Science.gov

Sample records for active geothermal systems

  1. Geothermal systems

    NASA Technical Reports Server (NTRS)

    Mohl, C.

    1978-01-01

    Several tasks of JPL related to geothermal energy are discussed. The major task is the procurement and test and evaluation of a helical screw drive (wellhead unit). A general review of geothermal energy systems is given. The presentation focuses attention on geothermal reservoirs in California, with graphs and charts to support the discussion. Included are discussions on cost analysis, systems maintenance, and a comparison of geothermal and conventional heating and cooling systems.

  2. Gold enrichment in active geothermal systems by accumulating colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Hannington, Mark; Harðardóttir, Vigdis; Garbe-Schönberg, Dieter; Brown, Kevin L.

    2016-04-01

    The origins of high-grade hydrothermal ore deposits are debated, but active geothermal systems provide important clues to their formation. The highest concentrations of gold are found in geothermal systems with direct links to island arc magmatism. Yet, similar concentrations have also been found in the absence of any input from arc magmas, for example, in the Reykjanes geothermal field, Iceland. Here we analyse brine samples taken from deep wells at Reykjanes and find that gold concentrations in the reservoir zone have increased over the past seven years from an average of 3 ppb to 14 ppb. The metal concentrations greatly exceed the maximum solubility of gold in the reservoir under saturated conditions and are now nearly two orders of magnitude higher than in mid-ocean ridge black smoker fluids--the direct analogues of Reykjanes deep liquids. We suggest that ongoing extraction of brine, the resulting pressure drop, and increased boiling have caused gold to drop out of solution and become trapped in the reservoir as a colloidal suspension. This process may explain how the stock of metal in the reservoirs of fossil geothermal systems could have increased over time and thus become available for the formation of gold-rich ore deposits.

  3. Calc-silicate mineralization in active geothermal systems

    SciTech Connect

    Bird, D.K.; Schiffman, P.; Elders, W.A.; Williams, A.E.; McDowell, S.D.

    1983-01-01

    The detailed study of calc-silicate mineral zones and coexisting phase relations in the Cerro Prieto geothermal system were used as examples for thermodynamic evaluation of phase relations among minerals of variable composition and to calculate the chemical characteristics of hydrothermal solutions compatible with the observed calc-silicate assemblages. In general there is a close correlation between calculated and observed fluid compositions. Calculated fugacities of O{sub 2} at about 320{degrees}C in the Cerro Prieto geothermal system are about five orders of magnitude less than that at the nearby Salton Sea geothermal system. This observation is consistent with the occurrence of Fe{sup 3+} rich epidotes in the latter system and the presence of prehnite at Cerro Prieto.

  4. National Geothermal Data System

    NASA Astrophysics Data System (ADS)

    Anderson, A. F.; Cuyler, D.; Snyder, W. S.; Allison, M. L.; Blackwell, D. D.; Williams, C. F.

    2011-12-01

    The goal of the U.S. Department of Energy's National Geothermal Data System is to design, build, implement, deploy and populate a national, sustainable, distributed, interoperable network of data and service (application) providers. These providers will develop, collect, serve, and maintain geothermal-relevant data that operates as an integral component of NGDS. As a result the geothermal industry, the public, and policy makers will have access to consistent and reliable data, which in turn, reduces the amount of staff time devoted to finding, retrieving, integrating, and verifying information. With easier access to information, the high cost and risk of geothermal power projects (especially exploration drilling) is reduced. Five separate NGDS projects provide the data support, acquisition, and access to cyber infrastructure necessary to reduce cost and risk of the nation's geothermal energy strategy and US DOE program goals focused on the production and utilization of geothermal energy. The U.S DOE Office of Energy Efficiency and Renewable Energy Geothermal Technologies Program is developing the knowledge and data foundation necessary for discovery and development of large-scale energy production while the Buildings Technology Program is focused on other practical applications such as direct use and residential/commercial ground source heat pumps. The NGDS provides expanded reference and resource data for research and development activities (a subset of the US DOE goals) and includes data from across all fifty states and the nation's leading academic geothermal centers. Thus, the project incorporates not only high-temperature potential but also moderate and low-temperature locations incorporating US DOE's goal of adding more geothermal electricity to the grid. The program, through its development of data integration cyberinfrastructure, will help lead to innovative exploration technologies through increased data availability on geothermal energy capacity. Finally

  5. Sensitivity of predicted scaling and permeability in Enhanced Geothermal Systems to Thermodynamic Data and Activity Models

    NASA Astrophysics Data System (ADS)

    Hingerl, Ferdinand F.; Wagner, Thomas; Kulik, Dmitrii A.; Kosakowski, Georg; Driesner, Thomas; Thomsen, Kaj

    2010-05-01

    A consortium of research groups from ETH Zurich, EPF Lausanne, the Paul Scherrer Institut and the University of Bonn collaborates in a comprehensive program of basic research on key aspects of the Enhanced Geothermal Systems (EGSs). As part of this GEOTHERM project (www.geotherm.ethz.ch), we concentrate on the fundamental investigation of thermodynamic models suitable for describing fluid-rock interactions at geothermal conditions. Predictions of the fluid-rock interaction in EGS still face several major challenges. Slight variations in the input thermodynamic and kinetic parameters may result in significant differences in the predicted mineral solubilities and stable assemblage. Realistic modeling of mineral precipitation in turn has implications onto our understanding of the permeability evolution of the geothermal reservoir, as well as the scaling in technical installations. In order to reasonably model an EGS, thermodynamic databases and activity models must be tailored to geothermal conditions. We therefore implemented in GEMS code the Pitzer formalism, which is the standard model used for computing thermodynamic excess properties of brines at elevated temperatures and pressures. This model, however, depends on a vast amount of interaction parameters, which are to a substantial extend unknown. Furthermore, a high order polynomial temperature interpolation makes extrapolation unreliable if not impossible. As an alternative we additionally implemented the EUNIQUAC activity model. EUNIQUAC requires fewer empirical fit parameters (only binary interaction parameters needed) and uses simpler and more stable temperature and pressure extrapolations. This results in an increase in computation speed, which is of crucial importance when performing coupled long term simulations of geothermal reservoirs. To achieve better performance under geothermal conditions, we are currently partly reformulating EUNIQUAC and refitting the existing parameter set. First results of the

  6. Hydrothermal mineralogy and fluid inclusions chemistry to understand the roots of active geothermal systems

    NASA Astrophysics Data System (ADS)

    Chambefort, I. S.; Dilles, J. H.; Heinrich, C.

    2013-12-01

    An integrated study to link magmatic textures, magmatic mineral compositions, hydrothermal alteration zoning, hydrothermal mineral chemistry, and fluid inclusion compositions has been undertaken to link an intrusive complex and its degassing alteration halo with their surface equivalent in an active geothermal system. Ngatamariki geothermal system, New Zealand, presents a unique feature in the Taupo Volcanic Zone (TVZ). Drilling intercepted an intrusive complex with a high temperature alteration halo similarly to what is observed in magmatic-derived ore deposits. Thus it presents the perfect opportunity to study the magmatic-hydrothermal transition of the TVZ by characterizing the nature of the deep magmatic fluids link to the heat source of the world known geothermal fields. The record of magmatic-hydrothermal fluid-rock interactions preserved at Ngatamariki may be analogous of processes presently occurring at depth beneath TVZ geothermal systems. The intrusive complex consists of over 5 km3 of tonalite, diorite, basalt and aplitic dykes. Evidence of undercooling subsolidus magmatic textures such as myrmekite and skeletal overgrowth are commonly observed and often linked to volatile loss. The fluids released during the crystallization of the intrusive complex are interpreted to be at the origin of the surrounding high temperature alteration halo. Advanced argillic to potassic alteration and high temperature acidic assemblage is associated with high-temperature quartz veining at depth and vuggy silica at the paleo-surface. Major element compositions of the white micas associated with the high temperature halo show a transition from, muscovite to phengite, muscovitic illite away from the intrusion, with a transition to pyrophyllite and/ or topaz, and andalusite characteristic of more acidic conditions. Abundant high-density (up to 59 wt% NaCl eq and homogenization temperatures of 550 degree Celsius and above) coexist with low-density vapor fluid inclusions. This

  7. Origin and Distribution of Thiophenes and Furans in Gas Discharges from Active Volcanoes and Geothermal Systems

    PubMed Central

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-01-01

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C4H8O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection. PMID:20480029

  8. Geotherm: the U.S. geological survey geothermal information system

    USGS Publications Warehouse

    Bliss, J.D.; Rapport, A.

    1983-01-01

    GEOTHERM is a comprehensive system of public databases and software used to store, locate, and evaluate information on the geology, geochemistry, and hydrology of geothermal systems. Three main databases address the general characteristics of geothermal wells and fields, and the chemical properties of geothermal fluids; the last database is currently the most active. System tasks are divided into four areas: (1) data acquisition and entry, involving data entry via word processors and magnetic tape; (2) quality assurance, including the criteria and standards handbook and front-end data-screening programs; (3) operation, involving database backups and information extraction; and (4) user assistance, preparation of such items as application programs, and a quarterly newsletter. The principal task of GEOTHERM is to provide information and research support for the conduct of national geothermal-resource assessments. The principal users of GEOTHERM are those involved with the Geothermal Research Program of the U.S. Geological Survey. Information in the system is available to the public on request. ?? 1983.

  9. Geotherm: the U.S. geological survey geothermal information system

    NASA Astrophysics Data System (ADS)

    Bliss, J. D.; Rapport, A.

    GEOTHERM is a comprehensive system of public databases and software used to store, locate, and evaluate information on the geology, geochemistry, and hydrology of geothermal systems. Three main databases address the general characteristics of geothermal wells and fields, and the chemical properties of geothermal fluids; the last database is currently the most active. System tasks are divided into four areas: (1) data acquisition and entry, involving data entry via word processors and magnetic tape; (2) quality assurance, including the criteria and standards handbook and front-end data-screening programs; (3) operation, involving database backups and information extraction; and (4) user assistance, preparation of such items as application programs, and a quarterly newsletter. The principal task of GEOTHERM is to provide information and research support for the conduct of national geothermal-resource assessments. The principal users of GEOTHERM are those involved with the Geothermal Research Program of the U.S. Geological Survey. Information in the system is available to the public on request.

  10. Geothermal Systems for School.

    ERIC Educational Resources Information Center

    Dinse, David H.

    1998-01-01

    Describes an award-winning school heating and cooling system in which two energy-efficient technologies, variable-flow pumping and geothermal heat pumps, were combined. The basic system schematic and annual energy use and cost savings statistics are provided. (GR)

  11. Seismic properties of fluid bearing formations in magmatic geothermal systems: can we directly detect geothermal activity with seismic methods?

    NASA Astrophysics Data System (ADS)

    Grab, Melchior; Scott, Samuel; Quintal, Beatriz; Caspari, Eva; Maurer, Hansruedi; Greenhalgh, Stewart

    2016-04-01

    Seismic methods are amongst the most common techniques to explore the earth's subsurface. Seismic properties such as velocities, impedance contrasts and attenuation enable the characterization of the rocks in a geothermal system. The most important goal of geothermal exploration, however, is to describe the enthalpy state of the pore fluids, which act as the main transport medium for the geothermal heat, and to detect permeable structures such as fracture networks, which control the movement of these pore fluids in the subsurface. Since the quantities measured with seismic methods are only indirectly related with the fluid state and the rock permeability, the interpretation of seismic datasets is difficult and usually delivers ambiguous results. To help overcome this problem, we use a numerical modeling tool that quantifies the seismic properties of fractured rock formations that are typically found in magmatic geothermal systems. We incorporate the physics of the pore fluids, ranging from the liquid to the boiling and ultimately vapor state. Furthermore, we consider the hydromechanics of permeable structures at different scales from small cooling joints to large caldera faults as are known to be present in volcanic systems. Our modeling techniques simulate oscillatory compressibility and shear tests and yield the P- and S-wave velocities and attenuation factors of fluid saturated fractured rock volumes. To apply this modeling technique to realistic scenarios, numerous input parameters need to be indentified. The properties of the rock matrix and individual fractures were derived from extensive literature research including a large number of laboratory-based studies. The geometries of fracture networks were provided by structural geologists from their published studies of outcrops. Finally, the physical properties of the pore fluid, ranging from those at ambient pressures and temperatures up to the supercritical conditions, were taken from the fluid physics

  12. OIT geothermal system improvements

    SciTech Connect

    Lienau, P.J.

    1996-08-01

    Three geothermal wells drilled during the original campus construction vary from 396 m (1,300 ft) to 550 m (1,800 ft). These wells supply all of the heating and part of the cooling needs of the 11-building, 62,200 m{sup 2} (670,000 ft{sup 2}) campus. The combined capacity of the well pumps is 62 L/s(980 gpm) of 89{degrees}C (192{degrees}F) geothermal fluids. Swimming pool and domestic hot water heating impose a small but nearly constant year-round flow requirement. In addition to heating, a portion of the campus is also cooled using the geothermal resource. This is accomplished through the use of an absorption chiller. The chiller, which operates on the same principle as a gas refrigerator, requires a flow of 38 L/s (600 gpm) of geothermal fluid and produces 541 kW (154 tons) of cooling capacity (Rafferty, 1989). The annual operating costs for the system is about $35,000 including maintenance salary, equipment replacement and cost of pumping. This amounts to about $0.05 per square foot per year.

  13. Geothermal instrumentation development activities at Sandia

    SciTech Connect

    Carson, C.C.

    1985-03-01

    A major element of Sandia's Geothermal Technology Development Program is the effort directed toward development of instrumentation. This effort has two aspects, the development of high temperature components and prototype tools and the investigation of new concepts and capabilities. The focus of these activities is the acquisition of information to make geothermal drilling and resource development more efficient. Several projects of varying nature and scope make up the instrumentation development element, and this element will expand as the program emphasis on development of an advanced geothermal drilling system and the need for improved information grow. 13 refs.

