the world's energy demand for all purposes (6,995-10,177 Mtoe) and over seven times the world electricity needs (1.6-1.8 TW). Several practical barriers need to be overcome to fully realize this potential. Wind intermittency could be perceived as one of them. However, interconnecting wind farms through the transmission grid, also known as distributed wind power, is a simple and effective way of reducing deliverable wind power swings caused by wind intermittency. As more farms are interconnected in an array, wind speed correlation among sites decreases and so does the probability that all sites experience the same wind regime at the same

  8. Wind Farm Power System Model Development: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.

    2004-07-01

    In some areas, wind power has reached a level where it begins to impact grid operation and the stability of local utilities. In this paper, the model development for a large wind farm will be presented. Wind farm dynamic behavior and contribution to stability during transmission system faults will be examined.

  9. Wind for Schools Project Power System Brief

    SciTech Connect

    Not Available

    2007-08-01

    This fact sheet provides an overview of the system components of a Wind Powering America Wind for Schools project. Wind Powering America's (WPA's) Wind for Schools project uses a basic system configuration for each school project. The system incorporates a single SkyStream(TM) wind turbine, a 70-ft guyed tower, disconnect boxes at the base of the turbine and at the school, and an interconnection to the school's electrical system. A detailed description of each system component is provided in this document.

  10. Wind Powering America's Wind for Schools Project: Summary Report

    SciTech Connect

    Baring-Gould, I.; Newcomb, C.

    2012-06-01

    This report provides an overview of the U.S. Department of Energy, Wind Powering America, Wind for Schools project. It outlines teacher-training activities and curriculum development; discusses the affiliate program that allows school districts and states to replicate the program; and contains reports that provide an update on activities and progress in the 11 states in which the Wind for Schools project operates.

  11. ValidWind applications: wind power prospecting, aerosol transport

    NASA Astrophysics Data System (ADS)

    Wilkerson, T.; Marchant, A.; Apedaile, T.; Scholes, D.; Simmons, J.; Bradford, B.

    2010-10-01

    The ValidWind™ system employs an XL200 laser rangefinder to track small, lightweight, helium-filled balloons (0.33 meters, 0.015 kg). We record their trajectories (range resolution 0.5 meters) and automatically produce local wind profiles in real time. Tracking range is enhanced beyond 2 km by applying retro-reflector tape to the balloons. Aerodynamic analysis shows that ValidWind balloon motion is well coupled to the local wind within relaxation times { 1 second, due to drag forces at subcritical Reynolds numbers Re < 2×105. Such balloons are Lagrangian sensors; i.e., they move with the wind as opposed to being fixed in space. In a field campaign involving many balloons, slight variations in ground level winds at launch lead to trajectory patterns that we analyze to derive 3D maps of the vertical and horizontal wind profiles downwind of the launch area. Field campaigns are focused on likely sites for wind power generation and on facilities from which airborne particulates are emitted. We describe results of wind measurements in Utah near the cities of Clarkston, Logan, and Ogden. ValidWind is a relatively inexpensive wind sensor that is easily and rapidly transported and deployed at remote sites. It is an ideal instrument for wind prospecting to support early decisions required, for example, in siting meteorology towers. ValidWind provides high-resolution, real time characterization of the average and changing 3D wind fields in which wind power turbines and other remote sensors must operate.

  12. Utility interconnection issues for wind power generation

    NASA Technical Reports Server (NTRS)

    Herrera, J. I.; Lawler, J. S.; Reddoch, T. W.; Sullivan, R. L.

    1986-01-01

    This document organizes the total range of utility related issues, reviews wind turbine control and dynamic characteristics, identifies the interaction of wind turbines to electric utility systems, and identifies areas for future research. The material is organized at three levels: the wind turbine, its controls and characteristics; connection strategies as dispersed or WPSs; and the composite issue of planning and operating the electric power system with wind generated electricity.

  13. Geophysical limits to global wind power

    NASA Astrophysics Data System (ADS)

    Marvel, Kate; Kravitz, Ben; Caldeira, Ken

    2013-02-01

    There is enough power in Earth's winds to be a primary source of near-zero-emission electric power as the global economy continues to grow through the twenty-first century. Historically, wind turbines are placed on Earth's surface, but high-altitude winds are usually steadier and faster than near-surface winds, resulting in higher average power densities. Here, we use a climate model to estimate the amount of power that can be extracted from both surface and high-altitude winds, considering only geophysical limits. We find wind turbines placed on Earth's surface could extract kinetic energy at a rate of at least 400TW, whereas high-altitude wind power could extract more than 1,800TW. At these high rates of extraction, there are pronounced climatic consequences. However, we find that at the level of present global primary power demand (~ 18TW ref. ), uniformly distributed wind turbines are unlikely to substantially affect the Earth's climate. It is likely that wind power growth will be limited by economic or environmental factors, not global geophysical limits.

  14. Wind power forecasting: IEA Wind Task 36 & future research issues

    DOE PAGES

    Giebel, G.; Cline, J.; Frank, H.; ...

    2016-10-03

    Here, this paper presents the new International Energy Agency Wind Task 36 on Forecasting, and invites to collaborate within the group. Wind power forecasts have been used operatively for over 20 years. Despite this fact, there are still several possibilities to improve the forecasts, both from the weather prediction side and from the usage of the forecasts. The new International Energy Agency (IEA) Task on Forecasting for Wind Energy tries to organise international collaboration, among national meteorological centres with an interest and/or large projects on wind forecast improvements (NOAA, DWD, MetOffice, met.no, DMI,...), operational forecaster and forecast users. The Taskmore » is divided in three work packages: Firstly, a collaboration on the improvement of the scientific basis for the wind predictions themselves. This includes numerical weather prediction model physics, but also widely distributed information on accessible datasets. Secondly, we will be aiming at an international pre-standard (an IEA Recommended Practice) on benchmarking and comparing wind power forecasts, including probabilistic forecasts. This WP will also organise benchmarks, in cooperation with the IEA Task WakeBench. Thirdly, we will be engaging end users aiming at dissemination of the best practice in the usage of wind power predictions. As first results, an overview of current issues for research in short-term forecasting of wind power is presented.« less

  15. Wind power forecasting: IEA Wind Task 36 & future research issues

    SciTech Connect

    Giebel, G.; Cline, J.; Frank, H.; Shaw, W.; Pinson, P.; Hodge, B-M; Kariniotakis, G.; Madsen, J.; Möhrlen, C.

    2016-10-03

    Here, this paper presents the new International Energy Agency Wind Task 36 on Forecasting, and invites to collaborate within the group. Wind power forecasts have been used operatively for over 20 years. Despite this fact, there are still several possibilities to improve the forecasts, both from the weather prediction side and from the usage of the forecasts. The new International Energy Agency (IEA) Task on Forecasting for Wind Energy tries to organise international collaboration, among national meteorological centres with an interest and/or large projects on wind forecast improvements (NOAA, DWD, MetOffice, met.no, DMI,...), operational forecaster and forecast users. The Task is divided in three work packages: Firstly, a collaboration on the improvement of the scientific basis for the wind predictions themselves. This includes numerical weather prediction model physics, but also widely distributed information on accessible datasets. Secondly, we will be aiming at an international pre-standard (an IEA Recommended Practice) on benchmarking and comparing wind power forecasts, including probabilistic forecasts. This WP will also organise benchmarks, in cooperation with the IEA Task WakeBench. Thirdly, we will be engaging end users aiming at dissemination of the best practice in the usage of wind power predictions. As first results, an overview of current issues for research in short-term forecasting of wind power is presented.

  16. Wind power forecasting: IEA Wind Task 36 & future research issues

    NASA Astrophysics Data System (ADS)

    Giebel, G.; Cline, J.; Frank, H.; Shaw, W.; Pinson, P.; Hodge, B.-M.; Kariniotakis, G.; Madsen, J.; Möhrlen, C.

    2016-09-01

    This paper presents the new International Energy Agency Wind Task 36 on Forecasting, and invites to collaborate within the group. Wind power forecasts have been used operatively for over 20 years. Despite this fact, there are still several possibilities to improve the forecasts, both from the weather prediction side and from the usage of the forecasts. The new International Energy Agency (IEA) Task on Forecasting for Wind Energy tries to organise international collaboration, among national meteorological centres with an interest and/or large projects on wind forecast improvements (NOAA, DWD, MetOffice, met.no, DMI,...), operational forecaster and forecast users. The Task is divided in three work packages: Firstly, a collaboration on the improvement of the scientific basis for the wind predictions themselves. This includes numerical weather prediction model physics, but also widely distributed information on accessible datasets. Secondly, we will be aiming at an international pre-standard (an IEA Recommended Practice) on benchmarking and comparing wind power forecasts, including probabilistic forecasts. This WP will also organise benchmarks, in cooperation with the IEA Task WakeBench. Thirdly, we will be engaging end users aiming at dissemination of the best practice in the usage of wind power predictions. As first results, an overview of current issues for research in short-term forecasting of wind power is presented.

  17. Harmonics in a Wind Power Plant: Preprint

    SciTech Connect

    Preciado, V.; Madrigal, M.; Muljadi, E.; Gevorgian, V.

    2015-04-02

    Wind power generation has been growing at a very fast pace for the past decade, and its influence and impact on the electric power grid is significant. As in a conventional power plant, a wind power plant (WPP) must ensure that the quality of the power being delivered to the grid is excellent. At the same time, the wind turbine should be able to operate immune to small disturbances coming from the grid. Harmonics are one of the more common power quality issues presented by large WPPs because of the high switching frequency of the power converters and the possible nonlinear behavior from electric machines (generator, transformer, reactors) within a power plant. This paper presents a summary of the most important issues related to harmonics in WPPs and discusses practical experiences with actual Type 1 and Type 3 wind turbines in two WPPs.

  18. Value of Wind Power Forecasting

    SciTech Connect

    Lew, D.; Milligan, M.; Jordan, G.; Piwko, R.

    2011-04-01

    This study, building on the extensive models developed for the Western Wind and Solar Integration Study (WWSIS), uses these WECC models to evaluate the operating cost impacts of improved day-ahead wind forecasts.

  19. Power Transformer Application for Wind Plant Substations

    SciTech Connect

    Behnke, M. R.; Bloethe, W.G.; Bradt, M.; Brooks, C.; Camm, E H; Dilling, W.; Goltz, B.; Li, J.; Niemira, J.; Nuckles, K.; Patino, J.; Reza, M; Richardson, B.; Samaan, N.; Schoene, Jens; Smith, Travis M; Snyder, Isabelle B; Starke, Michael R; Walling, R.; Zahalka, G.

    2010-01-01

    Wind power plants use power transformers to step plant output from the medium voltage of the collector system to the HV or EHV transmission system voltage. This paper discusses the application of these transformers with regard to the selection of winding configuration, MVA rating, impedance, loss evaluation, on-load tapchanger requirements, and redundancy.

  20. Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

    NASA Astrophysics Data System (ADS)

    Wen, Binrong; Wei, Sha; Wei, Kexiang; Yang, Wenxian; Peng, Zhike; Chu, Fulei

    2017-09-01

    The magnitude and stability of power output are two key indices of wind turbines. This study investigates the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine. First, wind speed models, particularly the wind shear model and the tower shadow model, are described in detail. The widely accepted tower shadow model is modified in view of the cone-shaped towers of modern large-scale wind turbines. Power fluctuation and power loss due to wind shear and tower shadow are analyzed by performing theoretical calculations and case analysis within the framework of a modified version of blade element momentum theory. Results indicate that power fluctuation is mainly caused by tower shadow, whereas power loss is primarily induced by wind shear. Under steady wind conditions, power loss can be divided into wind farm loss and rotor loss. Wind farm loss is constant at 3 α(3 α-1) R 2/(8 H 2). By contrast, rotor loss is strongly influenced by the wind turbine control strategies and wind speed. That is, when the wind speed is measured in a region where a variable-speed controller works, the rotor loss stabilizes around zero, but when the wind speed is measured in a region where the blade pitch controller works, the rotor loss increases as the wind speed intensifies. The results of this study can serve as a reference for accurate power estimation and strategy development to mitigate the fluctuations in aerodynamic loads and power output due to wind shear and tower shadow.

  1. Power fluctuation and power loss of wind turbines due to wind shear and tower shadow

    NASA Astrophysics Data System (ADS)

    Wen, Binrong; Wei, Sha; Wei, Kexiang; Yang, Wenxian; Peng, Zhike; Chu, Fulei

    2017-05-01

    The magnitude and stability of power output are two key indices of wind turbines. This study investigates the effects of wind shear and tower shadow on power output in terms of power fluctuation and power loss to estimate the capacity and quality of the power generated by a wind turbine. First, wind speed models, particularly the wind shear model and the tower shadow model, are described in detail. The widely accepted tower shadow model is modified in view of the cone-shaped towers of modern large-scale wind turbines. Power fluctuation and power loss due to wind shear and tower shadow are analyzed by performing theoretical calculations and case analysis within the framework of a modified version of blade element momentum theory. Results indicate that power fluctuation is mainly caused by tower shadow, whereas power loss is primarily induced by wind shear. Under steady wind conditions, power loss can be divided into wind farm loss and rotor loss. Wind farm loss is constant at 3α(3α-1)R 2/(8H 2). By contrast, rotor loss is strongly influenced by the wind turbine control strategies and wind speed. That is, when the wind speed is measured in a region where a variable-speed controller works, the rotor loss stabilizes around zero, but when the wind speed is measured in a region where the blade pitch controller works, the rotor loss increases as the wind speed intensifies. The results of this study can serve as a reference for accurate power estimation and strategy development to mitigate the fluctuations in aerodynamic loads and power output due to wind shear and tower shadow.

  2. Active Power Controls from Wind Power: Bridging the Gaps

    SciTech Connect

    Ela, E.; Gevorgian, V.; Fleming, P.; Zhang, Y. C.; Singh, M.; Muljadi, E.; Scholbrook, A.; Aho, J.; Buckspan, A.; Pao, L.; Singhvi, V.; Tuohy, A.; Pourbeik, P.; Brooks, D.; Bhatt, N.

    2014-01-01

    This paper details a comprehensive study undertaken by the National Renewable Energy Laboratory, Electric Power Research Institute, and the University of Colorado to understand how the contribution of wind power providing active power control (APC) can benefit the total power system economics, increase revenue streams, improve the reliability and security of the power system, and provide superior and efficient response while reducing any structural and loading impacts that may reduce the life of the wind turbine or its components. The study includes power system simulations, control simulations, and actual field tests using turbines at NREL's National Wind Technology Center (NWTC). The study focuses on synthetic inertial control, primary frequency control, and automatic generation control, and analyzes timeframes ranging from milliseconds to minutes to the lifetime of wind turbines, locational scope ranging from components of turbines to large wind plants to entire synchronous interconnections, and additional topics ranging from economics to power system engineering to control design.

  3. PowerJet Wind Turbine Project

    SciTech Connect

    Bartlett, Raymond J.

    2008-11-30

    The PowerJet wind turbine overcomes problems characteristic of the small wind turbines that are on the market today by providing reliable output at a wide range of wind speeds, durability, silent operation at all wind speeds, and bird-safe operation. Prime Energy's objective for this project was to design and integrate a generator with an electrical controller and mechanical controls to maximize the generation of electricity by its wind turbine. The scope of this project was to design, construct and test a mechanical back plate to control rotational speed in high winds, and an electronic controller to maximize power output and to assist the base plate in controlling rotational speed in high winds.

  4. SMALL SCALE BIOMASS FUELED GAS TURBINE ENGINE

    EPA Science Inventory

    A new generation of small scale (less than 20 MWe) biomass fueled, power plants are being developed based on a gas turbine (Brayton cycle) prime mover. These power plants are expected to increase the efficiency and lower the cost of generating power from fuels such as wood. The n...

  5. SMALL SCALE BIOMASS FUELED GAS TURBINE ENGINE

    EPA Science Inventory

    A new generation of small scale (less than 20 MWe) biomass fueled, power plants are being developed based on a gas turbine (Brayton cycle) prime mover. These power plants are expected to increase the efficiency and lower the cost of generating power from fuels such as wood. The n...

  6. Wind Power America Final Report

    SciTech Connect

    Spangler, Brian; Montgomery, Kathi; Cartwright, Paul

    2012-01-30

    The objective of this grant was to further the development of Montana’s vast wind resources for small, medium and large scale benefits to Montana and the nation. This was accomplished through collaborative work with wind industry representatives, state and local governments, the agricultural community and interested citizens. Through these efforts DEQ was able to identify development barriers, educate and inform citizens as well as participate in regional and national dialogue that will spur the development of wind resources

  7. Optimizing Baseload Power of Interconnected Wind Farms

    NASA Astrophysics Data System (ADS)

    Kobrin, B. H.

    2010-12-01

    Interconnecting wind farms has been proposed as a way to reduce the natural unreliability of wind power caused by the intermittency of winds. In a previous study, the benefits of interconnecting up to 19 sites in the Midwestern United States were evaluated with the assumption that the same number of turbines would be installed at each site. The goal of this study was to avoid this assumption and examine the advantages of optimizing the ratio of turbines at each site. An optimization algorithm based on the gradient method was used to maximize the baseload power, or guaranteed power 87.5% of the year, using hourly wind speed data for the same 19 sites. The result was a significant improvement in the reliability of the array, increasing the baseload power by 38% compared to the array with equally-weighted sites. Further analysis showed that the turbines were generally distributed according to the average wind power at each site and the wind correlation among sites. In addition to optimizing the average baseload of the array, this study examined the benefits of optimizing the baseload for peak usage time (between noon and 7 p.m), and thus a simplified model was created to analyze how interconnecting wind farms could increase correlation with energy consumption. Optimization for peak usage hours, however, provided no additional benefit over the original optimized array because the variation of average hourly wind speeds was well-correlated among the sites.

  8. Dynamic Models for Wind Turbines and Wind Power Plants

    SciTech Connect

    Singh, M.; Santoso, S.

    2011-10-01

    The primary objective of this report was to develop universal manufacturer-independent wind turbine and wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Manufacturer-specific models of wind turbines are favored for use in wind power interconnection studies. While they are detailed and accurate, their usages are limited to the terms of the non-disclosure agreement, thus stifling model sharing. The primary objective of the work proposed is to develop universal manufacturer-independent wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Each of these models includes representations of general turbine aerodynamics, the mechanical drive-train, and the electrical characteristics of the generator and converter, as well as the control systems typically used. To determine how realistic model performance is, the performance of one of the models (doubly-fed induction generator model) has been validated using real-world wind power plant data. This work also documents selected applications of these models.

  9. Optimizing Wind Power Generation while Minimizing Wildlife Impacts in an Urban Area

    PubMed Central

    Bohrer, Gil; Zhu, Kunpeng; Jones, Robert L.; Curtis, Peter S.

    2013-01-01

    The location of a wind turbine is critical to its power output, which is strongly affected by the local wind field. Turbine operators typically seek locations with the best wind at the lowest level above ground since turbine height affects installation costs. In many urban applications, such as small-scale turbines owned by local communities or organizations, turbine placement is challenging because of limited available space and because the turbine often must be added without removing existing infrastructure, including buildings and trees. The need to minimize turbine hazard to wildlife compounds the challenge. We used an exclusion zone approach for turbine-placement optimization that incorporates spatially detailed maps of wind distribution and wildlife densities with power output predictions for the Ohio State University campus. We processed public GIS records and airborne lidar point-cloud data to develop a 3D map of all campus buildings and trees. High resolution large-eddy simulations and long-term wind climatology were combined to provide land-surface-affected 3D wind fields and the corresponding wind-power generation potential. This power prediction map was then combined with bird survey data. Our assessment predicts that exclusion of areas where bird numbers are highest will have modest effects on the availability of locations for power generation. The exclusion zone approach allows the incorporation of wildlife hazard in wind turbine siting and power output considerations in complex urban environments even when the quantitative interaction between wildlife behavior and turbine activity is unknown. PMID:23409117

  10. Optimizing wind power generation while minimizing wildlife impacts in an urban area.

    PubMed

    Bohrer, Gil; Zhu, Kunpeng; Jones, Robert L; Curtis, Peter S

    2013-01-01

    The location of a wind turbine is critical to its power output, which is strongly affected by the local wind field. Turbine operators typically seek locations with the best wind at the lowest level above ground since turbine height affects installation costs. In many urban applications, such as small-scale turbines owned by local communities or organizations, turbine placement is challenging because of limited available space and because the turbine often must be added without removing existing infrastructure, including buildings and trees. The need to minimize turbine hazard to wildlife compounds the challenge. We used an exclusion zone approach for turbine-placement optimization that incorporates spatially detailed maps of wind distribution and wildlife densities with power output predictions for the Ohio State University campus. We processed public GIS records and airborne lidar point-cloud data to develop a 3D map of all campus buildings and trees. High resolution large-eddy simulations and long-term wind climatology were combined to provide land-surface-affected 3D wind fields and the corresponding wind-power generation potential. This power prediction map was then combined with bird survey data. Our assessment predicts that exclusion of areas where bird numbers are highest will have modest effects on the availability of locations for power generation. The exclusion zone approach allows the incorporation of wildlife hazard in wind turbine siting and power output considerations in complex urban environments even when the quantitative interaction between wildlife behavior and turbine activity is unknown.

  11. Wind power finding its competitive edge

    SciTech Connect

    Kaplan, D.

    1993-08-18

    When interviewing the head of the windpower association, one expects to hear a barrage of global warming, acid rain and other pollution horror stories, followed by a call for an expensive federal effort to replace fossil fuels with wind power. But not from Randy Swisher, president of the American Wind Energy Association. This article describes the technological advances made in wind energy during the last decade, and its cost competitiveness with conventional fossil fuels.

  12. Small scale sanitation technologies.

    PubMed

    Green, W; Ho, G

    2005-01-01

    Small scale systems can improve the sustainability of sanitation systems as they more easily close the water and nutrient loops. They also provide alternate solutions to centrally managed large scale infrastructures. Appropriate sanitation provision can improve the lives of people with inadequate sanitation through health benefits, reuse products as well as reduce ecological impacts. In the literature there seems to be no compilation of a wide range of available onsite sanitation systems around the world that encompasses black and greywater treatment plus stand-alone dry and urine separation toilet systems. Seventy technologies have been identified and classified according to the different waste source streams. Sub-classification based on major treatment methods included aerobic digestion, composting and vermicomposting, anaerobic digestion, sand/soil/peat filtration and constructed wetlands. Potential users or suppliers of sanitation systems can choose from wide range of technologies available and examine the different treatment principles used in the technologies. Sanitation systems need to be selected according to the local social, economic and environmental conditions and should aim to be sustainable.

  13. Short-Term Power Fluctuations of Large Wind Power Plants: Preprint

    SciTech Connect

    Wan, Y.; Bucaneg, D.

    2002-01-01

    With electric utilities and other power providers showing increased interest in wind power and with growing penetration of wind capacity into the market, questions about how wind power fluctuations affect power system operations and about wind power's ancillary services requirements are receiving lots of attention. The project's purpose is to acquire actual, long-term wind power output data for analyzing wind power fluctuations, frequency distribution of the changes, the effects of spatial diversity, and wind power ancillary services.

  14. Wind power and the conditions at a liberalized power market

    NASA Astrophysics Data System (ADS)

    Morthorst, P. E.

    2003-07-01

    Wind power is undergoing a rapid development nationally as well as globally and in a number of countries covers an increasing part of the power supply. At the same time an ongoing liberalization of power markets is taking place and to an increasing extent the owners of wind power plants will themselves have to be responsible for trading the power at the spot market and financially handling the balancing. In the western part of Denmark (Jutland/Funen area), wind-generated power from time to time covers almost 100% of total power consumption. Therefore some examples are chosen from this area to analyse in more detail how well large amounts of wind power in the short-term are handled at the power spot market. It turns out that there is a tendency that more wind power in the system in the short run leads to relatively lower spot prices, while less wind power implies relatively higher spot prices, although, with the exception of December 2002, in general no strong relationship is found. A stronger relationship is found at the regulating market, where there is a fairly clear tendency that the more wind power produced, the higher is the need for down-regulation, and, correspondingly, the less wind power produced, the higher is the need for up-regulation. In general for the Jutland/Funen area the average cost of down-regulation is calculated as 1.2 c/kWh regulated for 2002, while the cost of up-regulation amounts to 0.7 c/kWh regulated.

  15. A Study of the Effects of Large Scale Gust Generation in a Small Scale Atmospheric Wind Tunnel: Application to Micro Aerial Vehicles

    NASA Astrophysics Data System (ADS)

    Roadman, Jason; Mohseni, Kamran

    2009-11-01

    Modern technology operating in the atmospheric boundary layer could benefit from more accurate wind tunnel testing. While scaled atmospheric boundary layer tunnels have been well developed, tunnels replicating portions of the turbulence of the atmospheric boundary layer at full scale are a comparatively new concept. Testing at full-scale Reynolds numbers with full-scale turbulence in an ``atmospheric wind tunnel'' is sought. Many programs could utilize such a tool including that of Micro Aerial Vehicles (MAVs) and other unmanned aircraft, the wind energy industry, fuel efficient vehicles, and the study of bird and insect fight. The construction of an active ``gust generator'' for a new atmospheric tunnel is reviewed and the turbulence it generates is measured utilizing single and cross hot wires. Results from this grid are compared to atmospheric turbulence and it is shown that various gust strengths can be produced corresponding to days ranging from calm to quite gusty. An initial test is performed in the atmospheric wind tunnel whereby the effects of various turbulence conditions on transition and separation on the upper surface of a MAV wing is investigated using oil flow visualization.

  16. The impact of wind power on electricity prices

    SciTech Connect

    Brancucci Martinez-Anido, Carlo; Brinkman, Greg; Hodge, Bri-Mathias

    2016-08-01

    This paper investigates the impact of wind power on electricity prices using a production cost model of the Independent System Operator - New England power system. Different scenarios in terms of wind penetration, wind forecasts, and wind curtailment are modeled in order to analyze the impact of wind power on electricity prices for different wind penetration levels and for different levels of wind power visibility and controllability. The analysis concludes that electricity price volatility increases even as electricity prices decrease with increasing wind penetration levels. The impact of wind power on price volatility is larger in the shorter term (5-min compared to hour-to-hour). The results presented show that over-forecasting wind power increases electricity prices while under-forecasting wind power reduces them. The modeling results also show that controlling wind power by allowing curtailment increases electricity prices, and for higher wind penetrations it also reduces their volatility.

  17. Study of a Wind Farm Power System: Preprint

    SciTech Connect

    Muljadi, E.; Wan, Y.; Butterfield, C. P.; Parsons, B.

    2002-01-01

    A wind power system differs from a conventional power system. In a conventional power plant, the operator can control the plant's output. The output of a wind farm cannot be controlled because the output fluctuates with the wind. In this paper, we investigate the power-system interaction resulting from power variations at wind farms using steady-state analysis.

  18. Small Scale Discharge Studies

    DTIC Science & Technology

    1975-08-31

    pumping, the principal limitation on average laser power achievable can be calculated from the average power that can be put through the foil...separating the electron gun vacuum chamber from the laser cavity. The limitations on the average power through this foil can be calculated from a...density of a particular ro- tational line J NV,(2J + 1) r-BKJ+Dl Nv’(J) = VKT /B eXP (15) where N , is total number density of the NO

  19. Wind Powering America FY06 Activities Summary

    SciTech Connect

    Not Available

    2007-02-01

    The Wind Powering America FY06 Activities Summary reflects the accomplishments of our state wind working groups, our programs at the National Renewable Energy Laboratory, and our partner organizations. The national WPA team remains a leading force for moving wind energy forward in the United States. WPA continues to work with its national, regional, and state partners to communicate the opportunities and benefits of wind energy to a diverse set of stakeholders. WPA now has 29 state wind working groups (welcoming New Jersey, Indiana, Illinois, and Missouri in 2006) that form strategic alliances to communicate wind's benefits to the state stakeholders. More than 120 members of national and state public and private sector organizations from 34 states attended the 5th Annual WPA All-States Summit in Pittsburgh in June.

  20. Are local wind power resources well estimated?

    NASA Astrophysics Data System (ADS)

    Lundtang Petersen, Erik; Troen, Ib; Jørgensen, Hans E.; Mann, Jakob

    2013-03-01

    Planning and financing of wind power installations require very importantly accurate resource estimation in addition to a number of other considerations relating to environment and economy. Furthermore, individual wind energy installations cannot in general be seen in isolation. It is well known that the spacing of turbines in wind farms is critical for maximum power production. It is also well established that the collective effect of wind turbines in large wind farms or of several wind farms can limit the wind power extraction downwind. This has been documented by many years of production statistics. For the very large, regional sized wind farms, a number of numerical studies have pointed to additional adverse changes to the regional wind climate, most recently by the detailed studies of Adams and Keith [1]. They show that the geophysical limit to wind power production is likely to be lower than previously estimated. Although this problem is of far future concern, it has to be considered seriously. In their paper they estimate that a wind farm larger than 100 km2 is limited to about 1 W m-2. However, a 20 km2 off shore farm, Horns Rev 1, has in the last five years produced 3.98 W m-2 [5]. In that light it is highly unlikely that the effects pointed out by [1] will pose any immediate threat to wind energy in coming decades. Today a number of well-established mesoscale and microscale models exist for estimating wind resources and design parameters and in many cases they work well. This is especially true if good local data are available for calibrating the models or for their validation. The wind energy industry is still troubled by many projects showing considerable negative discrepancies between calculated and actually experienced production numbers and operating conditions. Therefore it has been decided on a European Union level to launch a project, 'The New European Wind Atlas', aiming at reducing overall uncertainties in determining wind conditions. The

  1. Wind for Schools Project Power System Brief, Wind Powering America Fact Sheet Series

    SciTech Connect

    Baring-Gould, I.

    2009-05-01

    Wind Powering America's (WPA's) Wind for Schools project uses a basic system configuration for each school project. The system incorporates a single SkyStream wind turbine, a 70-ft guyed tower, disconnect boxes at the base of the turbine and at the school, and an interconnection to the school's electrical system. This document provides a detailed description of each system component.

  2. Saturation wind power potential and its implications for wind energy

    PubMed Central

    Jacobson, Mark Z.; Archer, Cristina L.

    2012-01-01

    Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world’s all-purpose power from wind in a 2030 clean-energy economy. PMID:23019353

  3. Saturation wind power potential and its implications for wind energy.

    PubMed

    Jacobson, Mark Z; Archer, Cristina L

    2012-09-25

    Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world's all-purpose power from wind in a 2030 clean-energy economy.

  4. Spindle position regulation for wind power generators

    NASA Astrophysics Data System (ADS)

    Tsai, Nan-Chyuan; Chiang, Chao-Wen

    2010-04-01

    The three-time-scale plant model of a wind power generator, including a wind turbine, a flexible vertical shaft, a variable inertia flywheel (VIF) module, an active magnetic bearing (AMB) unit and the applied wind sequence, is constructed. In order to make the wind power generator be still able to operate as the spindle speed exceeds its rated speed, the VIF is equipped so that the spindle speed can be appropriately slowed down once any stronger wind field is exerted. Currently, most of wind energy input is, as a matter of fact, a waste since the commercially available wind power generators only operate for fairly mild or low-speed wind field. To prevent any potential damage due to collision by shaft against conventional bearings, the AMB unit is proposed to replace the traditional bearings and regulate the shaft position deviation. By singular perturbation order-reduction technique, a lower-order plant model can be established for the synthesis of feedback controller. It is found that two major system parameter uncertainties, an additive uncertainty and a multiplicative uncertainty, are constituted by the wind turbine and the VIF, respectively. The upper bounds of system parameters variation can be therefore estimated and the frequency shaping sliding mode control (FSSMC) loop is proposed to account for these uncertainties and suppress the unmodeled higher-order plant dynamics. At last, the efficacy of the FSSMC is verified by intensive computer and experimental simulations for regulation on position deviation of the shaft and counter-balance of unpredictable wind disturbance.

  5. A study on the power generation potential of mini wind turbine in east coast of Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Basrawi, Firdaus; Ismail, Izwan; Ibrahim, Thamir Khalil; Idris, Daing Mohamad Nafiz Daing; Anuar, Shahrani

    2017-03-01

    A small-scale wind turbine is an attractive renewable energy source, but its economic viability depends on wind speed. The aim of this study is to determine economic viability of small-scale wind turbine in East Coast of Peninsular Malaysia. The potential energy generated has been determined by wind speed data and power curved of. Hourly wind speed data of Kuantan throughout 2015 was collected as the input. Then, a model of wind turbine was developed based on a commercial a 300W mini wind turbine. It was found that power generation is 3 times higher during northeast monsoon season at 15 m elevation. This proved that the northeast monsoon season has higher potential in generating power by wind turbine in East Coast of Peninsular Malaysia. However, only a total of 153.4 kWh/year of power can be generated at this condition. The power generator utilization factor PGUI or capacity ratio was merely 0.06 and it is not technically viable. By increasing the height of wind turbine to 60 m elevation, power generation amount drastically increased to 344 kWh/year, with PGUI of 0.13. This is about two-thirds of PGUI for photovoltaic technology which is 0.21 at this site. If offshore condition was considered, power generation amount further increased to 1,328 kWh/year with PGUI of 0.51. Thus, for a common use of mini wind turbine that is usually installed on-site at low elevation, it has low power generation potential. But, if high elevation as what large wind turbine needed is implemented, it is technically viable option in East Coast of Peninsular Malaysia.

  6. Analysis of wind power for battery charging

    SciTech Connect

    Muljadi, E.; Drouilhet, S.; Holz, R.; Gevorgian, V.

    1995-11-01

    One type of wind-powered battery charging will be explored in this paper. It consists of a wind turbine driving a permanent magnet alternator and operates at variable speed. The alternator is connected to a battery bank via a rectifier. The characteristic of the system depends on the wind turbine, the alternator, and the system configuration. If the electrical load does not match the wind turbine, the performance of the system will be degraded. By matching the electrical load to the wind turbine, the system can be improved significantly. This paper analyzes the properties of the system components. The effects of parameter variation and the system configuration on the system performance are investigated. Two basic methods of shaping the torque-speed characteristic of the generator are presented. The uncompensated as well as the compensated systems will be discussed. Control strategies to improve the system performance will be explored. Finally, a summary of the paper will be presented in the last section.