  14. National Geothermal Data System (NGDS)

    DOE Data Explorer

    The National Geothermal Data System (NGDS) is a DOE-funded distributed network of databases and data sites. Much of the risk of geothermal energy development is associated with exploring for, confirming and characterizing the available geothermal resources. The overriding purpose of the NGDS is to help mitigate this up-front risk by serving as a central gateway for geothermal and relevant related data as well as a link to distributed data sources. Assessing and categorizing the nation's geothermal resources and consolidating all geothermal data through a publicly accessible data system will support research, stimulate public interest, promote market acceptance and investment, and, in turn, the growth of the geothermal industry. Major participants in the NGDS to date include universities, laboratories, the Arizona Geological Survey and Association of American State Geologists (Arizona Geological Survey, lead), the Geothermal Resources Council, and the U.S. Geological Survey. The Geothermal Energy Association is collaborating with the NGDS to insure that it meets the needs of the geothermal industry.

  15. Federal Interagency Geothermal Activities

    SciTech Connect

    Anderson, Arlene; Prencipe, Loretta; Todaro, Richard M.; Cuyler, David; Eide, Elizabeth

    2011-06-01

    This collaborative document describes the roles and responsibilities of key Federal agencies in the development of geothermal technologies including the U.S. Department of Energy (DOE); the U.S. Department of Agriculture (USDA), including the U.S. Forest Service; the U.S. Department of Interior (DOI), including the United States Geological Survey (USGS) and Bureau of Land Management (BLM); the Environmental Protection Agency (EPA); and the Department of Defense (DOD).

  16. Induced Microseismic Activity in non Pressure Stimulated Geothermal System - an Example From Southern Germany

    NASA Astrophysics Data System (ADS)

    Wassermann, J. M.; Megies, T.

    2011-12-01

    In order to be efficient in selling heat and electric power, the most favorable locations for deep geothermal power plants are in close proximity to urbanized areas. This advantage bears the inherent danger of induced earthquakes especially during the stimulation and production phase of enhanced geothermal systems, which at least are partially felt in the near surroundings. Felt earthquakes, however, severely reduce the level of acceptance of residents close to the plant. The Bavarian Molasse basin is characterized by its highly permeable, deep groundwater bearing limestone layers. This high permeability permits the abdication of pressure stimulation of the geothermal reservoir and makes the close proximity to the densely populated area around Munich possible. In addition to this favorable production conditions, the Bavarian Molasse Basin is being considered as generally aseismic. In contrast to this obvious advantages five Ml > 2.0 events south of Munich which were felt by local residents attracted public attention. These events were located in the vicinity of a geothermal plant that took up production about half a year earlier. In the last two years a temporary network was set up that recorded more than 80 events with magnitudes mainly ranging from Ml -0.5 to 1.5. Events below magnitude 1.5 could not be detected and located prior to the production stage of the geothermal plant in the main network of the local earthquake service Erdbebendienst Bayern. Still, the exact mechanism leading to the seismicity remains unknown. Most likely the orientation of pre-existing faults, which are pierced by the open-hole part of wells with respect to present stress field and the volume of re-injected cold water play a key role in understanding the mechanisms leading to the observed seismicity. Within the framework of a project financed by the German federal ministry of Environment, further field experiments are conducted to address these open questions and test some working

  17. Earthquake Swarm Activity Beneath the Tokaanu-Waihi Geothermal System, Lake Taupo, New Zealand

    SciTech Connect

    Hochstein, M.P.; Sherburn, S.; Tikku, J.

    1995-01-01

    The hypocenters of 4 earthquake swarms (total of 54 events), recorded with a local network between 1986 April and 1987 January, occur within upper crustal rocks of the deeper Tokaanu-Waihi geothermal reservoir; all the events had a magnitude M{sub L} {le} 3.2. Most foci are aligned along two NW-trending basement fault structures along which young rhyodacitic extrusions can be found. The swarm activity has been interpreted in terms of injections into basement fractures of magma from deeper chambers (dyke injection swarm activity).

  18. Geothermal activities in Central America

    SciTech Connect

    Whetten, J.T.; Hanold, R.J.

    1985-09-11

    The Agency for International Development is funding a new program in energy and minerals for Central America. Geothermal energy is an important component. A country-wide geothermal assessment has started in Honduras, and other assessment activities are in progress or planned for Costa Rica, El Salvador, Guatemala, and Panama. Instrumentation for well logging has been provided to Costa Rica, and a self-contained logging truck will be made available for use throughout Central America. An important objective of this program is to involve the private sector in resource development. 4 refs., 3 figs.

  19. Computerized international geothermal information systems

    SciTech Connect

    Phillips, S.L.; Lawrence, J.D.; Lepman, S.R.

    1980-03-01

    The computerized international geothermal energy information system is reviewed. The review covers establishment of the Italy - United States linked data centers by the NATO Committee on Challenges of Modern Society, through a bilateral agreement, and up to the present time. The result of the information exchange project is given as the bibliographic and numerical data available from the data centers. Recommendations for the exchange of computerized geothermal information at the international level are discussed.

  20. Lassen geothermal system

    SciTech Connect

    Muffler, L.J.P.; Nehring, N.L.; Truesdell, A.H.; Janik, C.J.; Clynne, M.A.; Thompson, J.M.

    1982-01-01

    The Lassen geothermal system consists of a central vapor-dominated reservoir underlain by hot water that discharges peripherally at lower elevations. The major thermal upflow at Bumpass Hell (elevation 2500 m) displays numerour superheated fumaroles, one of which in 1976 was 159/sup 0/C. Gas geothermometers from the fumarole areas and water geothermometers from boiling Cl-bearing waters at Morgan Hot Springs (elevation 1530 m; 8 km south of Bumpass Hell) and from 176/sup 0/C waters in a well 12 km southeast of Bumpass Hell both indicate 230 to 240/sup 0/C for the deep thermal water. With increasing distance from Bumpass Hell, gases are progressively depleted in H/sub 2/S relative to CO/sub 2/ and N/sub 2/, owing to oxidation of H/sub 2/S to pyrite, sulfur, and sulfates and to dilution with atmospheric N/sub 2/. H/sub 2/O/gas ratios and degree of superheat of fumaroles can be explained by mixing of steam of maximum enthalpy (2804 J g/sup -1/) with near-surface water and with the condensate layer overlying the vapor-dominated reservoir.

  1. Geothermal reservoirs in hydrothermal convection systems

    SciTech Connect

    Sorey, M.L.

    1982-01-01

    Geothermal reservoirs commonly exist in hydrothermal convection systems involving fluid circulation downward in areas of recharge and upwards in areas of discharge. Because such reservoirs are not isolated from their surroundings, the nature of thermal and hydrologic connections with the rest of the system may have significant effects on the natural state of the reservoir and on its response to development. Conditions observed at numerous developed and undeveloped geothermal fields are discussed with respect to a basic model of the discharge portion of an active hydrothermal convection system. Effects of reservoir development on surficial discharge of thermal fluid are also delineated.

  2. The role of active and ancient geothermal systems in evolution of Grant Canyon oil field, Railroad Valley, Nye County, Nevada

    SciTech Connect

    Hulen, J.B. ); Bereskin, S.R. ); Bortz, L.C.

    1991-06-01

    Since discovery in 1983, the Grant Canyon field has been among the most prolific oil producers (on a per-well basis) in the US. Production through June 1990 was 12,935,630 bbl of oil, principally from two wells which in tandem have consistently yielded more than 6,000 bbl of oil per day. The field is hosted by highly porous Devonian dolomite breccia loosely cemented with hydrothermal quartz. Results of fluid-inclusion and petrographic research in progress at Grant Canyon suggest that paleogeothermal and perhaps currently circulating geothermal systems may have played a major role in oil-reservoir evolution. For example, as previously reported, the breccia-cementing quartz hosts primary aqueous, aqueous/oil, and oil fluid inclusions which were trapped at about 120C (average homogenization temperature) and document initial oil migration and entrapment as droplets or globules dispersed in dilute (< 2.2 wt.% equivalent NaCl) aqueous solutions. Additional evidence of geothermal connection is that the horst-block trap at Grant Canyon is top and side sealed by valley-fill clastic and volcanic rocks which are locally hydrothermally altered and calcite flooded. These secondary seals are enhanced by disseminated, solid asphaltic residues locally accounting for 23% (volume) of the rock. Current reservoir temperatures at Grant Canyon (120C) and the adjacent Bacon Flat field (171C) attest to vigorous contemporary geothermal activity. Based on results of the authors' Grant Canyon work to date, they suggest that active and paleohydrothermal systems could be viable petroleum exploration targets in otherwise favorable terrain elsewhere in the Basin and Range.

  3. Geothermal systems of the Cascade Range

    USGS Publications Warehouse

    Muffler, L.J.; Bacon, Charles R.; Duffield, W.A.

    1982-01-01

    In the central and southern Cascade Range, plate convergence is oblique, and Quaternary volcanism produces mostly basalt and mafic andesite; large andesite-dacite composite volcanoes and silicic dome fields occur in restricted areas of long-lived igneous activity. To the north, plate convergence is normal, producing widely spaced centers in which mafic lavas are minor. Most Cascade volcanoes are short-lived and unlikely to be underlain at shallow levels by large magma bodies that could support high-temperature geothermal systems. Such systems are known, however, near Meager Mountain, at Newberry Volcano, and near Lassen Peak. Persistent fumaroles occur on several major composite volcanoes, but drilling to date has been insufficient to determine whether exploitable geothermal reservoirs occur at depth. Thermal springs away from the major volcanic centers are few and generally inconspicuous. However, significant geothermal systems along and west of the Cascade Range may well be masked by abundant cold ground water.

  4. A corrosivity classification system for geothermal resources

    SciTech Connect

    Conover, Marshall F.

    1982-10-08

    The most important difference between traditional steam systems and those that utilize geothermal fluids is the potential for corrosion of metals. The recently developed sourcebook ''Materials Selection Guidelines for Geothermal Energy Utilization Systems'' is expected to facilitate corrosion engineering decision making and reduce the cost of geothermal systems where new resources are similar to those presented by the corrosivity classification system.

  5. Geothermal systems: Principles and case histories

    NASA Astrophysics Data System (ADS)

    Rybach, L.; Muffler, L. J. P.

    The classification of geothermal systems is considered along with the geophysical and geochemical signatures of geothermal systems, aspects of conductive heat transfer and regional heat flow, and geothermal anomalies and their plate tectonic framework. An investigation of convective heat and mass transfer in hydrothermal systems is conducted, taking into account the mathematical modelling of hydrothermal systems, aspects of idealized convective heat and mass transport, plausible models of geothermal reservoirs, and preproduction models of hydrothermal systems. Attention is given to the prospecting for geothermal resources, the application of water geochemistry to geothermal exploration and reservoir engineering, heat extraction from geothermal reservoirs, questions of geothermal resource assessment, and environmental aspects of geothermal energy development. A description is presented of a number of case histories, taking into account the low enthalpy geothermal resource of the Pannonian Basin in Hungary, the Krafla geothermal field in Northeast Iceland, the geothermal system of the Jemez Mountains in New Mexico, and extraction-reinjection at the Ahuachapan geothermal field in El Salvador.

  6. An Evaluation of Enhanced Geothermal Systems Technology

    SciTech Connect

    Jelacic, Allan; Fortuna, Raymond; LaSala, Raymond; Nathwani, Jay; Nix, Gerald; Visser, Charles; Green, Bruce; Renner, Joel; Blankenship, Douglas; Kennedy, Mack; Bruton, Carol

    2008-04-01

    This 2008 document presents the results of an eight-month study by the Department of Energy (DOE) and its support staff at the national laboratories concerning the technological requirements to commercialize a new geothermal technology, Enhanced Geothermal Systems (EGS).

  7. Boise geothermal district heating system

    SciTech Connect

    Hanson, P.J.

    1985-10-01

    This document describes the Boise geothermal district heating project from preliminary feasibility studies completed in 1979 to a fully operational system by 1983. The report includes information about the two local governments that participated in the project - the City of Boise, Idaho and the Boise Warm Springs Water District. It also discusses the federal funding sources; the financial studies; the feasibility studies conducted; the general system planning and design; design of detailed system components; the legal issues involved in production; geological analysis of the resource area; distribution and disposal; the program to market system services; and the methods of retrofitting buildings to use geothermal hot water for space heating. Technically this report describes the Boise City district heating system based on 170/sup 0/F water, a 4000 gpm production system, a 41,000 foot pipeline system, and system economies. Comparable data are also provided for the Boise Warm Springs Water District. 62 figs., 31 tabs.

  8. Tiber delta CO2-CH4 degassing: A possible hybrid, tectonically active Sediment-Hosted Geothermal System near Rome

    NASA Astrophysics Data System (ADS)

    Ciotoli, G.; Etiope, G.; Marra, F.; Florindo, F.; Giraudi, C.; Ruggiero, L.

    2016-01-01

    Fiumicino town in the Tiber River delta, near Rome International Airport (Italy), is historically affected by large amounts of carbon dioxide (CO2) in the ground and gas eruptions triggered by shallow drilling. While it is known that CO2 originates from carbonate thermometamorphism and/or mantle degassing, the origin of methane (CH4) associated with CO2 is uncertain and the outgassing spatial distribution is unknown. Combining isotope gas geochemistry, soil gas, and structural-stratigraphic analyses, we provide evidence for a hybrid fluid source system, classifiable as Sediment-Hosted Geothermal System (SHGS), where biotic CH4 from sedimentary rocks is carried by deep geothermic CO2 through active segments of a half-graben. Molecular and isotopic composition of CH4 and concentration of heavier alkanes (ethane and propane), obtained from gas vents and soil gas throughout the delta area, reveal that thermogenic CH4 (up to 3.7 vol% in soil gas; δ13CCH4: -37 to -40‰ VPDB-Vienna Peedee Belemnite, and δ2HCH4: -162 to -203‰ VSMOW - Vienna Standard Mean Ocean Water in gas vents) prevails over possible microbial and abiotic components. The hydrocarbons likely result from known Meso-Cenozoic petroleum systems of the Latium Tyrrhenian coast. Overmaturation of source rocks or molecular fractionation induced by gas migration are likely responsible for increased C1/C2+ ratios. CO2 and CH4 soil gas anomalies are scattered along NW-SE and W-E alignments, which, based on borehole, geomorphologic, and structural-stratigraphic analyses, coincide with active faults of a half-graben that seems to have controlled the recent evolution of the Tiber delta. This SHGS can be a source of considerable greenhouse gas emissions to the atmosphere and hazards for humans and buildings.

  9. What is an Enhanced Geothermal System (EGS)? Fact Sheet

    SciTech Connect

    U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy

    2012-09-14

    This Geothermal Technologies Office fact sheet explains how engineered geothermal reservoirs called Enhanced Geothermal Systems are used to produce energy from geothermal resources that are otherwise not economical due to a lack of fluid and/or permeability.

  10. Enhanced Geothermal Systems

    SciTech Connect

    Jeanloz, R.; Stone, H.

    2013-12-31

    DOE, through the Geothermal Technologies Office (GTO) within the Office of Energy Efficiency and Renewable Energy, requested this study, identifying a focus on: i) assessment of technologies and approaches for subsurface imaging and characterization so as to be able to validate EGS opportunities, and ii) assessment of approaches toward creating sites for EGS, including science and engineering to enhance permeability and increase the recovery factor. Two days of briefings provided in-depth discussion of a wide range of themes and challenges in EGS, and represented perspectives from industry, government laboratories and university researchers. JASON also contacted colleagues from universities, government labs and industry in further conversations to learn the state of the field and potential technologies relevant to EGS.

  11. Geothermal Data from the National Geothermal Data System (NGDS)

    DOE Data Explorer

    The National Geothermal Data System (NGDS) is a distributed data system providing access to information resources related to geothermal energy from a network of data providers. Data are contributed by academic researchers, private industry, and state and federal agencies. Built on a scalable and open platform through the U.S. Geoscience Information Network (USGIN), NGDS respects data provenance while promoting shared resources.Since NGDS is built using a set of open protocols and standards, relying on the Open Geospatial Consortium (OGC) and International Organization for Standardization (ISO), members of the community may access the data in a variety of proprietary and open-source applications and software. In addition, developers can add functionality to the system by creating new applications based on the open protocols and standards of the NGDS. The NGDS, supported by the U.S. Department of Energy’s Geothermal Technology Program, is intended to provide access to all types of geothermal data to enable geothermal analysis and widespread public use in an effort to reduce the risk of geothermal energy development [copied from http://www.geothermaldata.org/page/about]. See the long list of data contributors at http://geothermaldata.org/page/data-types-and-contributors#data-contributors.

  12. NATIONAL GEOTHERMAL DATA SYSTEM (NGDS) GEOTHERMAL DATA DOMAIN: ASSESSMENT OF GEOTHERMAL COMMUNITY DATA NEEDS

    SciTech Connect

    Anderson, Arlene; Blackwell, David; Chickering, Cathy; Boyd, Toni; Horne, Roland; MacKenzie, Matthew; Moore, Joseph; Nickull, Duane; Richard, Stephen; Shevenell, Lisa A.

    2013-01-01

    To satisfy the critical need for geothermal data to ad- vance geothermal energy as a viable renewable ener- gy contender, the U.S. Department of Energy is in- vesting in the development of the National Geother- mal Data System (NGDS). This paper outlines efforts among geothermal data providers nationwide to sup- ply cutting edge geo-informatics. NGDS geothermal data acquisition, delivery, and methodology are dis- cussed. In particular, this paper addresses the various types of data required to effectively assess geother- mal energy potential and why simple links to existing data are insufficient. To create a platform for ready access by all geothermal stakeholders, the NGDS in- cludes a work plan that addresses data assets and re- sources of interest to users, a survey of data provid- ers, data content models, and how data will be ex- changed and promoted, as well as lessons learned within the geothermal community.

  13. Geothermal systems of northern Nevada

    USGS Publications Warehouse

    Hose, Richard Kenneth; Taylor, Bruce Edward

    1974-01-01

    Hot springs are numerous and nearly uniformly distributed in northern Nevada. Most occur on the flanks of basins, along Basin and Range (late Miocene to Holocene) faults, while some occur in the inner parts of the basins. Surface temperatures of the springs range from slightly above ambient to, boiling; some springs are superheated. Maximum subsurface water temperatures calculated on the basis of quartz solubility range as high as 252?C, although most are below 190?C. Flows range from a trickle to several hundred liters per minute. The Nevada geothermal systems differ markedly from the power-producing system at The Geysers, Calif., and from those areas with a high potential, for power production (e.g., Yellowstone Park, Wyo.; Jemez Mountains, N. Mex.). These other systems are associated with Quaternary felsic volcanic rocks and probably derive their heat from cooling magma rather high in the crust. In northern Nevada, however, felsic volcanic rocks are virtually all older than 10 million years, and. analogous magmatic heat sources are, therefore, probably lacking. Nevada is part of an area of much higher average heat flow than the rest of the United States. In north-central Nevada, geothermal gradients are as great as 64?C per kilometer in bedrock and even higher in basin fill. The high gradients probably result from a combination of thin crust and high temperature upper mantle. We suggest that the geothermal systems of northern Nevada result from circulation of meteoric waters along Basin and Range faults and that their temperature chiefly depends upon (1) depth of circulation and (2) the geothermal gradient near the faults.

  14. Monitoring Biological Activity at Geothermal Power Plants

    SciTech Connect

    Peter Pryfogle

    2005-09-01

    The economic impact of microbial growth in geothermal power plants has been estimated to be as high as $500,000 annually for a 100 MWe plant. Many methods are available to monitor biological activity at these facilities; however, very few plants have any on-line monitoring program in place. Metal coupon, selective culturing (MPN), total organic carbon (TOC), adenosine triphosphate (ATP), respirometry, phospholipid fatty acid (PLFA), and denaturing gradient gel electrophoresis (DGGE) characterizations have been conducted using water samples collected from geothermal plants located in California and Utah. In addition, the on-line performance of a commercial electrochemical monitor, the BIoGEORGE?, has been evaluated during extended deployments at geothermal facilities. This report provides a review of these techniques, presents data on their application from laboratory and field studies, and discusses their value in characterizing and monitoring biological activities at geothermal power plants.

  15. Enhanced Geothermal Systems (EGS) R&D Program, Status Report: Foreign Research on Enhanced Geothermal Systems

    SciTech Connect

    McLarty, Lynn; Entingh, Daniel

    2000-09-29

    This report reviews enhanced geothermal systems (EGS) research outside the United States. The term ''enhanced geothermal systems'' refers to the use of advanced technology to extract heat energy from underground in areas with higher than average heat flow but where the natural permeability or fluid content is limited. EGS covers the spectrum of geothermal resources from low permeability hydrothermal to hot dry rock.

  16. Geothermal activity helps life survive glacial cycles.

    PubMed

    Fraser, Ceridwen I; Terauds, Aleks; Smellie, John; Convey, Peter; Chown, Steven L

    2014-04-15

    Climate change has played a critical role in the evolution and structure of Earth's biodiversity. Geothermal activity, which can maintain ice-free terrain in glaciated regions, provides a tantalizing solution to the question of how diverse life can survive glaciations. No comprehensive assessment of this "geothermal glacial refugia" hypothesis has yet been undertaken, but Antarctica provides a unique setting for doing so. The continent has experienced repeated glaciations that most models indicate blanketed the continent in ice, yet many Antarctic species appear to have evolved in almost total isolation for millions of years, and hence must have persisted in situ throughout. How could terrestrial species have survived extreme glaciation events on the continent? Under a hypothesis of geothermal glacial refugia and subsequent recolonization of nongeothermal regions, we would expect to find greater contemporary diversity close to geothermal sites than in nongeothermal regions, and significant nestedness by distance of this diversity. We used spatial modeling approaches and the most comprehensive, validated terrestrial biodiversity dataset yet created for Antarctica to assess spatial patterns of diversity on the continent. Models clearly support our hypothesis, indicating that geothermally active regions have played a key role in structuring biodiversity patterns in Antarctica. These results provide critical insights into the evolutionary importance of geothermal refugia and the history of Antarctic species. PMID:24616489

  17. Geothermal activity helps life survive glacial cycles

    PubMed Central

    Fraser, Ceridwen I.; Terauds, Aleks; Smellie, John; Convey, Peter; Chown, Steven L.

    2014-01-01

    Climate change has played a critical role in the evolution and structure of Earth’s biodiversity. Geothermal activity, which can maintain ice-free terrain in glaciated regions, provides a tantalizing solution to the question of how diverse life can survive glaciations. No comprehensive assessment of this “geothermal glacial refugia” hypothesis has yet been undertaken, but Antarctica provides a unique setting for doing so. The continent has experienced repeated glaciations that most models indicate blanketed the continent in ice, yet many Antarctic species appear to have evolved in almost total isolation for millions of years, and hence must have persisted in situ throughout. How could terrestrial species have survived extreme glaciation events on the continent? Under a hypothesis of geothermal glacial refugia and subsequent recolonization of nongeothermal regions, we would expect to find greater contemporary diversity close to geothermal sites than in nongeothermal regions, and significant nestedness by distance of this diversity. We used spatial modeling approaches and the most comprehensive, validated terrestrial biodiversity dataset yet created for Antarctica to assess spatial patterns of diversity on the continent. Models clearly support our hypothesis, indicating that geothermally active regions have played a key role in structuring biodiversity patterns in Antarctica. These results provide critical insights into the evolutionary importance of geothermal refugia and the history of Antarctic species. PMID:24616489

  18. Towards understanding the puzzling lack of acid geothermal springs in Tibet (China): Insight from a comparison with Yellowstone (USA) and some active volcanic hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Guo, Qinghai; Kirk Nordstrom, D.; Blaine McCleskey, R.

    2014-11-01

    Explanations for the lack of acid geothermal springs in Tibet are inferred from a comprehensive hydrochemical comparison of Tibetan geothermal waters with those discharged from Yellowstone (USA) and two active volcanic areas, Nevado del Ruiz (Colombia) and Miravalles (Costa Rica) where acid springs are widely distributed and diversified in terms of geochemical characteristic and origin. For the hydrothermal areas investigated in this study, there appears to be a relationship between the depths of magma chambers and the occurrence of acid, chloride-rich springs formed via direct magmatic fluid absorption. Nevado del Ruiz and Miravalles with magma at or very close to the surface (less than 1-2 km) exhibit very acidic waters containing HCl and H2SO4. In contrast, the Tibetan hydrothermal systems, represented by Yangbajain, usually have fairly deep-seated magma chambers so that the released acid fluids are much more likely to be fully neutralized during transport to the surface. The absence of steam-heated acid waters in Tibet, however, may be primarily due to the lack of a confining layer (like young impermeable lavas at Yellowstone) to separate geothermal steam from underlying neutral chloride waters and the possible scenario that the deep geothermal fluids below Tibet carry less H2S than those below Yellowstone.

  19. Fine-grained clay fraction (,0.2 {mu}m): An interesting tool to approach the present thermal and permeability state in active geothermal systems

    SciTech Connect

    Patrier, P.; Papapanagiotou, P.; Beaufort, D.; Traineau, H.; Bril, H.

    1992-01-01

    We have investigated by X-ray diffraction the very fine grained secondary minerals (< 0.2 {micro}m) developed in geothermal systems, in relation with their present thermal and permeability state. Because the smallest particles are the most reactive part of a rock, they are the youngest mineral phases of the geothermal fields. This study has been performed on two active geothermal fields: Milos field, Greece (130 < T < 320 C) and Chipilapa field, Salvador (90 < T < 215 C). In the Milos field, the mineralogical composition of the < 0.2 {micro}m clay fraction observed in the reservoir strongly differs from the overlying altered metamorphic schists in the presence of abundant quantities of saponite and talc/saponite interstratified minerals at unusually high temperature. These phases are considered to be kinetically control-led ''metastable'' minerals which rapidly evolve towards actinolite and talc for present temperatures higher than 300 C. Their occurrence is a good indicator of discharge in highly permeable zones. In the geothermal field of Chipilapa, the mineralogical composition of the < 0.2 {micro}m clay fractions fairly agrees with the temperatures presently measured in the wells, whereas several discrepancies may be pointed out from the compositions of coarser clay fractions (< 5 {micro}m) which contain minerals inherited from higher temperature stages. Permeable zones may be evidenced from an increase of expandable components in the interstratified minerals and a decrease of the coherent domain of the unexpandable clay particles (chlorite).

  20. Arsenic geochemistry in geothermal systems

    SciTech Connect

    Ballantyne, J.M.; Moore, J.N.

    1988-02-01

    Arsenic is an important trace constituent in geothermal fluids, ranging in concentration from less than 0.1 to nearly 50 ppm. An evaluation of published fluid analyses from geothermal systems indicates that the As content of the reservoir fluids varies inversely with P/sub H/sub 2/S/ and directly with temperature. Aqueous As species occur in two oxidation states, As/sup III/ and As/sup V/. As/sup III/ predominates in the reservoir fluids, where H/sub 3/AsO/sub 3/ is inferred to be the dominant aqueous species. Both AS/sup III/ and As/sup V/ occur in hot spring fluids. The concentration of As in high-temperature reservoir fluids is regulated by reactions involving pyrite. Concentrations up to 3.8 weight percent As have been measured in pyrite from two systems. The erratic distribution of As in the samples studied is interpreted as resulting from local fluctuations in redox conditions. Arsenopyrite and other As minerals are undersaturated with respect to the high temperature fluids found in most reservoirs. In contrast, orpiment, realgar, As-rich stibnite and marcasite, and iron oxides control the deposition of As in hot spring environments. These minerals become stable in response to decreasing temperature and pH and increasing P/sub O/sub 2//.

  1. Geopressured-geothermal well activities in Louisiana

    SciTech Connect

    John, C.J.

    1992-10-01

    Since September 1978, microseismic networks have operated continuously around US Department of Energy (DOE) geopressured-geothermal well sites to monitor any microearthquake activity in the well vicinity. Microseismic monitoring is necessary before flow testing at a well site to establish the level of local background seismicity. Once flow testing has begun, well development may affect ground elevations and/or may activate growth faults, which are characteristic of the coastal region of southern Louisiana and southeastern Texas where these geopressured-geothermal wells are located. The microseismic networks are designed to detest small-scale local earthquakes indicative of such fault activation. Even after flow testing has ceased, monitoring continues to assess any microearthquake activity delayed by the time dependence of stress migration within the earth. Current monitoring shows no microseismicity in the geopressured-geothermal prospect areas before, during, or after flow testing.