  7. Variability in large-scale wind power generation: Variability in large-scale wind power generation

    SciTech Connect

    Kiviluoma, Juha; Holttinen, Hannele; Weir, David; Scharff, Richard; Söder, Lennart; Menemenlis, Nickie; Cutululis, Nicolaos A.; Danti Lopez, Irene; Lannoye, Eamonn; Estanqueiro, Ana; Gomez-Lazaro, Emilio; Bai, Jianhua; Wan, Yih-Huei; Milligan, Michael

    2015-10-25

    The paper demonstrates the characteristics of wind power variability and net load variability in multiple power systems based on real data from multiple years. Demonstrated characteristics include probability distribution for different ramp durations, seasonal and diurnal variability and low net load events. The comparison shows regions with low variability (Sweden, Spain and Germany), medium variability (Portugal, Ireland, Finland and Denmark) and regions with higher variability (Quebec, Bonneville Power Administration and Electric Reliability Council of Texas in North America; Gansu, Jilin and Liaoning in China; and Norway and offshore wind power in Denmark). For regions with low variability, the maximum 1 h wind ramps are below 10% of nominal capacity, and for regions with high variability, they may be close to 30%. Wind power variability is mainly explained by the extent of geographical spread, but also higher capacity factor causes higher variability. It was also shown how wind power ramps are autocorrelated and dependent on the operating output level. When wind power was concentrated in smaller area, there were outliers with high changes in wind output, which were not present in large areas with well-dispersed wind power.

  8. Wind Powering America FY07 Activities Summary

    SciTech Connect

    Not Available

    2008-02-01

    The Wind Powering America FY07 Activities Summary reflects the accomplishments of our state wind working groups, our programs at the National Renewable Energy Laboratory, and our partner organizations. The national WPA team remains a leading force for moving wind energy forward in the United States. WPA continues to work with its national, regional, and state partners to communicate the opportunities and benefits of wind energy to a diverse set of stakeholders. WPA now has 30 state wind working groups (welcoming Georgia and Wisconsin in 2007) that form strategic alliances to communicate wind's benefits to the state stakeholders. More than 140 members of national and state public and private sector organizations from 39 U.S. states and Canada attended the 6th Annual WPA All-States Summit in Los Angeles in June. WPA's emphasis remains on the rural agricultural sector, which stands to reap the significant economic development benefits of wind energy development. Additionally, WPA continues its program of outreach, education, and technical assistance to Native American communities, public power entities, and regulatory and legislative bodies.

  9. Mesoscale variations in available wind power potential

    SciTech Connect

    Lyons, T.J.; Bell, M.J. )

    1990-01-01

    Previous studies have suggested that mesoscale processes are important in determining available wind energy potential in southern Australia. These effects are quantified by application of a numerical mesoscale model to the Swan coastal plain of Western Australia, illustrating that the wind power potential in this area is dominated by the sea breeze circulation and topographical influences. While sea breezes are a common feature of the summer climate, they are a significant source of wind energy only under weak synoptic flows, whereas mesoscale topographical effects are significant under all synoptic conditions.

  10. WIND Toolkit Power Data Site Index

    SciTech Connect

    Draxl, Caroline; Mathias-Hodge, Bri

    2016-10-19

    This spreadsheet contains per-site metadata for the WIND Toolkit sites and serves as an index for the raw data hosted on Globus connect (nrel#globus:/globusro/met_data). Aside from the metadata, per site average power and capacity factor are given. This data was prepared by 3TIER under contract by NREL and is public domain. Authoritative documentation on the creation of the underlying dataset is at: Final Report on the Creation of the Wind Integration National Dataset (WIND) Toolkit and API: http://www.nrel.gov/docs/fy16osti/66189.pdf

  11. Short time ahead wind power production forecast

    NASA Astrophysics Data System (ADS)

    Sapronova, Alla; Meissner, Catherine; Mana, Matteo

    2016-09-01

    An accurate prediction of wind power output is crucial for efficient coordination of cooperative energy production from different sources. Long-time ahead prediction (from 6 to 24 hours) of wind power for onshore parks can be achieved by using a coupled model that would bridge the mesoscale weather prediction data and computational fluid dynamics. When a forecast for shorter time horizon (less than one hour ahead) is anticipated, an accuracy of a predictive model that utilizes hourly weather data is decreasing. That is because the higher frequency fluctuations of the wind speed are lost when data is averaged over an hour. Since the wind speed can vary up to 50% in magnitude over a period of 5 minutes, the higher frequency variations of wind speed and direction have to be taken into account for an accurate short-term ahead energy production forecast. In this work a new model for wind power production forecast 5- to 30-minutes ahead is presented. The model is based on machine learning techniques and categorization approach and using the historical park production time series and hourly numerical weather forecast.

  12. A new spatially scanning 2.7 µm laser hygrometer and new small-scale wind tunnel for direct analysis of the H2O boundary layer structure at single plant leaves

    NASA Astrophysics Data System (ADS)

    Wunderle, K.; Rascher, U.; Pieruschka, R.; Schurr, U.; Ebert, V.

    2015-01-01

    A new spatially scanning TDLAS in situ hygrometer based on a 2.7-µm DFB diode laser was constructed and used to analyse the water vapour concentration boundary layer structure at the surface of a single plant leaf. Using an absorption length of only 5.4 cm, the TDLAS hygrometer permits a H2O vapour concentration resolution of 31 ppmv. This corresponds to a normalized precision of 1.7 ppm m. In order to preserve and control the H2O boundary layer on an individual leaf and to study the boundary layer dependence on the wind speed to which the leaf might be exposed in nature, we also constructed a new, application specific, small-scale, wind tunnel for individual plant leaves. The rectangular, closed-loop tunnel has overall dimensions of 1.2 × 0.6 m and a measurement chamber dimension of 40 × 54 mm (H × W). It allows to generate a laminar flow with a precisely controlled wind speed at the plant leaf surface. Combining honeycombs and a miniaturized compression orifice, we could generate and control stable wind speeds from 0.1 to 0.9 m/s, and a highly laminar and homogeneous flow with an excellent relative spatial homogeneity of 0.969 ± 0.03. Combining the spectrometer and the wind tunnel, we analysed (for the first time) non-invasively the wind speed-dependent vertical structure of the H2O vapour distribution within the boundary layer of a single plant leaf. Using our time-lag-free data acquisition procedure for phase locked signal averaging, we achieved a temporal resolution of 0.2 s for an individual spatial point, while a complete vertical spatial scan at a spatial resolution of 0.18 mm took 77 s. The boundary layer thickness was found to decrease from 6.7 to 3.6 mm at increasing wind speeds of 0.1-0.9 m/s. According to our knowledge, this is the first experimental quantification of wind speed-dependent H2O vapour boundary layer concentration profiles of single plant leaves.

  13. Powerful Winds in Extreme RBS quasars (POWER)

    NASA Astrophysics Data System (ADS)

    Piconcelli, Enrico

    2013-10-01

    This proposal aims at studying powerful outflows in ultra-luminous (log Lx >45) Radio-Quiet Quasars (RQQ). We propose to observe four objects extracted from a luminosity limited sample in the ROSAT Bright Survey for a full orbit (130 ks) each. Both models and observations suggest that the efficiency of driving energetic outflows increases with the AGN luminosity. Therefore, our targets are potentially the best objects to hunt for very powerful outflows expected in the AGN/galaxy feedback scenario. Our observations represent the first attempt ever to obtain deep, high-resolution-driven spectroscopy of a representative sample of RQQ in this high-luminosity regime.

  14. The spectrum of power from wind turbines

    NASA Astrophysics Data System (ADS)

    Apt, Jay

    The power spectral density of the output of wind turbines provides information on the character of fluctuations in turbine output. Here both 1-second and 1-hour samples are used to estimate the power spectrum of several wind farms. The measured output power is found to follow a Kolmogorov spectrum over more than four orders of magnitude, from 30 s to 2.6 days. This result is in sharp contrast to the only previous study covering long time periods, published 50 years ago. The spectrum defines the character of fill-in power that must be provided to compensate for wind's fluctuations when wind is deployed at large scale. Installing enough linear ramp rate generation (such as a gas generator) to fill in fast fluctuations with amplitudes of 1% of the maximum fluctuation would oversize the fill-in generation capacity by a factor of two for slower fluctuations, greatly increasing capital costs. A wind system that incorporates batteries, fuel cells, supercapacitors, or other fast-ramp-rate energy storage systems would match fluctuations much better, and can provide an economic route for deployment of energy storage systems when renewable portfolio standards require large amounts of intermittent renewable generating sources.

  15. Equivalencing the Collector System of a Large Wind Power Plant

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Ellis, A.; Mechenbier, J.; Hocheimer, J.; Young, R.; Miller, N.; Delmerico, R.; Zavadil, R.; Smith, J. C.

    2006-01-01

    As the size and number of wind power plants (also called wind farms) increases, power system planners will need to study their impact on the power system in more detail. As the level of wind power penetration into the grid increases, the transmission system integration requirements will become more critical [1-2]. A very large wind power plant may contain hundreds of megawatt-size wind turbines. These turbines are interconnected by an intricate collector system. While the impact of individual turbines on the larger power system network is minimal, collectively, wind turbines can have a significant impact on the power systems during a severe disturbance such as a nearby fault. Since it is not practical to represent all individual wind turbines to conduct simulations, a simplified equivalent representation is required. This paper focuses on our effort to develop an equivalent representation of a wind power plant collector system for power system planning studies. The layout of the wind power plant, the size and type of conductors used, and the method of delivery (overhead or buried cables) all influence the performance of the collector system inside the wind power plant. Our effort to develop an equivalent representation of the collector system for wind power plants is an attempt to simplify power system modeling for future developments or planned expansions of wind power plants. Although we use a specific large wind power plant as a case study, the concept is applicable for any type of wind power plant.

  16. Study on synergetic schedule of hydro-wind power for minimizing impact on power grid

    NASA Astrophysics Data System (ADS)

    Zhu, Weijiang; Hu, Binqi; Cheng, Tao; Liu, Jianping; Wu, Yonggang; Yu, Yi

    2017-08-01

    For smoothing and weakening the random and fluctuant wind power, an approach of hydropower coordinate with wind power is proposed. Firstly, based on a certain capacity of wind farm and the hypothesis of indifference of wind power capacity in this paper, the capacity of hydropower station to absorb wind power has been analyzed quantitatively and the relationship characteristic curve between hydropower and wind power absorption has been depicted; secondly, the characteristic of the curve under the condition of different quantities of wind power electricity is analyzed and proved; finally, a model which maximizes the combination of hydro-wind power is built and an adjustable hydropower plant coordinated with wind power station is simulated. According to the results, the effect of wind power absorption was fairly good and the output of combo that hydropower cooperated with wind power was stable, and this research has provided a favorable strategy for absorbing wind power for power grid.

  17. Wind Power Plant Voltage Stability Evaluation: Preprint

    SciTech Connect

    Muljadi, E.; Zhang, Y. C.

    2014-09-01

    Voltage stability refers to the ability of a power system to maintain steady voltages at all buses in the system after being subjected to a disturbance from a given initial operating condition. Voltage stability depends on a power system's ability to maintain and/or restore equilibrium between load demand and supply. Instability that may result occurs in the form of a progressive fall or rise of voltages of some buses. Possible outcomes of voltage instability are the loss of load in an area or tripped transmission lines and other elements by their protective systems, which may lead to cascading outages. The loss of synchronism of some generators may result from these outages or from operating conditions that violate a synchronous generator's field current limit, or in the case of variable speed wind turbine generator, the current limits of power switches. This paper investigates the impact of wind power plants on power system voltage stability by using synchrophasor measurements.

  18. 77 FR 31839 - Wind and Water Power Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-30

    ... of Energy Efficiency and Renewable Energy Wind and Water Power Program AGENCY: Office of Energy... Water Power Program, Wind Power Peer Review Meeting will review wind technology development and market acceleration and deployment projects from the Program's research and development portfolio. The 2012 Wind...

  19. Small-scale hydropower systems

    SciTech Connect

    Not Available

    1988-04-01

    This report covers several aspects of small-scale hydropower systems. The topics covered are: head and flow; waterwheels; impulse and reaction turbines; feasibility and practicality; environmental impact; and economics. 24 refs., 5 figs. (JF)

  20. Suprathermal Charged Particle Acceleration by Small-scale Flux Ropes.

    NASA Astrophysics Data System (ADS)

    Zank, G. P.; le Roux, J. A.; Webb, G. M.

    2015-12-01

    We consider different limits of our recently developed kinetic transport theory to investigate the potential of super-Alvenic solar wind regions containing several small-scale flux ropes to explain the acceleration of suprathermal ions to power-law spectra as observations show. Particle acceleration is modeled in response to flux-rope activity involving contraction, merging (reconnection), and collisions in the limit where the particle gyoradius is smaller than the characteristic flux-rope scale length. The emphasis is mainly on the statistical variance in the electric fields induced by flux-rope dynamics rather than on the mean electric field induced by multiple flux ropes whose acceleration effects are discussed elsewhere. Our steady-state analytical solutions suggest that particle drift acceleration by flux ropes, irrespective of whether displaying incompressible or compressible behavior, can yield power laws asymptotically at higher energies whereas an exponential spectral rollover results asymptotically when field-aligned guiding center motion acceleration occur by reconnection electric fields from merging flux ropes. This implies that at sufficiently high particle energies, drift acceleration might dominate. We also expect compressive flux ropes to yield harder power-law spectra than incompressible flux ropes. Preliminary results will be discussed to illustrate how particle acceleration might be affected when both diffusive shock and small-scale flux acceleration occur simultaneously at interplanetary shocks.

  1. Breezy Power: From Wind to Energy

    ERIC Educational Resources Information Center

    Claymier, Bob

    2009-01-01

    This lesson combines the science concepts of renewable energy and producing electricity with the technology concepts of design, constraints, and technology's impact on the environment. Over five class periods, sixth-grade students "work" for a fictitious power company as they research wind as an alternative energy source and design and test a…

  2. Breezy Power: From Wind to Energy

    ERIC Educational Resources Information Center

    Claymier, Bob

    2009-01-01

    This lesson combines the science concepts of renewable energy and producing electricity with the technology concepts of design, constraints, and technology's impact on the environment. Over five class periods, sixth-grade students "work" for a fictitious power company as they research wind as an alternative energy source and design and test a…

  3. 76 FR 66284 - Wind and Water Power Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... Office of Energy Efficiency and Renewable Energy Wind and Water Power Program AGENCY: Office of Energy... Wind and Water Power Program, Water Power Peer Review Meeting will review the Program's portfolio of... the DOE Wind and Water Power Program website. Public Participation: Principal Investigators,...

  4. Wind-powered heat pump experiment

    NASA Astrophysics Data System (ADS)

    Regan, D. C.

    1983-05-01

    An evaluation of an automotive type freon compressor demonstrated that such a device could be operated at slow speeds (600 to 1200 rpm) and still produce useful amounts of heat transfer. This device was evaluated and output measured by temprature measurements made on tanks of water in which the condenser and evaporator coils were immersed. The second portion of the project was to have a demonstration using a wind turbine as the motive power and construction of a full scale system. However, after several different attempts to construct a working system, the work had to be terminated because the device to convert the wind power to mechanical power for turning the compressor could never be successfully operated for any extended perod of time. A description of the work completed and the reasons for failures of the concept are delineated.

  5. Wind-powered heat pump experiment

    SciTech Connect

    Regan, D.C.

    1983-05-01

    The work described in this report was completed in two parts. The first part was an evaluation of an automotive type freon compressor, which demonstrated that such a device could be operated at slow speeds (600 to 1200 rpm) and still produce useful amounts of heat transfer. This device was evaluated and output measured by temperature measurements made on tanks of water in which the condenser and evaporator coils were immersed. The second portion of the project was to have been a demonstration using a wind turbine as the motive power and construction of a full scale system. However, after several different attempts to construct a working system, the work had to be terminated because the device to convert the wind power to mechanical power for turning the compressor coud never be successfully operated for any extended period of time. A description of the work completed and the reasons for the failure of the concept are delineated.

  6. Autonomous Aerial Sensors for Wind Power Meteorology

    NASA Astrophysics Data System (ADS)

    Giebel, Gregor; Schmidt Paulsen, Uwe; Reuder, Joachim; La Cour-Harbo, Anders; Thomsen, Carsten; Bange, Jens; Buschmann, Marco

    2010-05-01

    This poster describes a new approach for measurements in wind power meteorology using small unmanned flying platforms. During a week of flying a lighter-than-air vehicle, two small electrically powered aeroplanes and a larger helicopter at the Risø test station at Høvsøre, we will compare wind speed measurements with fixed mast and LIDAR measurements, investigate optimal flight patterns for each measurement task, and measure other interesting meteorological features like the air-sea boundary in the vicinity of the wind farm. In order to prepare the measurement campaign, a workshop is held, soliciting input from various communities. Large-scale wind farms, especially offshore, need an optimisation between installed wind power density and the losses in the wind farm due to wake effects between the turbines. While the wake structure behind single wind turbines onshore is fairly well understood, there are different problems offshore, thought to be due mainly to the low turbulence. Good measurements of the wake and wake structure are not easy to come by, as the use of a met mast is static and expensive, while the use of remote sensing instruments either needs significant access to the turbine to mount an instrument, or is complicated to use on a ship due to the ship's own movement. In any case, a good LIDAR or SODAR will cost many tens of thousands of euros. Another current problem in wind energy is the coming generation of wind turbines in the 10-12 MW class, with tip heights of over 200 m. Very few measurement masts exist to verify our knowledge of atmospheric physics - all that is known is that the boundary layer description we used so far is not valid any more. Here, automated Unmanned Aerial Vehicles (UAVs) could be used as either an extension of current high masts or to build a network of very high ‘masts' in a region of complex terrain or coastal flow conditions. In comparison to a multitude of high masts, UAVs could be quite cost-effective. In order to test

  7. Wind Power Plant Prediction by Using Neural Networks: Preprint

    SciTech Connect

    Liu, Z.; Gao, W.; Wan, Y. H.; Muljadi, E.

    2012-08-01

    This paper introduces a method of short-term wind power prediction for a wind power plant by training neural networks based on historical data of wind speed and wind direction. The model proposed is shown to achieve a high accuracy with respect to the measured data.

  8. Navy Applications Experience with Small Wind Power Systems

    DTIC Science & Technology

    1985-05-01

    This report describes the experience gained and lesson learned from the ongoing field evaluations of seven small, 2-to 20-kW wind energy conversion... energy conversion systems, Wind energy power conditioning, Inverters, Electromagnetic interference, and Renewable energy sources....The field evaluations are continuing on the small WECS in order to develop operation, maintenance, and reliability data. Keywords: Wind power, Wind

  9. An estimate of the relative magnitude of small-scale tracer fluxes

    NASA Technical Reports Server (NTRS)

    Bacmeister, Julio T.; Schoeberl, Mark R.; Loewenstein, Max; Podolske, Jim R.; Strahan, Susan E.; Chan, K. R.

    1992-01-01

    The wind and constituent measurements from the polar aircraft data are used to compute the flux spectra. Although there is variation from flight to flight, the flux spectra generally fit a -2 to -1.5 power law as expected theoretically. This result suggests that tracer fluxes from small scale features do not substantially contribute to the overall tracer budget relative to the fluxes from the larger scales.

  10. Synchrophasor Applications for Wind Power Generation

    SciTech Connect

    Muljadi, E.; Zhang, Y. C.; Allen, A.; Singh, M.; Gevorgian, V.; Wan, Y. H.

    2014-02-01

    The U.S. power industry is undertaking several initiatives that will improve the operations of the electric power grid. One of those is the implementation of wide-area measurements using phasor measurement units to dynamically monitor the operations and status of the network and provide advanced situational awareness and stability assessment. The overviews of synchrophasors and stability analyses in this report are intended to present the potential future applications of synchrophasors for power system operations under high penetrations of wind and other renewable energy sources.

  11. Replacing baseload power plants with wind plants

    SciTech Connect

    Cavallo, A.J.

    1995-12-31

    Baseload nuclear power plants supply about 21 percent of the electricity consumed in the United States today, and as these plants are retired over the next 10 to 25 years, they will not be replicated. This will open a vast market for new generating facilities which should, if possible, be non-fossil fueled. Wind energy baseload systems are able to equal or exceed the technical performance of these nuclear plants at a delivered cost of energy of less than $0.05/kWh in wind class 4 regions. However, unless a new externality (the cost of maintaining the security of fossil fuel supply) is factored in to the extremely low market price of fossil fuels, wind and other renewable energy resources will not be able to compete with these fuels on the basis of simple economics over the next 20 to 30 years.

  12. Operation of Power Grids with High Penetration of Wind Power

    NASA Astrophysics Data System (ADS)

    Al-Awami, Ali Taleb

    The integration of wind power into the power grid poses many challenges due to its highly uncertain nature. This dissertation involves two main components related to the operation of power grids with high penetration of wind energy: wind-thermal stochastic dispatch and wind-thermal coordinated bidding in short-term electricity markets. In the first part, a stochastic dispatch (SD) algorithm is proposed that takes into account the stochastic nature of the wind power output. The uncertainty associated with wind power output given the forecast is characterized using conditional probability density functions (CPDF). Several functions are examined to characterize wind uncertainty including Beta, Weibull, Extreme Value, Generalized Extreme Value, and Mixed Gaussian distributions. The unique characteristics of the Mixed Gaussian distribution are then utilized to facilitate the speed of convergence of the SD algorithm. A case study is carried out to evaluate the effectiveness of the proposed algorithm. Then, the SD algorithm is extended to simultaneously optimize the system operating costs and emissions. A modified multi-objective particle swarm optimization algorithm is suggested to identify the Pareto-optimal solutions defined by the two conflicting objectives. A sensitivity analysis is carried out to study the effect of changing load level and imbalance cost factors on the Pareto front. In the second part of this dissertation, coordinated trading of wind and thermal energy is proposed to mitigate risks due to those uncertainties. The problem of wind-thermal coordinated trading is formulated as a mixed-integer stochastic linear program. The objective is to obtain the optimal tradeoff bidding strategy that maximizes the total expected profits while controlling trading risks. For risk control, a weighted term of the conditional value at risk (CVaR) is included in the objective function. The CVaR aims to maximize the expected profits of the least profitable scenarios, thus

  13. U.S. Wind Power Project Database

    SciTech Connect

    2007-12-15

    The database represents an inventory of wind power projects under development in the U.S. The database is designed to provide a concise overview of the current status of domestic projects (200 as of 1 Dec 2007). The database contains key project data on wind power plants currently being evaluated, developed, or constructed. It is of value to anyone interested in tracking wind power development including utilities, power project developers, equipment manufacturers, transporters and other vendors, investment banks, regulators, consultants, and analysts. The database is a Microsoft Excel spreadsheet which enables users to easily and quickly search for projects of interest by developer, technology, location, size, cost, status, or other characteristics. The database is updated as project specifics change to ensure that information is kept timely. Updates are provided via email on a monthly basis as part of an annual subscription. Database fields include: developer, owner, project name and description, location, technology, capacity, investment cost, proposed in-service date, status, air quality permit, and CPCN/siting approval.

  14. Measurement of unsteady loading and power output variability in a micro wind farm model in a wind tunnel

    NASA Astrophysics Data System (ADS)

    Bossuyt, Juliaan; Howland, Michael F.; Meneveau, Charles; Meyers, Johan

    2017-01-01

    Unsteady loading and spatiotemporal characteristics of power output are measured in a wind tunnel experiment of a microscale wind farm model with 100 porous disk models. The model wind farm is placed in a scaled turbulent boundary layer, and six different layouts, varied from aligned to staggered, are considered. The measurements are done by making use of a specially designed small-scale porous disk model, instrumented with strain gages. The frequency response of the measurements goes up to the natural frequency of the model, which corresponds to a reduced frequency of 0.6 when normalized by the diameter and the mean hub height velocity. The equivalent range of timescales, scaled to field-scale values, is 15 s and longer. The accuracy and limitations of the acquisition technique are documented and verified with hot-wire measurements. The spatiotemporal measurement capabilities of the experimental setup are used to study the cross-correlation in the power output of various porous disk models of wind turbines. A significant correlation is confirmed between streamwise aligned models, while staggered models show an anti-correlation.

  15. Wind power. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Hundemann, A. S.

    1980-06-01

    The feasibility, use, and engineering aspects of wind power and windmills are discussed in these citations of Federally funded research reports. Abstracts primarily cover the use of wind power for electric power generation and wind turbine design and performance. General studies dealing with comparative analyses of wind power and alternative energy sources are included, as are energy storage devices which can be used in these systems. This updated bibliography contains 253 abstracts, none of which are new entries to the previous edition.

  16. Wind power. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Hundemann, A. S.

    1980-06-01

    The feasibility, use and engineering aspects of wind power and windmills are discussed in these citations of Federally funded research reports. Abstracts primarily cover the use of wind power for electric power generation and wind turbine design and performance. General studies dealing with comparative analyses of wind power and alternative energy sources are included, as are energy storage devices which can be used in these systems. This updated bibliography contains 135 abstracts, 112 of which are new entries to the previous edition.

  17. 77 FR 5002 - Wind and Water Power Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ... of Energy Efficiency and Renewable Energy Wind and Water Power Program AGENCY: Office of Energy..., request for comment. SUMMARY: The Wind and Water Power Program (WWPP) within the U.S. Department of Energy...: Michael Hahn, Wind and Water Power Program, 1617 Cole Blvd. Golden, CO 80401. Please submit one...

  18. 77 FR 38277 - Wind and Water Power Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-27

    ... of Energy Efficiency and Renewable Energy Wind and Water Power Program AGENCY: Office of Energy... Department of Energy (DOE) Wind and Water Power Program is planning a coordination workshop to exchange... in Washington, DC on June 13, 2012. Mark Higgins, Wind and Water Power Acting Program Manager,...

  19. Wind tunnel testing of a closed-loop wake deflection controller for wind farm power maximization

    NASA Astrophysics Data System (ADS)

    Campagnolo, Filippo; Petrović, Vlaho; Schreiber, Johannes; Nanos, Emmanouil M.; Croce, Alessandro; Bottasso, Carlo L.

    2016-09-01

    This paper presents results from wind tunnel tests aimed at evaluating a closed- loop wind farm controller for wind farm power maximization by wake deflection. Experiments are conducted in a large boundary layer wind tunnel, using three servo-actuated and sensorized wind turbine scaled models. First, we characterize the impact on steady-state power output of wake deflection, achieved by yawing the upstream wind turbines. Next, we illustrate the capability of the proposed wind farm controller to dynamically driving the upstream wind turbines to the optimal yaw misalignment setting.

  20. Concurrent Wind Cooling in Power Transmission Lines

    SciTech Connect

    Jake P Gentle

    2012-08-01

    Idaho National Laboratory and the Idaho Power Company, with collaboration from Idaho State University, have been working on a project to monitor wind and other environmental data parameters along certain electrical transmission corridors. The combination of both real-time historical weather and environmental data is being used to model, validate, and recommend possibilities for dynamic operations of the transmission lines for power and energy carrying capacity. The planned results can also be used to influence decisions about proposed design criteria for or upgrades to certain sections of the transmission lines.

  1. Wind Power on Native American Lands: Process and Progress (Poster)

    SciTech Connect

    Jimenez, A.; Flowers, L.; Gough, R.; Taylor, R.

    2005-05-01

    The United States is home to more than 700 American Indian tribes and Native Alaska villages and corporations located on 96 million acres. Many of these tribes and villages have excellent wind resources that could be commercially developed to meet their electricity needs or for electricity export. The Wind Powering America program engages Native Americans in wind energy development. This poster describes the process and progress of Wind Powering America's involvement with Native American wind energy projects.

  2. Wind Power Ramping Product for Increasing Power System Flexibility

    SciTech Connect

    Cui, Mingjian; Zhang, Jie; Wu, Hongyu; Hodge, Bri-Mathias; Ke, Deping; Sun, Yuanzhang

    2016-05-05

    With increasing penetrations of wind power, system operators are concerned about a potential lack of system flexibility and ramping capacity in real-time dispatch stages. In this paper, a modified dispatch formulation is proposed considering the wind power ramping product (WPRP). A swinging door algorithm (SDA) and dynamic programming are combined and used to detect WPRPs in the next scheduling periods. The detected WPRPs are included in the unit commitment (UC) formulation considering ramping capacity limits, active power limits, and flexible ramping requirements. The modified formulation is solved by mixed integer linear programming. Numerical simulations on a modified PJM 5-bus System show the effectiveness of the model considering WPRP, which not only reduces the production cost but also does not affect the generation schedules of thermal units.

  3. Capacity value assessments of wind power: Capacity value assessments of wind power

    SciTech Connect

    Milligan, Michael; Frew, Bethany; Ibanez, Eduardo; Kiviluoma, Juha; Holttinen, Hannele; Söder, Lennart

    2016-10-05

    This article describes some of the recent research into the capacity value of wind power. With the worldwide increase in wind power during the past several years, there is increasing interest and significance regarding its capacity value because this has a direct influence on the amount of other (nonwind) capacity that is needed. We build on previous reviews from IEEE and IEA Wind Task 25a and examine recent work that evaluates the impact of multiple-year data sets and the impact of interconnected systems on resource adequacy. We also provide examples that explore the use of alternative reliability metrics for wind capacity value calculations. We show how multiple-year data sets significantly increase the robustness of results compared to single-year assessments. Assumptions regarding the transmission interconnections play a significant role. To date, results regarding which reliability metric to use for probabilistic capacity valuation show little sensitivity to the metric.

  4. Validation of Power Output for the WIND Toolkit

    SciTech Connect

    King, J.; Clifton, A.; Hodge, B. M.

    2014-09-01

    Renewable energy integration studies require wind data sets of high quality with realistic representations of the variability, ramping characteristics, and forecast performance for current wind power plants. The Wind Integration National Data Set (WIND) Toolkit is meant to be an update for and expansion of the original data sets created for the weather years from 2004 through 2006 during the Western Wind and Solar Integration Study and the Eastern Wind Integration Study. The WIND Toolkit expands these data sets to include the entire continental United States, increasing the total number of sites represented, and it includes the weather years from 2007 through 2012. In addition, the WIND Toolkit has a finer resolution for both the temporal and geographic dimensions. Three separate data sets will be created: a meteorological data set, a wind power data set, and a forecast data set. This report describes the validation of the wind power data set.

  5. Analytical expressions for maximum wind turbine average power in a Rayleigh wind regime

    SciTech Connect

    Carlin, P.W.

    1996-12-01

    Average or expectation values for annual power of a wind turbine in a Rayleigh wind regime are calculated and plotted as a function of cut-out wind speed. This wind speed is expressed in multiples of the annual average wind speed at the turbine installation site. To provide a common basis for comparison of all real and imagined turbines, the Rayleigh-Betz wind machine is postulated. This machine is an ideal wind machine operating with the ideal Betz power coefficient of 0.593 in a Rayleigh probability wind regime. All other average annual powers are expressed in fractions of that power. Cases considered include: (1) an ideal machine with finite power and finite cutout speed, (2) real machines operating in variable speed mode at their maximum power coefficient, and (3) real machines operating at constant speed.

  6. Wind Power: A Turning Point. Worldwatch Paper 45.

    ERIC Educational Resources Information Center

    Flavin, Christopher

    Recent studies have shown wind power to be an eminently practical and potentially substantial source of electricity and direct mechanical power. Wind machines range from simple water-pumping devices made of wood and cloth to large electricity producing turbines with fiberglass blades nearly 300 feet long. Wind is in effect a form of solar…

  7. Introducing Wind Power: Essentials for Bringing It into the Classroom

    ERIC Educational Resources Information Center

    Swapp, Andy; Schreuders, Paul; Reeve, Edward

    2011-01-01

    As a renewable source of energy, wind energy will play a significant role in the future. Public, commercial, and privately owned organizations are increasingly finding the value and profits in wind power. Including wind power in a technology and engineering education curriculum teaches students about an important technology that may effect their…

  8. Introducing Wind Power: Essentials for Bringing It into the Classroom

    ERIC Educational Resources Information Center

    Swapp, Andy; Schreuders, Paul; Reeve, Edward

    2011-01-01

    As a renewable source of energy, wind energy will play a significant role in the future. Public, commercial, and privately owned organizations are increasingly finding the value and profits in wind power. Including wind power in a technology and engineering education curriculum teaches students about an important technology that may effect their…

  9. Small-Scale-Field Dynamo

    SciTech Connect

    Gruzinov, A.; Cowley, S.; Sudan, R. ||

    1996-11-01

    Generation of magnetic field energy, without mean field generation, is studied. Isotropic mirror-symmetric turbulence of a conducting fluid amplifies the energy of small-scale magnetic perturbations if the magnetic Reynolds number is high, and the dimensionality of space {ital d} satisfies 2.103{lt}{ital d}{lt}8.765. The result does not depend on the model of turbulence, incompressibility, and isotropy being the only requirements. {copyright} {ital 1996 The American Physical Society.}

  10. New England Wind Forum: A Wind Powering America Project - Newsletter #6 - September 2010, (NEWF)

    SciTech Connect

    Grace, R.; Gifford, J.; Leeds, T.; Bauer, S.

    2010-09-01

    Wind Powering America program launched the New England Wind Forum (NEWF) in 2005 to provide a single comprehensive source of up-to-date, Web-based information on a broad array of wind energy issues pertaining to New England. The NEWF newsletter provides New England stakeholders with updates on wind energy development in the region.

  11. Development of an Equivalent Wind Plant Power-Curve: Preprint

    SciTech Connect

    Wan, Y. H.; Ela, E.; Orwig, K.

    2010-06-01

    Development of an equivalent wind plant power-curve becomes highly desirable and useful in predicting plant output for a given wind forecast. Such a development is described and summarized in this paper.

  12. Investigation on wind energy-compressed air power system.

    PubMed

    Jia, Guang-Zheng; Wang, Xuan-Yin; Wu, Gen-Mao

    2004-03-01

    Wind energy is a pollution free and renewable resource widely distributed over China. Aimed at protecting the environment and enlarging application of wind energy, a new approach to application of wind energy by using compressed air power to some extent instead of electricity put forward. This includes: explaining the working principles and characteristics of the wind energy-compressed air power system; discussing the compatibility of wind energy and compressor capacity; presenting the theoretical model and computational simulation of the system. The obtained compressor capacity vs wind power relationship in certain wind velocity range can be helpful in the designing of the wind power-compressed air system. Results of investigations on the application of high-pressure compressed air for pressure reduction led to conclusion that pressure reduction with expander is better than the throttle regulator in energy saving.

  13. Observations of How Magnetofluid Turbulence Dissipates at Small Scales

    NASA Technical Reports Server (NTRS)

    Goldstein, M. L.; Sahraoui, Fouad

    2012-01-01

    The solar wind is a turbulent magneto fluid that can be studied intensively at multiple scales. Investigations using single spacecraft have revealed much about the properties of the solar wind throughout the heliosphere (from 0.3 AU to 100 AU). More recently, data from multiple spacecraft have provided further details of both the statistical properties of the turbulence and its small-scale structure. In particular, high time resolution magnetic field measurements from the four Cluster spacecrafl have led to the conclusion that at spatial scales of order the proton inertial length and smaller, the turbulence becomes strongly anisotropic and the power in fluctuations that are perpendicular to the (local) magnetic field is measured to be much larger than that in fluctuations that are parallel to the magnetic field. As the spatial scales approach the electron inertial length, the power is almost completely dissipated. Various analysis techniques and theoretical ideas have been put forward to account for the properties of those measurements. The talk will describe the current state of observations, theory and simulations.

  14. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect

    Choi, Woo-Young; Lai, Jih-Sheng

    2010-04-15

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  15. New England Wind Forum: A Wind Powering America Project, Newsletter #5 -- January 2010, Wind and Hydropower Technologies Program (WHTP)

    SciTech Connect

    Grace, R. C.; Gifford, J.

    2010-01-01

    Wind Powering America program launched the New England Wind Forum (NEWF) in 2005 to provide a single comprehensive source of up-to-date, Web-based information on a broad array of wind energy issues pertaining to New England. The NEWF newsletter provides New England stakeholders with updates on wind energy development in the region. In addition to regional updates, Issue #5 offers an interview with Angus King, former governor of Maine and co-founder of Independence Wind.

  16. Development of an efficient, low cost, small-scale natural gas fuel reformer for residential scale electric power generation. Final report for the period October 1, 1998 - December 31, 1999

    SciTech Connect

    Kreutz, Thomas G; Ogden, Joan M

    2000-07-01

    In the final report, we present results from a technical and economic assessment of residential scale PEM fuel cell power systems. The objectives of our study are to conceptually design an inexpensive, small-scale PEMFC-based stationary power system that converts natural gas to both electricity and heat, and then to analyze the prospective performance and economics of various system configurations. We developed computer models for residential scale PEMFC cogeneration systems to compare various system designs (e.g., steam reforming vs. partial oxidation, compressed vs. atmospheric pressure, etc.) and determine the most technically and economically attractive system configurations at various scales (e.g., single family, residential, multi-dwelling, neighborhood).

  17. Wind Power: How Much, How Soon, and At What Cost?

    SciTech Connect

    Wiser, Ryan H; Hand, Maureen

    2010-01-01

    The global wind power market has been growing at a phenomenal pace, driven by favorable policies towards renewable energy and the improving economics of wind projects. On a going forward basis, utility-scale wind power offers the potential for significant reductions in the carbon footprint of the electricity sector. Specifically, the global wind resource is vast and, though accessing this potential is not costless or lacking in barriers, wind power can be developed at scale in the near to medium term at what promises to be an acceptable cost.

  18. Cooperative Extension Service & Wind Powering America Collaborate to Provide Wind Energy Information to Rural Stakeholders (Poster)

    SciTech Connect

    Jimenez, A.; Flower, L.; Hamlen, S.

    2009-05-01

    Cooperative Extension's presence blankets much of the United States and has been a trusted information source to rural Americans. By working together, Cooperative Extension, Wind Powering America, and the wind industry can better educate the public and rural stakeholders about wind energy and maximize the benefits of wind energy to local communities. This poster provides an overview of Cooperative Extension, wind energy issues addressed by the organization, and related activities.

  19. Small-scale Starshade Test

    NASA Image and Video Library

    2016-08-09

    A test of a small-scale starshade model (58 cm), made from metal, in a dry lake bed in central Nevada's Smith Creek, took place from May to June 2014. Nineteen different versions of the miniaturized starshade were tested over five days. The tests revealed that a starshade, or external occulter, is capable of blocking starlight to a degree that reveals the relatively dim reflected light of a planet next to its brighter star. Like holding your hand up to block sunlight, the starshade works to block excessive starlight from the "eyes" of a space telescope like Hubble. http://photojournal.jpl.nasa.gov/catalog/PIA20902

  20. Use of wind power forecasting in operational decisions.

    SciTech Connect

    Botterud, A.; Zhi, Z.; Wang, J.; Bessa, R.J.; Keko, H.; Mendes, J.; Sumaili, J.; Miranda, V.

    2011-11-29

    The rapid expansion of wind power gives rise to a number of challenges for power system operators and electricity market participants. The key operational challenge is to efficiently handle the uncertainty and variability of wind power when balancing supply and demand in ths system. In this report, we analyze how wind power forecasting can serve as an efficient tool toward this end. We discuss the current status of wind power forecasting in U.S. electricity markets and develop several methodologies and modeling tools for the use of wind power forecasting in operational decisions, from the perspectives of the system operator as well as the wind power producer. In particular, we focus on the use of probabilistic forecasts in operational decisions. Driven by increasing prices for fossil fuels and concerns about greenhouse gas (GHG) emissions, wind power, as a renewable and clean source of energy, is rapidly being introduced into the existing electricity supply portfolio in many parts of the world. The U.S. Department of Energy (DOE) has analyzed a scenario in which wind power meets 20% of the U.S. electricity demand by 2030, which means that the U.S. wind power capacity would have to reach more than 300 gigawatts (GW). The European Union is pursuing a target of 20/20/20, which aims to reduce greenhouse gas (GHG) emissions by 20%, increase the amount of renewable energy to 20% of the energy supply, and improve energy efficiency by 20% by 2020 as compared to 1990. Meanwhile, China is the leading country in terms of installed wind capacity, and had 45 GW of installed wind power capacity out of about 200 GW on a global level at the end of 2010. The rapid increase in the penetration of wind power into power systems introduces more variability and uncertainty in the electricity generation portfolio, and these factors are the key challenges when it comes to integrating wind power into the electric power grid. Wind power forecasting (WPF) is an important tool to help

  1. Scientists Track Collision of Powerful Stellar Winds

    NASA Astrophysics Data System (ADS)

    2005-04-01

    Astronomers using the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope have tracked the motion of a violent region where the powerful winds of two giant stars slam into each other. The collision region moves as the stars, part of a binary pair, orbit each other, and the precise measurement of its motion was the key to unlocking vital new information about the stars and their winds. WR 140 Image Sequence Motion of Wind Collision Region Graphic superimposes VLBA images of wind collision region on diagram of orbit of Wolf-Rayet (WR) star and its giant (O) companion. Click on image for larger version (412K) CREDIT: Dougherty et al., NRAO/AUI/NSF In Motion: Shockwave File Animated Gif File AVI file Both stars are much more massive than the Sun -- one about 20 times the mass of the Sun and the other about 50 times the Sun's mass. The 20-solar-mass star is a type called a Wolf-Rayet star, characterized by a very strong wind of particles propelled outward from its surface. The more massive star also has a strong outward wind, but one less intense than that of the Wolf-Rayet star. The two stars, part of a system named WR 140, circle each other in an elliptical orbit roughly the size of our Solar System. "The spectacular feature of this system is the region where the stars' winds collide, producing bright radio emission. We have been able to track this collision region as it moves with the orbits of the stars," said Sean Dougherty, an astronomer at the Herzberg Institute for Astrophysics in Canada. Dougherty and his colleagues presented their findings in the April 10 edition of the Astrophysical Journal. The supersharp radio "vision" of the continent-wide VLBA allowed the scientists to measure the motion of the wind collision region and then to determine the details of the stars' orbits and an accurate distance to the system. "Our new calculations of the orbital details and the distance are vitally important to understanding the nature of these

  2. Improving the Accuracy of Wind Turbine Power Curve Validation by the Rotor Equivalent Wind Speed Concept

    NASA Astrophysics Data System (ADS)

    Scheurich, Frank; Enevoldsen, Peder B.; Paulsen, Henrik N.; Dickow, Kristoffer K.; Fiedel, Moritz; Loeven, Alex; Antoniou, Ioannis

    2016-09-01

    The measurement of the wind speed at hub height is part of the current IEC standard procedure for the power curve validation of wind turbines. The inherent assumption is thereby made that this measured hub height wind speed sufficiently represents the wind speed across the entire rotor area. It is very questionable, however, whether the hub height wind speed (HHWS) method is appropriate for rotor sizes of commercial state-of-the-art wind turbines. The rotor equivalent wind speed (REWS) concept, in which the wind velocities are measured at several different heights across the rotor area, is deemed to be better suited to represent the wind speed in power curve measurements and thus results in more accurate predictions of the annual energy production (AEP) of the turbine. The present paper compares the estimated AEP, based on HHWS power curves, of two different commercial wind turbines to the AEP that is based on REWS power curves. The REWS was determined by LiDAR measurements of the wind velocities at ten different heights across the rotor area. It is shown that a REWS power curve can, depending on the wind shear profile, result in higher, equal or lower AEP estimations compared to the AEP predicted by a HHWS power curve.

  3. KANSAS WIND POWERING AMERICAN STATE OUTREACH: KANSAS WIND WORKING GROUP

    SciTech Connect

    HAMMARLUND, RAY

    2010-10-27

    The Kansas Wind Working Group (WWG) is a 33-member group announced by former Governor Kathleen Sebelius on Jan. 7, 2008. Formed through Executive Order 08-01, the WWG will educate stakeholder groups with the current information on wind energy markets, technologies, economics, policies, prospects and issues. Governor Mark Parkinson serves as chair of the Kansas Wind Working Group. The group has been instrumental in focusing on the elements of government and coordinating government and private sector efforts in wind energy development. Those efforts have moved Kansas from 364 MW of wind three years ago to over 1000 MW today. Further, the Wind Working Group was instrumental in fleshing out issues such as a state RES and net metering, fundamental parts of HB 2369 that was passed and is now law in Kansas. This represents the first mandatory RES and net metering in Kansas history.

  4. Case studies of the legal and institutional obstacles and incentives to the development of small-scale hydroelectric power: South Columbia Basin Irrigation District, Pasco, Washington

    SciTech Connect

    Schwartz, L.

    1980-05-01

    The case study concerns two modern human uses of the Columbia River - irrigation aimed at agricultural land reclamation and hydroelectric power. The Grand Coulee Dam has become synonomous with large-scale generation of hydroelectric power providing the Pacific Northwest with some of the least-expensive electricity in the United States. The Columbia Basin Project has created a half-million acres of farmland in Washington out of a spectacular and vast desert. The South Columbia River Basin Irrigation District is seeking to harness the energy present in the water which already runs through its canals, drains, and wasteways. The South District's development strategy is aimed toward reducing the costs its farmers pay for irrigation and raising the capital required to serve the remaining 550,000 acres originally planned as part of the Columbia Basin Project. The economic, institutional, and regulatory problems of harnessing the energy at site PEC 22.7, one of six sites proposed for development, are examined in this case study.

  5. Wind Power Finance and Investment Workshop 2004

    SciTech Connect

    anon.

    2004-11-01

    The workshop had 33 presentations by the leading industry experts in the wind finance and investment area. The workshop presented wind industry opportunities and advice to the financial community. The program also included two concurrent sessions, Wind 100, which offered wind energy novices a comprehensive introduction to wind energy fundamentals, and Transmission Policy and Regulations. Other workshop topics included: Bringing environmental and other issues into perspective; Policy impacts on wind financing; Technical/wind issues; Monetizing green attributes (Sale of green tags); Contractual issues; Debt issues; and Equity issues. There were approximately 230 attendees.

  6. Wind Power in Australia: Overcoming Technological and Institutional Barriers

    ERIC Educational Resources Information Center

    Healey, Gerard; Bunting, Andrea

    2008-01-01

    Until recently, Australia had little installed wind capacity, although there had been many investigations into its potential during the preceding decades. Formerly, state-owned monopoly utilities showed only token interest in wind power and could dictate the terms of energy debates. This situation changed in the late 1990s: Installed wind capacity…

  7. Wind Power in Australia: Overcoming Technological and Institutional Barriers

    ERIC Educational Resources Information Center

    Healey, Gerard; Bunting, Andrea

    2008-01-01

    Until recently, Australia had little installed wind capacity, although there had been many investigations into its potential during the preceding decades. Formerly, state-owned monopoly utilities showed only token interest in wind power and could dictate the terms of energy debates. This situation changed in the late 1990s: Installed wind capacity…

  8. Evaluation of a wind turbine electric power generator

    NASA Technical Reports Server (NTRS)

    Swim, W. B.

    1981-01-01

    A technical assessment of the aerodynamic performance of the wind wheel turbine (WWT) is reported. The potential of the WWT in utilizing wind as an alternate power source was evaluated. Scaling parameters were developed to predict the aerodynamic performance of WWT prototype sized to produce 3, 9, 30, and 100 kw outputs in a 6.7 m/sec wind.

  9. Classifying Vertical Wind Speed Profiles for Offshore Wind Resource and Available Power Assessment

    NASA Astrophysics Data System (ADS)

    St Pe, A.; Tippet, S.; Rabenhorst, S. D.; Delgado, R.

    2016-12-01

    Prior to offshore wind farm construction, an accurate estimate of preconstruction energy yield is required to optimize wind farm layout and justify the project's economic viability. Unfortunately, uncertainties exist during this stage due in-part to limited measurements to characterize the offshore wind resource and related uncertainties predicting a turbine's available power. To better understand these preconstruction energy yield uncertainties, Doppler wind lidar and other met-ocean measurements were collected offshore within Maryland's Wind Energy Area from July-August 2013. Given the diversity of vertical wind speed profile (VWP) observations, VWPs are classified based on the goodness-of-fit to several mathematical expressions. Results demonstrate on average VWP typevariability is related to the magnitude of hub-height (100m) wind speed and wind direction (i.e. offshore fetch), as power law, logarithmic-like, VWPs occur during slightly weaker, northeasterly flow, while more unexpected VWPs are associated with stronger, southwesterly flow, from land to sea. In addition, compared to power-law VWP classes, unexpected VWPs types demonstrate slightly warmer air and SSTs, as well as stable surface conditions. Classifying VWPs also provides a useful tool for relating preconstruction offshore wind resource and turbine available power uncertainties. Using an NREL 5MW offshore reference turbine's power curve, buoy extrapolated surface wind to hub-height (100m), lidar measured hub-height, and several Rotor Equivalent Wind (REW) available power estimates are compared. On average, traditional hub-height wind speed power yields the highest available power estimate, approximately 9-70 percent greater than other techniques. Further, unexpected VWPs demonstrate the greatest variability in critical superimposed meteorological controls known to impact turbine performance, thus yield greatest deviation from hub-height power and uncertainty between available power estimates

  10. Compensation of Reactive Power of Isolated Wind-Diesel Hybrid Power Systems

    NASA Astrophysics Data System (ADS)

    Sharma, P.; Bhatti, T. S.; Ramakrishna, K. S. S.

    2012-03-01

    This paper presents the automatic reactive power control of an isolated wind-diesel hybrid power system with a synchronous generator (SG) for a diesel genset and an induction generator (IG) with wind energy conversion systems (WECS) to generate electricity. To reduce the gap between reactive power generation and demand, a variable source of reactive power is used such as static synchronous compensator (STATCOM). The mathematical model of the system based on reactive power flow equations is developed. Three examples of the wind-diesel hybrid power systems are considered with different wind power generation capacities to study the effect of the wind power generation on the system performance. The study is based on small signal analysis by considering IEEE type-1 excitation system for the SG. The paper also shows the transient performance of the hybrid systems for 1 % step increase in reactive power load and 1 % step increase in reactive power load plus 1 % step increase in input wind power.

  11. Demonstrating a new framework for the comparison of environmental impacts from small- and large-scale hydropower and wind power projects.

    PubMed

    Bakken, Tor Haakon; Aase, Anne Guri; Hagen, Dagmar; Sundt, Håkon; Barton, David N; Lujala, Päivi

    2014-07-01

    Climate change and the needed reductions in the use of fossil fuels call for the development of renewable energy sources. However, renewable energy production, such as hydropower (both small- and large-scale) and wind power have adverse impacts on the local environment by causing reductions in biodiversity and loss of habitats and species. This paper compares the environmental impacts of many small-scale hydropower plants with a few large-scale hydropower projects and one wind power farm, based on the same set of environmental parameters; land occupation, reduction in wilderness areas (INON), visibility and impacts on red-listed species. Our basis for comparison was similar energy volumes produced, without considering the quality of the energy services provided. The results show that small-scale hydropower performs less favourably in all parameters except land occupation. The land occupation of large hydropower and wind power is in the range of 45-50 m(2)/MWh, which is more than two times larger than the small-scale hydropower, where the large land occupation for large hydropower is explained by the extent of the reservoirs. On all the three other parameters small-scale hydropower performs more than two times worse than both large hydropower and wind power. Wind power compares similarly to large-scale hydropower regarding land occupation, much better on the reduction in INON areas, and in the same range regarding red-listed species. Our results demonstrate that the selected four parameters provide a basis for further development of a fair and consistent comparison of impacts between the analysed renewable technologies. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. Small-scale hydroelectric power demonstration project. Riegel Textile Corporation, Fries, Virginia plant hydro-project. Final operation and maintenance report

    SciTech Connect

    Not Available

    1983-12-01

    Riegel Textile Corporation completed a 2163 KW rated turbine generator project at its plant on the New River in Fries, Virginia. A new powerhouse was constructed to enclose a used 2900 HP vertical Kaplan turbine and Westinghouse generator. The turbine is a 4-bladed 72-inch S. Morgan Smith manufactured in 1939. At the original setting of 46 feet, the unit had a rating of 3880 HP and the generator had a rating of 3000 KVA. Overhaul and installation of the used equipment was accomplished by the plant maintenance department. Overhaul of the used equipment and preparation of the license application began in June 1979. Construction of the new powerhouse began in June 1980. On July 24, 1981, construction was completed, the new unit was synchronized with Appalachian Power Company, and the first electrical energy was produced. The installation of this equipment, in conjunction with existing equipment already in place, increased the total plant generating capacity to 5251 KW. A total of four generators are now used and approximately 75% of the manufacturing plant's electrical requirements are self-generated. The purpose of this report is to summarize the operating and maintenance activities, costs, and revenues for the first two years of operation.

  13. Power Performance Test Report for the SWIFT Wind Turbine

    SciTech Connect

    Mendoza, I.; Hur, J.

    2012-12-01

    This report summarizes the results of a power performance test that NREL conducted on the SWIFT wind turbine. This test was conducted in accordance with the International Electrotechnical Commission's (IEC) standard, Wind Turbine Generator Systems Part 12: Power Performance Measurements of Electricity Producing Wind Turbines, IEC 61400-12-1 Ed.1.0, 2005-12. However, because the SWIFT is a small turbine as defined by IEC, NREL also followed Annex H that applies to small wind turbines. In these summary results, wind speed is normalized to sea-level air density.

  14. Small Scale High Speed Turbomachinery

    NASA Technical Reports Server (NTRS)

    London, Adam P. (Inventor); Droppers, Lloyd J. (Inventor); Lehman, Matthew K. (Inventor); Mehra, Amitav (Inventor)

    2015-01-01

    A small scale, high speed turbomachine is described, as well as a process for manufacturing the turbomachine. The turbomachine is manufactured by diffusion bonding stacked sheets of metal foil, each of which has been pre-formed to correspond to a cross section of the turbomachine structure. The turbomachines include rotating elements as well as static structures. Using this process, turbomachines may be manufactured with rotating elements that have outer diameters of less than four inches in size, and/or blading heights of less than 0.1 inches. The rotating elements of the turbomachines are capable of rotating at speeds in excess of 150 feet per second. In addition, cooling features may be added internally to blading to facilitate cooling in high temperature operations.

  15. An improved AVC strategy applied in distributed wind power system

    NASA Astrophysics Data System (ADS)

    Zhao, Y. N.; Liu, Q. H.; Song, S. Y.; Mao, W.

    2016-08-01

    Traditional AVC strategy is mainly used in wind farm and only concerns about grid connection point, which is not suitable for distributed wind power system. Therefore, this paper comes up with an improved AVC strategy applied in distributed wind power system. The strategy takes all nodes of distribution network into consideration and chooses the node having the most serious voltage deviation as control point to calculate the reactive power reference. In addition, distribution principles can be divided into two conditions: when wind generators access to network on single node, the reactive power reference is distributed according to reactive power capacity; when wind generators access to network on multi-node, the reference is distributed according to sensitivity. Simulation results show the correctness and reliability of the strategy. Compared with traditional control strategy, the strategy described in this paper can make full use of generators reactive power output ability according to the distribution network voltage condition and improve the distribution network voltage level effectively.

  16. Power fluctuations smoothing and regulations in wind turbine generator systems

    NASA Astrophysics Data System (ADS)

    Babazadehrokni, Hamed

    Wind is one of the most popular renewable energy sources and it has the potential to become the biggest energy source in future. Since the wind does not always blow constantly, the output wind power is not constant which may make some problem for the power grid. According to the grid code which is set by independent system operator, ISO, wind turbine generator systems need to follow some standards such as the predetermined acceptable power fluctuations. In order to smooth the output powers, the energy storage system and some power electronics modules are employed. The utilized power electronics modules in the wind turbine system can pursue many different goals, such as maintaining the voltage stability, frequency stability, providing the available and predetermined output active and reactive power. On the other side, the energy storage system can help achieving some of these goals but its main job is to store the extra energy when not needed and release the stored energy when needed. The energy storage system can be designed in different sizes, material and also combination of different energy storage systems (hybrid designs). Combination of power electronics devises and also energy storage system helps the wind turbine systems to smooth the output power according to the provided standards. In addition prediction of wind speed may improve the performance of wind turbine generator systems. In this research study all these three topics are studied and the obtained results are written in 10 papers which 7 of them are published and three of them are under process.

  17. The Potential Wind Power Resource in Australia: A New Perspective

    PubMed Central

    Hallgren, Willow; Gunturu, Udaya Bhaskar; Schlosser, Adam

    2014-01-01

    Australia’s wind resource is considered to be very good, and the utilization of this renewable energy resource is increasing rapidly: wind power installed capacity increased by 35% from 2006 to 2011 and is predicted to account for over 12% of Australia’s electricity generation in 2030. Due to this growth in the utilization of the wind resource and the increasing importance of wind power in Australia’s energy mix, this study sets out to analyze and interpret the nature of Australia’s wind resources using robust metrics of the abundance, variability and intermittency of wind power density, and analyzes the variation of these characteristics with current and potential wind turbine hub heights. We also assess the extent to which wind intermittency, on hourly or greater timescales, can potentially be mitigated by the aggregation of geographically dispersed wind farms, and in so doing, lessen the severe impact on wind power economic viability of long lulls in wind and power generated. Our results suggest that over much of Australia, areas that have high wind intermittency coincide with large expanses in which the aggregation of turbine output does not mitigate variability. These areas are also geographically remote, some are disconnected from the east coast’s electricity grid and large population centers, which are factors that could decrease the potential economic viability of wind farms in these locations. However, on the eastern seaboard, even though the wind resource is weaker, it is less variable, much closer to large population centers, and there exists more potential to mitigate it’s intermittency through aggregation. This study forms a necessary precursor to the analysis of the impact of large-scale circulations and oscillations on the wind resource at the mesoscale. PMID:24988222

  18. The potential wind power resource in Australia: a new perspective.

    PubMed

    Hallgren, Willow; Gunturu, Udaya Bhaskar; Schlosser, Adam

    2014-01-01

    Australia's wind resource is considered to be very good, and the utilization of this renewable energy resource is increasing rapidly: wind power installed capacity increased by 35% from 2006 to 2011 and is predicted to account for over 12% of Australia's electricity generation in 2030. Due to this growth in the utilization of the wind resource and the increasing importance of wind power in Australia's energy mix, this study sets out to analyze and interpret the nature of Australia's wind resources using robust metrics of the abundance, variability and intermittency of wind power density, and analyzes the variation of these characteristics with current and potential wind turbine hub heights. We also assess the extent to which wind intermittency, on hourly or greater timescales, can potentially be mitigated by the aggregation of geographically dispersed wind farms, and in so doing, lessen the severe impact on wind power economic viability of long lulls in wind and power generated. Our results suggest that over much of Australia, areas that have high wind intermittency coincide with large expanses in which the aggregation of turbine output does not mitigate variability. These areas are also geographically remote, some are disconnected from the east coast's electricity grid and large population centers, which are factors that could decrease the potential economic viability of wind farms in these locations. However, on the eastern seaboard, even though the wind resource is weaker, it is less variable, much closer to large population centers, and there exists more potential to mitigate it's intermittency through aggregation. This study forms a necessary precursor to the analysis of the impact of large-scale circulations and oscillations on the wind resource at the mesoscale.

  19. National-Scale Wind Resource Assessment for Power Generation (Presentation)

    SciTech Connect

    Baring-Gould, E. I.

    2013-08-01

    This presentation describes the current standards for conducting a national-scale wind resource assessment for power generation, along with the risk/benefit considerations to be considered when beginning a wind resource assessment. The presentation describes changes in turbine technology and viable wind deployment due to more modern turbine technology and taller towers and shows how the Philippines national wind resource assessment evolved over time to reflect changes that arise from updated technologies and taller towers.

  20. Maximum wind energy extraction strategies using power electronic converters

    NASA Astrophysics Data System (ADS)

    Wang, Quincy Qing

    2003-10-01

    This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind power generation, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind power generation system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through

  1. Calculation of guaranteed mean power from wind turbine generators

    NASA Technical Reports Server (NTRS)

    Spera, D. A.

    1981-01-01

    A method for calculating the 'guaranteed mean' power output of a wind turbine generator is proposed. The term 'mean power' refers to the average power generated at specified wind speeds during short-term tests. Correlation of anemometers, the method of bins for analyzing non-steady data, the PROP Code for predicting turbine power, and statistical analysis of deviations in test data from theory are discussed. Guaranteed mean power density for the Clayton Mod-OA system was found to be 8 watts per square meter less than theoretical power density at all power levels, with a confidence level of 0.999. This amounts to 4 percent of rated power.

  2. Wind power prediction based on genetic neural network

    NASA Astrophysics Data System (ADS)

    Zhang, Suhan

    2017-04-01

    The scale of grid connected wind farms keeps increasing. To ensure the stability of power system operation, make a reasonable scheduling scheme and improve the competitiveness of wind farm in the electricity generation market, it's important to accurately forecast the short-term wind power. To reduce the influence of the nonlinear relationship between the disturbance factor and the wind power, the improved prediction model based on genetic algorithm and neural network method is established. To overcome the shortcomings of long training time of BP neural network and easy to fall into local minimum and improve the accuracy of the neural network, genetic algorithm is adopted to optimize the parameters and topology of neural network. The historical data is used as input to predict short-term wind power. The effectiveness and feasibility of the method is verified by the actual data of a certain wind farm as an example.

  3. Wind turbine power tracking using an improved multimodel quadratic approach.

    PubMed

    Khezami, Nadhira; Benhadj Braiek, Naceur; Guillaud, Xavier

    2010-07-01

    In this paper, an improved multimodel optimal quadratic control structure for variable speed, pitch regulated wind turbines (operating at high wind speeds) is proposed in order to integrate high levels of wind power to actively provide a primary reserve for frequency control. On the basis of the nonlinear model of the studied plant, and taking into account the wind speed fluctuations, and the electrical power variation, a multimodel linear description is derived for the wind turbine, and is used for the synthesis of an optimal control law involving a state feedback, an integral action and an output reference model. This new control structure allows a rapid transition of the wind turbine generated power between different desired set values. This electrical power tracking is ensured with a high-performance behavior for all other state variables: turbine and generator rotational speeds and mechanical shaft torque; and smooth and adequate evolution of the control variables. 2010 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Simulation and optimization of wind and diesel power supply systems

    NASA Astrophysics Data System (ADS)

    Lukutin, B. V.; Shandarova, E. B.; Matukhin, D. L.; Igisenov, A. A.; Shandarov, S. M.

    2017-02-01

    The paper proposes an algorithm to optimize the structure and the choice of capacity of wind and diesel power units of the combined power plant, depending on the wind energy potential and electricity consumption of electrified facility. The algorithm is based on mathematical models of technical and economic characteristics of wind and diesel power plants as well as an optimization method of coordinate descent. The algorithm takes into account the structure of the combined power plant, changing modes of its operation, construction and operation costs of the power facility. The objective function of the algorithm is to minimize the cost of electricity generated.

  5. Self Excitation and Harmonics in Wind Power Generation: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Romanowitz, H.; Yinger, R.

    2004-11-01

    Traditional wind turbines are equipped with induction generators. Induction generators are preferred because they are inexpensive, rugged, and require very little maintenance. Unfortunately, induction generators require reactive power from the grid to operate. Because reactive power varies with the output power, the terminal voltage at the generator may become too low to compensate the induction generator. The interactions among the wind turbine, the power network, and the capacitor compensation, are important aspects of wind generation. In this paper, we will show the interactions among the induction generator, capacitor compensation, power system network, and magnetic saturations and examine the cause of resonance conditions and self-excitation.

  6. Self-Excitation and Harmonics in Wind Power Generation

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Romanowitz, H.; Yinger, R.

    2005-11-01

    Traditional wind turbines are commonly equipped with induction generators because they are inexpensive, rugged, and require very little maintenance. Unfortunately, induction generators require reactive power from the grid to operate; capacitor compensation is often used. Because the level of required reactive power varies with the output power, the capacitor compensation must be adjusted as the output power varies. The interactions among the wind turbine, the power network, and the capacitor compensation are important aspects of wind generation that may result in self-excitation and higher harmonic content in the output current. This paper examines the factors that control these phenomena and gives some guidelines on how they can be controlled or eliminated.

  7. 2. LOOKING DOWN THE LINED POWER CANAL AS IT WINDS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. LOOKING DOWN THE LINED POWER CANAL AS IT WINDS ITS WAY TOWARD THE CEMENT MILL Photographer: Walter J. Lubken, November 19, 1907 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

  8. Wind energy in electric power production, preliminary study

    NASA Astrophysics Data System (ADS)

    Lento, R.; Peltola, E.

    1984-01-01

    The wind speed conditions in Finland have been studied with the aid of the existing statistics of the Finnish Meteorological Institute. With the aid of the statistics estimates on the available wind energy were also made. Eight hundred wind power plants, 1.5 MW each, on the windiest west coast would produce about 2 TWh energy per year. Far more information on the temporal, geographical and vertical distribution of the wind speed than the present statistics included is needed when the available wind energy is estimated, when wind power plants are dimensioned optimally, and when suitable locations are chosen for them. The investment costs of a wind power plant increase when the height of the tower or the diameter of the rotor is increased, but the energy production increases, too. Thus, overdimensioning the wind power plant in view of energy needs or the wind conditions caused extra costs. The cost of energy produced by wind power can not yet compete with conventional energy, but the situation changes to the advantage of wind energy, if the real price of the plants decreases (among other things due to large series production and increasing experience), or if the real price of fuels rises. The inconvinience on the environment caused by the wind power plants is considered insignificant. The noise caused by the plant attenuates rapidly with distance. No harmful effects to birds and other animals caused by the wind power plants have been observed in the studies made abroad. Parts of the plant getting loose during an accident, or ice forming on the blades are estimated to fly even from a large plant only a few hundred meters.

  9. Wind Power Forecasting Error Distributions: An International Comparison; Preprint

    SciTech Connect

    Hodge, B. M.; Lew, D.; Milligan, M.; Holttinen, H.; Sillanpaa, S.; Gomez-Lazaro, E.; Scharff, R.; Soder, L.; Larsen, X. G.; Giebel, G.; Flynn, D.; Dobschinski, J.

    2012-09-01

    Wind power forecasting is expected to be an important enabler for greater penetration of wind power into electricity systems. Because no wind forecasting system is perfect, a thorough understanding of the errors that do occur can be critical to system operation functions, such as the setting of operating reserve levels. This paper provides an international comparison of the distribution of wind power forecasting errors from operational systems, based on real forecast data. The paper concludes with an assessment of similarities and differences between the errors observed in different locations.

  10. System-wide emissions implications of increased wind power penetration.

    PubMed

    Valentino, Lauren; Valenzuela, Viviana; Botterud, Audun; Zhou, Zhi; Conzelmann, Guenter

    2012-04-03

    This paper discusses the environmental effects of incorporating wind energy into the electric power system. We present a detailed emissions analysis based on comprehensive modeling of power system operations with unit commitment and economic dispatch for different wind penetration levels. First, by minimizing cost, the unit commitment model decides which thermal power plants will be utilized based on a wind power forecast, and then, the economic dispatch model dictates the level of production for each unit as a function of the realized wind power generation. Finally, knowing the power production from each power plant, the emissions are calculated. The emissions model incorporates the effects of both cycling and start-ups of thermal power plants in analyzing emissions from an electric power system with increasing levels of wind power. Our results for the power system in the state of Illinois show significant emissions effects from increased cycling and particularly start-ups of thermal power plants. However, we conclude that as the wind power penetration increases, pollutant emissions decrease overall due to the replacement of fossil fuels.

  11. System-wide emissions implications of increased wind power penetration.

    SciTech Connect

    Valentino, L.; Valenzuela, V.; Botterud, A.; Zhou, Z.; Conzelmann, G.

    2012-01-01

    This paper discusses the environmental effects of incorporating wind energy into the electric power system. We present a detailed emissions analysis based on comprehensive modeling of power system operations with unit commitment and economic dispatch for different wind penetration levels. First, by minimizing cost, the unit commitment model decides which thermal power plants will be utilized based on a wind power forecast, and then, the economic dispatch model dictates the level of production for each unit as a function of the realized wind power generation. Finally, knowing the power production from each power plant, the emissions are calculated. The emissions model incorporates the effects of both cycling and start-ups of thermal power plants in analyzing emissions from an electric power system with increasing levels of wind power. Our results for the power system in the state of Illinois show significant emissions effects from increased cycling and particularly start-ups of thermal power plants. However, we conclude that as the wind power penetration increases, pollutant emissions decrease overall due to the replacement of fossil fuels.

  12. A nonlinear dynamics approach for incorporating wind-speed patterns into wind-power project evaluation.

    PubMed

    Huffaker, Ray; Bittelli, Marco

    2015-01-01

    Wind-energy production may be expanded beyond regions with high-average wind speeds (such as the Midwest U.S.A.) to sites with lower-average speeds (such as the Southeast U.S.A.) by locating favorable regional matches between natural wind-speed and energy-demand patterns. A critical component of wind-power evaluation is to incorporate wind-speed dynamics reflecting documented diurnal and seasonal behavioral patterns. Conventional probabilistic approaches remove patterns from wind-speed data. These patterns must be restored synthetically before they can be matched with energy-demand patterns. How to accurately restore wind-speed patterns is a vexing problem spurring an expanding line of papers. We propose a paradigm shift in wind power evaluation that employs signal-detection and nonlinear-dynamics techniques to empirically diagnose whether synthetic pattern restoration can be avoided altogether. If the complex behavior of observed wind-speed records is due to nonlinear, low-dimensional, and deterministic system dynamics, then nonlinear dynamics techniques can reconstruct wind-speed dynamics from observed wind-speed data without recourse to conventional probabilistic approaches. In the first study of its kind, we test a nonlinear dynamics approach in an application to Sugarland Wind-the first utility-scale wind project proposed in Florida, USA. We find empirical evidence of a low-dimensional and nonlinear wind-speed attractor characterized by strong temporal patterns that match up well with regular daily and seasonal electricity demand patterns.