  2. Geothermal reservoir characterization through active thermal testing

    NASA Astrophysics Data System (ADS)

    Jung, Martin; Klepikova, Maria; Jalali, Mohammadreza; Fisch, Hansruedi; Loew, Simon; Amann, Florian

    2016-04-01

    Development and deployment of Enhanced Geothermal Systems (EGS) as renewable energy resources are part of the Swiss Energy Strategy 2050. To pioneer further EGS projects in Switzerland, a decameter-scale in-situ hydraulic stimulation and circulation (ISC) experiment has been launched at the Grimsel Test Site (GTS). The experiments are hosted in a low fracture density volume of the Grimsel granodiorite, similar to those expected at the potential enhanced geothermal system sites in the deep basement rocks of Northern Switzerland. One of the key goals of this multi-disciplinary experiment is to provide a pre- and post-stimulation characterization of the hydraulic and thermal properties of the stimulated fracture network with high resolution and to determine natural structures controlling the fluid flow and heat transport. Active thermal tests including thermal dilution tests and heat tracer tests allow for investigation of groundwater fluid flow and heat transport. Moreover, the spatial and temporal integrity of distributed temperature sensing (DTS) monitoring upgrades the potential and applicability of thermal tests in boreholes (e.g. Read et al., 2013). Here, we present active thermal test results and discuss the advantages and limitations of this method compared to classical approaches (hydraulic packer tests, solute tracer tests, flowing fluid electrical conductivity logging). The experimental tests were conducted in two boreholes intersected by a few low to moderately transmissive fault zones (fracture transmissivity of about 1E-9 m2/s - 1E-7 m2/s). Our preliminary results show that even in low-permeable environments active thermal testing may provide valuable insights into groundwater and heat transport pathways. Read T., O. Bour, V. Bense, T. Le Borgne, P. Goderniaux, M.V. Klepikova, R. Hochreutener, N. Lavenant, and V. Boschero (2013), Characterizing groundwater flow and heat transport in fractured rock using Fiber-Optic Distributed Temperature Sensing

  3. Philip, South Dakota geothermal district heating systems

    SciTech Connect

    Lund, J.W.

    1997-12-01

    The geothermal heating project in Philip, South Dakota which uses the waste water from the Haakon School has now been in operation for 15 years. This project was one of the 23 cost shared by the U.S. DOE starting in 1978, of which 15 became operational. This article describes the geothermal heating system for eight buildings in downtown Philip.

  4. Neutron imaging for geothermal energy systems

    SciTech Connect

    Bingham, Philip R; Anovitz, Lawrence {Larry} M; Polsky, Yarom

    2013-01-01

    Geothermal systems extract heat energy from the interior of the earth using a working fluid, typically water. Three components are required for a commercially viable geothermal system: heat, fluid, and permeability. Current commercial electricity production using geothermal energy occurs where the three main components exist naturally. These are called hydrothermal systems. In the US, there is an estimated 30 GW of base load electrical power potential for hydrothermal sites. Next generation geothermal systems, named Enhanced Geothermal Systems (EGS), have an estimated potential of 4500 GW. EGSs lack in-situ fluid, permeability or both. As such, the heat exchange system must be developed or engineered within the rock. The envisioned method for producing permeability in the EGS reservoir is hydraulic fracturing, which is rarely practiced in the geothermal industry, and not well understood for the rocks typically present in geothermal reservoirs. High costs associated with trial and error learning in the field have led to an effort to characterize fluid flow and fracturing mechanisms in the laboratory to better understand how to design and manage EGS reservoirs. Neutron radiography has been investigated for potential use in this characterization. An environmental chamber has been developed that is suitable for reproduction of EGS pressures and temperatures and has been tested for both flow and precipitations studies with success for air/liquid interface imaging and 3D reconstruction of precipitation within the core.

  5. Enhanced Geothermal Systems (EGS) R&D Program: US Geothermal Resources Review and Needs Assessment

    SciTech Connect

    Entingh, Dan; McLarty, Lynn

    2000-11-30

    The purpose of this report is to lay the groundwork for an emerging process to assess U.S. geothermal resources that might be suitable for development as Enhanced Geothermal Systems (EGS). Interviews of leading geothermists indicate that doing that will be intertwined with updating assessments of U.S. higher-quality hydrothermal resources and reviewing methods for discovering ''hidden'' hydrothermal and EGS resources. The report reviews the history and status of assessment of high-temperature geothermal resources in the United States. Hydrothermal, Enhanced, and Hot Dry Rock resources are addressed. Geopressured geothermal resources are not. There are three main uses of geothermal resource assessments: (1) They inform industry and other interest parties of reasonable estimates of the amounts and likely locations of known and prospective geothermal resources. This provides a basis for private-sector decisions whether or not to enter the geothermal energy business at all, and for where to look for useful resources. (2) They inform government agencies (Federal, State, local) of the same kinds of information. This can inform strategic decisions, such as whether to continue to invest in creating and stimulating a geothermal industry--e.g., through research or financial incentives. And it informs certain agencies, e.g., Department of Interior, about what kinds of tactical operations might be required to support such activities as exploration and leasing. (3) They help the experts who are performing the assessment(s) to clarify their procedures and data, and in turn, provide the other two kinds of users with a more accurate interpretation of what the resulting estimates mean. The process of conducting this assessment brings a spotlight to bear on what has been accomplished in the domain of detecting and understanding reservoirs, in the period since the last major assessment was conducted.

  6. Small geothermal electric systems for remote powering

    SciTech Connect

    Entingh, Daniel J.; Easwaran, Eyob.; McLarty, Lynn

    1994-08-08

    This report describes conditions and costs at which quite small (100 to 1,000 kilowatt) geothermal systems could be used for off-grid powering at remote locations. This is a first step in a larger process of determining locations and conditions at which markets for such systems could be developed. The results suggest that small geothermal systems offer substantial economic and environmental advantages for powering off-grid towns and villages. Geothermal power is most likely to be economic if the system size is 300 kW or greater, down to reservoir temperatures of 100{degree}C. For system sizes smaller than 300 kW, the economics can be favorable if the reservoir temperature is about 120{degree}C or above. Important markets include sites remote from grids in many developing and developed countries. Estimates of geothermal resources in many developing countries are shown.

  7. Radionuclide mobility in the shallow portion of an active high-temperature geothermal system

    SciTech Connect

    Sturchio, N.C.; Seitz, M.G.

    1984-01-01

    Accurate knowledge of the behavior of radionuclides in natural rock-water systems is crucial for the prediction of the consequences of failure of a high-level nuclear waste repository. Work in progress at Argonne National Laboratory involves the detailed geochemical analysis of rock, mineral, and water samples from shallow drill holes in a thermal area of Yellowstone National Park. This study is designed to provide data that will increase our understanding of the behavior of a group of radionuclides in an environment similar to that of the near field of a high-level nuclear waste repository.

  8. Water Resource Assessment of Geothermal Resources and Water Use in Geopressured Geothermal Systems

    SciTech Connect

    Clark, C. E.; Harto, C. B.; Troppe, W. A.

    2011-09-01

    This technical report from Argonne National Laboratory presents an assessment of fresh water demand for future growth in utility-scale geothermal power generation and an analysis of fresh water use in low-temperature geopressured geothermal power generation systems.

  9. Town of Pagosa Springs geothermal heating system

    SciTech Connect

    Garcia, M.B.

    1997-08-01

    The Town of Pagosa Springs has owned and operated a geothermal heating system since December 1982 to provide geothermal heating during the fall, winter and spring to customers in this small mountain town. Pagosa Springs is located in Archuleta County, Colorado in the southwestern corner of the State. The Town, nestled in majestic mountains, including the Continental Divide to the north and east, has an elevation of 7,150 feet. The use of geothermal water in the immediate area, however, dates back to the 1800`s, with the use of Ute Bands and the Navajo Nation and later by the U.S. Calvery in the 1880`s (Lieutenant McCauley, 1878). The Pagosa area geothermal water has been reported to have healing and therapeutic qualities.

  10. Geothermal heat pump system assisted by geothermal hot spring

    NASA Astrophysics Data System (ADS)

    Nakagawa, M.; Koizumi, Y.

    2016-01-01

    The authors propose a hybrid geothermal heat pump system that could cool buildings in summer and melt snow on the pedestrian sidewalks in winter, utilizing cold mine water and hot spring water. In the proposed system, mine water would be used as cold thermal energy storage, and the heat from the hot spring after its commercial use would be used to melt snow for a certain section of sidewalks. Neither of these sources is viable for direct use application of geothermal resources, however, they become contributing energy factors without producing any greenhouse gases. To assess the feasibility of the proposed system, a series of temperature measurements in the Edgar Mine (Colorado School of Mines' experimental mine) in Idaho Springs, Colorado, were first conducted, and heat/mass transfer analyses of geothermal hot spring water was carried out. The result of the temperature measurements proved that the temperature of Edgar Mine would be low enough to store cold groundwater for use in summer. The heat loss of the hot spring water during its transportation was also calculated, and the heat requirement for snow melt was compared with the heat available from the hot spring water. It was concluded that the heat supply in the proposed usage of hot spring water was insufficient to melt the snow for the entire area that was initially proposed. This feasibility study should serve as an example of "local consumption of locally available energy". If communities start harnessing economically viable local energy in a responsible manner, there will be a foundation upon which to build a sustainable community.

  11. The Geothermal Field Camp: Capacity building for geothermal energy systems in Indonesia

    NASA Astrophysics Data System (ADS)

    Moeck, I.; Sule, R.; Saptadji, N. M.; Deon, F.; Herdianita, N. R.; Jolie, E.; Suryantini, N.; Erbas, K.

    2012-04-01

    In July 2011, the first geothermal field camp was hold on Java/Indonesia near the city Bandung south of the volcanic field Tangkuban Perahu. The course was organized by the Institut Teknologie Bandung (ITB) and International Centre for Geothermal Research (ICGR) of the German Centre of Geosciences (GFZ). The purpose of the Geothermal Field Camp is to combine both field based work and laboratory analysis to ultimately better understand the data collected in field and to integrate data gained by various disciplines. The training belongs to a capacity building program for geothermal energy systems in Indonesia and initially aims to train the trainers. In a later stage, the educational personal trained by the Geothermal Field Camp shall be able to hold their individual Geothermal Field Camp. This is of special interest for Indonesia where the multitude of islands hindered a broad uniform education in geothermal energy systems. However, Indonesia hold the largest geothermal potential worldwide and educated personal is necessary to successfully develop this huge potential scattered over region in future. The interdisciplinary and integrative approach combined with field based and laboratory methodologies is the guiding principle of the Geothermal Field Camp. Tangkuban Perahu was selected because this field allows the integration of field based structural geological analysis, observation and sampling of geothermal manifestations as hot springs and sinters and ultimately of structural geology and surface geochemistry. This innovative training introduces in methods used in exploration geology to study both, fault and fracture systems and fluid chemistry to better understand the selective fluid flow along certain fractures and faults. Field geology covered the systematic measurement of faults and fractures, fault plane and fracture population analysis. In addition, field hydro-geochemistry focused on sampling techniques and field measurements onsite. Subsequent data analysis

  12. Performance of deep geothermal energy systems

    NASA Astrophysics Data System (ADS)

    Manikonda, Nikhil

    Geothermal energy is an important source of clean and renewable energy. This project deals with the study of deep geothermal power plants for the generation of electricity. The design involves the extraction of heat from the Earth and its conversion into electricity. This is performed by allowing fluid deep into the Earth where it gets heated due to the surrounding rock. The fluid gets vaporized and returns to the surface in a heat pipe. Finally, the energy of the fluid is converted into electricity using turbine or organic rankine cycle (ORC). The main feature of the system is the employment of side channels to increase the amount of thermal energy extracted. A finite difference computer model is developed to solve the heat transport equation. The numerical model was employed to evaluate the performance of the design. The major goal was to optimize the output power as a function of parameters such as thermal diffusivity of the rock, depth of the main well, number and length of lateral channels. The sustainable lifetime of the system for a target output power of 2 MW has been calculated for deep geothermal systems with drilling depths of 8000 and 10000 meters, and a financial analysis has been performed to evaluate the economic feasibility of the system for a practical range of geothermal parameters. Results show promising an outlook for deep geothermal systems for practical applications.

  13. National Geothermal Data System (NGDS) Geothermal Data: Community Requirements and Information Engineering

    SciTech Connect

    Anderson, Arlene; Blackwell, David; Chickering, Cathy; Boyd, Toni; Horne, Roland; MacKenzie, Matthew; Moore, Joseph; Nickull, Duane; Richard, Stephen; Shevenell, Lisa A.

    2013-10-01

    To satisfy the critical need for geothermal data to advance geothermal energy as a viable renewable energy contender, the U.S. Department of Energy is investing in the development of the National Geothermal Data System (NGDS). This paper outlines efforts among geothermal data providers nationwide to supply cutting edge geo-informatics. NGDS geothermal data acquisition, delivery, and methodology are discussed. In particular, this paper addresses the various types of data required to effectively assess geothermal energy potential and why simple links to existing data are insufficient. To create a platform for ready access by all geothermal stakeholders, the NGDS includes a work plan that addresses data assets and resources of interest to users, a survey of data providers, data content models, and how data will be exchanged and promoted, as well as lessons learned within the geothermal community.

  14. A Geothermal GIS for Nevada: Defining Regional Controls and Favorable Exploration Terrains for Extensional Geothermal Systems

    USGS Publications Warehouse

    Coolbaugh, M.F.; Taranik, J.V.; Raines, G.L.; Shevenell, L.A.; Sawatzky, D.L.; Bedell, R.; Minor, T.B.

    2002-01-01

    Spatial analysis with a GIS was used to evaluate geothermal systems in Nevada using digital maps of geology, heat flow, young faults, young volcanism, depth to groundwater, groundwater geochemistry, earthquakes, and gravity. High-temperature (>160??C) extensional geothermal systems are preferentially associated with northeast-striking late Pleistocene and younger faults, caused by crustal extension, which in most of Nevada is currently oriented northwesterly (as measured by GPS). The distribution of sparse young (160??C) geothermal systems in Nevada are more likely to occur in areas where the groundwater table is shallow (<30m). Undiscovered geothermal systems may occur where groundwater levels are deeper and hot springs do not issue at the surface. A logistic regression exploration model was developed for geothermal systems, using young faults, young volcanics, positive gravity anomalies, and earthquakes to predict areas where deeper groundwater tables are most likely to conceal geothermal systems.