  13. Wind Turbine Generator System Power Performance Test Report for the ARE442 Wind Turbine

    SciTech Connect

    van Dam, J.; Jager, D.

    2010-02-01

    This report summarizes the results of a power performance test that NREL conducted on the ARE 442 wind turbine. This test was conducted in accordance with the International Electrotechnical Commission's (IEC) standard, Wind Turbine Generator Systems Part 12: Power Performance Measurements of Electricity Producing Wind Turbines, IEC 61400-12-1 Ed.1.0, 2005-12. However, because the ARE 442 is a small turbine as defined by IEC, NREL also followed Annex H that applies to small wind turbines. In these summary results, wind speed is normalized to sea-level air density.

  14. Wind Energy: A Maturing Power Supply Possibility.

    ERIC Educational Resources Information Center

    Petersen, Erik Lundtang; And Others

    1987-01-01

    Suggests that wind energy for electrification will prove to be an appropriate technology with very positive socioeconomic benefits, especially in developing countries. Provides examples of projects conducted by a Danish wind research laboratory. (TW)

  15. Wind Energy: A Maturing Power Supply Possibility.

    ERIC Educational Resources Information Center

    Petersen, Erik Lundtang; And Others

    1987-01-01

    Suggests that wind energy for electrification will prove to be an appropriate technology with very positive socioeconomic benefits, especially in developing countries. Provides examples of projects conducted by a Danish wind research laboratory. (TW)

  16. Quantifying the hurricane catastrophe risk to offshore wind power.

    PubMed

    Rose, Stephen; Jaramillo, Paulina; Small, Mitchell J; Apt, Jay

    2013-12-01

    The U.S. Department of Energy has estimated that over 50 GW of offshore wind power will be required for the United States to generate 20% of its electricity from wind. Developers are actively planning offshore wind farms along the U.S. Atlantic and Gulf coasts and several leases have been signed for offshore sites. These planned projects are in areas that are sometimes struck by hurricanes. We present a method to estimate the catastrophe risk to offshore wind power using simulated hurricanes. Using this method, we estimate the fraction of offshore wind power simultaneously offline and the cumulative damage in a region. In Texas, the most vulnerable region we studied, 10% of offshore wind power could be offline simultaneously because of hurricane damage with a 100-year return period and 6% could be destroyed in any 10-year period. We also estimate the risks to single wind farms in four representative locations; we find the risks are significant but lower than those estimated in previously published results. Much of the hurricane risk to offshore wind turbines can be mitigated by designing turbines for higher maximum wind speeds, ensuring that turbine nacelles can turn quickly to track the wind direction even when grid power is lost, and building in areas with lower risk. © 2013 Society for Risk Analysis.

  17. Modeling the Benefits of Storage Technologies to Wind Power

    SciTech Connect

    Sullivan, P.; Short, W.; Blair, N.

    2008-06-01

    Rapid expansion of wind power in the electricity sector is raising questions about how wind resource variability might affect the capacity value of wind farms at high levels of penetration. Electricity storage, with the capability to shift wind energy from periods of low demand to peak times and to smooth fluctuations in output, may have a role in bolstering the value of wind power at levels of penetration envisioned by a new Department of Energy report ('20% Wind by 2030, Increasing Wind Energy's Contribution to U.S. Electricity Supply'). This paper quantifies the value storage can add to wind. The analysis was done employing the Regional Energy Deployment System (ReEDS) model, formerly known as the Wind Deployment System (WinDS) model. ReEDS was used to estimate the cost and development path associated with 20% penetration of wind in the report. ReEDS differs from the WinDS model primarily in that the model has been modified to include the capability to build and use three storage technologies: pumped-hydroelectric storage (PHS), compressed-air energy storage (CAES), and batteries. To assess the value of these storage technologies, two pairs of scenarios were run: business-as-usual, with and without storage; 20% wind energy by 2030, with and without storage. This paper presents the results from those model runs.

  18. A summary of impacts of wind power integration on power system small-signal stability

    NASA Astrophysics Data System (ADS)

    Yan, Lei; Wang, Kewen

    2017-05-01

    Wind power has been increasingly integrated into power systems over the last few decades because of the global energy crisis and the pressure on environmental protection, and the stability of the system connected with wind power is becoming more prominent. This paper summaries the research status, achievements as well as deficiencies of the research on the impact of wind power integration on power system small-signal stability. In the end, the further research needed are discussed.

  19. Detection of Wind Turbine Power Performance Abnormalities Using Eigenvalue Analysis

    DTIC Science & Technology

    2014-10-02

    seen for Turbine #09 in figure 9. Then, a noise reduction mode was enabled for the current wind turbine (and for the vast major- ity of the turbines ...Production, Wind Speed and Power Curve - Case: Enabling of noise reduction mode. Figure 11. Turbine #07 - Noise reduction mode - Trending behaviour of...Detection of Wind Turbine Power Performance Abnormalities Using Eigenvalue Analysis Georgios Alexandros Skrimpas1, Christian Walsted Sweeney2, Kun S

  20. The probability distribution of wind power from a dispersed array of wind turbine generators

    NASA Astrophysics Data System (ADS)

    Carlin, J.; Haslett, J.

    1982-03-01

    A method is presented for estimating the probability distribution of wind power from a dispersed array of wind turbine sites where the correlation between wind speeds at distinct sites is less than unity. The distribution is obtained from a model for the joint probability distribution of wind speeds. This is able to incorporate arbitrary inter-site correlations. It is shown that this joint distribution reduces in the single site case to a wind speed distribution closely approximating the widely used Weibull; the multiple site power distribution is also shown to fit adequately to data on wind speeds from four sites in Western Australia. Results presented in graphical and tabular form for a range of representative cases show that a significant reduction in the variability of total wind power output may result from dispersion of aerogenerator sites; a quantitative guide to the magnitude of these effects is also provided.

  1. Power control and management of the grid containing largescale wind power systems

    NASA Astrophysics Data System (ADS)

    Aula, Fadhil Toufick

    The ever increasing demand for electricity has driven many countries toward the installation of new generation facilities. However, concerns such as environmental pollution and global warming issues, clean energy sources, high costs associated with installation of new conventional power plants, and fossil fuels depletion have created many interests in finding alternatives to conventional fossil fuels for generating electricity. Wind energy is one of the most rapidly growing renewable power sources and wind power generations have been increasingly demanded as an alternative to the conventional fossil fuels. However, wind power fluctuates due to variation of wind speed. Therefore, large-scale integration of wind energy conversion systems is a threat to the stability and reliability of utility grids containing these systems. They disturb the balance between power generation and consumption, affect the quality of the electricity, and complicate load sharing and load distribution managing and planning. Overall, wind power systems do not help in providing any services such as operating and regulating reserves to the power grid. In order to resolve these issues, research has been conducted in utilizing weather forecasting data to improve the performance of the wind power system, reduce the influence of the fluctuations, and plan power management of the grid containing large-scale wind power systems which consist of doubly-fed induction generator based energy conversion system. The aims of this research, my dissertation, are to provide new methods for: smoothing the output power of the wind power systems and reducing the influence of their fluctuations, power managing and planning of a grid containing these systems and other conventional power plants, and providing a new structure of implementing of latest microprocessor technology for controlling and managing the operation of the wind power system. In this research, in order to reduce and smooth the fluctuations, two

  2. NREL's Wind Powering America Team Helps Indiana Develop Wind Resources (Fact Sheet)

    SciTech Connect

    Not Available

    2010-10-01

    How does a state advance, in just five years, from having no installed wind capacity to having more than 1000 megawatts (MW) of installed capacity? The Wind Powering America (WPA) initiative, based at the National Renewable Energy Laboratory (NREL), employs a state-focused approach that has helped accelerate wind energy deployment in many states. One such state is Indiana, which is now home to the largest wind plant east of the Mississippi.

  3. Equilibrium pricing in electricity markets with wind power

    NASA Astrophysics Data System (ADS)

    Rubin, Ofir David

    Estimates from the World Wind Energy Association assert that world total wind power installed capacity climbed from 18 Gigawatt (GW) to 152 GW from 2000 to 2009. Moreover, according to their predictions, by the end of 2010 global wind power capacity will reach 190 GW. Since electricity is a unique commodity, this remarkable expansion brings forward several key economic questions regarding the integration of significant amount of wind power capacity into deregulated electricity markets. The overall dissertation objective is to develop a comprehensive theoretical framework that enables the modeling of the performance and outcome of wind-integrated electricity markets. This is relevant because the state of knowledge of modeling electricity markets is insufficient for the purpose of wind power considerations. First, there is a need to decide about a consistent representation of deregulated electricity markets. Surprisingly, the related body of literature does not agree on the very economic basics of modeling electricity markets. That is important since we need to capture the fundamentals of electricity markets before we introduce wind power to our study. For example, the structure of the electric industry is a key. If market power is present, the integration of wind power has large consequences on welfare distribution. Since wind power uncertainty changes the dynamics of information it also impacts the ability to manipulate market prices. This is because the quantity supplied by wind energy is not a decision variable. Second, the intermittent spatial nature of wind over a geographical region is important because the market value of wind power capacity is derived from its statistical properties. Once integrated into the market, the distribution of wind will impact the price of electricity produced from conventional sources of energy. Third, although wind power forecasting has improved in recent years, at the time of trading short-term electricity forwards, forecasting

  4. Electric power from offshore wind via synoptic-scale interconnection

    PubMed Central

    Kempton, Willett; Pimenta, Felipe M.; Veron, Dana E.; Colle, Brian A.

    2010-01-01

    World wind power resources are abundant, but their utilization could be limited because wind fluctuates rather than providing steady power. We hypothesize that wind power output could be stabilized if wind generators were located in a meteorologically designed configuration and electrically connected. Based on 5 yr of wind data from 11 meteorological stations, distributed over a 2,500 km extent along the U.S. East Coast, power output for each hour at each site is calculated. Each individual wind power generation site exhibits the expected power ups and downs. But when we simulate a power line connecting them, called here the Atlantic Transmission Grid, the output from the entire set of generators rarely reaches either low or full power, and power changes slowly. Notably, during the 5-yr study period, the amount of power shifted up and down but never stopped. This finding is explained by examining in detail the high and low output periods, using reanalysis data to show the weather phenomena responsible for steady production and for the occasional periods of low power. We conclude with suggested institutions appropriate to create and manage the power system analyzed here. PMID:20368464

  5. Electric power from offshore wind via synoptic-scale interconnection.

    PubMed

    Kempton, Willett; Pimenta, Felipe M; Veron, Dana E; Colle, Brian A

    2010-04-20

    World wind power resources are abundant, but their utilization could be limited because wind fluctuates rather than providing steady power. We hypothesize that wind power output could be stabilized if wind generators were located in a meteorologically designed configuration and electrically connected. Based on 5 yr of wind data from 11 meteorological stations, distributed over a 2,500 km extent along the U.S. East Coast, power output for each hour at each site is calculated. Each individual wind power generation site exhibits the expected power ups and downs. But when we simulate a power line connecting them, called here the Atlantic Transmission Grid, the output from the entire set of generators rarely reaches either low or full power, and power changes slowly. Notably, during the 5-yr study period, the amount of power shifted up and down but never stopped. This finding is explained by examining in detail the high and low output periods, using reanalysis data to show the weather phenomena responsible for steady production and for the occasional periods of low power. We conclude with suggested institutions appropriate to create and manage the power system analyzed here.

  6. Multifractal and local correlation of simultaneous wind speed-power output from a single wind trubine

    NASA Astrophysics Data System (ADS)

    Calif, Rudy; Schmitt, François G.; Huang, Yongxiang

    2014-05-01

    The wind energy production is a nonlinear and no stationary resource, due to the intermittent statistics of atmospheric wind speed at all spatial and temporal scales ranging from large scale variations to very short scale variations. Recently, Rudy et al.[1] observed the intermittent and multifractal properties of wind energy production. Classically, IEC standard 4100 is used by the wind energy community, for modeling the interactions of wind speed with the wind turbine. However, this model reflects gaussian statistics contrary to observed wind and energy production measurements. Modeling of power curve of a single wind turbine remains a challenge. The precise understanding of the dynamics of nonlinear power curve over very short time scales, is necessary. Hence, multifractal cross-correlation methods such as Generalized Correlations Exponents (GCE), multifractal detrended cross-correlation analysis (MFXDFA), multifractal detrending moving average cross-correlation analysis (MFXDMA) are applied to simultaneous wind speed power output from a single wind turbine to determine the nature of scaling correlation behavior. Furthermore, in order to detect eventual local correlation, an application of empirical mode decomposition based on time dependent intrinsic correlation to simultaneous measurements is performed. The simultaneous wind speed-power output measurements are recorded continuously with a sampling rate f = 1Hz, during 115 days in 2006. The wind speed measurements are obtained at 31 m above the ground, and the power output is delivered by 500 kW Nordtank wind turbine positionned at the Technical University, Risœ, Denmark. References [1] Calif, R., Schmitt, F.G., Huang, Y., Multifractal description of wind power fluctuations using arbitrary order Hilbert spectral analysis, Physica, 392, 4106-4120, 2013.

  7. Offshore wind speed and wind power characteristics for ten locations in Aegean and Ionian Seas

    NASA Astrophysics Data System (ADS)

    Bagiorgas, Haralambos S.; Mihalakakou, Giouli; Rehman, Shafiqur; Al-Hadhrami, Luai M.

    2012-08-01

    This paper utilizes wind speed data measured at 3 and 10 m above water surface level using buoys at 10 stations in Ionian and Aegean Seas to understand the behaviour of wind and thereafter energy yield at these stations using 5 MW rated power offshore wind turbine. With wind power densities of 971 and 693 W/m2 at 50 m above water surface level, Mykonos and Lesvos were found to be superb and outstanding windy sites with wind class of 7 and 6, respectively. Other locations like Athos, Santorini and Skyros with wind power density of more than 530 W/m2 and wind class of 5 were found to be the excellent sites. Around 15-16% higher winds were observed at 10 m compared to that at 3 m. Lower values of wind speed were found during summer months and higher during winter time in most of the cases reported in the present work. Slightly decreasing (~2% per year) linear trends were observed in annual mean wind speed at Lesvos and Santorini. These trends need to be verified with more data from buoys or from nearby onshore meteorological stations. At Athos and Mykonos, increasing linear trends were estimated. At all the stations the chosen wind turbine could produce energy for more than 70% of the time. The wind speed distribution was found to be well represented by Weibull parameters obtained using Maximum likelihood method compared to WAsP and Method of Moments.

  8. Small-scale universality in fluid turbulence

    PubMed Central

    Schumacher, Jörg; Scheel, Janet D.; Krasnov, Dmitry; Donzis, Diego A.; Yakhot, Victor; Sreenivasan, Katepalli R.

    2014-01-01

    Turbulent flows in nature and technology possess a range of scales. The largest scales carry the memory of the physical system in which a flow is embedded. One challenge is to unravel the universal statistical properties that all turbulent flows share despite their different large-scale driving mechanisms or their particular flow geometries. In the present work, we study three turbulent flows of systematically increasing complexity. These are homogeneous and isotropic turbulence in a periodic box, turbulent shear flow between two parallel walls, and thermal convection in a closed cylindrical container. They are computed by highly resolved direct numerical simulations of the governing dynamical equations. We use these simulation data to establish two fundamental results: (i) at Reynolds numbers Re ∼ 102 the fluctuations of the velocity derivatives pass through a transition from nearly Gaussian (or slightly sub-Gaussian) to intermittent behavior that is characteristic of fully developed high Reynolds number turbulence, and (ii) beyond the transition point, the statistics of the rate of energy dissipation in all three flows obey the same Reynolds number power laws derived for homogeneous turbulence. These results allow us to claim universality of small scales even at low Reynolds numbers. Our results shed new light on the notion of when the turbulence is fully developed at the small scales without relying on the existence of an extended inertial range. PMID:25024175

  9. The Great Plains Wind Power Test Facility

    SciTech Connect

    Schroeder, John

    2014-01-30

    This multi-year, multi-faceted project was focused on the continued development of a nationally-recognized facility for the testing, characterization, and improvement of grid-connected wind turbines, integrated wind-water desalination systems, and related educational and outreach topics. The project involved numerous faculty and graduate students from various engineering departments, as well as others from the departments of Geosciences (in particular the Atmospheric Science Group) and Economics. It was organized through the National Wind Institute (NWI), which serves as an intellectual hub for interdisciplinary and transdisciplinary research, commercialization and education related to wind science, wind energy, wind engineering and wind hazard mitigation at Texas Tech University (TTU). Largely executed by an academic based team, the project resulted in approximately 38 peer-reviewed publications, 99 conference presentations, the development/expansion of several experimental facilities, and two provisional patents.

  10. Estimating maximum global wind power availability and associated climatic consequences

    NASA Astrophysics Data System (ADS)

    Miller, Lee; Gans, Fabian; Kleidon, Axel

    2010-05-01

    Estimating maximum global wind power availability and associated climatic consequences Wind speed reflects the continuous generation of kinetic energy and its dissipation, primarily in the atmospheric boundary layer. When wind turbines extract kinetic wind energy, less kinetic energy remains in the atmosphere in the mean state. While this effect does not play a significant role for a single turbine, it becomes a critical factor for the estimation of large-scale wind power availability. This extraction of kinetic energy by turbines also competes with the natural processes of kinetic energy dissipation, thus setting fundamental limits on extractability that are not considered in previous large-scale studies [1,2,3]. Our simple momentum balance model using ECMWF climate data illustrates a fundamental limit to global wind power extractability and thereby electricity potential (93TW). This is independent of engineering advances in turbine design and wind farm layout. These results are supported by similar results using a global climate model of intermediate complexity. Varying the surface drag coefficient with different simulations allows us to directly relate changes in atmospheric and boundary layer dissipation with resulting climate indices and wind power potential. These new estimates of the maximum power generation by wind turbines are well above the currently installed capacity. Hence, present day installations are unlikely to have a global impact. However, when compared to the current human energy demand of 17TW combined with plans by the US and EU to drastically increase onshore and offshore wind turbine installations [4,5,6], understanding the climatic response and ultimate limitations of wind power as a large-scale renewable energy source is critical. [1] Archer, C., and M.Z. Jacobson, (2005) Evaluation of global wind power, J. Geophys. Res. 110:D12110. [2] Lu, X., M.B. McElroy, and J. Kiviluoma, (2009) Global potential for wind-generated electricity, Proc

  11. Control voltage and power fluctuations when connecting wind farms

    SciTech Connect

    Berinde, Ioan Bălan, Horia Oros, Teodora Susana

    2015-12-23

    Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

  12. Control voltage and power fluctuations when connecting wind farms

    NASA Astrophysics Data System (ADS)

    Berinde, Ioan; Bǎlan, Horia; Oros Pop, Teodora Susana

    2015-12-01

    Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

  13. COE projection for the modular WARP{trademark} wind power system for wind farms and electric utility power transmission

    SciTech Connect

    Weisbrich, A.L.; Ostrow, S.L.; Padalino, J.

    1995-09-01

    Wind power has emerged as an attractive alternative source of electricity for utilities. Turbine operating experience from wind farms has provided corroborating data of wind power potential for electric utility application. Now, a patented modular wind power technology, the Toroidal Accelerator Rotor Platform (TARP{trademark}) Windframe{trademark}, forms the basis for next generation megawatt scale wind farm and/or distributed wind power plants. When arranged in tall vertically clustered TARP{trademark} module stacks, such power plant units are designated Wind Amplified Rotor Platform (WARP{trademark}) Systems. While heavily building on proven technology, these systems are projected to surpass current technology windmills in terms of performance, user-friendly operation and ease of maintenance. In its unique generation and transmission configuration, the WARP{trademark}-GT System combines both electricity generation through wind energy conversion and electric power transmission. Furthermore, environmental benefits include dramatically less land requirement, architectural appearance, lower noise and EMI/TV interference, and virtual elimination of bird mortality potential. Cost-of-energy (COE) is projected to be from under $0.02/kWh to less than $0.05/kWh in good to moderate wind resource sites.

  14. A Bayesian optimization approach for wind farm power maximization

    NASA Astrophysics Data System (ADS)

    Park, Jinkyoo; Law, Kincho H.

    2015-03-01

    The objective of this study is to develop a model-free optimization algorithm to improve the total wind farm power production in a cooperative game framework. Conventionally, for a given wind condition, an individual wind turbine maximizes its own power production without taking into consideration the conditions of other wind turbines. Under this greedy control strategy, the wake formed by the upstream wind turbine, due to the reduced wind speed and the increased turbulence intensity inside the wake, would affect and lower the power productions of the downstream wind turbines. To increase the overall wind farm power production, researchers have proposed cooperative wind turbine control approaches to coordinate the actions that mitigate the wake interference among the wind turbines and thus increase the total wind farm power production. This study explores the use of a data-driven optimization approach to identify the optimum coordinated control actions in real time using limited amount of data. Specifically, we propose the Bayesian Ascent (BA) method that combines the strengths of Bayesian optimization and trust region optimization algorithms. Using Gaussian Process regression, BA requires only a few number of data points to model the complex target system. Furthermore, due to the use of trust region constraint on sampling procedure, BA tends to increase the target value and converge toward near the optimum. Simulation studies using analytical functions show that the BA method can achieve an almost monotone increase in a target value with rapid convergence. BA is also implemented and tested in a laboratory setting to maximize the total power using two scaled wind turbine models.

  15. Design and implementation of power system stabilizers in wind plants

    NASA Astrophysics Data System (ADS)

    Martinez, Carlos

    Wind energy, increasing its share in the generation mix, is intended to replace fossil fuel plants in order to reduce green house gas emissions. However, the replacement of conventional synchronous units by wind generators reduces the number of online Power Systems Stabilizers (PSS) and may therefore deteriorate the damping of critical swing modes, leading to a reduction of the power transfer capacity in transmission corridors. Several reports indicate that angular instability, due to insufficient damping and inadequate tuning or disabling of power system stabilizers, is one of the major events that lead and/or contributed to wide area blackouts. Variable speed wind turbine generators are capable of fast decoupled real and reactive power control. A damping torque can be generated by modulating a fraction of the real and reactive power output of the wind farm. Supplementary active and reactive power control loops are designed and integrated in the wind turbine controls. Operating limits are added to restrict the kinetic energy exchange of the supplementary control loop within a specified turbine speed. An analytical method is developed in order to assess the effectiveness of real and reactive power modulation in damping inter-area oscillations and to justify the use and commissioning of wind based PSS. A wide area measurement based power system stabilizer suitable for wind farms is designed and integrated in the global and local controls of wind turbines. Feedback signals are selected based on an observability index of the selected mode(s). The proposed stabilizer transfer function is derived via a constrained Hinfinity optimization. The controller is tested in time domain simulations using a two area four generators benchmark suffering from interarea oscillatory mode within the range of 0.4-0.6Hz. Testing scenarios show the resiliency and effectiveness of the wind based PSS in damping angular oscillations and stabilizing the power system. The damping contribution

  16. Return time statistic of wind power ramp events

    NASA Astrophysics Data System (ADS)

    Calif, Rudy; Schmitt, François G.

    2015-04-01

    Detection and forecasting of wind power ramp events is a critical issue for the management of power generated by wind turbine and a cluster of wind turbines. The wind power ramp events occur suddenly with larges changes (increases or decreases) of wind power output. In this work, the statistic and the dynamic of wind power ramp events are examined. For that, we analyze several datasets of wind power output with different sampling rate and duration. The data considered are delivered by five wind farms and two single turbines, located at different geographic locations. From these datasets, the return time series τr of wind power ramp events, i.e., the time between two successive ramps above a given threshold Δ p. The return time statistic is investigated plotting the complementary cumulative distribution C(τ_r) in log-log representation. Using a robust method developed by Clauset et al., combining maximum-likelihood fitting methods with goodness-of-fit tests based on the Kolmogorov Smirnov statistic, we show a scaling behavior of the return time statistic, of the form: C(τ_r)˜ kτ_r-α where k is a positive constant and the exponent α called the tail exponent of the distribution. In this study, the value of α ranges from 1.68 to 2.20. This result is a potential information for the estimation risk of wind power generation based on the return time series. Clauset A, Shalizi CR, Newman MEJ. Power-Law distributions in empirical data. SIAM Review 2009;51(4):661-703.

  17. System frequency support of permanent magnet synchronous generator-based wind power plant

    NASA Astrophysics Data System (ADS)

    Wu, Ziping

    on rotor speed control. The proposed control scheme is achieved through the coordinated control between rotor speed and modified pitch angle in accordance with different specified wind speed modes. Fourth, an improved inertial control method based on the maximum power point tracking operation curve is introduced to boost the overall frequency support capability of PMSG-WTGs based on rotor speed control. Fifth, a novel control method based on the torque limit (TLC) is proposed for the purpose of maximizing the wind turbine (WT)'s inertial response. To avoid the SFD caused by the deloaded operation of WT, a small-scale battery energy storage system (BESS) model is established and implemented to eliminate this impact and meanwhile assist the restoration of wind turbine to MPPT mode by means of coordinated control strategy between BESS and PMSG-WTG. Last but not the least, all three types of control strategies are implemented in the CART2-PMSG integrated model based on rotor speed control or active power control respectively to evaluate their impacts on the wind turbine's structural loads during the frequency regulation process. Simulation results demonstrate that all the proposed methods can enhance the overall frequency regulation performance while imposing very slight negative impact on the major mechanical components of the wind turbine.

  18. A model to predict the power output from wind farms

    SciTech Connect

    Landberg, L.

    1997-12-31

    This paper will describe a model that can predict the power output from wind farms. To give examples of input the model is applied to a wind farm in Texas. The predictions are generated from forecasts from the NGM model of NCEP. These predictions are made valid at individual sites (wind farms) by applying a matrix calculated by the sub-models of WASP (Wind Atlas Application and Analysis Program). The actual wind farm production is calculated using the Riso PARK model. Because of the preliminary nature of the results, they will not be given. However, similar results from Europe will be given.

  19. Comparison of Wind Power and Load Forecasting Error Distributions: Preprint

    SciTech Connect

    Hodge, B. M.; Florita, A.; Orwig, K.; Lew, D.; Milligan, M.

    2012-07-01

    The introduction of large amounts of variable and uncertain power sources, such as wind power, into the electricity grid presents a number of challenges for system operations. One issue involves the uncertainty associated with scheduling power that wind will supply in future timeframes. However, this is not an entirely new challenge; load is also variable and uncertain, and is strongly influenced by weather patterns. In this work we make a comparison between the day-ahead forecasting errors encountered in wind power forecasting and load forecasting. The study examines the distribution of errors from operational forecasting systems in two different Independent System Operator (ISO) regions for both wind power and load forecasts at the day-ahead timeframe. The day-ahead timescale is critical in power system operations because it serves the unit commitment function for slow-starting conventional generators.

  20. Optimization of Power Coefficient of Wind Turbine Using Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Rajakumar, Sappani; Ravindran, Durairaj; Sivakumar, Mahalingam; Venkatachalam, Gopalan; Muthukumar, Shunmugavelu

    2016-06-01

    In the design of a wind turbine, the goal is to attain the highest possible power output under specified atmospheric conditions. The optimization of power coefficient of horizontal axis wind turbine has been carried out by integration of blade element momentum method and genetic algorithm (GA). The design variables considered are wind velocity, angle of attack and tip speed ratio. The objective function is power coefficient of wind turbine. The different combination of design variables are optimized using GA and then the Power coefficient is optimized. The optimized design variables are validated with the experimental results available in the literature. By this optimization work the optimum design variables of wind turbine can be found economically than experimental work. NACA44XX series airfoils are considered for this optimization work.

  1. Wind Power Price Trends in the United States

    SciTech Connect

    Bolinger, Mark; Wiser, Ryan

    2009-07-15

    For the fourth year in a row, the United States led the world in adding new wind power capacity in 2008, and also surpassed Germany to take the lead in terms of cumulative installed wind capacity. The rapid growth of wind power in the U.S. over the past decade (Figure 1) has been driven by a combination of increasingly supportive policies (including the Federal production tax credit (PTC) and a growing number of state renewables portfolio standards), uncertainty over the future fuel costs and environmental liabilities of natural gas and coal-fired power plants, and wind's competitive position among generation resources. This article focuses on just the last of these drivers - i.e., trends in U.S. wind power prices - over the period of strong capacity growth since 1998.

  2. Optimization of Power Coefficient of Wind Turbine Using Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Rajakumar, Sappani; Ravindran, Durairaj; Sivakumar, Mahalingam; Venkatachalam, Gopalan; Muthukumar, Shunmugavelu

    2017-04-01

    In the design of a wind turbine, the goal is to attain the highest possible power output under specified atmospheric conditions. The optimization of power coefficient of horizontal axis wind turbine has been carried out by integration of blade element momentum method and genetic algorithm (GA). The design variables considered are wind velocity, angle of attack and tip speed ratio. The objective function is power coefficient of wind turbine. The different combination of design variables are optimized using GA and then the Power coefficient is optimized. The optimized design variables are validated with the experimental results available in the literature. By this optimization work the optimum design variables of wind turbine can be found economically than experimental work. NACA44XX series airfoils are considered for this optimization work.

  3. 78 FR 76643 - Atlantic Wind Lease Sale 3 (ATLW3) Commercial Leasing for Wind Power on the Outer Continental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-18

    ... Bureau of Ocean Energy Management Atlantic Wind Lease Sale 3 (ATLW3) Commercial Leasing for Wind Power on... Management (BOEM), Interior. ACTION: Proposed Sale Notice for Commercial Leasing for Wind Power on the Outer... grid) relative to the wind facility's generation at continuous full power operation at...

  4. 78 FR 44150 - Atlantic Wind Lease Sale 1 (ATLW1) Commercial Leasing for Wind Power on the Outer Continental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-23

    ... Bureau of Ocean Energy Management Atlantic Wind Lease Sale 1 (ATLW1) Commercial Leasing for Wind Power on... Management (BOEM), Interior. ACTION: Final Sale Notice for Commercial Leasing for Wind Power on the Outer... Proposed Sale Notice (PSN) for Commercial Leasing for Wind Power on the Outer Continental Shelf...

  5. WPA Omnibus Award MT Wind Power Outreach

    SciTech Connect

    Brian Spangler, Manager Energy Planning and Renewables

    2012-01-30

    The objective of this grant was to further the development of Montana's vast wind resources for small, medium, and large scale benefits to Montana and the nation. This was accomplished through collaborative work with wind industry representatives, state and local governments, the agricultural community, and interested citizens. Through these efforts MT Dept Environmental Quality (DEQ) was able to identify development barriers, educate and inform citizens, as well as to participate in regional and national dialogue that will spur the development of wind resources. The scope of DEQ's wind outreach effort evolved over the course of this agreement from the development of the Montana Wind Working Group and traditional outreach efforts, to the current focus on working with the state's university system to deliver a workforce trained to enter the wind industry.

  6. Wind energy can power a strong recovery.

    PubMed

    Bode, Denise

    2009-01-01

    The U.S. wind industry is a dynamic one that pumps billions of dollars into our economy each year. Wind has gone mainstream and today is the most affordable near-term carbon-free energy source. The U.S. industry experienced a nearly 70 percent increase in total jobs last year-well-paying, family-supporting jobs. But new wind farms now find it hard to secure financing. Thus, the economic stimulus package moving through Congress is critical.

  7. Variable-Speed Wind Power Plant Operating With Reserve Power Capability: Preprint

    SciTech Connect

    Singh, M.; Gevorgian, V.; Muljadi, E.; Ela, E.

    2013-10-01

    As the level of wind penetration increases, wind turbine technology must move from merely generating power from wind to taking a role in supporting the bulk power system. Wind turbines should have the capability to provide inertial response and primary frequency (governor) response. Wind turbine generators with this capability can support the frequency stability of the grid. To provide governorresponse, wind turbines should be able to generate less power than the available wind power and hold the rest in reserves, ready to be accessed as needed. In this paper, we explore several ways to control wind turbine output to enable reserve-holding capability. The focus of this paper is on doubly-fed induction generator (also known as Type 3) and full-converter (also known as Type 4) windturbines.

  8. Short-Term Wind Power Forecasts using Doppler Lidar

    NASA Astrophysics Data System (ADS)

    Magerman, Beth

    With a ground-based Doppler lidar on the upwind side of a wind farm in the Tehachapi Pass of California, radial wind velocity measurements were collected for repeating sector sweeps, scanning up to 10 kilometers away. This region consisted of complex terrain, with the scans made between mountains. The dataset was utilized for techniques being studied for short-term forecasting of wind power by correlating changes in energy content and of turbulence intensity by tracking spatial variance, in the wind ahead of a wind farm. A ramp event was also captured and its propagation was tracked. Orthogonal horizontal wind vectors were retrieved from the radial velocity using a sector Velocity Azimuth Display method. Streamlines were plotted to determine the potential sites for a correlation of upstream wind speed with wind speed at downstream locations near the wind farm. A "virtual wind turbine" was "placed" in locations along the streamline by using the time-series velocity data at the location as the input to a modeled wind turbine, to determine the extractable energy content at that location. The relationship between this time-dependent energy content upstream and near the wind farm was studied. By correlating the energy content with each upstream location based on a time shift estimated according to advection at the mean wind speed, several fits were evaluated. A prediction of the downstream energy content was produced by shifting the power output in time and applying the best-fit function. This method made predictions of the power near the wind farm several minutes in advance. Predictions were also made up to an hour in advance for a large ramp event. The Magnitude Absolute Error and Standard Deviation are presented for the predictions based on each selected upstream location.

  9. Wind Power Potential at Abandoned Mines in Korea

    NASA Astrophysics Data System (ADS)

    jang, M.; Choi, Y.; Park, H.; Go, W.

    2013-12-01

    This study performed an assessment of wind power potential at abandoned mines in the Kangwon province by analyzing gross energy production, greenhouse gas emission reduction and economic effects estimated from a 600 kW wind turbine. Wind resources maps collected from the renewable energy data center in Korea Institute of Energy Research(KIER) were used to determine the average wind speed, temperature and atmospheric pressure at hub height(50 m) for each abandoned mine. RETScreen software developed by Natural Resources Canada(NRC) was utilized for the energy, emission and financial analyses of wind power systems. Based on the results from 5 representative mining sites, we could know that the average wind speed at hub height is the most critical factor for assessing the wind power potential. Finally, 47 abandoned mines that have the average wind speed faster than 6.5 m/s were analyzed, and top 10 mines were suggested as relatively favorable sites with high wind power potential in the Kangwon province.

  10. The Role of Atmospheric Measurements in Wind Power Statistical Models

    NASA Astrophysics Data System (ADS)

    Wharton, S.; Bulaevskaya, V.; Irons, Z.; Newman, J. F.; Clifton, A.

    2015-12-01

    The simplest wind power generation curves model power only as a function of the wind speed at turbine hub-height. While the latter is an essential predictor of power output, it is widely accepted that wind speed information in other parts of the vertical profile, as well as additional atmospheric variables including atmospheric stability, wind veer, and hub-height turbulence are also important factors. The goal of this work is to determine the gain in predictive ability afforded by adding additional atmospheric measurements to the power prediction model. In particular, we are interested in quantifying any gain in predictive ability afforded by measurements taken from a laser detection and ranging (lidar) instrument, as lidar provides high spatial and temporal resolution measurements of wind speed and direction at 10 or more levels throughout the rotor-disk and at heights well above. Co-located lidar and meteorological tower data as well as SCADA power data from a wind farm in Northern Oklahoma will be used to train a set of statistical models. In practice, most wind farms continue to rely on atmospheric measurements taken from less expensive, in situ instruments mounted on meteorological towers to assess turbine power response to a changing atmospheric environment. Here, we compare a large suite of atmospheric variables derived from tower measurements to those taken from lidar to determine if remote sensing devices add any competitive advantage over tower measurements alone to predict turbine power response.

  11. Performance optimization for doubly fed wind power generation systems

    SciTech Connect

    Bhowmik, S.; Spee, R.; Enslin, J.H.R.

    1999-08-01

    Significant variation of the resource kinetic energy, in the form of wind speed, results in substantially reduced energy capture in a fixed-speed wind turbine. In order to increase the wind energy capture in the turbine, variable-speed generation (VSG) strategies have been proposed and implemented. However, that requires an expensive ac/ac power converter, which increases the capital investment significantly. Consequently, doubly fed systems have been proposed to reduce the size of the power converter and, thereby, the associated cost. Additionally, in doubly fed systems, as a fixed operating point (power and speed), power flow can be regulated between the two winding systems on the machine. This feature can by utilized to essentially minimize losses in the machine associated with the given operating point or achieve other desired performance enhancements. In this paper, a brushless doubly fed machine (BDFM) is utilized to develop a VSG wind power generator. The VSG controller employs a wind-speed-estimation-based maximum power point tracker and a heuristic-model-based maximum efficiency point tracker to optimize the power output of the system. The controller has been verified for efficacy on a 1.5-kW laboratory VSG wind generator. The strategy is applicable to all doubly fed configurations, including conventional wound-rotor induction machines, Scherbius cascades, BDFM's and doubly fed reluctance machines.

  12. Quantifying Uncertainty of Wind Power Production Through an Analog Ensemble

    NASA Astrophysics Data System (ADS)

    Shahriari, M.; Cervone, G.

    2016-12-01

    The Analog Ensemble (AnEn) method is used to generate probabilistic weather forecasts that quantify the uncertainty in power estimates at hypothetical wind farm locations. The data are from the NREL Eastern Wind Dataset that includes more than 1,300 modeled wind farms. The AnEn model uses a two-dimensional grid to estimate the probability distribution of wind speed (the predictand) given the values of predictor variables such as temperature, pressure, geopotential height, U-component and V-component of wind. The meteorological data is taken from the NCEP GFS which is available on a 0.25 degree grid resolution. The methodology first divides the data into two classes: training period and verification period. The AnEn selects a point in the verification period and searches for the best matching estimates (analogs) in the training period. The predictand value at those analogs are the ensemble prediction for the point in the verification period. The model provides a grid of wind speed values and the uncertainty (probability index) associated with each estimate. Each wind farm is associated with a probability index which quantifies the degree of difficulty to estimate wind power. Further, the uncertainty in estimation is related to other factors such as topography, land cover and wind resources. This is achieved by using a GIS system to compute the correlation between the probability index and geographical characteristics. This study has significant applications for investors in renewable energy sector especially wind farm developers. Lower level of uncertainty facilitates the process of submitting bids into day ahead and real time electricity markets. Thus, building wind farms in regions with lower levels of uncertainty will reduce the real-time operational risks and create a hedge against volatile real-time prices. Further, the links between wind estimate uncertainty and factors such as topography and wind resources, provide wind farm developers with valuable

  13. Wind speed power spectrum analysis for Bushland, Texas

    SciTech Connect

    Eggleston, E.D.

    1996-12-31

    Numerous papers and publications on wind turbulence have referenced the wind speed spectrum presented by Isaac Van der Hoven in his article entitled Power Spectrum of Horizontal Wind Speed Spectrum in the Frequency Range from 0.0007 to 900 Cycles per Hour. Van der Hoven used data measured at different heights between 91 and 125 meters above the ground, and represented the high frequency end of the spectrum with data from the peak hour of hurricane Connie. These facts suggest we should question the use of his power spectrum in the wind industry. During the USDA - Agricultural Research Service`s investigation of wind/diesel system power storage, using the appropriate wind speed power spectrum became a significant issue. We developed a power spectrum from 13 years of hourly average data, 1 year of 5 minute average data, and 2 particularly gusty day`s 1 second average data all collected at a height of 10 meters. While the general shape is similar to the Van der Hoven spectrum, few of his peaks were found in the Bushland spectrum. While higher average wind speeds tend to suggest higher amplitudes in the high frequency end of the spectrum, this is not always true. Also, the high frequency end of the spectrum is not accurately described by simple wind statistics such as standard deviation and turbulence intensity. 2 refs., 5 figs., 1 tab.

  14. Characterization of wind power resource and its intermittency

    NASA Astrophysics Data System (ADS)

    Gunturu, U. B.; Schlosser, C. A.

    2011-12-01

    Wind resource in the continental and offshore United States has been calculated and characterized using metrics that describe - apart from abundance - its availability, persistence and intermittency. The Modern Era Retrospective-Analysis for Research and Applications (MERRA) boundary layer flux data has been used to construct wind power density profiles at 50, 80, 100 and 120 m turbine hub heights. The wind power density estimates at 50 m are qualitatively similar to those in the US wind atlas developed by the National Renewable Energy Laboratory (NREL), but quantitatively a class less in some regions, but are within the limits of uncertainty. We also show that for long tailed distributions like those of the wind power density, the mean is an overestimation and median is a more robust metric for summary representation of wind power resource.Generally speaking, the largest and most available wind power density resources are found in off-shore regions of the Atlantic and Pacific coastline, and the largest on-shore resource potential lies in the central United States. However, the intermittency and widespread synchronicity of on-shore wind power density are substantial, and highlights areas where considerable back-up generation technologies will be required. Generation-duration curves are also presented for the independent systems operator (ISO) zones of the U.S. to highlight the regions with the largest capacity factor (MISO, ERCOT, and SWPP) as well as the periods and extent to which all ISOs contain no wind power and the potential benefits of aggregation on wind power intermittency in each region. The impact of raising the wind turbine hub height on metrics of abundance, persistence, variability and intermittency is analyzed. There is a general increase in availability and abundance of wind resource but there is also an increase in intermittency with respect to a 'usable wind power' crossing level in low resource regions. A similar perspective of wind resource for

  15. Final Scientific Report - Wind Powering America State Outreach Project

    SciTech Connect

    Sinclair, Mark; Margolis, Anne

    2012-02-01

    The goal of the Wind Powering America State Outreach Project was to facilitate the adoption of effective state legislation, policy, finance programs, and siting best practices to accelerate public acceptance and development of wind energy. This was accomplished by Clean Energy States Alliance (CESA) through provision of informational tools including reports and webinars as well as the provision of technical assistance to state leaders on wind siting, policy, and finance best practices, identification of strategic federal-state partnership activities for both onshore and offshore wind, and participation in regional wind development collaboratives. The Final Scientific Report - Wind Powering America State Outreach Project provides a summary of the objectives, activities, and outcomes of this project as accomplished by CESA over the period 12/1/2009 - 11/30/2011.

  16. Economical wind powered bioventing systems successfully applied at remote locations

    SciTech Connect

    Graves, D.; Klein, J.; Dillon, T. Jr.; Wilson, B.; Walker, K.

    1996-12-31

    Wind-powered bioventing systems were designed to operate at remote locations in the absence of electrical power. Laboratory measurements of soil respiration under bioventing conditions indicated the biodegradation of up to 25 mg of weathered diesel per kg of site soil per day. Further testing demonstrated the potential for harnessing wind-power to stimulate air movement through vadose zone soil. Several wind-powered bioventing systems were installed near Nome, Alaska. In situ respiration tests, soil gas composition measurements and measurable pressure changes in the soil indicated that the systems were capable of aerating the soil. Diesel range oil measurements indicated contaminant reductions up to 90% after only two treatments seasons. The results demonstrate the effectiveness of wind-powered biovents. The low cost, low maintenance, and simplicity of the biovents make them a very attractive treatment option for windy, remote sites with unsaturated soil impacted by biodegradable contaminants.

  17. On the causes of spectral enhancements in solar wind power spectra

    NASA Technical Reports Server (NTRS)

    Unti, T.; Russell, C. T.

    1976-01-01

    Enhancements in power spectra of the solar-wind ion flux in the frequency neighborhood of 0.5 Hz had been noted by Unti et al. (1973). It was speculated that these were due to convected small-scale density irregularities. In this paper, 54 flux spectra calculated from OGO 5 data are examined. It is seen that the few prominent spectral peaks which occur were not generated by density irregularities, but were due to several different causes, including convected discontinuities and propagating transverse waves. A superposition of many spectra, however, reveals a moderate enhancement at a frequency corresponding to convected features with a correlation length of a proton gyroradius, consistent with the results of Neugebauer (1975).

  18. On the causes of spectral enhancements in solar wind power spectra

    NASA Technical Reports Server (NTRS)

    Unti, T.; Russell, C. T.

    1976-01-01

    Enhancements in power spectra of the solar-wind ion flux in the frequency neighborhood of 0.5 Hz had been noted by Unti et al. (1973). It was speculated that these were due to convected small-scale density irregularities. In this paper, 54 flux spectra calculated from OGO 5 data are examined. It is seen that the few prominent spectral peaks which occur were not generated by density irregularities, but were due to several different causes, including convected discontinuities and propagating transverse waves. A superposition of many spectra, however, reveals a moderate enhancement at a frequency corresponding to convected features with a correlation length of a proton gyroradius, consistent with the results of Neugebauer (1975).

  19. Prediction of Wind Energy Resources (PoWER) Users Guide

    DTIC Science & Technology

    2016-01-01

    ARL-TR-7573● JAN 2016 US Army Research Laboratory Prediction of Wind Energy Resources (PoWER) User’s Guide by David P Sauter...not return it to the originator. ARL-TR-7573 ● JAN 2016 US Army Research Laboratory Prediction of Wind Energy Resources (PoWER...2016 2. REPORT TYPE Final 3. DATES COVERED (From - To) 09/2015–11/2015 4. TITLE AND SUBTITLE Prediction of Wind Energy Resources (PoWER) User’s

  20. Systems and methods for an integrated electrical sub-system powered by wind energy

    DOEpatents

    Liu, Yan; Garces, Luis Jose

    2008-06-24

    Various embodiments relate to systems and methods related to an integrated electrically-powered sub-system and wind power system including a wind power source, an electrically-powered sub-system coupled to and at least partially powered by the wind power source, the electrically-powered sub-system being coupled to the wind power source through power converters, and a supervisory controller coupled to the wind power source and the electrically-powered sub-system to monitor and manage the integrated electrically-powered sub-system and wind power system.

  1. Systems and methods for an integrated electrical sub-system powered by wind energy

    DOEpatents

    Liu, Yan [Ballston Lake, NY; Garces, Luis Jose [Niskayuna, NY

    2008-06-24

    Various embodiments relate to systems and methods related to an integrated electrically-powered sub-system and wind power system including a wind power source, an electrically-powered sub-system coupled to and at least partially powered by the wind power source, the electrically-powered sub-system being coupled to the wind power source through power converters, and a supervisory controller coupled to the wind power source and the electrically-powered sub-system to monitor and manage the integrated electrically-powered sub-system and wind power system.

  2. Wind Power Technologies FY 2017 Budget At-A-Glance

    SciTech Connect

    None, None

    2016-03-01

    The Wind Program accelerates U.S. deployment of clean, affordable, and reliable domestic wind power through research, development, and demonstration activities. These advanced technology investments directly contribute to the goals for the United States to generate 80% of the nation’s electricity from clean, carbon-free energy sources by 2035; reduce carbon emissions 26%-28% below 2005 levels by 2025; and reduce carbon emissions 80% by 2050 by reducing costs and increasing performance of wind energy systems.

  3. Global assessment of high-altitude wind power

    NASA Astrophysics Data System (ADS)

    Archer, C. L.; Caldeira, K.

    2008-12-01

    Wind speed generally increases with altitude to the tropopause; hence, the power available in high-altitude winds is enormous, especially near the jet streams. We assess for the first time the available wind power resource worldwide at altitudes between 500 and 12,000 m. The highest wind power densities are found near 10,000 m over Japan and eastern China, the eastern coast of the United States, southern Australia, and north-eastern Africa. Below 1000 m, the best locations are the southern tip of South America, the coasts along the northern Pacific and Atlantic oceans, the central-eastern coast of Africa, and the north-eastern coast of South America. Because jet streams vary locally and seasonally, however, the high-altitude wind power resource is less steady than needed for baseload power. However, dynamically reaching the height with the highest winds, increasing the area covered with high-altitude devices, and using batteries for storage can effectively reduce intermittency. When high-altitude wind power devices are distributed uniformly throughout the entire atmosphere, numerical simulations show negligible effects on the global climate for low densities, but surface cooling, decreased precipitation, and greater sea ice cover for high densities.

  4. Wind power project siting workshop: emerging issues and technologies

    SciTech Connect

    anon.

    2004-12-01

    With wind power development extending more broadly across the various regions of the United States, and with new participants entering the wind development business, AWEA developed a workshop on the various ways in which wind power projects affect--and don't affect--elements of the human and natural environment. Over 180 people gathered in Portland, OR on October 13-14, 2004 to participate in a day and a half of presentations by 20 leading industry specialists. Their presentations covered emerging issues of project siting, such as bat interactions and wildlife survey techniques, and methods of generating local support for wind projects. Workshop topics included: Avian and Bat Research Updates; Wildlife Survey Technologies & Techniques; Technical Issues such as Noise, Aesthetics, and Lighting; National Environmental Policy Act (NEPA) Scenarios and Federal Land Policies; Tribal & Community Relations; Federal & State Permitting Process; and Bureau of Land Management Wind Power Developments.

  5. Scaling forecast models for wind turbulence and wind turbine power intermittency

    NASA Astrophysics Data System (ADS)

    Duran Medina, Olmo; Schmitt, Francois G.; Calif, Rudy

    2017-04-01

    The intermittency of the wind turbine power remains an important issue for the massive development of this renewable energy. The energy peaks injected in the electric grid produce difficulties in the energy distribution management. Hence, a correct forecast of the wind power in the short and middle term is needed due to the high unpredictability of the intermittency phenomenon. We consider a statistical approach through the analysis and characterization of stochastic fluctuations. The theoretical framework is the multifractal modelisation of wind velocity fluctuations. Here, we consider three wind turbine data where two possess a direct drive technology. Those turbines are producing energy in real exploitation conditions and allow to test our forecast models of power production at a different time horizons. Two forecast models were developed based on two physical principles observed in the wind and the power time series: the scaling properties on the one hand and the intermittency in the wind power increments on the other. The first tool is related to the intermittency through a multifractal lognormal fit of the power fluctuations. The second tool is based on an analogy of the power scaling properties with a fractional brownian motion. Indeed, an inner long-term memory is found in both time series. Both models show encouraging results since a correct tendency of the signal is respected over different time scales. Those tools are first steps to a search of efficient forecasting approaches for grid adaptation facing the wind energy fluctuations.

  6. SMALL-SCALE ANISOTROPIES OF COSMIC RAYS FROM RELATIVE DIFFUSION

    SciTech Connect

    Ahlers, Markus; Mertsch, Philipp

    2015-12-10

    The arrival directions of multi-TeV cosmic rays show significant anisotropies at small angular scales. It has been argued that this small-scale structure can naturally arise from cosmic ray scattering in local turbulent magnetic fields that distort a global dipole anisotropy set by diffusion. We study this effect in terms of the power spectrum of cosmic ray arrival directions and show that the strength of small-scale anisotropies is related to properties of relative diffusion. We provide a formalism for how these power spectra can be inferred from simulations and motivate a simple analytic extension of the ensemble-averaged diffusion equation that can account for the effect.

  7. Wind Turbine Generator System Power Quality Test Report for the Gaia Wind 11-kW Wind Turbine

    SciTech Connect

    Curtis, A.; Gevorgian, V.

    2011-07-01

    This report details the power quality test on the Gaia Wind 11-kW Wind Turbine as part of the U.S. Department of Energy's Independent Testing Project. In total five turbines are being tested as part of the project. Power quality testing is one of up to five test that may be performed on the turbines including power performance, safety and function, noise, and duration tests. The results of the testing provide manufacturers with reports that may be used for small wind turbine certification.

  8. CWEX (Crop/Wind-Energy Experiment): Measurements of the interaction between crop agriculture and wind power

    NASA Astrophysics Data System (ADS)

    Rajewski, Daniel Andrew

    The current expansion of wind farms in the U.S. Midwest promotes an alternative renewable energy portfolio to conventional energy sources derived from fossil fuels. The construction of wind turbines and large wind farms within several millions of cropland acres creates a unique interaction between two unlike energy sources: electric generation by wind and bio-fuel production derived from crop grain and plant tissues. Wind turbines produce power by extracting mean wind speed and converting a portion of the flow to turbulence downstream of each rotor. Turbine-scale turbulence modifies fluxes of momentum, heat, moisture, and other gaseous constituents (e.g. carbon dioxide) between the crop canopy and the atmospheric boundary layer. Conversely, crop surfaces and tillage elements produce drag on the hub-height wind resource, and the release of sensible and latent heat flux from the canopy or soil influences the wind speed profile. The Crop-Wind Energy Experiment (CWEX) measured momentum, energy, and CO2 fluxes at several locations within the leading line of turbines in a large operational wind farm, and overall turbines promote canopy mixing of wind speed, temperature, moisture, and carbon dioxide in both the day and night. Turbine-generated perturbations of these fluxes are dependent on several factors influencing the turbine operation (e.g. wind speed, wind direction, stability, orientation of surrounding turbines within a wind park) and the cropland surface (e.g. crop type and cultivar, planting density, chemical application, and soil composition and drainage qualities). Additional strategies are proposed for optimizing the synergy between crop and wind power.

  9. Small Scale Air Driven Generator

    DTIC Science & Technology

    2016-12-01

    current (DC). The electricity generated was then stored in a 16-volt supercapacitor. While testing the system, it was discovered that more shaft power... current (DC). The electricity generated was then stored in a 16- volt supercapacitor. While testing the system, it was discovered that more shaft power...system, testing was then shifted to actually charging the supercapacitor. A high current breaker switch was installed to be able to electrically

  10. Final Technical Report - Kotzebue Wind Power Porject - Volume I

    SciTech Connect

    Rana Zucchi, Global Energy Concepts, LLC; Brad Reeve, Kotzebue Electric Association; DOE Project Officer - Doug Hooker

    2007-10-26

    The Kotzebue Wind Power Project is a joint undertaking of the U.S. Department of Energy (DOE); Kotzebue Electric Association (KEA); and the Alaska Energy Authority (AEA). The goal of the project is to develop, construct, and operate a wind power plant interconnected to a small isolated utility grid in an arctic climate in Northwest Alaska. The primary objective of KEA’s wind energy program is to bring more affordable electricity and jobs to remote Alaskan communities. DOE funding has allowed KEA to develop a multi-faceted approach to meet these objectives that includes wind project planning and development, technology transfer, and community outreach. The first wind turbines were installed in the summer of 1997 and the newest turbines were installed in the spring of 2007. The total installed capacity of the KEA wind power project is 1.16 MW with a total of 17 turbines rated between 65 kW and 100 kW. The operation of the wind power plant has resulted in a wind penetration on the utility system in excess of 35% during periods of low loads. This document and referenced attachments are presented as the final technical report for the U.S. Department of Energy (DOE) grant agreement DE-FG36-97GO10199. Interim deliverables previously submitted are also referenced within this document and where reasonable to do so, specific sections are incorporated in the report or attached as appendices.

  11. Understanding Inertial and Frequency Response of Wind Power Plants: Preprint

    SciTech Connect

    Muljadi, E.; Gevorgian, V.; Singh, M.; Santoso, S.

    2012-07-01

    The objective of this paper is to analyze and quantify the inertia and frequency responses of wind power plants with different wind turbine technologies (particularly those of fixed speed, variable slip with rotor-resistance controls, and variable speed with vector controls).

  12. Wind Power Curve Modeling in Simple and Complex Terrain

    SciTech Connect

    Bulaevskaya, V.; Wharton, S.; Irons, Z.; Qualley, G.

    2015-02-09

    Our previous work on wind power curve modeling using statistical models focused on a location with a moderately complex terrain in the Altamont Pass region in northern California (CA). The work described here is the follow-up to that work, but at a location with a simple terrain in northern Oklahoma (OK). The goal of the present analysis was to determine the gain in predictive ability afforded by adding information beyond the hub-height wind speed, such as wind speeds at other heights, as well as other atmospheric variables, to the power prediction model at this new location and compare the results to those obtained at the CA site in the previous study. While we reach some of the same conclusions at both sites, many results reported for the CA site do not hold at the OK site. In particular, using the entire vertical profile of wind speeds improves the accuracy of wind power prediction relative to using the hub-height wind speed alone at both sites. However, in contrast to the CA site, the rotor equivalent wind speed (REWS) performs almost as well as the entire profile at the OK site. Another difference is that at the CA site, adding wind veer as a predictor significantly improved the power prediction accuracy. The same was true for that site when air density was added to the model separately instead of using the standard air density adjustment. At the OK site, these additional variables result in no significant benefit for the prediction accuracy.

  13. Proceedings of National Avian-Wind Power Planning Meeting IV

    SciTech Connect

    NWCC Avian Subcommittee

    2001-05-01

    OAK-B135 The purpose of the fourth meeting was to (1) share research and update research conducted on avian wind interactions (2) identify questions and issues related to the research results, (3) develop conclusions about some avian/wind power issues, and (4) identify questions and issues for future avian research.

  14. Wind Power in Ontario: Its Contribution to the Electricity Grid

    ERIC Educational Resources Information Center

    Rowlands, Ian H.; Jernigan, Carey

    2008-01-01

    The purpose of this article is to investigate wind turbine production, the variability of that production, and the relationship between output and system-wide demand. A review of the literature reveals that a variety of measures (and methods) to explore the variability of wind power production exist. Attention then turns to the province of Ontario…

  15. Wind Power in Ontario: Its Contribution to the Electricity Grid

    ERIC Educational Resources Information Center

    Rowlands, Ian H.; Jernigan, Carey

    2008-01-01

    The purpose of this article is to investigate wind turbine production, the variability of that production, and the relationship between output and system-wide demand. A review of the literature reveals that a variety of measures (and methods) to explore the variability of wind power production exist. Attention then turns to the province of Ontario…

  16. Final Technical Report - Kotzebue Wind Power Project - Volume II

    SciTech Connect

    Rana Zucchi, Global Energy Concepts, LLC; Brad Reeve, Kotzebue Electric Association; DOE Project Officer - Doug Hooker

    2007-10-31

    The Kotzebue Wind Power Project is a joint undertaking of the U.S. Department of Energy (DOE); Kotzebue Electric Association (KEA); and the Alaska Energy Authority (AEA). The goal of the project is to develop, construct, and operate a wind power plant interconnected to a small isolated utility grid in an arctic climate in Northwest Alaska. The primary objective of KEA’s wind energy program is to bring more affordable electricity and jobs to remote Alaskan communities. DOE funding has allowed KEA to develop a multi-faceted approach to meet these objectives that includes wind project planning and development, technology transfer, and community outreach. The first wind turbines were installed in the summer of 1997 and the newest turbines were installed in the spring of 2007. The total installed capacity of the KEA wind power project is 1.16 MW with a total of 17 turbines rated between 65 kW and 100 kW. The operation of the wind power plant has resulted in a wind penetration on the utility system in excess of 35% during periods of low loads. This document and referenced attachments are presented as the final technical report for the U.S. Department of Energy (DOE) grant agreement DE-FG36-97GO10199. Interim deliverables previously submitted are also referenced within this document and where reasonable to do so, specific sections are incorporated in the report or attached as appendices.

  17. Electrical Collection and Transmission Systems for Offshore Wind Power: Preprint

    SciTech Connect

    Green, J.; Bowen, A.; Fingersh, L.J.; Wan, Y.

    2007-03-01

    The electrical systems needed for offshore wind farms to collect power from wind turbines--and transmit it to shore--will be a significant cost element of these systems. This paper describes the development of a simplified model of the cost and performance of such systems.

  18. Wind-power site-screening methodology

    NASA Astrophysics Data System (ADS)

    Walton, J. J.; Sherman, C. A.; Knox, J. B.

    1980-10-01

    Principal components analysis techniques for classifying types of regional flow fields and a three dimensional diagnostic flow model were blended into a rotational for screening wind sites in the presence of complex terrain. Relevant contributing capabilities, the developed screening methodology, the prospectors' preliminary wind resource maps for the island of Oahu generated to guide the development of the observational network, and the data base developed for testing are described. The use of the methodology on the island of Oahu is illustrated and two annual assessments of Oahu's wind energy potential are described.

  19. Assessment of distributed wind-power systems. Final report

    SciTech Connect

    Kaupang, B.M.

    1983-02-01

    A utility-oriented methodology for the purpose of evaluating distributed wind-power systems was developed and tested, utilizing data from three actual utility systems. Conventional utility planning techniques were used, including loss-of-load probability and production-cost-simulation methods in the generation planning area, transmission and distribution (T and D) system expansion models, and loss calculations. Evaluations were based on comparison of total utility-system cost with an without wind-power plants, and wre expressed in terms of wind-power-plant value and cost. Value is measured by the worth of displaced energy and capacity of conventional power plants, of T and D equipmen deferrals, and of T and D loss savings. Cost consists of he capital, and operating and maintenace costs of the wind-power plants. The value of distributed wind-power generation was found to be dominated by the generation energy and capacity value, as opposed to T and D system impacts. The energy value alone did, in two of the three utilities studied, result in a favorable value/cost relationship for the cost assumptions that were used. The problem of voltage fluctuation on distribution feeders from wind turbines due to wind gusts was studied for several sites. In most relaistic applications, the voltage fluctuations would not be a limiting criterion for practical wind-turbine penetration levels. If the wind turbine is connected to the distributionfeeder through a rectifier-inverter, voltage fluctuations become a negligible factor. However, reactive-power compensation of the inverter would most likely be required for this application.

  20. Wind tunnel measurements of wake structure and wind farm power for actuator disk model wind turbines in yaw

    NASA Astrophysics Data System (ADS)

    Howland, Michael; Bossuyt, Juliaan; Kang, Justin; Meyers, Johan; Meneveau, Charles

    2016-11-01

    Reducing wake losses in wind farms by deflecting the wakes through turbine yawing has been shown to be a feasible wind farm control approach. In this work, the deflection and morphology of wakes behind a wind turbine operating in yawed conditions are studied using wind tunnel experiments of a wind turbine modeled as a porous disk in a uniform inflow. First, by measuring velocity distributions at various downstream positions and comparing with prior studies, we confirm that the nonrotating wind turbine model in yaw generates realistic wake deflections. Second, we characterize the wake shape and make observations of what is termed a "curled wake," displaying significant spanwise asymmetry. Through the use of a 100 porous disk micro-wind farm, total wind farm power output is studied for a variety of yaw configurations. Strain gages on the tower of the porous disk models are used to measure the thrust force as a substitute for turbine power. The frequency response of these measurements goes up to the natural frequency of the model and allows studying the spatiotemporal characteristics of the power output under the effects of yawing. This work has been funded by the National Science Foundation (Grants CBET-113380 and IIA-1243482, the WINDINSPIRE project). JB and JM are supported by ERC (ActiveWindFarms, Grant No. 306471).

  1. Federal Incentives for Wind Power (Fact Sheet)

    SciTech Connect

    Not Available

    2013-05-01

    This fact sheet describes the federal incentives available as of April 2013 that encourage increased development and deployment of wind energy technologies, including research grants, tax incentives, and loan programs.

  2. Phase locking of wind turbines leads to intermittent power production

    NASA Astrophysics Data System (ADS)

    Anvari, M.; Wächter, M.; Peinke, J.

    2016-12-01

    Wind energy, inserted into the power grid by wind turbines, is strongly influenced by the turbulent fluctuations of wind speed in the atmospheric layer. Here we investigate the power production of a wind farm and show that due to the presence of large-scale and long-time correlation in wind velocity, turbines interact with each other. This interaction can result in phase locking in pairs of turbines. We show that there are time intervals during which some pairs of turbines are temporally phase locked. This intermediate phase locking leads to the statistical effect that the short-time fluctuations of the cumulative power output of the wind farm become non-Gaussian, i.e., intermittent power production occurs. Contrary to phase-locked states, there are some time intervals where all turbines are phase unlocking and consequently the probability density function of the temporal increment of cumulative power production of the wind farm has almost Gaussian distribution. The phase-locked states, which can be distinct from phase-unlocked states by their dynamical features, are evaluated by reconstructed stochastic differential equations.

  3. Triboelectric nanogenerator for harvesting wind energy and as self-powered wind vector sensor system.

    PubMed

    Yang, Ya; Zhu, Guang; Zhang, Hulin; Chen, Jun; Zhong, Xiandai; Lin, Zong-Hong; Su, Yuanjie; Bai, Peng; Wen, Xiaonan; Wang, Zhong Lin

    2013-10-22

    We report a triboelectric nanogenerator (TENG) that plays dual roles as a sustainable power source by harvesting wind energy and as a self-powered wind vector sensor system for wind speed and direction detection. By utilizing the wind-induced resonance vibration of a fluorinated ethylene-propylene film between two aluminum foils, the integrated TENGs with dimensions of 2.5 cm × 2.5 cm × 22 cm deliver an output voltage up to 100 V, an output current of 1.6 μA, and a corresponding output power of 0.16 mW under an external load of 100 MΩ, which can be used to directly light up tens of commercial light-emitting diodes. Furthermore, a self-powered wind vector sensor system has been developed based on the rationally designed TENGs, which is capable of detecting the wind direction and speed with a sensitivity of 0.09 μA/(m/s). This work greatly expands the applicability of TENGs as power sources for self-sustained electronics and also self-powered sensor systems for ambient wind detection.

  4. Application and performance of remote bioventing systems powered by wind

    SciTech Connect

    Graves, D.; Hague, K.; Wilson, B.; Dillon, T. Jr.; Klein, J.; McLaughlin, J.; Olson, G.

    1995-12-31

    Wind-powered bioventing systems were designed to operate at remote locations in the absence of electrical power. Laboratory measurements of soil respiration under bioventing conditions indicated the biodegradation of up to 25 mg of weathered diesel per kg of site soil per day. Further testing demonstrated the potential for harnessing wind-power to stimulate air movement through vadose zone soil. A 12-in. attic turbine in a 10-mph wind was found to generate 0.025 in. of water vacuum with an airflow of approximately 2.5 ft{sup 3} per min. Two wind-powered bioventing systems were installed near Nome, Alaska. In situ respiration tests and soil gas composition measurements indicated that the systems were capable of aerating the soil. Measurements of diesel-range organics (DRO) taken during installation and at the end of the treatment season show concentration reductions of 29 and 87% at the two sites.

  5. Cold dark matter: Controversies on small scales

    PubMed Central

    Weinberg, David H.; Bullock, James S.; Governato, Fabio; Kuzio de Naray, Rachel; Peter, Annika H. G.

    2015-01-01

    The cold dark matter (CDM) cosmological model has been remarkably successful in explaining cosmic structure over an enormous span of redshift, but it has faced persistent challenges from observations that probe the innermost regions of dark matter halos and the properties of the Milky Way’s dwarf galaxy satellites. We review the current observational and theoretical status of these “small-scale controversies.” Cosmological simulations that incorporate only gravity and collisionless CDM predict halos with abundant substructure and central densities that are too high to match constraints from galaxy dynamics. The solution could lie in baryonic physics: Recent numerical simulations and analytical models suggest that gravitational potential fluctuations tied to efficient supernova feedback can flatten the central cusps of halos in massive galaxies, and a combination of feedback and low star formation efficiency could explain why most of the dark matter subhalos orbiting the Milky Way do not host visible galaxies. However, it is not clear that this solution can work in the lowest mass galaxies, where discrepancies are observed. Alternatively, the small-scale conflicts could be evidence of more complex physics in the dark sector itself. For example, elastic scattering from strong dark matter self-interactions can alter predicted halo mass profiles, leading to good agreement with observations across a wide range of galaxy mass. Gravitational lensing and dynamical perturbations of tidal streams in the stellar halo provide evidence for an abundant population of low-mass subhalos in accord with CDM predictions. These observational approaches will get more powerful over the next few years. PMID:25646464

  6. Cold dark matter: Controversies on small scales.

    PubMed

    Weinberg, David H; Bullock, James S; Governato, Fabio; Kuzio de Naray, Rachel; Peter, Annika H G

    2015-10-06

    The cold dark matter (CDM) cosmological model has been remarkably successful in explaining cosmic structure over an enormous span of redshift, but it has faced persistent challenges from observations that probe the innermost regions of dark matter halos and the properties of the Milky Way's dwarf galaxy satellites. We review the current observational and theoretical status of these "small-scale controversies." Cosmological simulations that incorporate only gravity and collisionless CDM predict halos with abundant substructure and central densities that are too high to match constraints from galaxy dynamics. The solution could lie in baryonic physics: Recent numerical simulations and analytical models suggest that gravitational potential fluctuations tied to efficient supernova feedback can flatten the central cusps of halos in massive galaxies, and a combination of feedback and low star formation efficiency could explain why most of the dark matter subhalos orbiting the Milky Way do not host visible galaxies. However, it is not clear that this solution can work in the lowest mass galaxies, where discrepancies are observed. Alternatively, the small-scale conflicts could be evidence of more complex physics in the dark sector itself. For example, elastic scattering from strong dark matter self-interactions can alter predicted halo mass profiles, leading to good agreement with observations across a wide range of galaxy mass. Gravitational lensing and dynamical perturbations of tidal streams in the stellar halo provide evidence for an abundant population of low-mass subhalos in accord with CDM predictions. These observational approaches will get more powerful over the next few years.