  15. Convective heat transport in geothermal systems

    SciTech Connect

    Lippmann, M.J.; Bodvarsson, G.S.

    1986-08-01

    Most geothermal systems under exploitation for direct use or electrical power production are of the hydrothermal type, where heat is transferred essentially by convection in the reservoir, conduction being secondary. In geothermal systems, buoyancy effects are generally important, but often the fluid and heat flow patterns are largely controlled by geologic features (e.g., faults, fractures, continuity of layers) and location of recharge and discharge zones. During exploitation, these flow patterns can drastically change in response to pressure and temperature declines, and changes in recharge/discharge patterns. Convective circulation models of several geothermal systems, before and after start of fluid production, are described, with emphasis on different characteristics of the systems and the effects of exploitation on their evolution. Convective heat transport in geothermal fields is discussed, taking into consideration (1) major geologic features; (2) temperature-dependent rock and fluid properties; (3) fracture- versus porous-medium characteristics; (4) single- versus two-phase reservoir systems; and (5) the presence of noncondensible gases.

  16. What is the National Geothermal Data System (NGDS)? Fact Sheet

    SciTech Connect

    U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy

    2012-09-03

    Overview of the National Geothermal Data System, a distributed, interoperable network of data repositories and state geological service providers from across the U.S. and the nation's leading academic geothermal centers.

  17. National Geothermal Data System Hub Deployment Timeline (Appendix E-1-d)

    SciTech Connect

    Caudill, Christy

    2015-12-20

    Excel spreadsheet describing activity, spending, and development for the four data hubs (Arizona Geoloical Survey, Kentucky Geological Survey, Illinois Geological Survey, and Nevada Bureau of Mines and Geology) serving data for the National Geothermal Data System under the State Contributions to the National Geothermal Data System Project.

  18. Induced seismicity associated with enhanced geothermal system

    SciTech Connect

    Majer, Ernest; Majer, Ernest L.; Baria, Roy; Stark, Mitch; Oates, Stephen; Bommer, Julian; Smith, Bill; Asanuma, Hiroshi

    2006-09-26

    Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role of microseismicity during the creation of the underground reservoir and the subsequent extraction of the energy. The primary objectives of this white paper are to present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and to point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced seismicity. The information was collected though literature searches as well as convening three workshops to gather information from a wide audience. Although microseismicity has been associated with the development of production and injection operations in a variety of geothermal regions, there have been no or few adverse physical effects on the operations or on surrounding communities. Still, there is public concern over the possible amount and magnitude of the seismicity associated with current and future EGS operations. It is pointed out that microseismicity has been successfully dealt with in a variety of non-geothermal as well as geothermal environments. Several case histories are also presented to illustrate a variety of technical and public acceptance issues. It is concluded that EGS Induced seismicity need not pose any threat to the development of geothermal resources if community issues are properly handled. In fact, induced seismicity provides benefits because it can be used as a monitoring tool to understand the

  19. Advancements in 3D Structural Analysis of Geothermal Systems

    SciTech Connect

    Siler, Drew L; Faulds, James E; Mayhew, Brett; McNamara, David

    2013-06-23

    Robust geothermal activity in the Great Basin, USA is a product of both anomalously high regional heat flow and active fault-controlled extension. Elevated permeability associated with some fault systems provides pathways for circulation of geothermal fluids. Constraining the local-scale 3D geometry of these structures and their roles as fluid flow conduits is crucial in order to mitigate both the costs and risks of geothermal exploration and to identify blind (no surface expression) geothermal resources. Ongoing studies have indicated that much of the robust geothermal activity in the Great Basin is associated with high density faulting at structurally complex fault intersection/interaction areas, such as accommodation/transfer zones between discrete fault systems, step-overs or relay ramps in fault systems, intersection zones between faults with different strikes or different senses of slip, and horse-tailing fault terminations. These conceptualized models are crucial for locating and characterizing geothermal systems in a regional context. At the local scale, however, pinpointing drilling targets and characterizing resource potential within known or probable geothermal areas requires precise 3D characterization of the system. Employing a variety of surface and subsurface data sets, we have conducted detailed 3D geologic analyses of two Great Basin geothermal systems. Using EarthVision (Dynamic Graphics Inc., Alameda, CA) we constructed 3D geologic models of both the actively producing Brady’s geothermal system and a ‘greenfield’ geothermal prospect at Astor Pass, NV. These 3D models allow spatial comparison of disparate data sets in 3D and are the basis for quantitative structural analyses that can aid geothermal resource assessment and be used to pinpoint discrete drilling targets. The relatively abundant data set at Brady’s, ~80 km NE of Reno, NV, includes 24 wells with lithologies interpreted from careful analysis of cuttings and core, a 1

  20. A new classification scheme for deep geothermal systems based on geologic controls

    NASA Astrophysics Data System (ADS)

    Moeck, I.

    2012-04-01

    the characteristics of a geothermal system. The thermal regime and heat flow, hydrogeologic regime, fluid dynamics, fluid chemistry, faults and fractures, stress regime, and lithological sequence are controlled by the plate tectonic framework, hence critical for understanding the geothermal system. It is important to identify if the geothermal system is located at active plate boundaries or in intracontinental tectonically quiescent settings and thus how it relates to both active volcanism and active tectonics.

  1. Geothermal Resource Analysis and Structure of Basin and Range Systems, Especially Dixie Valley Geothermal Field, Nevada

    SciTech Connect

    David Blackwell; Kenneth Wisian; Maria Richards; Mark Leidig; Richard Smith; Jason McKenna

    2003-08-14

    Publish new thermal and drill data from the Dizie Valley Geothermal Field that affect evaluation of Basin and Range Geothermal Resources in a very major and positive way. Completed new geophysical surveys of Dizie Valley including gravity and aeromagnetics and integrated the geophysical, seismic, geological and drilling data at Dizie Valley into local and regional geologic models. Developed natural state mass and energy transport fluid flow models of generic Basin and Range systems based on Dizie Valley data that help to understand the nature of large scale constraints on the location and characteristics of the geothermal systems. Documented a relation between natural heat loss for geothermal and electrical power production potential and determined heat flow for 27 different geothermal systems. Prepared data set for generation of a new geothermal map of North American including industry data totaling over 25,000 points in the US alone.

  2. Towards the Understanding of Induced Seismicity in Enhanced Geothermal Systems

    SciTech Connect

    Gritto, Roland; Dreger, Douglas; Heidbach, Oliver

    2014-08-29

    This DOE funded project was a collaborative effort between Array Information Technology (AIT), the University of California at Berkeley (UCB), the Helmholtz Centre Potsdam - German Research Center for Geosciences (GFZ) and the Lawrence Berkeley National Laboratory (LBNL). It was also part of the European research project “GEISER”, an international collaboration with 11 European partners from six countries including universities, research centers and industry, with the goal to address and mitigate the problems associated with induced seismicity in Enhanced Geothermal Systems (EGS). The goal of the current project was to develop a combination of techniques, which evaluate the relationship between enhanced geothermal operations and the induced stress changes and associated earthquakes throughout the reservoir and the surrounding country rock. The project addressed the following questions: how enhanced geothermal activity changes the local and regional stress field; whether these activities can induce medium sized seismicity M > 3; (if so) how these events are correlated to geothermal activity in space and time; what is the largest possible event and strongest ground motion, and hence the potential hazard associated with these activities. The development of appropriate technology to thoroughly investigate and address these questions required a number of datasets to provide the different physical measurements distributed in space and time. Because such a dataset did not yet exist for an EGS system in the United State, we used current and past data from The Geysers geothermal field in northern California, which has been in operation since the 1960s. The research addressed the need to understand the causal mechanisms of induced seismicity, and demonstrated the advantage of imaging the physical properties and temporal changes of the reservoir. The work helped to model the relationship between injection and production and medium sized magnitude events that have

  3. Materials selection guidelines for geothermal energy utilization systems

    SciTech Connect

    Ellis, P.F. II; Conover, M.F.

    1981-01-01

    This manual includes geothermal fluid chemistry, corrosion test data, and materials operating experience. Systems using geothermal energy in El Salvador, Iceland, Italy, Japan, Mexico, New Zealand, and the United States are described. The manual provides materials selection guidelines for surface equipment of future geothermal energy systems. The key chemical species that are significant in determining corrosiveness of geothermal fluids are identified. The utilization modes of geothermal energy are defined as well as the various physical fluid parameters that affect corrosiveness. Both detailed and summarized results of materials performance tests and applicable operating experiences from forty sites throughout the world are presented. The application of various non-metal materials in geothermal environments are discussed. Included in appendices are: corrosion behavior of specific alloy classes in geothermal fluids, corrosion in seawater desalination plants, worldwide geothermal power production, DOE-sponsored utilization projects, plant availability, relative costs of alloys, and composition of alloys. (MHR)

  4. Geothermal down well pumping system

    NASA Technical Reports Server (NTRS)

    Matthews, H. B.; Mcbee, W. D.

    1974-01-01

    A key technical problem in the exploitation of hot water geothermal energy resources is down-well pumping to inhibit mineral precipitation, improve thermal efficiency, and enhance flow. A novel approach to this problem involves the use of a small fraction of the thermal energy of the well water to boil and super-heat a clean feedwater flow in a down-hole exchanger adjacent to the pump. This steam powers a high-speed turbine-driven pump. The exhaust steam is brought to the surface through an exhaust pipe, condensed, and recirculated. A small fraction of the high-pressure clean feedwater is diverted to lubricate the turbine pump bearings and prevent leakage of brine into the turbine-pump unit. A project demonstrating the feasibility of this approach by means of both laboratory and down-well tests is discussed.

  5. Hydrothermal model of the Momotombo geothermal system, Nicaragua

    SciTech Connect

    Verma, M.P.; Martinez, E.; Sanchez, M.; Miranda, K.

    1996-12-31

    The Momotombo geothermal field is situated on the northern shore of Lake Managua at the foot of the active Momotombo volcano. The field has been producing electricity since 1983 and has an installed capacity of 70 MWe. The results of geological, geochemical and geophysical studies have been reported in various internal reports. The isotopic studies were funded by the International Atomic Energy Agency (IAEA), Vienna to develop a hydrothermal model of the geothermal system. The chemical and stable isotopic data ({delta}{sup 18}O and {delta}D) of the geothermal fluid suggest that the seasonal variation in the production characteristics of the wells is related to the rapid infiltration of local precipitation into the reservoir. The annual average composition of Na{sup +}, K{sup +} and Mg{sup 2+} plotted on the Na-K-Mg triangular diagram presented by Giggenbach (1988) to identify the state of rock-water interaction in geothermal reservoirs, shows that the fluids of almost every well are shifting towards chemically immature water due to reservoir exploitation. This effect is prominent in wells Mt-2, Mt-12, Mt-22 and Mt-27. The local groundwaters including surface water from Lake Managua have much lower tritium concentrations than some of the geothermal well fluids, which have about 6 T.U. The high-tritium wells are located along a fault inferred from a thermal anomaly. The tritium concentration is also higher in fluids from wells close to the lake. This could indicate that older local precipitation waters are stored in a deep layer within the lake and that they are infiltrating into the geothermal reservoir.

  6. Finite-element solutions for geothermal systems

    NASA Technical Reports Server (NTRS)

    Chen, J. C.; Conel, J. E.

    1977-01-01

    Vector potential and scalar potential are used to formulate the governing equations for a single-component and single-phase geothermal system. By assuming an initial temperature field, the fluid velocity can be determined which, in turn, is used to calculate the convective heat transfer. The energy equation is then solved by considering convected heat as a distributed source. Using the resulting temperature to compute new source terms, the final results are obtained by iterations of the procedure. Finite-element methods are proposed for modeling of realistic geothermal systems; the advantages of such methods are discussed. The developed methodology is then applied to a sample problem. Favorable agreement is obtained by comparisons with a previous study.

  7. Forecast of geothermal-drilling activity

    SciTech Connect

    Mansure, A.J.; Brown, G.L.

    1982-07-01

    The number of geothermal wells that will be drilled to support electric power production in the United States through 2000 A.D. are forecasted. Results of the forecast are presented by 5-year periods for the five most significant geothermal resources.

  8. The Examination of Afyonkarahisar's Geothermal System Corrosion

    NASA Astrophysics Data System (ADS)

    Buyuksagis, A.; Erol, S.

    2013-02-01

    Corrosion and scaling of metal surfaces are the major problems caused by geothermal fluids when metallic structures are used. This article describes a study of corrosion and scaling problems in the Afyonkarahisar Geothermal Heating System (AFJET) in Afyonkarahisar, Turkey. Water analysis, XRD, SEM, EDX, IC, ICP-OES analyses, and electrochemical methods were used in this study. Pentasodium triphosphate (Na5P3O10), maleic anhydride (C4H2O3), and 1,3-benzendisulfonic acid disodium salt (C6H4Na2O6S2) were used as corrosion inhibitors. Tests were carried out using geothermal water from AF11 well. The experimental temperatures were chosen as 298, 333, and 358 K. Inhibitor concentrations were chosen as 1 × 10-1, 1 × 10-2, 1 × 10-3, and 1 × 10-4 mol/dm3. Moreover, mixed inhibitor solutions were prepared using the inhibitor concentrations that showed the best inhibition. The first mixed inhibitor solution showed 96% inhibition. The second mixed inhibitor solution showed 90% inhibition. The tested inhibitors act as anodic inhibitors. XRD analysis shows that there is CaCO3 aragonite scaling in the system. Increasing TDS, alkalinity, and hardness all promote scale formation. The photomicrographs from SEM-EDX and the metallographic microscope show that the tested inhibitors form a protective film on the surface. IC and ICP-OES analyses show that the concentration of Ca2+ is very high, which supports scale formation.

  9. Tracing Injection Fluids in Engineered Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Rose, P. E.; Leecaster, K.; Mella, M.; Ayling, B.; Bartl, M. H.

    2011-12-01

    The reinjection of produced fluids is crucial to the effective management of geothermal reservoirs, since it provides a mechanism for maintaining reservoir pressures while allowing for the disposal of a toxic byproduct. Tracers are essential to the proper location of injection wells since they are the only known tool for reliably characterizing the flow patterns of recirculated fluids. If injection wells are placed too close to production wells, then reinjected fluids do not have sufficient residence time to extract heat from the reservoir and premature thermal breakthrough results. If injection wells are placed too far away, then the reservoir risks unacceptable pressure loss. Several thermally stable compounds from a family of very detectable fluorescent organic compounds (the naphthalene sulfonates) were characterized and found to be effective for use as geothermal tracers. Through batch-autoclave reactions, their Arrhenius pseudo-first-order decay-rate constants were determined. An analytical method was developed that allows for the laboratory determination of concentrations in the low parts-per-trillion range. Field experiments in numerous geothermal reservoirs throughout the world have confirmed the laboratory findings. Whereas conservative tracers such as the naphthalene sulfonates are effective tools for indicating interwell flow patterns and for measuring reservoir pore volumes, 'reactive' tracers can be used to constrain fracture surface area, which is the effective area for heat extraction. This is especially important for engineered geothermal system (EGS) wells, since reactive tracers can be used to measure fracture surface area immediately after drilling and while the well stimulation equipment is still on site. The reactive properties of these tracers that can be exploited to constrain fracture surface area are reversible sorption, contrasting diffusivity, and thermal decay. Laboratory batch- and flow-reactor experiments in combination with numerical

  10. Blind Geothermal System Exploration in Active Volcanic Environments; Multi-phase Geophysical and Geochemical Surveys in Overt and Subtle Volcanic Systems, Hawai’i and Maui

    SciTech Connect

    Fercho, Steven; Owens, Lara; Walsh, Patrick; Drakos, Peter; Martini, Brigette; Lewicki, Jennifer L.; Kennedy, Burton M.

    2015-08-01

    Suites of new geophysical and geochemical exploration surveys were conducted to provide evidence for geothermal resource at the Haleakala Southwest Rift Zone (HSWRZ) on Maui Island, Hawai’i. Ground-based gravity (~400 stations) coupled with heli-bourne magnetics (~1500 line kilometers) define both deep and shallow fractures/faults, while also delineating potentially widespread subsurface hydrothermal alteration on the lower flanks (below approximately 1800 feet a.s.l.). Multi-level, upward continuation calculations and 2-D gravity and magnetic modeling provide information on source depths, but lack of lithologic information leaves ambiguity in the estimates. Additionally, several well-defined gravity lows (possibly vent zones) lie coincident with magnetic highs suggesting the presence of dike intrusions at depth which may represent a potentially young source of heat. Soil CO2 fluxes were measured along transects across geophysically-defined faults and fractures as well as young cinder cones along the HSWRZ. This survey generally did not detect CO2 levels above background, with the exception of a weak anomalous flux signal over one young cinder cone. The general lack of observed CO2 flux signals on the HSWRZ is likely due to a combination of lower magmatic CO2 fluxes and relatively high biogenic surface CO2 fluxes which mix with the magmatic signal. Similar surveys at the Puna geothermal field on the Kilauea Lower East Rift Zone (KLERZ) also showed a lack of surface CO2 flux signals, however aqueous geochemistry indicated contribution of magmatic CO2 and He to shallow groundwater here. As magma has been intercepted in geothermal drilling at the Puna field, the lack of measured surface CO2 flux indicative of upflow of magmatic fluids here is likely due to effective “scrubbing” by high groundwater and a mature hydrothermal system. Dissolved inorganic carbon (DIC) concentrations, δ13C compositions and 3He/4He values were sampled at Maui from several shallow

  11. Natural radioactivity levels of geothermal waters and their influence on soil and agricultural activities.

    PubMed

    Murat Saç, Müslim; Aydemir, Sercan; Içhedef, Mutlu; Kumru, Mehmet N; Bolca, Mustafa; Ozen, Fulsen

    2014-01-01

    All over the world geothermal sources are used for different purposes. The contents of these waters are important to understand positive/negative effects on human life. In this study, natural radioactivity concentrations of geothermal waters were investigated to evaluate the effect on soils and agricultural activities. Geothermal water samples were collected from the Seferihisar Geothermal Region, and the radon and radium concentrations of these waters were analysed using a collector chamber method. Also soil samples, which are irrigated with geothermal waters, were collected from the surroundings of geothermal areas, and natural radioactivity concentrations of collected samples (U, Th and K) were determined using an NaI(Tl) detector system. The activity concentrations of radon and radium were found to be 0.6-6.0 and 0.1-1.0 Bq l(-1), respectively. Generally, the obtained results are not higher compared with the geothermal waters of the world. The activity concentrations in soils were found to be in the range of 3.3-120.3 Bq kg(-1) for (226)Ra (eU), 0.3-108.5 Bq kg(-1) for (232)Th (eTh), 116.0-850.0 Bq kg(-1) for (40)K (% K). PMID:24026900

  12. Temporary Cementitious Sealers in Enhanced Geothermal Systems

    SciTech Connect

    Sugama T.; Pyatina, T.; Butcher, T.; Brothers, L.; Bour, D.

    2011-12-31

    Unlike conventional hydrothennal geothermal technology that utilizes hot water as the energy conversion resources tapped from natural hydrothermal reservoir located at {approx}10 km below the ground surface, Enhanced Geothermal System (EGS) must create a hydrothermal reservoir in a hot rock stratum at temperatures {ge}200 C, present in {approx}5 km deep underground by employing hydraulic fracturing. This is the process of initiating and propagating a fracture as well as opening pre-existing fractures in a rock layer. In this operation, a considerable attention is paid to the pre-existing fractures and pressure-generated ones made in the underground foundation during drilling and logging. These fractures in terms of lost circulation zones often cause the wastage of a substantial amount of the circulated water-based drilling fluid or mud. Thus, such lost circulation zones must be plugged by sealing materials, so that the drilling operation can resume and continue. Next, one important consideration is the fact that the sealers must be disintegrated by highly pressured water to reopen the plugged fractures and to promote the propagation of reopened fractures. In response to this need, the objective of this phase I project in FYs 2009-2011 was to develop temporary cementitious fracture sealing materials possessing self-degradable properties generating when {ge} 200 C-heated scalers came in contact with water. At BNL, we formulated two types of non-Portland cementitious systems using inexpensive industrial by-products with pozzolanic properties, such as granulated blast-furnace slag from the steel industries, and fly ashes from coal-combustion power plants. These byproducts were activated by sodium silicate to initiate their pozzolanic reactions, and to create a cemetitious structure. One developed system was sodium silicate alkali-activated slag/Class C fly ash (AASC); the other was sodium silicate alkali-activated slag/Class F fly ash (AASF) as the binder of temper

  13. Enthalpy restoration in geothermal energy processing system

    DOEpatents

    Matthews, Hugh B.

    1983-01-01

    A geothermal deep well energy extraction system is provided of the general type in which solute-bearing hot water is pumped to the earth's surface from a relatively low temperature geothermal source by transferring thermal energy from the hot water to a working fluid for driving a primary turbine-motor and a primary electrical generator at the earth's surface. The superheated expanded exhaust from the primary turbine motor is conducted to a bubble tank where it bubbles through a layer of sub-cooled working fluid that has been condensed. The superheat and latent heat from the expanded exhaust of the turbine transfers thermal energy to the sub-cooled condensate. The desuperheated exhaust is then conducted to the condenser where it is condensed and sub-cooled, whereupon it is conducted back to the bubble tank via a barometric storage tank. The novel condensing process of this invention makes it possible to exploit geothermal sources which might otherwise be non-exploitable.

  14. The Radiator-Enhanced Geothermal System

    NASA Astrophysics Data System (ADS)

    Hilpert, M.; Marsh, B. D.; Geiser, P.

    2015-12-01

    Standard Enhanced Geothermal Systems (EGS) have repeatedly been hobbled by the inability of rock to conductively transfer heat at rates sufficient to re-supply heat extracted convectively via artificially made fracture systems. At the root of this imbalance is the basic magnitude of thermal diffusivity for most rocks, which severely hampers heat flow once the cooled halos about fractures reach ~0.1 m or greater. This inefficiency is exacerbated by the standard EGS design of mainly horizontally constructed fracture systems with inflow and outflow access at the margins of the fracture network. We introduced an alternative system whereby the heat exchanger mimics a conventional radiator in an internal combustion engine, which we call a Radiator-EGS (i.e., RAD-EGS). The heat exchanger is built vertically with cool water entering the base and hot water extracted at the top. The RAD-EGS itself consists of a family of vertical vanes produced through sequential horizontal drilling and permeability stimulation through propellant fracking. The manufactured fracture zones share the orientation of the natural transmissive fracture system. As below about 700 m, S1 is vertical and the average strike of transmissive fractures parallels SHmax, creating vertical fractures that include S1 and SHmax requires drilling stacked laterals parallel to SHmax. The RAD-EGS is also based on the observation that the longevity of natural hydrothermal systems depends on thermal recharge through heat convection but not heat conduction. In this paper, we present numerical simulations that examine the effects of the depths of the injector and extraction wells, vane size, coolant flow rate, the natural crustal geothermal gradient, and natural regional background flow on geothermal energy extraction.

  15. National Geothermal Data System: Transforming the Discovery, Access, and Analytics of Data for Geothermal Exploration

    SciTech Connect

    Patten, Kim

    2013-05-01

    Compendium of Papers from the 38th Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California February 11-13, 2013 The National Geothermal Data System (NGDS) is a distributed, interoperable network of data collected from state geological surveys across all fifty states and the nation’s leading academic geothermal centers. The system serves as a platform for sharing consistent, reliable, geothermal-relevant technical data with users of all types, while supplying tools relevant for their work. As aggregated data supports new scientific findings, this content-rich linked data ultimately broadens the pool of knowledge available to promote discovery and development of commercial-scale geothermal energy production. Most of the up-front risks associated with geothermal development stem from exploration and characterization of subsurface resources. Wider access to distributed data will, therefore, result in lower costs for geothermal development. NGDS is on track to become fully operational by 2014 and will provide a platform for custom applications for accessing geothermal relevant data in the U.S. and abroad. It is being built on the U.S. Geoscience Information Network (USGIN) data integration framework to promote interoperability across the Earth sciences community. The basic structure of the NGDS employs state-of-the art informatics to advance geothermal knowledge. The following four papers comprising this Open-File Report are a compendium of presentations, from the 38th Annual Workshop on Geothermal Reservoir Engineering, taking place February 11-13, 2013 at Stanford University, Stanford, California. “NGDS Geothermal Data Domain: Assessment of Geothermal Community Data Needs,” outlines the efforts of a set of nationwide data providers to supply data for the NGDS. In particular, data acquisition, delivery, and methodology are discussed. The paper addresses the various types of data and metadata required and why simple links to existing

  16. Numerical models for the evaluation of geothermal systems

    SciTech Connect

    Bodvarsson, G.S.; Pruess, K.; Lippmann, M.J.

    1986-08-01

    We have carried out detailed simulations of various fields in the USA (Bada, New Mexico; Heber, California); Mexico (Cerro Prieto); Iceland (Krafla); and Kenya (Olkaria). These simulation studies have illustrated the usefulness of numerical models for the overall evaluation of geothermal systems. The methodology for modeling the behavior of geothermal systems, different approaches to geothermal reservoir modeling and how they can be applied in comprehensive evaluation work are discussed.

  17. Hydrothermal model of the Momotombo geothermal system, Nicaragua

    SciTech Connect

    Verma, M.P.; Martinez, E.; Sanchez, M.; Miranda, K.; Gerardo, J.Y.; Araguas, L.

    1996-01-24

    The Momotombo geotherinal field is situated on the northern shore of Lake Managua at the foot of the active Momotombo volcano. The field has been producing electricity since 1983 and has an installed capacity of 70 MWe. The results of geological, geochemical and geophysical studies have been reported in various internal reports. The isotopic studies were funded by the International Atomic Energy Agency (IAEA), Vienna to develop a hydrothermal model of the geothermal system. The chemical and stable isotopic data (δ18O and δD) of the geothermal fluid suggest that the seasonal variation in the production characteristics of the wells is related to the rapid infiltration of local precipitation into the reservoir. The annual average composition of Na+, K+ and Mg2+ plotted on the Na- K-Mg triangular diagram presented by Giggenbach (1988) to identify the state of rock-water interaction in geothermal reservoirs, shows that the fluids of almost every well are shifting towards chemically immature water due to resenroir exploitation. This effect is prominent in wells Mt-2. Mt-12, Mt-22 and Mt-27. The local groundwaters including surface water from Lake Managua have much lower tritium concentrations than sonic of the geothermal well fluids, which have about 6 T.U. The high-tritium wells are located along a fault inferred froin a thermal anomaly. The tritium concentration is also higher in fluids from wells close to the lake. This could indicate that older local precipitation waters are stored in a deep layer within the lake and that they are infiltrating into the geothermal reservoir.

  18. Geothermal Systems of the Yellowstone Caldera Field Trip Guide

    SciTech Connect

    Foley, Duncan; Neilson, Dennis L.; Nichols, Clayton R.

    1980-09-08

    Geothermal studies are proceedings on two fronts in the West Yellowstone area. High-temperature resources for the generation of electricity are being sought in the Island Park area, and lower temperatures resources for direct applications, primarily space heating, are being explored for near the town of West Yellowstone. Potential electric geothermal development in the Island Park area has been the subject of widespread publicity over fears of damage to thermal features in Yellowstone Park. At the time of writing this guide, companies have applied for geothermal leases in the Island Park area, but these leases have not yet been granted by the US Forest Service. The Senate is now discussing a bill that would regulate geothermal development in Island Park; outcome of this debate will determine the course of action on the lease applications. The Island Park area was the site of two cycles of caldera activity, with major eruptions at 2.0 and 1.2 million years ago. The US Geological Survey estimates that 16,850 x 10{sup 18} joules of energy may remain in the system. Geothermal resources suitable for direct applications are being sought in the West Yellowstone vicinity by the Montana Bureau of Mines and Geology, under funding from the US Department of Energy. West Yellowstone has a mean annual temperature of 1-2 C. Research thus far suggests that basement rocks in the vicinity are at a depth of about 600 m and are probably similar to the rocks exposed north of Hebgen Lake, where Precambrian, Paleozoic and Mesozoic rocks have been mapped. A few sites with anomalously warm water have been identified near the town. Work is continuing on this project.

  19. Geothermal energy control system and method

    DOEpatents

    Matthews, Hugh B.