  7. Wind Turbine Generator System Power Performance Test Report for the Gaia-Wind 11-kW Wind Turbine

    SciTech Connect

    Huskey, A.; Bowen, A.; Jager, D.

    2009-12-01

    This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. It is a power performance test that the National Renewable Energy Laboratory (NREL) conducted on the Gaia-Wind 11-kW small wind turbine.

  8. Wind power stabilization to achieve proper grid connection using power convertor & DSP Controller

    NASA Astrophysics Data System (ADS)

    Shejal, B. D.; Jamge, S. B.

    2010-11-01

    The wind power sources are characterized by irregularity, instability and unpredictability. In normal operation, random properties of wind and blade rotational turbulence can produce unwanted fluctuation on the voltage and power supplied into the system. Power output of a wind turbine is a function of wind speed. Wind turbine is a source of power fluctuations due to the nature of wind speed. This fluctuating power will have its impact on power balance and voltage at the point of common coupling. Small variation of wind speed could cause a large variation in the extracted power. As a result, large voltage fluctuation may result in voltage variations outside the regulation limit at connection point. In this paper, a method has been developed to reduce output power fluctuations of a wind turbine with an energy storage system using stator side converter. The developed method has been tested through modeling a doubly fed wind turbine and a battery storage system, using SimPower Systems tools of MATLAB and simulated for operation as a grid connected system.

  9. Hoopa Valley Small Scale Hydroelectric Feasibility Project

    SciTech Connect

    Curtis Miller

    2009-03-22

    This study considered assessing the feasibility of developing small scale hydro-electric power from seven major tributaries within the Hoopa Valley Indian Reservation of Northern California (http://www.hoopa-nsn.gov/). This study pursued the assessment of seven major tributaries of the Reservation that flow into the Trinity River. The feasibility of hydropower on the Hoopa Valley Indian Reservation has real potential for development and many alternative options for project locations, designs, operations and financing. In order to realize this opportunity further will require at least 2-3 years of intense data collection focusing on stream flow measurements at multiple locations in order to quantify real power potential. This also includes on the ground stream gradient surveys, road access planning and grid connectivity to PG&E for sale of electricity. Imperative to this effort is the need for negotiations between the Hoopa Tribal Council and PG&E to take place in order to finalize the power rate the Tribe will receive through any wholesale agreement that utilizes the alternative energy generated on the Reservation.

  10. Wind Powering America: Clean Energy for the 21st Century (Revised)

    SciTech Connect

    Not Available

    2004-09-01

    Wind Powering America: Clean Energy for the 21st Century continues to be one of the most popular publications produced by the Wind Powering America team. This latest revision incorporates new wind facts from the American Wind Energy Association, as well as wind FAQs for consumers, updated wind resource maps, and a list of WPA publications.

  11. Acoustic noise from tandem wind rotors of intelligent wind power unit

    NASA Astrophysics Data System (ADS)

    Kubo, Koichi; Mihara, Nobuhiko; Enishi, Akira; Kanemoto, Toshiaki

    2010-04-01

    The authors had invented the unique wind power unit composed of the large-sized front wind rotor, the small-sized rear wind rotor and the peculiar generator with the inner and the outer rotational armatures without the conventional stator. This unit is called "Intelligent Wind Power Unit" by the authors. The front and the rear wind rotors drive the inner and the outer armatures, respectively, while the rotational torque is counter-balanced between both armatures/wind rotors. This paper discusses experimentally the acoustic noise from the front and the rear wind rotors. The acoustic noise, in the counter-rotating operation, is induced mainly from the flow interaction between both rotors, and has the dominant power spectrum density at the frequency of the blade passing interaction. The noise is caused mainly from the turbulent fluctuation due to the flow separation on the blade, when the rear wind rotor stops or rotates in the same direction as the front wind rotor.

  12. Rotor equivalent wind speed for power curve measurement - comparative exercise for IEA Wind Annex 32

    NASA Astrophysics Data System (ADS)

    Wagner, R.; Cañadillas, B.; Clifton, A.; Feeney, S.; Nygaard, N.; Poodt, M.; St. Martin, C.; Tüxen, E.; Wagenaar, J. W.

    2014-06-01

    A comparative exercise has been organised within the International Energy Agency (IEA) Wind Annex 32 in order to test the Rotor Equivalent Wind Speed (REWS) method under various conditions of wind shear and measurement techniques. Eight organisations from five countries participated in the exercise. Each member of the group has derived both the power curve based on the wind speed at hub height and the power curve based on the REWS. This yielded results for different wind turbines, located in diverse types of terrain and where the wind speed profile was measured with different instruments (mast or various lidars). The participants carried out two preliminary steps in order to reach consensus on how to implement the REWS method. First, they all derived the REWS for one 10 minute wind speed profile. Secondly, they all derived the power curves for one dataset. The main point requiring consensus was the definition of the segment area used as weighting for the wind speeds measured at the various heights in the calculation of the REWS. This comparative exercise showed that the REWS method results in a significant difference compared to the standard method using the wind speed at hub height in conditions with large shear and low turbulence intensity.

  13. Variability of wind power near Oklahoma City and implications for siting of wind turbines

    SciTech Connect

    Kessler, E.; Eyster, R.

    1987-09-01

    Data from five sites near Oklahoma City were examined to assess wind power availability. Wind turbines of identical manufacture were operated at three of the sites, one of which was also equipped with anemometers on a 100-ft tower. Comprehensive anemometric data were available from the other two sites. The study indicates that the average wind speed varies substantially over Oklahoma's rolling plains, which have often been nominally regarded as flat for purposes of wind power generation. Average wind differences may be as much as 5 mph at 20 ft above ground level, and 7 mph at 100 ft above ground level for elevation differences of about 200 ft above mean sea level, even in the absence of substantial features of local terrain. Local altitude above mean sea level seems to be as influential as the shape of local terrain in determining the average wind speed. The wind turbine used at a meteorologically instrumented site in the study produced the power expected from it for the wind regime in which it was situated. The observed variations of local wind imply variations in annual kWh of as much as a factor of four between identical turbines located at similar heights above ground level in shallow valleys and on hilltops or elevated extended flat areas. 17 refs., 39 figs., 11 tabs.

  14. Wind Power predictability a risk factor in the design, construction and operation of Wind Generation Turbines

    NASA Astrophysics Data System (ADS)

    Thiesen, J.; Gulstad, L.; Ristic, I.; Maric, T.

    2010-09-01

    Summit: The wind power predictability is often a forgotten decision and planning factor for most major wind parks, both onshore and offshore. The results of the predictability are presented after having examined a number of European offshore and offshore parks power predictability by using three(3) mesoscale model IRIE_GFS and IRIE_EC and WRF. Full description: It is well known that the potential wind production is changing with latitude and complexity in terrain, but how big are the changes in the predictability and the economic impacts on a project? The concept of meteorological predictability has hitherto to some degree been neglected as a risk factor in the design, construction and operation of wind power plants. Wind power plants are generally built in places where the wind resources are high, but these are often also sites where the predictability of the wind and other weather parameters is comparatively low. This presentation addresses the question of whether higher predictability can outweigh lower average wind speeds with regard to the overall economy of a wind power project. Low predictability also tends to reduce the value of the energy produced. If it is difficult to forecast the wind on a site, it will also be difficult to predict the power production. This, in turn, leads to increased balance costs and a less reduced carbon emission from the renewable source. By investigating the output from three(3) mesoscale models IRIE and WRF, using ECMWF and GFS as boundary data over a forecasting period of 3 months for 25 offshore and onshore wind parks in Europe, the predictability are mapped. Three operational mesoscale models with two different boundary data have been chosen in order to eliminate the uncertainty with one mesoscale model. All mesoscale models are running in a 10 km horizontal resolution. The model output are converted into "day a head" wind turbine generation forecasts by using a well proven advanced physical wind power model. The power models

  15. 77 FR 71612 - Atlantic Wind Lease Sale 2 (ATLW2) Commercial Leasing for Wind Power on the Outer Continental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-03

    ... Bureau of Ocean Energy Management Atlantic Wind Lease Sale 2 (ATLW2) Commercial Leasing for Wind Power on... for wind power on the Outer Continental Shelf offshore Rhode Island and Massachusetts. SUMMARY: This document is the Proposed Sale Notice (PSN) for the sale of commercial wind energy leases on the...

  16. 77 FR 71621 - Atlantic Wind One (ATLW1) Commercial Leasing for Wind Power on the Outer Continental Shelf...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-03

    ... Bureau of Ocean Energy Management Atlantic Wind One (ATLW1) Commercial Leasing for Wind Power on the... Management (BOEM), Interior. ACTION: Proposed Sale Notice for Commercial Leasing for Wind Power on the Outer... Assessment (EA) and Finding of No Significant Impact (FONSI) for commercial wind lease issuance and...

  17. A wind energy powered wireless temperature sensor node.

    PubMed

    Zhang, Chuang; He, Xue-Feng; Li, Si-Yu; Cheng, Yao-Qing; Rao, Yang

    2015-02-27

    A wireless temperature sensor node composed of a piezoelectric wind energy harvester, a temperature sensor, a microcontroller, a power management circuit and a wireless transmitting module was developed. The wind-induced vibration energy harvester with a cuboid chamber of 62 mm × 19.6 mm × 10 mm converts ambient wind energy into electrical energy to power the sensor node. A TMP102 temperature sensor and the MSP430 microcontroller are used to measure the temperature. The power management module consists of LTC3588-1 and LT3009 units. The measured temperature is transmitted by the nRF24l01 transceiver. Experimental results show that the critical wind speed of the harvester was about 5.4 m/s and the output power of the harvester was about 1.59 mW for the electrical load of 20 kΩ at wind speed of 11.2 m/s, which was sufficient to power the wireless sensor node to measure and transmit the temperature every 13 s. When the wind speed increased from 6 m/s to 11.5 m/s, the self-powered wireless sensor node worked normally.

  18. A Wind Energy Powered Wireless Temperature Sensor Node

    PubMed Central

    Zhang, Chuang; He, Xue-Feng; Li, Si-Yu; Cheng, Yao-Qing; Rao, Yang

    2015-01-01

    A wireless temperature sensor node composed of a piezoelectric wind energy harvester, a temperature sensor, a microcontroller, a power management circuit and a wireless transmitting module was developed. The wind-induced vibration energy harvester with a cuboid chamber of 62 mm × 19.6 mm × 10 mm converts ambient wind energy into electrical energy to power the sensor node. A TMP102 temperature sensor and the MSP430 microcontroller are used to measure the temperature. The power management module consists of LTC3588-1 and LT3009 units. The measured temperature is transmitted by the nRF24l01 transceiver. Experimental results show that the critical wind speed of the harvester was about 5.4 m/s and the output power of the harvester was about 1.59 mW for the electrical load of 20 kΩ at wind speed of 11.2 m/s, which was sufficient to power the wireless sensor node to measure and transmit the temperature every 13 s. When the wind speed increased from 6 m/s to 11.5 m/s, the self-powered wireless sensor node worked normally. PMID:25734649

  19. Wind Power Forecasting Error Frequency Analyses for Operational Power System Studies: Preprint

    SciTech Connect

    Florita, A.; Hodge, B. M.; Milligan, M.

    2012-08-01

    The examination of wind power forecasting errors is crucial for optimal unit commitment and economic dispatch of power systems with significant wind power penetrations. This scheduling process includes both renewable and nonrenewable generators, and the incorporation of wind power forecasts will become increasingly important as wind fleets constitute a larger portion of generation portfolios. This research considers the Western Wind and Solar Integration Study database of wind power forecasts and numerical actualizations. This database comprises more than 30,000 locations spread over the western United States, with a total wind power capacity of 960 GW. Error analyses for individual sites and for specific balancing areas are performed using the database, quantifying the fit to theoretical distributions through goodness-of-fit metrics. Insights into wind-power forecasting error distributions are established for various levels of temporal and spatial resolution, contrasts made among the frequency distribution alternatives, and recommendations put forth for harnessing the results. Empirical data are used to produce more realistic site-level forecasts than previously employed, such that higher resolution operational studies are possible. This research feeds into a larger work of renewable integration through the links wind power forecasting has with various operational issues, such as stochastic unit commitment and flexible reserve level determination.

  20. On wind turbine power performance measurements at inclined airflow

    NASA Astrophysics Data System (ADS)

    Pedersen, T. F.

    2004-07-01

    The average airflow inclination in complex terrain may be substantial. The airflow inclination affects wind turbine performance and also affects the cup anemometer being used in power performance measurements. In this article the overall dependence of the power curve on inclined airflow is analysed for its influence on both the wind turbine and the cup anemometer. The wind turbine performance analysis is based on results of measurements and theoretical calculations with the aeroelastic code HAWC coupled to a 3D actuator disc model for varying yaw angle. The cup anemometer analysis at inclined flow is based on an averaging of measured angular characteristics in a wind tunnel with the distribution of airflow inclination angles over time. The relative difference in annual energy production in terrain with inclined airflow compared with flat terrain is simulated for cup anemometers with theoretical optimal angular characteristics for two different definitions of wind speed, as well as for five commercial cup anemometers with measured angular characteristics. Copyright

  1. Development of large wind energy power generation system

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The background and development of an experimental 100 kW wind-energy generation system are described, and the results of current field tests are presented. The experimental wind turbine is a two-bladed down-wind horizontal axis propeller type with a 29.4 m diameter rotor and a tower 28 m in height. The plant was completed in March, 1983, and has been undergoing trouble-free tests since then. The present program calls for field tests during two years from fiscal 1983 to 1984. The development of technologies relating to the linkage and operation of wind-energy power generation system networks is planned along with the acquisition of basic data for the development of a large-scale wind energy power generation system.

  2. Integrating energy storage with wind power in weak electricity grids

    NASA Astrophysics Data System (ADS)

    McDowall, Jim

    Energy storage is required to match wind generation to consumption. This time shifting can be accomplished with several hours of storage, but studies have shown that the economic value of such storage systems is unlikely to support their widespread use. This does not mean that the outlook is uniformly bleak for storage with wind power. This paper discusses storage systems ranging from a few seconds of run time to several hours, and provides a rationale for the use of systems with several minutes of run time to support a high penetration of wind power into weak electricity grids.

  3. Multi-decadal Variability of the Wind Power Output

    NASA Astrophysics Data System (ADS)

    Kirchner Bossi, Nicolas; García-Herrera, Ricardo; Prieto, Luis; Trigo, Ricardo M.

    2014-05-01

    The knowledge of the long-term wind power variability is essential to provide a realistic outlook on the power output during the lifetime of a planned wind power project. In this work, the Power Output (Po) of a market wind turbine is simulated with a daily resolution for the period 1871-2009 at two different locations in Spain, one at the Central Iberian Plateau and another at the Gibraltar Strait Area. This is attained through a statistical downscaling of the daily wind conditions. It implements a Greedy Algorithm as classificator of a geostrophic-based wind predictor, which is derived by considering the SLP daily field from the 56 ensemble members of the longest homogeneous reanalysis available (20CR, 1871-2009). For calibration and validation purposes we use 10 years of wind observations (the predictand) at both sites. As a result, a series of 139 annual wind speed Probability Density Functions (PDF) are obtained, with a good performance in terms of wind speed uncertainty reduction (average daily wind speed MAE=1.48 m/s). The obtained centennial series allow to investigate the multi-decadal variability of wind power from different points of view. Significant periodicities around the 25-yr frequency band, as well as long-term linear trends are detected at both locations. In addition, a negative correlation is found between annual Po at both locations, evidencing the differences in the dynamical mechanisms ruling them (and possible complementary behavior). Furthermore, the impact that the three leading large-scale circulation patterns over Iberia (NAO, EA and SCAND) exert over wind power output is evaluated. Results show distinct (and non-stationary) couplings to these forcings depending on the geographical position and season or month. Moreover, significant non-stationary correlations are observed with the slow varying Atlantic Multidecadal Oscillation (AMO) index for both case studies. Finally, an empirical relationship is explored between the annual Po and the

  4. Increasing Wind Turbine Power Generation Through Optimized Flow Control Design

    NASA Astrophysics Data System (ADS)

    Cooney, John; Williams, Theodore; Corke, Thomas

    2013-11-01

    A practical, validated methodology is outlined for implementing flow control systems into wind turbine designs to maximize power generation. This approach involves determining optimal flow control strategies to minimize aerodynamic losses for horizontal axis wind turbines during Region II operation. A quantitative design optimization (QDO) process is completed for the wind turbine utilized in the Notre Dame Laboratory for Enhanced Wind Energy Research. QDO utilizes CFD simulations and shape optimization tools to maximize effectiveness of flow control. Here, only flow control schemes that could be retrofitted on the existing turbine were explored. The final geometry is discussed along with accompanying validations of the predicted performance from wind tunnel experiments at full-scale conditions. Field data from the wind energy laboratory is included.

  5. R & D on Offshore Wind Power Generation System in Japan

    NASA Astrophysics Data System (ADS)

    Oishi, Kazuhito; Fukumoto, Yukinari

    Offshore wind energy has been widely exploited in Europe. Having a long coastline, the offshore wind energy will be the one of the important solutions for the increase of renewable energy in Japan. However, due to the difference in wind and marine condition between Japan and Europe, the safety, the environmental impact and the economical feasibility of the offshore wind power generation system have to be investigated in Japan. According to the data observed offshore, the wind speed is enough higher than that on land and the wind energy is economically feasible. In order to utilize the energy, the design method of the foundation against very high waves in typhoon storm should be established. For shallow offshore coastal area, gravity foundation type has been improved by hydraulic experiment. Additionally, for deeper ocean, floating types such as semi-submersible float and spar-buoy have been researched.

  6. Introduction to Voigt's wind power plant. [energy conversion efficiency

    NASA Technical Reports Server (NTRS)

    Tompkin, J.

    1973-01-01

    The design and operation of a 100 kilowatt wind driven generator are reported. Its high speed three-bladed turbine operates at a height of 50 meters. Blades are rigidly connected to the hub and turbine revolutions change linearly with wind velocity, maintaining a constant speed ratio of blade tip velocity to wind velocity over the full predetermined wind range. Three generators installed in the gondola generate either dc or ac current. Based on local wind conditions, the device has a maximum output of 720 kilowatts at a wind velocity of 16 meters per second. Total electrical capacity is 750 kilowatts, and power output per year is 2,135,000 kilowatt/hours.

  7. Small-scale gradients of charged particles in the heliospheric magnetic field

    SciTech Connect

    Guo, Fan; Giacalone, Joe

    2014-01-01

    Using numerical simulations of charged-particles propagating in the heliospheric magnetic field, we study small-scale gradients, or 'dropouts,' in the intensity of solar energetic particles seen at 1 AU. We use two turbulence models, the foot-point random motion model and the two-component model, to generate fluctuating magnetic fields similar to spacecraft observations at 1 AU. The turbulence models include a Kolmogorov-like magnetic field power spectrum containing a broad range of spatial scales from those that lead to large-scale field-line random walk to small scales leading to resonant pitch-angle scattering of energetic particles. We release energetic protons (20 keV-10 MeV) from a spatially compact and instantaneous source. The trajectories of energetic charged particles in turbulent magnetic fields are numerically integrated. Spacecraft observations are mimicked by collecting particles in small windows when they pass the windows at a distance of 1 AU. We show that small-scale gradients in the intensity of energetic particles and velocity dispersions observed by spacecraft can be reproduced using the foot-point random motion model. However, no dropouts are seen in simulations using the two-component magnetic turbulence model. We also show that particle scattering in the solar wind magnetic field needs to be infrequent for intensity dropouts to form.

  8. Quadrennial Technology Review 2015: Technology Assessments--Wind Power

    SciTech Connect

    none,

    2015-10-07

    Wind power has become a mainstream power source in the U.S. electricity portfolio, supplying 4.9% of the nation’s electricity demand in 2014. With more than 65 GW installed across 39 states at the end of 2014, utility-scale wind power is a cost-effective source of low-emissions power generation throughout much of the nation. The United States has significant sustainable land-based and offshore wind resource potential, greater than 10 times current total U.S. electricity consumption. A technical wind resource assessment conducted by the Department of Energy (DOE) in 2009 estimated that the land-based wind energy potential for the contiguous United States is equivalent to 10,500 GW capacity at 80 meters (m) hub and 12,000 GW capacity at 100 meters (m) hub heights, assuming a capacity factor of at least 30%. A subsequent 2010 DOE report estimated the technical offshore wind energy potential to be 4,150 GW. The estimate was calculated from the total offshore area within 50 nautical miles of shore in areas where average annual wind speeds are at least 7 m per second at a hub height of 90 m.

  9. Offshore based WARP{trademark} Power Spar buoys for multi-megawatt wind power plants

    SciTech Connect

    Weisbrich, A.L.; Rhodes, A.F.

    1998-12-31

    Since the earliest use of wind as a stationary power source, major consideration and effort has gone into the selection of a location with relatively high wind speed as well as proximity to the place of energy demand. As wind speed increases, collectible energy from the wind increases by the third power. That is, in a location with 20% higher wind speed, it is possible to generate 73% more power. If 50% higher wind velocity is available, 300% more power and energy can be generated. In the ideal, an offshore wind power plant should be easily and relatively inexpensively constructed, and economically sited in any depth water. In addition to these characteristics, if the typically excellent offshore winds could be amplified by as much as 50% to 80% and captured by low cost, highly reliable aircraft propeller sized wind turbines, substantial cost effectiveness and practicality would result. ENECO`s Wind amplified Rotor Platform (WARP{trademark}) Power Spar buoy system design appears to have the features needed to achieve these objectives and is proposed for test and commercialization.

  10. Thermodynamic modelling of an onsite methanation reactor for upgrading producer gas from commercial small scale biomass gasifiers.

    PubMed

    Vakalis, S; Malamis, D; Moustakas, K

    2017-06-26

    Small scale biomass gasifiers have the advantage of having higher electrical efficiency in comparison to other conventional small scale energy systems. Nonetheless, a major drawback of small scale biomass gasifiers is the relatively poor quality of the producer gas. In addition, several EU Member States are seeking ways to store the excess energy that is produced from renewables like wind power and hydropower. A recent development is the storage of energy by electrolysis of water and the production of hydrogen in a process that is commonly known as "power-to-gas". The present manuscript proposes an onsite secondary reactor for upgrading producer gas by mixing it with hydrogen in order to initiate methanation reactions. A thermodynamic model has been developed for assessing the potential of the proposed methanation process. The model utilized input parameters from a representative small scale biomass gasifier and molar ratios of hydrogen from 1:0 to 1:4.1. The Villar-Cruise-Smith algorithm was used for minimizing the Gibbs free energy. The model returned the molar fractions of the permanent gases, the heating values and the Wobbe Index. For mixtures of hydrogen and producer gas on a 1:0.9 ratio the increase of the heating value is maximized with an increase of 78%. For ratios higher than 1:3, the Wobbe index increases significantly and surpasses the value of 30 MJ/Nm(3). Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. A Nonlinear Dynamics Approach for Incorporating Wind-Speed Patterns into Wind-Power Project Evaluation

    PubMed Central

    Huffaker, Ray; Bittelli, Marco

    2015-01-01

    Wind-energy production may be expanded beyond regions with high-average wind speeds (such as the Midwest U.S.A.) to sites with lower-average speeds (such as the Southeast U.S.A.) by locating favorable regional matches between natural wind-speed and energy-demand patterns. A critical component of wind-power evaluation is to incorporate wind-speed dynamics reflecting documented diurnal and seasonal behavioral patterns. Conventional probabilistic approaches remove patterns from wind-speed data. These patterns must be restored synthetically before they can be matched with energy-demand patterns. How to accurately restore wind-speed patterns is a vexing problem spurring an expanding line of papers. We propose a paradigm shift in wind power evaluation that employs signal-detection and nonlinear-dynamics techniques to empirically diagnose whether synthetic pattern restoration can be avoided altogether. If the complex behavior of observed wind-speed records is due to nonlinear, low-dimensional, and deterministic system dynamics, then nonlinear dynamics techniques can reconstruct wind-speed dynamics from observed wind-speed data without recourse to conventional probabilistic approaches. In the first study of its kind, we test a nonlinear dynamics approach in an application to Sugarland Wind—the first utility-scale wind project proposed in Florida, USA. We find empirical evidence of a low-dimensional and nonlinear wind-speed attractor characterized by strong temporal patterns that match up well with regular daily and seasonal electricity demand patterns. PMID:25617767

  12. The Santa Cruz eddy and United States wind power

    NASA Astrophysics Data System (ADS)

    Archer, Cristina Lozej

    In the first part of this dissertation, a shallow cyclonic circulation that occurs in the summer over the Monterey Bay (California) is investigated. Since it is often centered over the city of Santa Cruz, it was named "Santa Cruz Eddy" (SCE). Its horizontal size is 10--40 km and its vertical extent 100--200 m. The SCE is unique because it forms 75--79% of the days during the summer, more frequently than any other known vortex. The SCE frequency was determined after analyzing two years of satellite imagery and data from an observational network. Simulations with the MM5 model showed that two eddies form, one in the early evening and one at night. Both eddies are formed by the vorticity generated baroclinically by the interaction of the synoptic northwesterly flow and the western side of the Santa Cruz mountains. Friction against these mountains further enhances vorticity production. In the late afternoon, the sea breeze and a favorable pressure gradient cause more vorticity to form near Santa Cruz. Since the latter two mechanisms do not act at night, the evening eddy is stronger, deeper, and larger than the nocturnal one. The second part of this dissertation aims at quantifying U.S. wind power at 80 m (the hub height of large wind turbines) and investigating whether winds from a network of farms can provide electric power steadily and reliably. A new method to extrapolate 10-m wind measurements (from 1327 surface stations and 88 soundings) to 80 m was introduced, which resulted in 80-m wind speeds that are, on average, 1.3--1.7 m/s faster than those obtained from other methods. It was found that 22% of all stations (and 35% of all coastal/offshore stations) are suitable for wind power generation. The greatest previously uncharted reservoir of wind power is offshore and near shore along the southeastern and southern U.S. coasts. When multiple wind sites are considered, the number of days with no wind power and the standard deviation of the wind speed are

  13. Small scale structure on cosmic strings

    NASA Technical Reports Server (NTRS)

    Albrecht, Andreas

    1989-01-01

    The current understanding of cosmic string evolution is discussed, and the focus placed on the question of small scale structure on strings, where most of the disagreements lie. A physical picture designed to put the role of the small scale structure into more intuitive terms is presented. In this picture it can be seen how the small scale structure can feed back in a major way on the overall scaling solution. It is also argued that it is easy for small scale numerical errors to feed back in just such a way. The intuitive discussion presented here may form the basis for an analytic treatment of the small scale structure, which argued in any case would be extremely valuable in filling the gaps in the present understanding of cosmic string evolution.

  14. Using ensemble NWP wind power forecasts to improve national power system management

    NASA Astrophysics Data System (ADS)

    Cannon, D.; Brayshaw, D.; Methven, J.; Coker, P.; Lenaghan, D.

    2014-12-01

    National power systems are becoming increasingly sensitive to atmospheric variability as generation from wind (and other renewables) increases. As such, the days-ahead predictability of wind power has significant implications for power system management. At this time horizon, power system operators plan transmission line outages for maintenance. In addition, forecast users begin to form backup strategies to account for the uncertainty in wind power predictions. Under-estimating this uncertainty could result in a failure to meet system security standards, or in the worst instance, a shortfall in total electricity supply. On the other hand, overly conservative assumptions about the forecast uncertainty incur costs associated with the unnecessary holding of reserve power. Using the power system of Great Britain (GB) as an example, we construct time series of GB-total wind power output using wind speeds from either reanalyses or global weather forecasts. To validate the accuracy of these data sets, wind power reconstructions using reanalyses and forecast analyses over a recent period are compared to measured GB-total power output. The results are found to be highly correlated on time scales greater than around 6 hours. Results are presented using ensemble wind power forecasts from several national and international forecast centres (obtained through TIGGE). Firstly, the skill with which global ensemble forecasts can represent the uncertainty in the GB-total power output at up to 10 days ahead is quantified. Following this, novel ensemble forecast metrics are developed to improve estimates of forecast uncertainty within the context of power system operations, thus enabling the development of more cost effective strategies. Finally, the predictability of extreme events such as prolonged low wind periods or rapid changes in wind power output are examined in detail. These events, if poorly forecast, induce high stress scenarios that could threaten the security of the power

  15. A Scenario Generation Method for Wind Power Ramp Events Forecasting

    SciTech Connect

    Cui, Ming-Jian; Ke, De-Ping; Sun, Yuan-Zhang; Gan, Di; Zhang, Jie; Hodge, Bri-Mathias

    2015-07-03

    Wind power ramp events (WPREs) have received increasing attention in recent years due to their significant impact on the reliability of power grid operations. In this paper, a novel WPRE forecasting method is proposed which is able to estimate the probability distributions of three important properties of the WPREs. To do so, a neural network (NN) is first proposed to model the wind power generation (WPG) as a stochastic process so that a number of scenarios of the future WPG can be generated (or predicted). Each possible scenario of the future WPG generated in this manner contains the ramping information, and the distributions of the designated WPRE properties can be stochastically derived based on the possible scenarios. Actual data from a wind power plant in the Bonneville Power Administration (BPA) was selected for testing the proposed ramp forecasting method. Results showed that the proposed method effectively forecasted the probability of ramp events.

  16. Impact of Increasing Distributed Wind Power and Wind Turbine Siting on Rural Distribution Feeder Voltage Profiles: Preprint

    SciTech Connect

    Allen, A.; Zhang, Y. C.; Hodge, B. M.

    2013-09-01

    Many favorable wind energy resources in North America are located in remote locations without direct access to the transmission grid. Building transmission lines to connect remotely-located wind power plants to large load centers has become a barrier to increasing wind power penetration in North America. By connecting utility-sized megawatt-scale wind turbines to the distribution system, wind power supplied to consumers could be increased greatly. However, the impact of including megawatt-scale wind turbines on distribution feeders needs to be studied. The work presented here examined the impact that siting and power output of megawatt-scale wind turbines have on distribution feeder voltage. This is the start of work to present a general guide to megawatt-scale wind turbine impact on the distribution feeder and finding the amount of wind power that can be added without adversely impacting the distribution feeder operation, reliability, and power quality.

  17. Detecting and characterising ramp events in wind power time series

    NASA Astrophysics Data System (ADS)

    Gallego, Cristóbal; Cuerva, Álvaro; Costa, Alexandre

    2014-12-01

    In order to implement accurate models for wind power ramp forecasting, ramps need to be previously characterised. This issue has been typically addressed by performing binary ramp/non-ramp classifications based on ad-hoc assessed thresholds. However, recent works question this approach. This paper presents the ramp function, an innovative wavelet- based tool which detects and characterises ramp events in wind power time series. The underlying idea is to assess a continuous index related to the ramp intensity at each time step, which is obtained by considering large power output gradients evaluated under different time scales (up to typical ramp durations). The ramp function overcomes some of the drawbacks shown by the aforementioned binary classification and permits forecasters to easily reveal specific features of the ramp behaviour observed at a wind farm. As an example, the daily profile of the ramp-up and ramp-down intensities are obtained for the case of a wind farm located in Spain.

  18. Thermal Performance of Wind Turbine Power System's Engine Room

    NASA Astrophysics Data System (ADS)

    Liu, Zhili; Jiang, Yanlong; Zhou, Nianyong; Shi, Hong; Kang, Na; Wang, Yu

    Greatly expanded use of wind energy has been proposed to reduce dependence on fossil and nuclear fuels for electricity generation. For wind turbine power generation, as a mature technology in the field of wind power utilization, its large-scale deployment is limited by the cooling technology. Therefore, the temperature distribution of the wind turbine power generation is a key issue for the design of the cooling system. It is because the characteristics of cooling system have a great effect on the performance of the wind turbine power generation. Based on some assumptions and simplifications, a thermal model is developed to describe the heat transfer behavior of wind turbine power system. The numerical calculation method is adopted to solve the governing equation. The heat generation and heat flux are investigated with a given operating boundary. The achieved results can be used to verify whether the cooling system meets the design requirements. Meanwhile, they also can reveal that among the influencing factors, the meteorological conditions, generated output and operation state as well seriously influence its thermal performance. Numerical calculation of the cooling system enables better understanding and results in performance improvement of the system.

  19. Wind, Wave, and Tidal Energy Without Power Conditioning

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    2013-01-01

    Most present wind, wave, and tidal energy systems require expensive power conditioning systems that reduce overall efficiency. This new design eliminates power conditioning all, or nearly all, of the time. Wind, wave, and tidal energy systems can transmit their energy to pumps that send high-pressure fluid to a central power production area. The central power production area can consist of a series of hydraulic generators. The hydraulic generators can be variable displacement generators such that the RPM, and thus the voltage, remains constant, eliminating the need for further power conditioning. A series of wind blades is attached to a series of radial piston pumps, which pump fluid to a series of axial piston motors attached to generators. As the wind is reduced, the amount of energy is reduced, and the number of active hydraulic generators can be reduced to maintain a nearly constant RPM. If the axial piston motors have variable displacement, an exact RPM can be maintained for all, or nearly all, wind speeds. Analyses have been performed that show over 20% performance improvements with this technique over conventional wind turbines

  20. Wind-assist irrigation and electrical-power generation

    NASA Astrophysics Data System (ADS)

    Nelson, V.; Starcher, K.

    1982-07-01

    A wind turbine is mechanically connected to an existing irrigation well. The system can be operated in three modes: electric motor driving the water turbine pump. Wind assist mode where wind turbine supplements power from the utility line to drive the water turbine pump. At wind speeds of 12 m/s and greater, the wind turbine can pump water (15 kW) and feed power (10 kW) back into the utility grid at the same time. Electrical generation mode where the water pump is disconnected and all power is fed back to the utility grid. The concept is technically viable as the mechanical connection allows for a smooth transfer of power in parallel with an existing power source. Minor problems caused delays and major problems of two rotor failures precluded enough operation time to obtain a good estimation of the economics. Because reliability and maintenance are difficult problems with prototype or limited production wind energy conversion systems, the expense of the demonstration project has exceeded the estimated cost by a large amount.