    1977-01-01

    A geothermal energy transfer and utilization system makes use of thermal energy stored in hot solute-bearing well water to generate super-heated steam from an injected flow of clean water; the super-heated steam is then used for operating a turbine-driven pump at the well bottom for pumping the hot solute-bearing water at high pressure and in liquid state to the earth's surface, where it is used by transfer of its heat to a closed-loop boiler-turbine-alternator combination for the generation of electrical or other power. Residual concentrated solute-bearing water is pumped back into the earth. The clean cooled water is regenerated at the surface-located system and is returned to the deep well pumping system also for lubrication of a novel bearing arrangement supporting the turbine-driven pump system. The bearing system employs liquid lubricated thrust and radial bearings with all bearing surfaces bathed in clean water serving as a lubricant and maintained under pressure to prevent entry into the bearings of contaminated geothermal fluid, an auxiliary thrust ball bearing arrangement comes into operation when starting or stopping the pumping system.

  20. AASG State Geothermal Data Repository for the National Geothermal Data System.

    Energy Science and Technology Software Center (ESTSC)

    2012-01-01

    This Drupal metadata and documents capture and management system is a repository, used for maintenance of metadata which describe resources contributed to the AASG State Geothermal Data System. The repository also provides an archive for files that are not hosted by the agency contributing the resource. Data from all 50 state geological surveys is represented here, and is contributed in turn to the National Geothermal Data System.

  1. Triggered Swarms and Induced Aftershock Sequences in Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Shcherbakov, R.; Turcotte, D. L.; Yikilmaz, M. B.; Kellogg, L. H.; Rundle, J. B.

    2015-12-01

    Natural geothermal systems, which are used for energy generation, are usually associated with high seismic activity. This can be related to the large-scale injection and extraction of fluids to enhance geothermal recovery. This results in the changes of the pore pressure and pore-elastic stress field and can stimulate the occurrence of earthquakes. These systems are also prone to triggering of seismicity by the passage of seismic waves generated by large distant main shocks. In this study, we analyze clustering and triggering of seismicity at several geothermal fields in California. Particularly, we consider the seismicity at the Geysers, Coso, and Salton Sea geothermal fields. We analyze aftershock sequences generated by local large events with magnitudes greater than 4.0 and earthquake swarms generated by several significant long distant main shocks. We show that the rate of the aftershock sequences generated by the local large events in the two days before and two days after the reference event can be modelled reasonably well by the time dependent Epidemic Type Aftershock Sequence (ETAS) model. On the other hand, the swarms of activity triggered by large distant earthquakes cannot be described by the ETAS model. To model the increase in the rate of seismicity associated with triggering by large distant main shocks we introduce an additional time-dependent triggering mechanism into the ETAS model. In almost all cases the frequency-magnitude statistics of triggered sequences follow Gutenberg-Richter scaling to a good approximation. The analysis indicates that the seismicity triggered by relatively large local events can initiate sequences similar to regular aftershock sequences. In contrast, the distant main shocks trigger swarm like activity with faster decaying rates.

  2. Choosing a Geothermal as an HVAC System.

    ERIC Educational Resources Information Center

    Lensenbigler, John D.

    2002-01-01

    Describes the process of selecting and installing geothermal water source heat pumps for new residence halls at Johnson Bible College in Knoxville, Tennessee, including choosing the type of geothermal design, contractors, and interior equipment, and cost and payback. (EV)

  3. Geothermal systems in volcanic arcs: Volcanic characteristics and surface manifestations as indicators of geothermal potential and favorability worldwide

    NASA Astrophysics Data System (ADS)

    Stelling, P.; Shevenell, L.; Hinz, N.; Coolbaugh, M.; Melosh, G.; Cumming, W.

    2016-09-01

    This paper brings a global perspective to volcanic arc geothermal assessments by evaluating trends and correlations of volcanic characteristic and surface manifestation data from world power production sites in subduction zone volcanic settings. The focus of the work was to evaluate volcanic centers individually and as a group in these arcs by correlating various geologic characteristics with known potential to host electricity grade geothermal systems at the volcanic centers. A database was developed that describes key geologic factors expected to be indicative of productive geothermal systems in a global training set, which includes all 74 subduction zone volcanic centers world-wide with current or proven power production capability. Importantly, this data set only contains data from subduction zone volcanoes and contains no negative cases, limiting the populations of any statistical groups. Regardless, this is the most robust geothermal benchmark training set for magmatic-heated systems to date that has been made public. The work reported here is part of a larger project that included data collection, evaluation, correlations and weightings, fairway and favorability modeling and mapping, prediction of blind systems, and uncertainty analysis to estimate errors associated with model predictions. This first paper describes volcano characteristics, compositions and eruption ages and trends along with surface manifestation observations and temperatures as they relate to known power producing systems. Our findings show a strong correlation between the presence and size of active flank fumarole areas and installed power production. Additionally, the majority of volcanic characteristics, including long-held anecdotal correlations related to magmatic composition or size, have limited to no correlation with power production potential. Notable exceptions are correlations between greater power yield from geothermal systems associated with older (Pleistocene) caldera systems

  4. ELVIS: Multi-Electrolyte Aqueous Activity Model for Geothermal Solutions

    NASA Astrophysics Data System (ADS)

    Hingerl, F. F.; Wagner, T.; Driesner, T.; Kulik, D. A.; Kosakowski, G.

    2011-12-01

    High temperature, pressure, and fluid salinities render geochemical modeling of fluid-rock interactions in Enhanced Geothermal Systems a demanding task. Accurate prediction of fluid-mineral equilibria strongly depends on the availability of thermodynamic data and activity models. Typically, the Pitzer activity model is applied for geothermal fluids. A drawback of this model is the large number of parameters required to account for temperature and pressure dependencies, which significantly reduces computational efficiency of reactive transport simulations. In addition, most available parameterizations are valid only at vapor-saturated conditions. As an alternative we implemented the EUNIQUAC local composition model [2] that needs substantially fewer fitting parameters. However, the current EUNIQUAC model design does not include provision for high temperature (>150°C) applications and lacks a formulation for pressure dependence. Therefore, its application to geothermal conditions requires a re-formulation and re-fitting of the model. We developed a new tool termed GEMSFIT that allows generic fitting of activity models (for aqueous electrolyte and non-electrolyte solutions) and equations of state implemented in our geochemical equilibrium solver GEM-Selektor (http://gems.web.psi.ch). GEMSFIT combines a PostgreSQL database for storing and managing the datasets of experimental measurements and interaction parameters, the parallelized genetic algorithm toolbox of MATLAB° for the parameter fitting, and an interface to the numerical kernel of GEM-Selektor to access activity models and perform chemical equilibrium calculations. Benchmarking of the partly re-parameterized EUNIQUAC model against Pitzer revealed that the former is less accurate, which can result in incorrect predictions of mineral precipitation/dissolution. Consequently, we modified the EUNIQUAC model and concurrently introduced a pressure dependence to be able to fit experimental data over wide ranges of

  5. GEOTHERMAL ENVIRONMENTAL IMPACT ASSESSMENT: SUBSURFACE ENVIRONMENTAL ASSESSMENT FOR FOUR GEOTHERMAL SYSTEMS

    EPA Science Inventory

    This is the second in a series of reports concerning the environmental assessments of effluent extraction, energy conversion, and waste disposal in geothermal systems. This study involves the subsurface environmental impact of the Imperial Valley and The Geysers, California; Klam...

  6. Tracers for Characterizing Enhanced Geothermal Systems

    SciTech Connect

    Karen Wright; George Redden; Carl D. Palmer; Harry Rollins; Mark Stone; Mason Harrup; Laurence C. Hull

    2010-02-01

    Information about the times of thermal breakthrough and subsequent rates of thermal drawdown in enhanced geothermal systems (EGS) is necessary for reservoir management, designing fracture stimulation and well drilling programs, and forecasting economic return. Thermal breakthrough in heterogeneous porous media can be estimated using conservative tracers and assumptions about heat transfer rates; however, tracers that undergo temperature-dependent changes can provide more detailed information about the thermal profile along the flow path through the reservoir. To be effectively applied, the thermal reaction rates of such temperature sensitive traces must be well characterized for the range of conditions that exist in geothermal systems. Reactive tracers proposed in the literature include benzoic and carboxylic acids (Adams) and organic esters and amides (Robinson et al.); however, the practical temperature range over which these tracers can be applied (100-275°C) is somewhat limited. Further, for organic esters and amides, little is known about their sorption to the reservoir matrix and how such reactions impact data interpretation. Another approach involves tracers where the reference condition is internal to the tracer itself. Two examples are: 1) racemization of polymeric amino acids, and 2) mineral thermoluminescence. In these cases internal ratios of states are measured rather than extents of degradation and mass loss. Racemization of poly-L-lactic acid (for example) is temperature sensitive and therefore can be used as a temperature-recording tracer depending on the rates of racemization and stability of the amino acids. Heat-induced quenching of thermoluminescence of pre-irradiated LiF can also be used. To protect the tracers from alterations (extraneous reactions, dissolution) in geothermal environments we are encapsulating the tracers in core-shell colloidal structures that will subsequently be tested for their ability to be transported and to protect the

  7. Geothermal energy control system and method

    DOEpatents

    Matthews, Hugh B.

    1976-01-01

    A geothermal energy transfer and utilization system makes use of thermal energy stored in hot solute-bearing well water to generate super-heated steam from an injected flow of clean water; the super-heated steam is then used for operating a turbine-driven pump at the well bottom for pumping the hot solute-bearing water at high pressure and in liquid state to the earth's surface, where it is used by transfer of its heat to a closed-loop boiler-turbine-alternator combination for the generation of electrical or other power. Residual concentrated solute-bearing water is pumped back into the earth. The clean cooled water is regenerated at the surface-located system and is returned to the deep well pumping system also for lubrication of a novel bearing arrangement supporting the turbine-driven pump system.

  8. National Geothermal Data System: A Geothermal Data System for Exploration and Development

    SciTech Connect

    Allison, Lee; Richard, Stephen; Patten, Kim; Love, Diane; Coleman, Celia; Chen, Genhan

    2012-09-30

    Geothermal-relevant geosciences data from all 50 states (www.stategeothermaldata.org), federal agencies, national labs, and academic centers are being digitized and linked in a distributed online network funded by the U.S. Department of Energy Geothermal Data System (GDS) to foster geothermal energy exploration and development through use of interactive online ‘mashups,’data integration, and applications. Emphasis is first to make as much information as possible accessible online, with a long range goal to make data interoperable through standardized services and interchange formats. A growing set of more than thirty geoscience data content models is in use or under development to define standardized interchange formats for: aqueous chemistry, borehole temperature data, direct use feature, drill stem test, seismic event hypocenter, fault feature, geologic contact feature, geologic unit feature, thermal/hot spring description, metadata, quaternary fault, volcanic vent description, well header feature, borehole lithology log, crustal stress, gravity, heat flow/temperature gradient, permeability, and feature description data like developed geothermal systems, geologic unit geothermal characterization, permeability, production data, rock alteration description, rock chemistry, and thermal conductivity. Map services are also being developed for isopach maps, aquifer temperature maps, and several states are working on geothermal resource overview maps. Content models are developed based on existing community datasets to encourage widespread adoption and promulgate content quality standards. Geoscience data and maps from other GDS participating institutions, or “nodes” (e.g., U.S. Geological Survey, Southern Methodist University, Oregon Institute of Technology, Stanford University, the University of Utah) are being supplemented with extensive land management and land use resources from the Western Regional Partnership (15 federal agencies and 5 Western states) to

  9. Mantle helium and carbon isotopes in Separation Creek Geothermal Springs, Three Sisters area, Central Oregon: Evidence for renewed volcanic activity or a long term steady state system?

    SciTech Connect

    van Soest, M.C.; Kennedy, B.M.; Evans, W.C.; Mariner, R.H.

    2002-04-30

    Cold bubbling springs in the Separation Creek area, the locus of current uplift at South Sister volcano show strong mantle signatures in helium and carbon isotopes and CO{sub 2}/{sup 3}He. This suggests the presence of fresh basaltic magma in the volcanic plumbing system. Currently there is no evidence to link this system directly to the uplift, which started in 1998. To the contrary, all geochemical evidence suggests that there is a long-lived geothermal system in the Separation Creek area, which has not significantly changed since the early 1990s. There was no archived helium and carbon data, so a definite conclusion regarding the strong mantle signature observed in these tracers cannot yet be drawn. There is a distinct discrepancy between the yearly magma supply required to explain the current uplift (0.006 km{sup 3}/yr) and that required to explain the discharge of CO{sub 2} from the system (0.0005 km{sup 3}/yr). This discrepancy may imply that the chemical signal associated with the increase in magma supply has not reached the surface yet. With respect to this the small changes observed at upper Mesa Creek require further attention, due to the recent volcanic vent in that area it may be the location were the chemical signal related to the uplift can most quickly reach the surface. Occurrence of such strong mantle signals in cold/diffuse geothermal systems suggests that these systems should not be ignored during volcano monitoring or geothermal evaluation studies. Although the surface-expression of these springs in terms of heat is minimal, the chemistry carries important information concerning the size and nature of the underlying high-temperature system and any changes taking place in it.

  10. Quantitative Risk Assessment for Enhanced Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Lowry, T. S.; McKenna, S. A.; Hadgu, T.; Kalinina, E.