  1. Managing Wind Power Uncertainty Through Strategic Reserve Purchasing

    SciTech Connect

    Du, Ershun; Zhang, Ning; Kang, Chongqing; Kroposki, Benjamin; Huang, Han; Miao, Miao; Xia, Qing

    2016-10-18

    With the rapidly increasing penetration of wind power, wind producers are becoming increasingly responsible for the deviation of the wind power output from the forecast. Such uncertainty results in revenue losses to the wind power producers (WPPs) due to penalties in ex-post imbalance settlements. This paper explores the opportunities available for WPPs if they can purchase or schedule some reserves to offset part of their deviation rather than being fully penalized in the real time market. The revenue for WPPs under such mechanism is modeled. The optimal strategy for managing the uncertainty of wind power by purchasing reserves to maximize the WPP's revenue is analytically derived with rigorous optimality conditions. The amount of energy and reserves that should be bid in the market are explicitly quantified by the probabilistic forecast and the prices of the energy and reserves. A case study using the price data from ERCOT and wind power data from NREL is performed to verify the effectiveness of the derived optimal bidding strategy and the benefits of reserve purchasing. Additionally, the proposed bidding strategy can also reduce the risk of variations on WPP's revenue.

  2. Generation Expansion Planning with High Penetration of Wind Power

    NASA Astrophysics Data System (ADS)

    Sharan, Ishan; Balasubramanian, R.

    2016-08-01

    Worldwide thrust is being provided in generation of electricity from wind. Planning for the developmental needs of wind based power has to be consistent with the objective and basic framework of overall resource planning. The operational issues associated with the integration of wind power must be addressed at the planning stage. Lack of co-ordinated planning of wind turbine generators, conventional generating units and expansion of the transmission system may lead to curtailment of wind power due to transmission inadequacy or operational constraints. This paper presents a generation expansion planning model taking into account fuel transportation and power transmission constraints, while addressing the operational issues associated with the high penetration of wind power. For analyzing the operational issues, security constrained unit commitment algorithm is embedded in the integrated generation and transmission expansion planning model. The integrated generation and transmission expansion planning problem has been formulated as a mixed integer linear problem involving both binary and continuous variables in GAMS. The model has been applied to the expansion planning of a real system to illustrate the proposed approach.

  3. Wind speed reductions by large-scale wind turbine deployments lower turbine efficiencies and set low wind power potentials

    NASA Astrophysics Data System (ADS)

    Miller, Lee; Kleidon, Axel

    2017-04-01

    Wind turbines generate electricity by removing kinetic energy from the atmosphere. Large numbers of wind turbines are likely to reduce wind speeds, which lowers estimates of electricity generation from what would be presumed from unaffected conditions. Here, we test how well wind power potentials that account for this effect can be estimated without explicitly simulating atmospheric dynamics. We first use simulations with an atmospheric general circulation model (GCM) that explicitly simulates the effects of wind turbines to derive wind power limits (GCM estimate), and compare them to a simple approach derived from the climatological conditions without turbines [vertical kinetic energy (VKE) estimate]. On land, we find strong agreement between the VKE and GCM estimates with respect to electricity generation rates (0.32 and 0.37 We m-2) and wind speed reductions by 42 and 44%. Over ocean, the GCM estimate is about twice the VKE estimate (0.59 and 0.29 We m-2) and yet with comparable wind speed reductions (50 and 42%). We then show that this bias can be corrected by modifying the downward momentum flux to the surface. Thus, large-scale limits to wind power can be derived from climatological conditions without explicitly simulating atmospheric dynamics. Consistent with the GCM simulations, the approach estimates that only comparatively few land areas are suitable to generate more than 1 We m-2 of electricity and that larger deployment scales are likely to reduce the expected electricity generation rate of each turbine. We conclude that these atmospheric effects are relevant for planning the future expansion of wind power.

  4. Wind power forecasting : state-of-the-art 2009.

    SciTech Connect

    Monteiro, C.; Bessa, R.; Miranda, V.; Botterud, A.; Wang, J.; Conzelmann, G.; Decision and Information Sciences; INESC Porto

    2009-11-20

    Many countries and regions are introducing policies aimed at reducing the environmental footprint from the energy sector and increasing the use of renewable energy. In the United States, a number of initiatives have been taken at the state level, from renewable portfolio standards (RPSs) and renewable energy certificates (RECs), to regional greenhouse gas emission control schemes. Within the U.S. Federal government, new energy and environmental policies and goals are also being crafted, and these are likely to increase the use of renewable energy substantially. The European Union is pursuing implementation of its ambitious 20/20/20 targets, which aim (by 2020) to reduce greenhouse gas emissions by 20% (as compared to 1990), increase the amount of renewable energy to 20% of the energy supply, and reduce the overall energy consumption by 20% through energy efficiency. With the current focus on energy and the environment, efficient integration of renewable energy into the electric power system is becoming increasingly important. In a recent report, the U.S. Department of Energy (DOE) describes a model-based scenario, in which wind energy provides 20% of the U.S. electricity demand in 2030. The report discusses a set of technical and economic challenges that have to be overcome for this scenario to unfold. In Europe, several countries already have a high penetration of wind power (i.e., in the range of 7 to 20% of electricity consumption in countries such as Germany, Spain, Portugal, and Denmark). The rapid growth in installed wind power capacity is expected to continue in the United States as well as in Europe. A large-scale introduction of wind power causes a number of challenges for electricity market and power system operators who will have to deal with the variability and uncertainty in wind power generation when making their scheduling and dispatch decisions. Wind power forecasting (WPF) is frequently identified as an important tool to address the variability and

  5. Status of Centralized Wind Power Forecasting in North America: May 2009-May 2010

    SciTech Connect

    Porter, K.; Rogers, J.

    2010-04-01

    Report surveys grid wind power forecasts for all wind generators, which are administered by utilities or regional transmission organizations (RTOs), typically with the assistance of one or more wind power forecasting companies.

  6. Examining the Variability of Wind Power Output in the Regulation Time Frame: Preprint

    SciTech Connect

    Hodge, B. M.; Shedd, S.; Florita, A.

    2012-08-01

    This work examines the distribution of changes in wind power for different time scales in the regulation time frame as well as the correlation of changes in power output for individual wind turbines in a wind plant.

  7. Fundamental economic issues in the development of small scale hydro

    SciTech Connect

    Not Available

    1980-05-01

    Some basic economic issues involved in the development of small-scale hydroelectric power are addressed. The discussion represents an economist's view of the investment process in this resource. Very little investment has been made in small-scale hydro development and an attempt is made to show that the reason for this may not be that the expected present worth of the returns of the project do not exceed the construction cost by a sufficient amount. Rather, a set of factors in combination impose costs on the project not normally incurred in small businesses. The discussion covers costs, supply, demand, and profitability.

  8. A proposed national wind power R and D program. [offshore wind power system for electric energy supplies

    NASA Technical Reports Server (NTRS)

    Heronemus, W.

    1973-01-01

    An offshore wind power system is described that consists of wind driven electrical dc generators mounted on floating towers in offshore waters. The output from the generators supplies underwater electrolyzer stations in which water is converted into hydrogen and oxygen. The hydrogen is piped to shore for conversion to electricity in fuel cell stations. It is estimated that this system can produce 159 x 10 to the ninth power kilowatt-hours per year. It is concluded that solar energy - and that includes wind energy - is the only way out of the US energy dilemma in the not too distant future.

  9. Wind powered direct drive water pumping systems

    SciTech Connect

    Sadhu, D.

    1983-12-01

    Wind turbine of comparatively large capacities are used exclusively for electricity generation, and so far small multiblade horizontal axis turbines are extensively employed for water pumping with reciprocating piston pumps. However, the advent of wind turbines for irrigation, characterised with large discharge volume pumps, require application of large capacity and efficient ones to make the operation viable. An analysis is made in this paper to find matching pump coupled directly with wind turbine for optimum system operation in variable speed. There exist various type of wind turbines, operating on different principles having characteristics different, dependent not only on the types but also on the design criteria of the individuals. Water pumps are also of various types whose operation characteristics vary with the type, mode of operation and design parameters. A nondimensional analysis is carried out to match the two, to operate at optimum, by superimposing the operating characteristics of the one over the other. The transmission method is also taken in account on the investment analysis of the whole system. Positive displacement pumps are best suited for high starting torque turbines e.g. Savonius or Filippini or multiblade horizontal axis rotors, and consequently are less efficient, though is advantageous for high water lift operation.

  10. Harnessing the Power of Wind Technology

    ERIC Educational Resources Information Center

    Dotson, Tawny M.

    2009-01-01

    "Where the wind comes sweepin' down the plain" is more than just a song lyric for Oklahoma's career and technical education community. It's the acknowledgement of an untapped natural resource that has the potential to translate into both energy independence for the country and jobs for the state. Statewide, technology center instructors…

  11. 78 FR 33897 - Atlantic Wind Lease Sale 2 (ATLW2) Commercial Leasing for Wind Power on the Outer Continental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-05

    ... for Wind Power on the Outer Continental Shelf Offshore Rhode Island and Massachusetts-- Final Sale...) Commercial Leasing for Wind Power on the Outer Continental Shelf Offshore Rhode Island and Massachusetts... for Commercial Leasing for Wind Power on the Outer Continental Shelf Offshore Rhode Island...

  12. Piezoelectric wind turbine

    NASA Astrophysics Data System (ADS)

    Kishore, Ravi Anant; Priya, Shashank

    2013-03-01

    In past few years, there has been significant focus towards developing small scale renewable energy based power sources for powering wireless sensor nodes in remote locations such as highways and bridges to conduct continuous health monitoring. These prior efforts have led to the development of micro-scale solar modules, hydrogen fuel cells and various vibration based energy harvesters. However, the cost effectiveness, reliability, and practicality of these solutions remain a concern. Harvesting the wind energy using micro-to-small scale wind turbines can be an excellent solution in variety of outdoor scenarios provided they can operate at few miles per hour of wind speed. The conventional electromagnetic generator used in the wind mills always has some cogging torque which restricts their operation above certain cut-in wind speed. This study aims to develop a novel piezoelectric wind turbine that utilizes bimorph actuators for electro-mechanical energy conversion. This device utilizes a Savonius rotor that is connected to a disk having magnets at the periphery. The piezoelectric actuators arranged circumferentially around the disk also have magnets at the tip which interacts with the magnetic field of the rotating disk and produces cyclical deflection. The wind tunnel experiments were conducted between 2-12 mph of wind speeds to characterize and optimize the power output of the wind turbine. Further, testing was conducted in the open environment to quantify the response to random wind gusts. An attempt was made towards integration of the piezoelectric wind turbine with the wireless sensor node.

  13. Wind Generation Participation in Power System Frequency Response: Preprint

    SciTech Connect

    Gevorgian, Vahan; Zhang, Yingchen

    2017-01-01

    The electrical frequency of an interconnected power system must be maintained close its nominal level at all times. Excessive under- and overfrequency excursions can lead to load shedding, instability, machine damage, and even blackouts. There is a rising concern in the electric power industry in recent years about the declining amount of inertia and primary frequency response (PFR) in many interconnections. This decline may continue due to increasing penetrations of inverter-coupled generation and the planned retirements of conventional thermal plants. Inverter-coupled variable wind generation is capable of contributing to PFR and inertia with a response that is different from that of conventional generation. It is not yet entirely understood how such a response will affect the system at different wind power penetration levels. The modeling work presented in this paper evaluates the impact of wind generation's provision of these active power control strategies on a large, synchronous interconnection. All simulations were conducted on the U.S. Western Interconnection with different levels of instantaneous wind power penetrations (up to 80%). The ability of wind power plants to provide PFR - and a combination of synthetic inertial response and PFR - significantly improved the frequency response performance of the system.

  14. 75 FR 82130 - WTO Dispute Settlement Proceeding Regarding China-Subsidies on Wind Power Equipment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... Proceeding Regarding China--Subsidies on Wind Power Equipment AGENCY: Office of the United States Trade... consultations regarding certain subsidies provided by the People's Republic of China (China) on wind power... Administration of Special Fund for Industrialization of Wind Power Equipment'' (``Wind Power Equipment...

  15. Wind Turbine Generator System Duration Test Report for the Mariah Power Windspire Wind Turbine

    SciTech Connect

    Huskey, A.; Bowen, A.; Jager, D.

    2010-05-01

    This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, five turbines are being tested at the National Wind Technology Center (NWTC) as a part of the first round of this project. Duration testing is one of up to five tests that may be performed on the turbines. Other tests include power performance, safety and function, noise, and power quality tests. NWTC testing results provide manufacturers with reports that may be used to meet part of small wind turbine certification requirements. This duration test report focuses on the Mariah Power Windspire wind turbine.

  16. Wake Mitigation Strategies for Optimizing Wind Farm Power Production

    NASA Astrophysics Data System (ADS)

    Dilip, Deepu; Porté-Agel, Fernando

    2016-04-01

    Although wind turbines are designed individually for optimum power production, they are often arranged into groups of closely spaced turbines in a wind farm rather than in isolation. Consequently, most turbines in a wind farm do not operate in unobstructed wind flows, but are affected by the wakes of turbines in front of them. Such wake interference significantly reduces the overall power generation from wind farms and hence, development of effective wake mitigation strategies is critical for improving wind farm efficiency. One approach towards this end is based on the notion that the operation of each turbine in a wind farm at its optimum efficiency might not lead to optimum power generation from the wind farm as a whole. This entails a down regulation of individual turbines from its optimum operating point, which can be achieved through different methods such as pitching the turbine blades, changing the turbine tip speed ratio or yawing of the turbine, to name a few. In this study, large-eddy simulations of a two-turbine arrangement with the second turbine fully in the wake of the first are performed. Different wake mitigation techniques are applied to the upstream turbine, and the effects of these on its wake characteristics are investigated. Results for the combined power from the two turbines for each of these methods are compared to a baseline scenario where no wake mitigation strategies are employed. Analysis of the results shows the potential for improved power production from such wake control methods. It should be noted, however, that the magnitude of the improvement is strongly affected by the level of turbulence in the incoming atmospheric flow.

  17. Performance of a small wind powered water pumping system

    USDA-ARS?s Scientific Manuscript database

    Lorentz helical pumps (Henstedt-Ulzburg, Germany) have been powered by solar energy for remote water pumping applications for many years, but from October 2005 to March 2008 a Lorentz helical pump was powered by wind energy at the USDA-ARS Conservation and Production Research Laboratory (CPRL) near ...

  18. Livestock water pumping with wind and solar power

    USDA-ARS?s Scientific Manuscript database

    Recent developments in pumping technologies have allowed for efficient use of renewable energies like wind and solar to power new pumps for remote water pumping. A helical type, positive displacement pump was developed a few years ago and recently modified to accept input from a variable power sourc...

  19. Kolmogorov spectrum of renewable wind and solar power fluctuations

    NASA Astrophysics Data System (ADS)

    Tabar, M. Reza Rahimi; Anvari, M.; Lohmann, G.; Heinemann, D.; Wächter, M.; Milan, P.; Lorenz, E.; Peinke, Joachim

    2014-10-01

    With increasing the contribution of renewable energies in power production, the task of reducing dynamic instability in power grids must also be addressed from the generation side, because the power delivered from such sources is spatiotemporally stochastic in nature. Here we characterize the stochastic properties of the wind and solar energy sources by studying their spectrum and multifractal exponents. The computed power spectrum from high frequency time series of solar irradiance and wind power reveals a power-law behaviour with an exponent ˜ 5/3 (Kolmogorov exponent) for the frequency domain 0.001 Hz < f < 0.05 Hz, which means that the power grid is being fed by turbulent-like sources. Our results bring important evidence on the stochastic and turbulent-like behaviour of renewable power production from wind and solar energies, which can cause instability in power grids. Our statistical analysis also provides important information that must be used as a guideline for an optimal design of power grids that operate under intermittent renewable sources of power.

  20. A unified large/small-scale dynamo in helical turbulence

    NASA Astrophysics Data System (ADS)

    Bhat, Pallavi; Subramanian, Kandaswamy; Brandenburg, Axel

    2016-09-01

    We use high resolution direct numerical simulations (DNS) to show that helical turbulence can generate significant large-scale fields even in the presence of strong small-scale dynamo action. During the kinematic stage, the unified large/small-scale dynamo grows fields with a shape-invariant eigenfunction, with most power peaked at small scales or large k, as in Subramanian & Brandenburg. Nevertheless, the large-scale field can be clearly detected as an excess power at small k in the negatively polarized component of the energy spectrum for a forcing with positively polarized waves. Its strength overline{B}, relative to the total rms field Brms, decreases with increasing magnetic Reynolds number, ReM. However, as the Lorentz force becomes important, the field generated by the unified dynamo orders itself by saturating on successively larger scales. The magnetic integral scale for the positively polarized waves, characterizing the small-scale field, increases significantly from the kinematic stage to saturation. This implies that the small-scale field becomes as coherent as possible for a given forcing scale, which averts the ReM-dependent quenching of overline{B}/B_rms. These results are obtained for 10243 DNS with magnetic Prandtl numbers of PrM = 0.1 and 10. For PrM = 0.1, overline{B}/B_rms grows from about 0.04 to about 0.4 at saturation, aided in the final stages by helicity dissipation. For PrM = 10, overline{B}/B_rms grows from much less than 0.01 to values of the order the 0.2. Our results confirm that there is a unified large/small-scale dynamo in helical turbulence.

  1. Method and system for small scale pumping

    DOEpatents

    Insepov, Zeke; Hassanein, Ahmed

    2010-01-26

    The present invention relates generally to the field of small scale pumping and, more specifically, to a method and system for very small scale pumping media through microtubes. One preferred embodiment of the invention generally comprises: method for small scale pumping, comprising the following steps: providing one or more media; providing one or more microtubes, the one or more tubes having a first end and a second end, wherein said first end of one or more tubes is in contact with the media; and creating surface waves on the tubes, wherein at least a portion of the media is pumped through the tube.

  2. Small scale bipolar nickel-hydrogen testing

    NASA Technical Reports Server (NTRS)

    Manzo, Michelle A.

    1988-01-01

    Bipolar nickel-hydrogen batteries, ranging in capacity from 6 to 40 A-hr, have been tested at the NASA Lewis Research Center over the past six years. Small scale tests of 1 A-hr nickel-hydrogen stacks have been initiated as a means of screening design and component variations for bipolar nickel-hydrogen cells and batteries. Four small-scale batteries have been built and tested. Characterization and limited cycle testing were performed to establish the validity of test results in the scaled down hardware. The results show characterization test results to be valid. LEO test results in the small scale hardware have limited value.

  3. Wind farm density and harvested power in very large wind farms: A low-order model

    NASA Astrophysics Data System (ADS)

    Cortina, G.; Sharma, V.; Calaf, M.

    2017-07-01

    In this work we create new understanding of wind turbine wakes recovery process as a function of wind farm density using large-eddy simulations of an atmospheric boundary layer diurnal cycle. Simulations are forced with a constant geostrophic wind and a time varying surface temperature extracted from a selected period of the Cooperative Atmospheric Surface Exchange Study field experiment. Wind turbines are represented using the actuator disk model with rotation and yaw alignment. A control volume analysis around each turbine has been used to evaluate wind turbine wake recovery and corresponding harvested power. Results confirm the existence of two dominant recovery mechanisms, advection and flux of mean kinetic energy, which are modulated by the background thermal stratification. For the low-density arrangements advection dominates, while for the highly loaded wind farms the mean kinetic energy recovers through fluxes of mean kinetic energy. For those cases in between, a smooth balance of both mechanisms exists. From the results, a low-order model for the wind farms' harvested power as a function of thermal stratification and wind farm density has been developed, which has the potential to be used as an order-of-magnitude assessment tool.

  4. Wind Powering America: Goals, Approach, Perspectives, and Prospects; Preprint

    SciTech Connect

    Flowers, L. T.; Dougherty, P. J.

    2002-03-01

    While wind development activity in the United States has dramatically increased over the last 3 years, it has been mainly driven by policy mandates in the investor owned utility community. Also, while significant wind development has and is now occurring in the Northwest, the Great Plains, the Rocky Mountains, Texas, and several eastern states, there remain a number of states that have excellent resources that are essentially undeveloped. Additionally, the U.S. federal agencies represent the largest institutional load in the world, and thus are a potential large market for green (wind) energy. Rural America is economically stressed and traditional agricultural incomes are seriously threatened; wind development in these windy regions offers one of the most promising''crops'' of the 21st century. Public power serves these communities, and local development of wind with low-cost financing appears to be competitive with new conventional fossil energy sources.

  5. Factors driving wind power development in the United States

    SciTech Connect

    Bird, Lori A.; Parsons, Brian; Gagliano, Troy; Brown, Matthew H.; Wiser, Ryan H.; Bolinger, Mark

    2003-05-15

    In the United States, there has been substantial recent growth in wind energy generating capacity, with growth averaging 24 percent annually during the past five years. About 1,700 MW of wind energy capacity was installed in 2001, while another 410 MW became operational in 2002. This year (2003) shows promise of significant growth with more than 1,500 MW planned. With this growth, an increasing number of states are experiencing investment in wind energy projects. Wind installations currently exist in about half of all U.S. states. This paper explores the key factors at play in the states that have achieved a substantial amount of wind energy investment. Some of the factors that are examined include policy drivers, such as renewable portfolio standards (RPS), federal and state financial incentives, and integrated resource planning; as well as market drivers, such as consumer demand for green power, natural gas price volatility, and wholesale market rules.

  6. Ice Accretion Prediction on Wind Turbines and Consequent Power Losses

    NASA Astrophysics Data System (ADS)

    Yirtici, Ozcan; Tuncer, Ismail H.; Ozgen, Serkan

    2016-09-01

    Ice accretion on wind turbine blades modifies the sectional profiles and causes alteration in the aerodynamic characteristic of the blades. The objective of this study is to determine performance losses on wind turbines due to the formation of ice in cold climate regions and mountainous areas where wind energy resources are found. In this study, the Blade Element Momentum method is employed together with an ice accretion prediction tool in order to estimate the ice build-up on wind turbine blades and the energy production for iced and clean blades. The predicted ice shapes of the various airfoil profiles are validated with the experimental data and it is shown that the tool developed is promising to be used in the prediction of power production losses of wind turbines.

  7. Transforming intermittent wind energy to a baseload power supply economically

    SciTech Connect

    Cavallo, A.J.

    1996-12-31

    Wind generated electricity can be transformed from an intermittent to a baseload power supply cost-effectively by taking advantage of the fundamental properties of wind and by the efficient utilization of compressed air energy storage (CAES) systems. A utility scale wind-CAES-transmission system can have a 95 percent capacity factor at a cost of delivered electricity that is about 15 percent greater than a conventional wind energy system with a 34 percent capacity factor. This approach has several compelling advantages. It is based on existing technology and makes best use of costly transmission lines. It produces electricity that is the technical equivalent of that from fossil fuel or nuclear power stations. It minimizes greenhouse gas and other fossil fuel pollution, and is an industrial scale system that could cover a significant fraction of total electrical demand in regions such as the US, Mexico, China or Europe.

  8. Detection of Wind Turbine Power Performance Abnormalities Using Eigenvalue Analysis

    DTIC Science & Technology

    2014-12-23

    Detection of Wind Turbine Power Performance Abnormalities Using Eigenvalue Analysis Georgios Alexandros Skrimpas1, Christian Walsted Sweeney2, Kun S...University of Denmark, Lyngby, 2800, Denmark nm@elektro.dtu.dk jh@elektro.dtu.dk ABSTRACT Condition monitoring of wind turbines is a field of continu...ous research and development as new turbine configurations enter into the market and new failure modes appear. Systems utilising well established

  9. Controlled power transfer from wind driven reluctance generator

    SciTech Connect

    Rahim, Y.H.A.; Al-Sabbagh, A.M.L.

    1997-12-01

    The paper describes the dynamic performance of a wind driven reluctance generator connected to an electric network of large capacity. A controller that makes possible the regular flow of power to the network has been considered. Controller parameters that successfully suppress unwanted mechanical and electrical stresses and overshoots due to wind gust, have been estimated. The performance of the controller has also been examined for short-circuit faults at the terminals of the generators.

  10. The production potential of wind power in Finland

    NASA Astrophysics Data System (ADS)

    Peltola, Esa

    1989-03-01

    The production potential of wind power in Finland is estimated by mapping and classifying the coastal areas and the archipelago of Finland by the terrain and by land use restrictions. Estimates for production costs are given based on present cost levels of wind turbines. An area of 106,000 sq km was mapped. The classification by terrain was made using topographic maps in scale 1:100,000. The restrictions of land use were classified according to regional plans published by regional authorities. The production potential was calculated for land-based and island-based wind power plants using areas belonging to terrain class 1 (coastal areas, open farm lands) and to land use category with no restrictions. These areas have an area of 2000 sq km, which is about 2 percent of the total area investigated. The terrain classification was used to described the wind conditions in coastal Finland. The mean wind speed at the height of 100 m is 7 to 8 m/s on off-shore areas near the coast line and on a narrow strip on shore and 6 to 7 m/s at the height of 50 m. The wind speed declines fast from coast line to inland locations. The production potential for land based wind power plants was about 4.3 TWh/a using wind turbines of about 50 m both in hub height and in rotor diameter and having rated power of about 1 MW. Production costs of less than 0.50 FIM/kWh were estimated for some 1.3 TWh/a of this potential.

  11. Fixed pitch wind turbine control to generate the maximum power

    NASA Astrophysics Data System (ADS)

    Martinez Rodrigo, Fernando

    This Doctoral Thesis firstly shows the state of the art about wind power, wind turbines and alternating current generators. A part is intended for the state of the art of the commercial small wind turbines: their applications, the technology used, the elements topology according to the application type, the investigation lines in this field, the political respects that have an influence in using or not small turbines, and lastly it analyses in detail four commercial small turbines. One chapter contains the models and equations of the alternating current generators used in the Doctoral Thesis, which are the induction generator and the permanent magnets generator. Other chapter explains some methods to control the alternating current generators speed. Chapter 7 is oriented to the induction machines speed estimators. These estimators will let to eliminate the generators speed sensor. In the Thesis, some of them are simulated to test their behaviour. It presents an original analysis, which is oriented to choose the most right estimators for such an application as small wind turbines. Chapter 8 introduces the control systems developed for wind turbines. They let to extract the maximum power for every wind speed. The base of all of them is the algorithm proposed in the Thesis. Some control systems are proposed for squirrel cage induction generators and permanent magnets generators, which use voltage source and current source schemes. Some of them use generator speed sensors and others use speed estimators. The schemes do not need wind speed sensor.

  12. Rotor dynamic considerations for large wind power generator systems

    NASA Technical Reports Server (NTRS)

    Ormiston, R. A.

    1973-01-01

    Successful large, reliable, low maintenance wind turbines must be designed with full consideration for minimizing dynamic response to aerodynamic, inertial, and gravitational forces. Much of existing helicopter rotor technology is applicable to this problem. Compared with helicopter rotors, large wind turbines are likely to be relatively less flexible with higher dimensionless natural frequencies. For very large wind turbines, low power output per unit weight and stresses due to gravitational forces are limiting factors. The need to reduce rotor complexity to a minimum favors the use of cantilevered (hingeless) rotor configurations where stresses are relieved by elastic deformations.

  13. Economic analysis of wind-powered crop drying. Final report

    SciTech Connect

    Garling, W.S.; Harper, M.R.; Merchant-Geuder, L.; Welch, M.

    1980-03-01

    Potential applications of wind energy include not only large central turbines that can be utilized by utilities, but also dispersed systems for farms and other applications. The US Departments of Energy (DOE) and Agriculture (USDA) currently are establishing the feasibility of wind energy use in applications where the energy can be used as available, or stored in a simple form. These applications include production of hot water for rural sanitation, heating and cooling of rural structures and products, drying agricultural products, and irrigation. This study, funded by USDA, analyzed the economic feasibility of wind power in crop drying. Drying of corn, soybeans, rice, peanuts, tobacco, and dehydrated alfalfa were addressed.

  14. Small scale structure on cosmic strings

    SciTech Connect

    Albrecht, A.

    1989-10-30

    I discuss our current understanding of cosmic string evolution, and focus on the question of small scale structure on strings, where most of the disagreements lie. I present a physical picture designed to put the role of the small scale structure into more intuitive terms. In this picture one can see how the small scale structure can feed back in a major way on the overall scaling solution. I also argue that it is easy for small scale numerical errors to feed back in just such a way. The intuitive discussion presented here may form the basis for an analytic treatment of the small structure, which I argue in any case would be extremely valuable in filling the gaps in our resent understanding of cosmic string evolution. 24 refs., 8 figs.

  15. Small-scale explosive welding of aluminum

    NASA Technical Reports Server (NTRS)

    Bement, L. J.

    1972-01-01

    Welding technique uses very small quantities of explosive ribbon to accomplish small-scale lap-welding of aluminum plates. Technique can perform small controlled welding with no length limitations and requires minimal protective shielding.

  16. Small Scale Features at Vesta South Pole

    NASA Image and Video Library

    2011-10-01

    This image from NASA Dawn spacecraft shows a raised mound material overlying the brighter material that makes up the floor of the south polar depression of asteroid Vesta. Many small scale craters are clear in this image.

  17. Power quality control of an autonomous wind-diesel power system based on hybrid intelligent controller.

    PubMed

    Ko, Hee-Sang; Lee, Kwang Y; Kang, Min-Jae; Kim, Ho-Chan

    2008-12-01

    Wind power generation is gaining popularity as the power industry in the world is moving toward more liberalized trade of energy along with public concerns of more environmentally friendly mode of electricity generation. The weakness of wind power generation is its dependence on nature-the power output varies in quite a wide range due to the change of wind speed, which is difficult to model and predict. The excess fluctuation of power output and voltages can influence negatively the quality of electricity in the distribution system connected to the wind power generation plant. In this paper, the authors propose an intelligent adaptive system to control the output of a wind power generation plant to maintain the quality of electricity in the distribution system. The target wind generator is a cost-effective induction generator, while the plant is equipped with a small capacity energy storage based on conventional batteries, heater load for co-generation and braking, and a voltage smoothing device such as a static Var compensator (SVC). Fuzzy logic controller provides a flexible controller covering a wide range of energy/voltage compensation. A neural network inverse model is designed to provide compensating control amount for a system. The system can be optimized to cope with the fluctuating market-based electricity price conditions to lower the cost of electricity consumption or to maximize the power sales opportunities from the wind generation plant.

  18. Direct power measurements on wind turbine array configurations

    NASA Astrophysics Data System (ADS)

    Delucia, Dominic; Cal, Raul Bayoan

    2012-11-01

    The reliability on the power extraction through wind turbines is an area of need given the increasing size of the arrays and energy demand. The turbulence effects generated by wind turbines on the subsequent rows downstream are assessed. Mechanical torque on the hubs of the model wind turbine is recorded and the power is calculated, where the measurements are performed in the Portland State University wind tunnel. Simultaneous torque and angular frequency of the rotors is record at three locations in a 3 by 4 wind turbine array. In this study, the effects due to in-line and staggered configurations are investigated. The base case configuration is a 3 by 4 array with a 6D downstream spacing and a 3D transverse spacing. The results are compared to wind turbine arrays of different spacing configurations. The trends in the data suggest the power is significantly increased when the downstream position are offset by 1.5D in the transverse direction not only for subsequent turbines but also when the turbines are staggered.

  19. Applications of remote sensing to wind power facility siting

    NASA Astrophysics Data System (ADS)

    Wade, J. E.; Rosenfeld, C. L.; Maule, P. A.

    A method by which wind energy prospectors can use remote sensing to rapidly examine extensive geographical areas to identify potential wind turbine generators' sites is outlined. Remote sensing in wind prospecting is not being considered as a tool for determining wind power potential but, rather, as an aid in identifying terrestrial, marine, and atmospheric characteristics associated with desirable wind power sites. It is noted that locations with interesting features noted in a regional assessment can be more closely evaluated using medium-scale imagery, which can be acquired from a number of different agencies, among them the U.S. Forest Service, the Bureau of Land Management, Water and Power Resources and the Soil Conservation Service. Once specific locations have been identified from small- and medium-scale imagery, low-level aerial reconnaissance in a locally chartered aircraft can verify the information obtained. Wind-deformed trees, active slip faces on dunes, snow cornices, snow fences, and the slopes of ridges can be evaluated.

  20. Toward improved statistical treatments of wind power forecast errors

    NASA Astrophysics Data System (ADS)

    Hart, E.; Jacobson, M. Z.

    2011-12-01

    The ability of renewable resources to reliably supply electric power demand is of considerable interest in the context of growing renewable portfolio standards and the potential for future carbon markets. Toward this end, a number of probabilistic models have been applied to the problem of grid integration of intermittent renewables, such as wind power. Most of these models rely on simple Markov or autoregressive models of wind forecast errors. While these models generally capture the bulk statistics of wind forecast errors, they often fail to reproduce accurate ramp rate distributions and do not accurately describe extreme forecast error events, both of which are of considerable interest to those seeking to comment on system reliability. The problem often lies in characterizing and reproducing not only the magnitude of wind forecast errors, but also the timing or phase errors (ie. when a front passes over a wind farm). Here we compare time series wind power data produced using different forecast error models to determine the best approach for capturing errors in both magnitude and phase. Additionally, new metrics are presented to characterize forecast quality with respect to both considerations.

  1. Yaw-Misalignment and its Impact on Wind Turbine Loads and Wind Farm Power Output

    NASA Astrophysics Data System (ADS)

    van Dijk, Mike T.; van Wingerden, Jan-Willem; Ashuri, Turaj; Li, Yaoyu; Rotea, Mario A.

    2016-09-01

    To make wind energy cost competitive with traditional resources, wind turbines are commonly placed in groups. Aerodynamic interaction between the turbines causes sub-optimal energy production. A control strategy to mitigate these losses is by redirecting the wake by yaw misalignment. This paper aims to assess the influence of load variations of the rotor due to partial wake overlap and presents a combined optimization of the power and loads using wake redirection. For this purpose, we design a computational framework which computes the wind farm power production and the wind turbine rotor loads based on the yaw settings. The simulation results show that partial wake overlap can significantly increase asymmetric loading of the rotor disk and that yaw misalignment is beneficial in situations where the wake can be sufficiently directed away from the downstream turbine.

  2. Fouling assemblages on offshore wind power plants and adjacent substrata

    NASA Astrophysics Data System (ADS)

    Wilhelmsson, Dan; Malm, Torleif

    2008-09-01

    A significant expansion of offshore wind power is expected in the near future, with thousands of turbines in coastal waters, and various aspects of how this may influence the coastal ecology including disturbance effects from noise, shadows, electromagnetic fields, and changed hydrological conditions are accordingly of concern. Further, wind power plants constitute habitats for a number of organisms, and may locally alter assemblage composition and biomass of invertebrates, algae and fish. In this study, fouling assemblages on offshore wind turbines were compared to adjacent hard substrate. Influences of the structures on the seabed were also investigated. The turbines differed significantly from adjacent boulders in terms of assemblage composition of epibiota and motile invertebrates. Species number and Shannon-Wiener diversity were, also, significantly lower on the wind power plants. It was also indicated that the turbines might have affected assemblages of invertebrates and algae on adjacent boulders. Off shore wind power plant offer atypical substrates for fouling assemblages in terms of orientation, depth range, structure, and surface texture. Some potential ecological implications of the addition of these non-natural habitats for coastal ecology are discussed.

  3. Compensation for Harmonic Currents and Reactive Power in Wind Power Generation System using PWM Inverter

    NASA Astrophysics Data System (ADS)

    Shinohara, Katsuji; Shinhatsubo, Kurato; Iimori, Kenichi; Yamamoto, Kichiro; Saruban, Takamichi; Yamaemori, Takahiro

    In recent year, consciousness of environmental problems is enhancing, and the price of the electric power purchased by an electric power company is established expensive for the power plant utilizing the natural energy. So, the introduction of the wind power generation is promoted in Japan. Generally, squirrel-cage induction machines are widely used as a generator in wind power generation system because of its small size, lightweight and low-cost. However, the induction machines do not have a source of excitation. Thus, it causes the inrush currents and the instantaneous voltage drop when the generator is directly connected to a power grid. To reduce the inrush currents, an AC power regulator is used. Wind power generations are frequently connected to and disconnected from the power grid. However, when the inrush currents are reduced, harmonic currents are caused by phase control of the AC power regulator. And the phase control of AC power regulator cannot control the power factor. Therefore, we propose the use of the AC power regulator to compensate for the harmonic currents and reactive power in the wind power generation system, and demonstrate the validity of its system by simulated and experimental results.

  4. Key challenges of offshore wind power: Three essays addressing public acceptance, stakeholder conflict, and wildlife impacts

    NASA Astrophysics Data System (ADS)

    Bates, Alison Waterbury

    been proposed. The essay examines how the public considers the societal tradeoffs that are made to develop small-scale, in-view demonstration wind projects instead of larger facilities farther offshore. Results indicate that a strong majority of the public supports near-shore demonstration wind projects in both states. Primary reasons for support include benefits to wildlife, cost of electricity, and job creation, while the primary reasons for opposition include wildlife impacts, aesthetics, tourism, and user conflicts. These factors differ between coastal Delaware and greater Atlantic City and highlight the importance of local, community engagement in the early stages of development. The second essay examines the interaction of a new proposed use of the ocean---offshore wind---and a key existing ocean user group---commercial fishers. A key component of offshore wind planning includes consideration of existing uses of the marine environment in order to optimally site wind projects while minimizing conflicts. Commercial fisheries comprise an important stakeholder group, and may be one of the most impacted stakeholders from offshore renewable energy development. Concern of the fishing industry stems from possible interference with productive fishing grounds and access within wind developments resulting in costs from increased effort or reduction in catch. Success of offshore wind development may in part depend on the acceptance of commercial fishers, who are concerned about loss of access to fishing grounds. Using a quantitative, marine spatial planning approach in the siting of offshore wind projects with respect to commercial fishing in the mid-Atlantic, U.S., this essay develops a spatially explicit representation of potential conflicts and compatibilities between these two industries in the mid-Atlantic region of the United States. Areas that are highly valuable to the wind industry are determined through a spatial suitability model using variable cost per unit

  5. GPP Webinar: Market Outlook and Innovations in Wind and Solar Power

    EPA Pesticide Factsheets

    Green Power Partnership webinar reviewing the state of the renewable energy industry as a whole, with a focus on wind and solar power and exploring recent marketplace innovations in wind and solar power and renewable energy purchases.

  6. Proposition for the measurement of power characteristics of wind turbines

    NASA Astrophysics Data System (ADS)

    Kuik, W.

    1983-07-01

    A method to measure the power curve and the curve of the dimensionless power as a function of the high speed of a tip vane rotor with blades of a certain angle (Cp-lambda curve), was developed. The standardized bin method demands a 3 month measuring period, too long for tip vane design. From rough data the dispersion in torque direction was made small, so that mediation in wind velocity direction yields a good estimate of the wind velocity related to the torque. In experimental tip vane turbine measurements, a large part of the Cp-lambda curves were determined in 15 min.

  7. Catching a steady breeze: Putting wind power to work on electric utility systems

    SciTech Connect

    Brower, M.C.; Tennis, M.W.

    1995-03-01

    Wind energy can provide very low-cost, environmentally clean electricity generation. Below, we describe progress we have made in refining our understanding of wind resources in the Midwest, and some considerations regarding the reliability of wind power. Power suppliers interested in wind power should consider using similar approaches.

  8. Spatial and temporal distributions of U.S. winds and wind power at 80 m derived from measurements

    NASA Astrophysics Data System (ADS)

    Archer, Cristina L.; Jacobson, Mark Z.

    2003-05-01

    This is a study to quantify U.S. wind power at 80 m (the hub height of large wind turbines) and to investigate whether winds from a network of farms can provide a steady and reliable source of electric power. Data from 1327 surface stations and 87 soundings in the United States for the year 2000 were used. Several methods were tested to extrapolate 10-m wind measurements to 80 m. The most accurate, a least squares fit based on twice-a-day wind profiles from the soundings, resulted in 80-m wind speeds that are, on average, 1.3-1.7 m/s faster than those obtained from the most common methods previously used to obtain elevated data for U.S. wind power maps, a logarithmic law and a power law, both with constant coefficients. The results suggest that U.S. wind power at 80 m may be substantially greater than previously estimated. It was found that 24% of all stations (and 37% of all coastal/offshore stations) are characterized by mean annual speeds ≥6.9 m/s at 80 m, implying that the winds over possibly one quarter of the United States are strong enough to provide electric power at a direct cost equal to that of a new natural gas or coal power plant. The greatest previously uncharted reservoir of wind power in the continental United States is offshore and nearshore along the southeastern and southern coasts. When multiple wind sites are considered, the number of days with no wind power and the standard deviation of the wind speed, integrated across all sites, are substantially reduced in comparison with when one wind site is considered. Therefore a network of wind farms in locations with high annual mean wind speeds may provide a reliable and abundant source of electric power.

  9. Windmills: Ancestors of the wind power generation

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Russo, Flavio; Savino, Sergio

    2017-09-01

    A brief description of the windmills from the second millennium BC to the Renaissance is presented. This survey is a part of several studies conducted by the authors on technology in the ancient world. The windmills are the first motor, other than human muscles, and are the ancestors of the modern wind turbines. Some authors' virtual reconstructions of old windmills are also presented. The paper shows that the operating principle of many modern machines had already been conceived in the ancient times by using a technology that was more advanced than expected, but with two main differences, as follows: Similar tasks were accomplished by using much less energy; and the environmental impact was nil or very low. Modern designers should sometimes consider simplicity rather than the use of a large amount of energy.

  10. Windmills: Ancestors of the wind power generation

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Russo, Flavio; Savino, Sergio

    2016-12-01

    A brief description of the windmills from the second millennium BC to the Renaissance is presented. This survey is a part of several studies conducted by the authors on technology in the ancient world. The windmills are the first motor, other than human muscles, and are the ancestors of the modern wind turbines. Some authors' virtual reconstructions of old windmills are also presented. The paper shows that the operating principle of many modern machines had already been conceived in the ancient times by using a technology that was more advanced than expected, but with two main differences, as follows: Similar tasks were accomplished by using much less energy; and the environmental impact was nil or very low. Modern designers should sometimes consider simplicity rather than the use of a large amount of energy.

  11. Unit commitment with wind power generation: integrating wind forecast uncertainty and stochastic programming.

    SciTech Connect

    Constantinescu, E. M.; Zavala, V. M.; Rocklin, M.; Lee, S.; Anitescu, M.

    2009-10-09

    We present a computational framework for integrating the state-of-the-art Weather Research and Forecasting (WRF) model in stochastic unit commitment/energy dispatch formulations that account for wind power uncertainty. We first enhance the WRF model with adjoint sensitivity analysis capabilities and a sampling technique implemented in a distributed-memory parallel computing architecture. We use these capabilities through an ensemble approach to model the uncertainty of the forecast errors. The wind power realizations are exploited through a closed-loop stochastic unit commitment/energy dispatch formulation. We discuss computational issues arising in the implementation of the framework. In addition, we validate the framework using real wind speed data obtained from a set of meteorological stations. We also build a simulated power system to demonstrate the developments.

  12. Wind power as an electrical energy source in Illinois

    NASA Astrophysics Data System (ADS)

    Wendland, W. M.

    1982-03-01

    A preliminary estimate of the total wind power available in Illinois was made using available historical data, and projections of cost savings due to the presence of wind-generated electricity were attempted. Wind data at 10 m height were considered from nine different sites in the state, with three years data nominally being included. Wind-speed frequency histograms were developed for day and night periods, using a power law function to extrapolate the 10 m readings to 20 m. Wind speeds over the whole state were found to average over 8 mph, the cut-in point for most wind turbines, for from 40-63% of the time. A maximum of 75% run-time was determined for daylight hours in April-May. A reference 1.8 kW windpowered generator was used in annual demand projections for a reference one family home, using the frequency histograms. The small generator was projected to fulfill from 25-53% of the annual load, and, based on various cost assumptions, exhibited paybacks taking from 14-27 yr.

  13. Using Bayes Model Averaging for Wind Power Forecasts

    NASA Astrophysics Data System (ADS)

    Preede Revheim, Pål; Beyer, Hans Georg

    2014-05-01

    For operational purposes predictions of the forecasts of the lumped output of groups of wind farms spread over larger geographic areas will often be of interest. A naive approach is to make forecasts for each individual site and sum them up to get the group forecast. It is however well documented that a better choice is to use a model that also takes advantage of spatial smoothing effects. It might however be the case that some sites tends to more accurately reflect the total output of the region, either in general or for certain wind directions. It will then be of interest giving these a greater influence over the group forecast. Bayesian model averaging (BMA) is a statistical post-processing method for producing probabilistic forecasts from ensembles. Raftery et al. [1] show how BMA can be used for statistical post processing of forecast ensembles, producing PDFs of future weather quantities. The BMA predictive PDF of a future weather quantity is a weighted average of the ensemble members' PDFs, where the weights can be interpreted as posterior probabilities and reflect the ensemble members' contribution to overall forecasting skill over a training period. In Revheim and Beyer [2] the BMA procedure used in Sloughter, Gneiting and Raftery [3] were found to produce fairly accurate PDFs for the future mean wind speed of a group of sites from the single sites wind speeds. However, when the procedure was attempted applied to wind power it resulted in either problems with the estimation of the parameters (mainly caused by longer consecutive periods of no power production) or severe underestimation (mainly caused by problems with reflecting the power curve). In this paper the problems that arose when applying BMA to wind power forecasting is met through two strategies. First, the BMA procedure is run with a combination of single site wind speeds and single site wind power production as input. This solves the problem with longer consecutive periods where the input data

  14. Water-supported wind actuated power generating assembly

    SciTech Connect

    Hoar, R.A.

    1982-02-23

    A counterweighted elongate buoyant body that floats on the surface of the sea or a lake has at least one sail supporting mast extending upwardly therefrom as well as vanes that tend to maintain the sails substantially normal to the direction of movement of the wind. The buoyant body is by frame means maintained within the confines of a circular series of piles. The counterweight and means for pivoting each sail from a position normal to the direction of the wind to substantially parallel thereto cooperate to impart a transverse rocking motion to the buoyant body that has an eccentric transverse arcuate member depending therefrom that is engaged by a pair of rollers, as the transverse member moves relative to the pair of rollers a bellows is receprocated upwardly and downwardly to draw water into and discharge it from a check valve controlled confined space to a reservoir situated at a substantial distance above the surface of the body of water. Water discharges by gravity from the reservoir to a turbine or the like to power a generator to produce electricity for power purposes. Power means pivot the sails substantially parallel to the direction of the wind after the latter has rolled the buoyant body to a first position. The counterweight then rolls the buoyant body to a second position where upon the power means pivot the sails to positions substantially normal to the direction of the wind to start another power generating cycle.

  15. Air emissions due to wind and solar power.

    PubMed

    Katzenstein, Warren; Apt, Jay

    2009-01-15

    Renewables portfolio standards (RPS) encourage large-scale deployment of wind and solar electric power. Their power output varies rapidly, even when several sites are added together. In many locations, natural gas generators are the lowest cost resource available to compensate for this variability, and must ramp up and down quickly to keep the grid stable, affecting their emissions of NOx and CO2. We model a wind or solar photovoltaic plus gas system using measured 1-min time-resolved emissions and heat rate data from two types of natural gas generators, and power data from four wind plants and one solar plant. Over a wide range of renewable penetration, we find CO2 emissions achieve approximately 80% of the emissions reductions expected if the power fluctuations caused no additional emissions. Using steam injection, gas generators achieve only 30-50% of expected NOx emissions reductions, and with dry control NOx emissions increase substantially. We quantify the interaction between state RPSs and NOx constraints, finding that states with substantial RPSs could see significant upward pressure on NOx permit prices, if the gas turbines we modeled are representative of the plants used to mitigate wind and solar power variability.

  16. Power Control of New Wind Power Generation System with Induction Generator Excited by Voltage Source Converter

    NASA Astrophysics Data System (ADS)

    Morizane, Toshimitsu; Kimura, Noriyuki; Taniguchi, Katsunori

    This paper investigates advantages of new combination of the induction generator for wind power and the power electronic equipment. Induction generator is popularly used for the wind power generation. The disadvantage of it is impossible to generate power at the lower rotor speed than the synchronous speed. To compensate this disadvantage, expensive synchronous generator with the permanent magnets is sometimes used. In proposed scheme, the diode rectifier is used to convert the real power from the induction generator to the intermediate dc voltage, while only the reactive power necessary to excite the induction generator is supplied from the voltage source converter (VSC). This means that the rating of the expensive VSC is minimized and total cost of the wind power generation system is decreased compared to the system with synchronous generator. Simulation study to investigate the control strategy of proposed system is performed. The results show the reduction of the VSC rating is prospective.

  17. Short term fluctuations of wind and solar power systems

    NASA Astrophysics Data System (ADS)

    Anvari, M.; Lohmann, G.; Wächter, M.; Milan, P.; Lorenz, E.; Heinemann, D.; Rahimi Tabar, M. Reza; Peinke, Joachim

    2016-06-01

    Wind and solar power are known to be highly influenced by weather events and may ramp up or down abruptly. Such events in the power production influence not only the availability of energy, but also the stability of the entire power grid. By analysing significant amounts of data from several regions around the world with resolutions of seconds to minutes, we provide strong evidence that renewable wind and solar sources exhibit multiple types of variability and nonlinearity in the time scale of seconds and characterise their stochastic properties. In contrast to previous findings, we show that only the jumpy characteristic of renewable sources decreases when increasing the spatial size over which the renewable energies are harvested. Otherwise, the strong non-Gaussian, intermittent behaviour in the cumulative power of the total field survives even for a country-wide distribution of the systems. The strong fluctuating behaviour of renewable wind and solar sources can be well characterised by Kolmogorov-like power spectra and q-exponential probability density functions. Using the estimated potential shape of power time series, we quantify the jumpy or diffusive dynamic of the power. Finally we propose a time delayed feedback technique as a control algorithm to suppress the observed short term non-Gaussian statistics in spatially strong correlated and intermittent renewable sources.

  18. On the effect of spatial dispersion of wind power plants on the wind energy capacity credit in Greece

    NASA Astrophysics Data System (ADS)

    Caralis, George; Perivolaris, Yiannis; Rados, Konstantinos; Zervos, Arthouros

    2008-01-01

    Wind energy is now a mature technology and can be considered as a significant contributor in reducing CO2 emissions and protecting the environment. To meet the wind energy national targets, effective implementation of massive wind power installed capacity in the power supply system is required. Additionally, capacity credit is an important issue for an unstable power supply system as in Greece. To achieve high and reliable wind energy penetration levels into the system, the effect of spatial dispersion of wind energy installations within a very wide area (e.g. national level) on the power capacity credit should be accounted for. In the present paper, a methodology for estimating the effect of spatial dispersion of wind farm installations on the capacity credit is presented and applied for the power supply system of Greece. The method is based on probability theory and makes use of wind forecasting models to represent the wind energy potential over any candidate area for future wind farm installations in the country. Representative wind power development scenarios are studied and evaluated. Results show that the spatial dispersion of wind power plants contributes beneficially to the wind capacity credit.

  19. An optimal sizing method for energy storage system in wind farms based on the analysis of wind power forecast error

    NASA Astrophysics Data System (ADS)

    Ye, R. L.; Guo, Z. Z.; Liu, R. Y.; Liu, J. N.

    2016-11-01

    Energy storage system (ESS) in a wind farm can effectively compensate the fluctuations of wind power. How to determine the size of ESS in wind farms is an urgent problem to be solved. A novel method is proposed for designing the optimal size of ESS considering wind power uncertainty. This approach uses non-parametric estimation method to analysis the wind power forecast error (WPFE) and the cumulative wind power deviation (CWPD) within the scheduling period. Then a cost-benefit analysis model is established to obtain the optimal size of ESS based on the analysis of WPFE and CWPD. A series of wind farm data in California are used as numerical cases, which presents that the algorithm presented in this paper has good feasibility and performance in optimal ESS sizing in wind farms.

  20. Development and testing of improved statistical wind power forecasting methods.

    SciTech Connect

    Mendes, J.; Bessa, R.J.; Keko, H.; Sumaili, J.; Miranda, V.; Ferreira, C.; Gama, J.; Botterud, A.; Zhou, Z.; Wang, J.

    2011-12-06

    Wind power forecasting (WPF) provides important inputs to power system operators and electricity market participants. It is therefore not surprising that WPF has attracted increasing interest within the electric power industry. In this report, we document our research on improving statistical WPF algorithms for point, uncertainty, and ramp forecasting. Below, we provide a brief introduction to the research presented in the following chapters. For a detailed overview of the state-of-the-art in wind power forecasting, we refer to [1]. Our related work on the application of WPF in operational decisions is documented in [2]. Point forecasts of wind power are highly dependent on the training criteria used in the statistical algorithms that are used to convert weather forecasts and observational data to a power forecast. In Chapter 2, we explore the application of information theoretic learning (ITL) as opposed to the classical minimum square error (MSE) criterion for point forecasting. In contrast to the MSE criterion, ITL criteria do not assume a Gaussian distribution of the forecasting errors. We investigate to what extent ITL criteria yield better results. In addition, we analyze time-adaptive training algorithms and how they enable WPF algorithms to cope with non-stationary data and, thus, to adapt to new situations without requiring additional offline training of the model. We test the new point forecasting algorithms on two wind farms located in the U.S. Midwest. Although there have been advancements in deterministic WPF, a single-valued forecast cannot provide information on the dispersion of observations around the predicted value. We argue that it is essential to generate, together with (or as an alternative to) point forecasts, a representation of the wind power uncertainty. Wind power uncertainty representation can take the form of probabilistic forecasts (e.g., probability density function, quantiles), risk indices (e.g., prediction risk index) or scenarios

  1. Effect of accuracy of wind power prediction on power system operator

    NASA Astrophysics Data System (ADS)

    Schlueter, R. A.; Sigari, G.; Costi, T.

    1985-06-01

    This research project proposed a modified unit commitment that schedules connection and disconnection of generating units in response to load. A modified generation control is also proposed that controls steam units under automatic generation control, fast responding diesels, gas turbines and hydro units under a feedforward control, and wind turbine array output under a closed loop array control. This modified generation control and unit commitment require prediction of trend wind power variation one hour ahead and the prediction of error in this trend wind power prediction one half hour ahead. An improved meter for predicting trend wind speed variation is developed. Methods for accurately simulating the wind array power from a limited number of wind speed prediction records was developed. Finally, two methods for predicting the error in the trend wind power prediction were developed. This research provides a foundation for testing and evaluating the modified unit commitment and generation control that was developed to maintain operating reliability at a greatly reduced overall production cost for utilities with wind generation capacity.

  2. Effect of accuracy of wind power prediction on power system operator

    NASA Technical Reports Server (NTRS)

    Schlueter, R. A.; Sigari, G.; Costi, T.

    1985-01-01

    This research project proposed a modified unit commitment that schedules connection and disconnection of generating units in response to load. A modified generation control is also proposed that controls steam units under automatic generation control, fast responding diesels, gas turbines and hydro units under a feedforward control, and wind turbine array output under a closed loop array control. This modified generation control and unit commitment require prediction of trend wind power variation one hour ahead and the prediction of error in this trend wind power prediction one half hour ahead. An improved meter for predicting trend wind speed variation is developed. Methods for accurately simulating the wind array power from a limited number of wind speed prediction records was developed. Finally, two methods for predicting the error in the trend wind power prediction were developed. This research provides a foundation for testing and evaluating the modified unit commitment and generation control that was developed to maintain operating reliability at a greatly reduced overall production cost for utilities with wind generation capacity.

  3. Small scale geothermal development strategy framework

    SciTech Connect

    Ciptomulyono, U.

    1995-12-31

    With request to the promotion for diversification of energy resources geothermal energy is an alternative energy, renewable, relatively clean and nonexportable resource; the maximum utilization of these resources therefore has a first priority as Indonesia is one of the world prominent volcanics countries with many active volcanic phenomena. Most of the geothermal prospects are located in rural areas, which have limited small diesel generating plants or no electricity at all; under the energy sector policy of the Government of Indonesia which stressed rural electrification, taking into account the equity of development for ail Indonesia`s regions and with the goal of National benefits. To ensure that small scale geothermal power plants for rural electrification can be implemented most effectively and efficiently, a strategy framework needs to include appropriate arrangement for project planning; from scientific study to construction periods, which are currently a constraint on both cost and time domains. This paper discusses the strategy framework approaches, including a possible combining of a serial plural activities and streamlining of contract packages. Indonesia as a country which is made up more than 16,000 islands of varying sizes, located between 6{degrees} N-11{degrees} S Lat and 95{degrees}-141{degrees} E Long. The Government of Indonesia stresses a guideline for the energy policy, namely: intensification on the survey and exploration of resources; diversification of energy by means of reducing oil depency utilization and promoting through development, utilization and customary use of substitute fuels; conservation of natural resources with goals to economize and efficiently use energy utilization; and indexation of each energy need with the most appropriate energy resources available in the country.

  4. Estimation of power in low velocity vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Sampath, S. S.; Shetty, Sawan; Chithirai Pon Selvan, M.

    2015-06-01

    The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical components of the entire setup are built to obtain maximum rotation per minute. The mechanical energy is converted into the electrical energy by coupling coaxially between the shaft and the generator. This setup produces sufficient power for consumption of household purposes which is economic and easily available.

  5. Control of wind turbine generators connected to power systems

    NASA Technical Reports Server (NTRS)

    Hwang, H. H.; Mozeico, H. V.; Gilbert, L. J.

    1978-01-01

    A unique simulation model based on a Mode-O wind turbine is developed for simulating both speed and power control. An analytical representation for a wind turbine that employs blade pitch angle feedback control is presented, and a mathematical model is formulated. For Mode-O serving as a practical case study, results of a computer simulation of the model as applied to the problems of synchronization and dynamic stability are provided. It is shown that the speed and output of a wind turbine can be satisfactorily controlled within reasonable limits by employing the existing blade pitch control system under specified conditions. For power control, an additional excitation control is required so that the terminal voltage, output power factor, and armature current can be held within narrow limits. As a result, the variation of torque angle is limited even if speed control is not implemented simultaneously with power control. Design features of the ERDA/NASA 100-kW Mode-O wind turbine are included.

  6. Wind Power Project Repowering: History, Economics, and Demand (Presentation)

    SciTech Connect

    Lantz, E.

    2015-01-01

    This presentation summarizes a related NREL technical report and seeks to capture the current status of wind power project repowering in the U.S. and globally, analyze the economic and financial decision drivers that surround repowering, and to quantify the level and timing of demand for new turbine equipment to supply the repowering market.

  7. Control of wind turbine generators connected to power systems

    NASA Technical Reports Server (NTRS)

    Hwang, H. H.; Mozeico, H. V.; Gilbert, L. J.

    1978-01-01

    A unique simulation model based on a Mode-O wind turbine is developed for simulating both speed and power control. An analytical representation for a wind turbine that employs blade pitch angle feedback control is presented, and a mathematical model is formulated. For Mode-O serving as a practical case study, results of a computer simulation of the model as applied to the problems of synchronization and dynamic stability are provided. It is shown that the speed and output of a wind turbine can be satisfactorily controlled within reasonable limits by employing the existing blade pitch control system under specified conditions. For power control, an additional excitation control is required so that the terminal voltage, output power factor, and armature current can be held within narrow limits. As a result, the variation of torque angle is limited even if speed control is not implemented simultaneously with power control. Design features of the ERDA/NASA 100-kW Mode-O wind turbine are included.

  8. Examination of Capacity and Ramping Impacts of Wind Energy on Power Systems

    SciTech Connect

    Kirby, B.; Milligan, M.

    2008-07-01

    When wind plants serve load within the balancing area, no additional capacity required to integrate wind power into the system. We present some thought experiments to illustrate some implications for wind integration studies.

  9. Overview of the Testing of a Small-Scale Proprotor

    NASA Technical Reports Server (NTRS)

    Young, Larry A.; Yamauchi, Gloria K.; Booth, Earl R., Jr.; Botha, Gavin; Dawson, Seth

    1999-01-01

    This paper presents an overview of results from the wind tunnel test of a 1/4-scale V-22 proprotor in the Duits-Nederlandse Windtunnel (DNW) in The Netherlands. The small-scale proprotor was tested on the isolated rotor configuration of the Tilt Rotor Aeroacoustic Model (TRAM). The test was conducted by a joint team from NASA Ames, NASA Langley, U.S. Army Aeroflightdynamics Directorate, and The Boeing Company. The objective of the test was to acquire a benchmark database for validating aeroacoustic analyses. Representative examples of airloads, acoustics, structural loads, and performance data are provided and discussed.

  10. Small-scale physics of the ocean

    NASA Technical Reports Server (NTRS)

    Caldwell, D. R.

    1983-01-01

    Progress in research on the small-scale physics of the ocean is reviewed. The contribution of such research to the understanding of the large scales is addressed and compared for various depth ranges of the ocean. The traditional framework for discussing small-scale measurements and turbulence is outlined, and recent research in the area is reviewed, citing references. Evidence for the existence of salt fingering in oceanic mixing is discussed. Factors that might inhibit the growth of salt fingers are assessed, and the influence of differences between laboratory tank and ocean in studying the fingers is discussed. The role of salt fingers in creating intrusions is examined. Instruments and methods used to measure the smallest scales at which there is appreciable variation and the stability of the patch of ocean in which the small-scale motions take place are considered.

  11. The Phenomenology of Small-Scale Turbulence

    NASA Astrophysics Data System (ADS)

    Sreenivasan, K. R.; Antonia, R. A.

    I have sometimes thought that what makes a man's work classic is often just this multiplicity [of interpretations], which invites and at the same time resists our craving for a clear understanding. Wright (1982, p. 34), on Wittgenstein's philosophy Small-scale turbulence has been an area of especially active research in the recent past, and several useful research directions have been pursued. Here, we selectively review this work. The emphasis is on scaling phenomenology and kinematics of small-scale structure. After providing a brief introduction to the classical notions of universality due to Kolmogorov and others, we survey the existing work on intermittency, refined similarity hypotheses, anomalous scaling exponents, derivative statistics, intermittency models, and the structure and kinematics of small-scale structure - the latter aspect coming largely from the direct numerical simulation of homogeneous turbulence in a periodic box.

  12. Grid-scale fluctuations and forecast error in wind power

    NASA Astrophysics Data System (ADS)

    Bel, G.; Connaughton, C. P.; Toots, M.; Bandi, M. M.

    2016-02-01

    Wind power fluctuations at the turbine and farm scales are generally not expected to be correlated over large distances. When power from distributed farms feeds the electrical grid, fluctuations from various farms are expected to smooth out. Using data from the Irish grid as a representative example, we analyze wind power fluctuations entering an electrical grid. We find that not only are grid-scale fluctuations temporally correlated up to a day, but they possess a self-similar structure—a signature of long-range correlations in atmospheric turbulence affecting wind power. Using the statistical structure of temporal correlations in fluctuations for generated and forecast power time series, we quantify two types of forecast error: a timescale error ({e}τ ) that quantifies deviations between the high frequency components of the forecast and generated time series, and a scaling error ({e}\\zeta ) that quantifies the degree to which the models fail to predict temporal correlations in the fluctuations for generated power. With no a priori knowledge of the forecast models, we suggest a simple memory kernel that reduces both the timescale error ({e}τ ) and the scaling error ({e}\\zeta ).

  13. Wind turbine power curve prediction with consideration of rotational augmentation effects

    NASA Astrophysics Data System (ADS)

    Tang, X.; Huang, X.; Sun, S.; Peng, R.

    2016-11-01

    Wind turbine power curve expresses the relationship between the rotor power and the hub wind speed. Wind turbine power curve prediction is of vital importance for power control and wind energy management. To predict power curve, the Blade Element Moment (BEM) method is used in both academic and industrial communities. Due to the limited range of angles of attack measured in wind tunnel testing and the three-dimensional (3D) rotational augmentation effects in rotating turbines, wind turbine power curve prediction remains a challenge especially at high wind speeds. This paper presents an investigation of considering the rotational augmentation effects using characterized lift and drag coefficients from 3D computational fluid dynamics (CFD) simulations coupled in the BEM method. A Matlab code was developed to implement the numerical calculation. The predicted power outputs were compared with the NREL Phase VI wind turbine measurements. The results demonstrate that the coupled method improves the wind turbine power curve prediction.

  14. Geologic utility of small-scale airphotos

    NASA Technical Reports Server (NTRS)

    Clark, M. M.

    1969-01-01

    The geologic value of small scale airphotos is emphasized by describing the application of high altitude oblique and 1:120,000 to 1:145,000 scale vertical airphotos to several geologic problems in California. These examples show that small-scale airphotos can be of use to geologists in the following ways: (1) high altitude, high oblique airphotos show vast areas in one view; and (2) vertical airphotos offer the most efficient method of discovering the major topographic features and structural and lithologic characteristics of terrain.

  15. Wind Farm Monitoring at Storm Lake I Wind Power Project -- Equipment Only: Cooperative Research and Development Final Report, CRADA Number CRD-10-369

    SciTech Connect

    Gevorgian, Vahan

    2015-07-09

    Long-term, high-resolution wind turbine and wind power plant output data are important to assess the impact of wind power on grid operations and to derive meaningful statistics for better understanding of the variability of wind power. These data are used for many research and analysis activities consistent with the Wind Program mission.

  16. Wind power forecasting for a real onshore wind farm on complex terrain using WRF high resolution simulations.

    NASA Astrophysics Data System (ADS)

    Ángel Prósper Fernández, Miguel; Casal, Carlos Otero; Canoura Fernández, Felipe; Miguez-Macho, Gonzalo

    2017-04-01

    Regional meteorological models are becoming a generalized tool for forecasting wind resource, due to their capacity to simulate local flow dynamics impacting wind farm production. This study focuses on the production forecast and validation of a real onshore wind farm using high horizontal and vertical resolution WRF (Weather Research and Forecasting) model simulations. The wind farm is located in Galicia, in the northwest of Spain, in a complex terrain region with high wind resource. Utilizing the Fitch scheme, specific for wind farms, a period of one year is simulated with a daily operational forecasting set-up. Power and wind predictions are obtained and compared with real data provided by the management company. Results show that WRF is able to yield good wind power operational predictions for this kind of wind farms, due to a good representation of the planetary boundary layer behaviour of the region and the good performance of the Fitch scheme under these conditions.

  17. Research on unit commitment with large-scale wind power connected power system

    NASA Astrophysics Data System (ADS)

    Jiao, Ran; Zhang, Baoqun; Chi, Zhongjun; Gong, Cheng; Ma, Longfei; Yang, Bing

    2017-01-01

    Large-scale integration of wind power generators into power grid brings severe challenges to power system economic dispatch due to its stochastic volatility. Unit commitment including wind farm is analyzed from the two parts of modeling and solving methods. The structures and characteristics can be summarized after classification has been done according to different objective function and constraints. Finally, the issues to be solved and possible directions of research and development in the future are discussed, which can adapt to the requirements of the electricity market, energy-saving power generation dispatching and smart grid, even providing reference for research and practice of researchers and workers in this field.

  18. A Magnetar Wind Nebula: the Spin-down-Powered Wind is not Enough

    NASA Astrophysics Data System (ADS)

    Gill, Ramandeep; Granot, Jonathan; Baring, Matthew G.; Gelfand, Joseph; Younes, George A.; Kargaltsev, Oleg; Kust Harding, Alice; Kouveliotou, Chryssa; Huppenkothen, Daniela

    2016-04-01

    Magnetars are a small class of slowly-rotating (P~2-12 s) highly magnetized (surface dipole fields ~10^{14}-10^{15} G) that show a variety of bursting activity, powered by the decay of their super-strong magnetic field. While many rotation-powered pulsars are surrounded by a pulsar wind nebula (PWN) powered by their spin-down MHD wind (the prime example being the Crab nebula), only now has the first magnetar wind nebula (MWN) been discovered in X-rays, around Swift J1834.9-0846. We have analyzed this system in detail to see what can be learned from it. We find good evidence that unlike normal PWNe, this MWN cannot be powered by its spin-down MHD wind alone. A considerable contribution to the MWN energy should come from a different source, most likely sporadic outflows associated with the magnetar's bursting activity. This suggests that the MWN may serve as a calorimeter, and provide a new and robust estimate for the magnetar's long-term mean energy output rate in outflows. We also discuss other interesting aspects of this system.

  19. Network Wind Power Over the Pacific Northwest. Progress Report, October 1979-September 1980.

    SciTech Connect

    Baker, Robert W.; Hewson, E. Wendell

    1980-10-01

    The research in FY80 is composed of six primary tasks. These tasks include data collection and analysis, wind flow studies around an operational wind turbine generator (WTG), kite anemometer calibration, wind flow analysis and prediction, the Klickitat County small wind energy conversion system (SWECS) program, and network wind power analysis. The data collection and analysis task consists of four sections, three of which deal with wind flow site surveys and the fourth with collecting and analyzing wind data from existing data stations. This report also includes an appendix which contains mean monthly wind speed data summaries, wind spectrum summaries, time series analysis plots, and high wind summaries.

  20. Analysis of powerful local acceleration of solar wind particles

    NASA Astrophysics Data System (ADS)

    Molotkov, I. A.; Ryabova, N. A.

    2017-07-01

    Collisionless plasma of the solar wind is considered. A number of physical processes in this plasma lead to the formation of magnetic islands that are potential traps for charged particles. The merging and contractions of magnetic islands cause a powerful acceleration of these particles to energies over 1 MeV. This work continues the study in recent years on modeling of the acceleration of charged particles of the solar wind. Our analytical solution of the transport equations allowed us to find the exact number of particles with energies exceeding given level.