    2011-12-01

    This study uses a quantitative risk-assessment approach to place the uncertainty associated with enhanced geothermal systems (EGS) development into meaningful context and to identify points of attack that can reduce risk the most. Using the integrated geothermal assessment tool, GT-Mod, we calculate the complimentary cumulative distribution function of the levelized cost of electricity (LCOE) that results from uncertainty in a variety of geologic and economic input parameter values. EGS is a developing technology that taps deep (2-10km) geologic heat sources for energy production by "enhancing" non-permeable hot rock through hydraulic stimulation. Despite the promise of EGS, uncertainties in predicting the physical end economic performance of a site has hindered its development. To address this, we apply a quantitative risk-assessment approach that calculates risk as the sum of the consequence, C, multiplied by the range of the probability, ΔP, over all estimations of a given exceedance probability, n, over time, t. The consequence here is defined as the deviation from the best estimate LCOE, which is calculated using the 'best-guess' input parameter values. The analysis assumes a realistic but fictitious EGS site with uncertainties in the exploration success rate, the sub-surface thermal gradient, the reservoir fracture pattern, and the power plant performance. Uncertainty in the exploration, construction, O&M, and drilling costs are also included. The depth to the resource is calculated from the thermal gradient and a target resource temperature of 225 °C. Thermal performance is simulated using the Gringarten analytical solution. The mass flow rate is set to produce 30 MWe of power for the given conditions and is adjusted over time to maintain that rate over the plant lifetime of 30 years. Simulations are conducted using GT-Mod, which dynamically links the physical systems of a geothermal site to simulate, as an integrated, multi-system component, the

  11. A U Th calcite isochron age from an active geothermal field in New Zealand

    NASA Astrophysics Data System (ADS)

    Grimes, Stephen; Rickard, David; Hawkesworth, Chris; van Calsteren, Peter; Browne, Patrick

    1998-05-01

    We report here the first U-Th disequilibrium age for a hydrothermal mineral from an active geothermal system in New Zealand. Vein calcite recovered from a depth of 389 m in Well Thm-1 at the Tauhara geothermal field has an age of 99±44 ka BP. This age was determined using a leachate-leachate isochron technique on four silicate containing sub-samples of calcite from a single vein. Although the error on this isochron age is considerable, it is significantly younger than the earlier estimated age of ˜200 ka BP for the onset of activity at the Tauhara system and probably records the date of brecciation and veining, which may be associated with volcanic activity at the adjacent dacitic Tauhara Volcanic Complex. These results demonstrate that hydrothermal vein calcite can now be dated directly, and opens the way for more detailed studies of the evolution of the New Zealand geothermal systems.

  12. Geothermal activity in Italy: present status and future prospects

    SciTech Connect

    Carella, R.; Palmerini, C.G.; Stefani, G.C.; Verdiani, G.

    1985-01-01

    In the Italian Peninsula the Apennines separate a relatively cold Po-Adriatic-Ionian ''foredeep'' external belt from a warmer Tyrrhenian ''back-arc'' internal tensional belt. The latter i characterized by high geothermal heat flow together with conspicuous recent or present-day volcani phenomena. In this area, extending from Tuscany to Campania, lie the known steam- and waterdominated fields. Other ''warm'' areas are located on some Tyrrhenian islands. Within the ''cold'' external belt, interesting locations for low enthalpy utilizations can be found in the Po river valley, particularly in the eastern part near Ferrara and Abano. Since 1977 ENEL (National Electri Energy Agency) and AGIP (State Oil Company) have been jointly conducting geothermal activities in Italy, with the exception of the Tuscan geothermal area where ENEL operates on an exclusive basis. At present the areas surveyed cover about 8250 kmS. As of December 1983 the geothermal installed capacity was 456.2 MW (net capacity 340 MW) and low-temperature geothermal resources equivalent to 100,000 OET /yr were being used. The National Energy Plant (PEN), issued on 4 December 1981, forecast for the year 1990 a geothermal power increment of 200 MW /SUB e/ above the 449.1 MW /SUB e/ already installed. The target in the low enthalpy non-electric sector is to save 300,000 OET/yr by 1990. This paper describes the activities carried out from March 1975 to December 1983 and the main projects in progress.

  13. Active and passive seismic studies of geothermal resources in New Mexico and investigations of earthquake hazards to geothermal development

    SciTech Connect

    Morgan, P.; Daggett, P.H.

    1980-01-01

    Seismic data were collected in southwestern New Mexico to investigate the sources of the geothermal anomalies and to investigate the potential earthquake hazards of geothermal development. No major crustal structure anomalies have been located related to known geothermal resources, and no areas of continual seismicity have been identified, which is interpreted to indicate a lack of active, or recently active crustal intrusions in southwestern New Mexico. Without a magnetic heat source, the geothermal potential of the known anomalies is probably limited to intermediate and low temperature applications (<180/sup 0/C). The lack of continual seismicity indicates low seismic hazard in the area directly related to geothermal development, although the historic and geologically recent tectonic activity should be taken into consideration during any development in the area. A model of forced groundwater convection is presented to explain the geothermal anomalies in southwestern New Mexico, which is consistent with all available geological and geophysical data from the area.

  14. Active and Fossil Geothermal Activity at Lake Chapala, Mexico

    NASA Astrophysics Data System (ADS)

    Zârate-del Vall, P.

    2002-12-01

    Geothermal systems are very abundant in the tectonically active zones of the earth's crust and the Citala rift, where Lake Chapala is located, is not the exception. The Lake Chapala basin is characterized by its paleo- and actual geothermal activity that includes: thermal springs, fossil sinter deposits and hydrothermal petroleum manifestations. Thermal springs occur both inside and outside the lake. The spring water in out-shore thermal springs around Lake Chapala is carbonate (Medina-Heredia A, 1986). To the NE area is San Luis Agua Caliente (69°C; ~ 240 mg L-1 [HCO3]1) in the NW at Jocotepec (36°C; ~263mg L-1 [HCO3]-); in the South we find Tuxcueca and Tizap n El Alto (30°C; 193 mg L-1 [HCO3]-). However, there is an exception, the spring water at the San Juan Cosal sector (North), which is sulfate (64-83°C; ~479 mg L-1, [SO4]-2). Examples of in-shore thermal springs are "Los Gorgos" (near South shore) and "El Fuerte" (near East shore and temporary "out-shore" because of actual severe drought); the characterisation of water of this in-shore sites is in progress. On the SE shore and five km NW from Regules village, outcrops a carbonate deposit named "La Calera". This carbonate fossil sinter outcrops 2 km in E-W direction and 600 m in N-S direction and overlays andesitic rock. With a thickness of approximately 5m and a roughly horizontal attitude, the carbonated sinter material is characterized by both massive and banded structure. When massive, it is colored in yellow brownish and grey and elsewhere it shows a pseudo-brecciated structure and when banded, alternated of yellow and dark millimetre bands can be seen; is characterized by vuggy porosity and silica (quartz and chalcedony) vein lets. Under microscope a pseudo-micritic texture is observed; vugs coated by iron oxides, are filled with calcite, and/or quartz, chalcedony and clay minerals. Six samples of carbonate of "La Calera" deposit were analysed for their stable isotopes (LODC-UParis VI). From δ 13

  15. GEOTHERM Data Set

    DOE Data Explorer

    DeAngelo, Jacob

    1983-01-01

    GEOTHERM is a comprehensive system of public databases and software used to store, locate, and evaluate information on the geology, geochemistry, and hydrology of geothermal systems. Three main databases address the general characteristics of geothermal wells and fields, and the chemical properties of geothermal fluids; the last database is currently the most active. System tasks are divided into four areas: (1) data acquisition and entry, involving data entry via word processors and magnetic tape; (2) quality assurance, including the criteria and standards handbook and front-end data-screening programs; (3) operation, involving database backups and information extraction; and (4) user assistance, preparation of such items as application programs, and a quarterly newsletter. The principal task of GEOTHERM is to provide information and research support for the conduct of national geothermal-resource assessments. The principal users of GEOTHERM are those involved with the Geothermal Research Program of the U.S. Geological Survey.

  16. Combined cycle power unit with a binary system based on waste geothermal brine at Mutnovsk geothermal power plant

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Shipkov, A. A.; Nikol'skii, A. I.; Semenov, V. N.

    2016-06-01

    The Russian geothermal power systems developed in the last few decades outperform their counterparts around the world in many respects. However, all Russian geothermal power stations employ steam as the geothermal fluid and discard the accompanying geothermal brine. In reality, the power of the existing Russian geothermal power stations may be increased without drilling more wells, if the waste brine is employed in combined cycle systems with steam and binary turbine units. For the example of the 50 MW Mutnovsk geothermal power plant, the optimal combined cycle power unit based on the waste geothermal brine is considered. It is of great interest to determine how the thermodynamic parameters of the secondary steam in the expansion unit and the pressure in the condenser affect the performance of the equipment in the combined cycle power unit at Mutnovsk geothermal power plant. For the utilization of the waste geothermal brine at Mutnovsk geothermal power plant, the optimal air temperature in the condensers of the combined cycle power unit is +5°C. The use of secondary steam obtained by flashing of the geothermal brine at Mutnovsk geothermal power plant 1 at a pressure of 0.2 MPa permits the generation of up to 8 MW of electric power in steam turbines and additional power of 5 MW in the turbines of the binary cycle.

  17. Mapping temperature and radiant geothermal heat flux anomalies in the Yellowstone geothermal system using ASTER thermal infrared data

    USGS Publications Warehouse

    Vaughan, R. Greg; Lowenstern, Jacob B.; Keszthelyi, Laszlo P.; Jaworowski, Cheryl; Heasler, Henry

    2012-01-01

    The purpose of this work was to use satellite-based thermal infrared (TIR) remote sensing data to measure, map, and monitor geothermal activity within the Yellowstone geothermal area to help meet the missions of both the U.S. Geological Survey Yellowstone Volcano Observatory and the Yellowstone National Park Geology Program. Specifically, the goals were to: 1) address the challenges of remotely characterizing the spatially and temporally dynamic thermal features in Yellowstone by using nighttime TIR data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and 2) estimate the temperature, geothermal radiant emittance, and radiant geothermal heat flux (GHF) for Yellowstone’s thermal areas (both Park wide and for individual thermal areas). ASTER TIR data (90-m pixels) acquired at night during January and February, 2010, were used to estimate surface temperature, radiant emittance, and radiant GHF from all of Yellowstone’s thermal features, produce thermal anomaly maps, and update field-based maps of thermal areas. A background subtraction technique was used to isolate the geothermal component of TIR radiance from thermal radiance due to insolation. A lower limit for the Yellowstone’s total radiant GHF was established at ~2.0 GW, which is ~30-45% of the heat flux estimated through geochemical (Cl-flux) methods. Additionally, about 5 km2 was added to the geodatabase of mapped thermal areas. This work provides a framework for future satellite-based thermal monitoring at Yellowstone as well as exploration of other volcanic / geothermal systems on a global scale.

  18. The significance of "geothermal microzonation" for the correct planning of low-grade source geothermal systems

    NASA Astrophysics Data System (ADS)

    Viccaro, Marco; Pezzino, Antonino; Belfiore, Giuseppe Maria; Campisano, Carlo

    2016-04-01

    Despite the environmental-friendly energy systems are solar thermal technologies, photovoltaic and wind power, other advantageous technologies exist, although they have not found wide development in countries such as Italy. Given the almost absent environmental impact and the rather favorable cost/benefit ratio, low-enthalpy geothermal systems are, however, likely to be of strategic importance also in Italy during the next years. The importance of geology for a sustainable exploitation of the ground through geothermal systems from low-grade sources is becoming paramount. Specifically, understanding of the lithological characteristics of the subsurface along with structures and textures of rocks is essential for a correct planning of the probe/geo-exchanger field and their associated ground source heat pumps. The complex geology of Eastern Sicily (Southern Italy), which includes volcanic, sedimentary and metamorphic units over limited extension, poses the question of how thermal conductivity of rocks is variable at the scale of restricted areas (even within the same municipality). This is the innovative concept of geothermal microzonation, i.e., how variable is the geothermal potential as a function of geology at the microscale. Some pilot areas have been therefore chosen to test how the geological features of the subsurface can influence the low-enthalpy geothermal potential of an area. Our geologically based evaluation and micro-zonation of the low-grade source geothermal potential of the selected areas have been verified to be fundamental for optimization of all the main components of a low-enthalpy geothermal system. Saving realization costs and limiting the energy consumption through correct sizing of the system are main ambitions to have sustainable development of this technology with intensive utilization of the subsurface. The variegated territory of countries such as Italy implies that these goals can be only reached if, primarily, the geological features

  19. 3D characterization of a Great Basin geothermal system: Astor Pass, NV

    SciTech Connect

    Siler, Drew L; Brett, Mayhew; Faulds, James E

    2012-12-03

    The Great Basin exhibits both anomalously high heat flow (~75±5 mWm-2) and active faulting and extension resulting in robust geothermal activity. There are ~430 known geothermal systems in the Great Basin, with evidence suggesting that undiscovered blind geothermal systems may actually represent the majority of geothermal activity. These systems employ discrete fault intersection/interaction areas as conduits for geothermal circulation. Recent studies show that steeply dipping normal faults with step-overs, fault intersections, accommodation zones, horse-tailing fault terminations and transtensional pull-aparts are the most prominent structural controls of Great Basin geothermal systems. These fault geometries produce sub-vertical zones of high fault and fracture density that act as fluid flow conduits. Structurally controlled fluid flow conduits are further enhanced when critically stressed with respect to the ambient stress conditions. The Astor Pass blind geothermal system, northwestern Nevada, lies along the boundary between the Basin and Range to the east and the Walker Lane to the west. Along this boundary, strain is transferred from dextral shear in the Walker Lane to west-northwest directed extension in the Basin and Range. As such, the Astor Pass area lies in a transtensional setting consisting of both northwest-striking, left-stepping dextral faults and more northerly striking normal faults. The Astor Pass tufa tower implies the presence of a blind geothermal system. Previous studies suggest that deposition of the Astor Pass tufa was controlled by the intersection of a northwest-striking dextral normal fault and north-northwest striking normal fault. Subsequent drilling (to ~1200 m) has revealed fluid temperatures of ~94°C, confirming the presence of a blind geothermal system at Astor Pass. Expanding upon previous work and employing additional detailed geologic mapping, interpretation of 2D seismic reflection data and analysis of well cuttings, a 3

  20. Geology of the Rotorua geothermal system

    SciTech Connect

    Wood, C.P. )

    1992-04-01

    This paper discusses the Rotorua geothermal system located in the south part of Rotorua Caldera, which collapsed during and after the eruption of Mamaku Ignimbrite some 140 ka ago. Drillholes provide geological and hydrological information to 300 m depth. The Mamaku Ignimbrite aquifer has been drilled in the east and south of the field where it contains fluid at or near boiling point. The Ignimbrite drops from south to north across exposed and buried caldera collapse scarps. Rotorua City domes comprise a buried N-S ridge rising at either end to form north and south domes; both contain mostly sub-boiling water up to 190{degrees} C which flows laterally through the outer 40 m of permeably rhyolite as indicated by temperature data. The Fenton Park aquifer comprises sands and gravels in the shallow sedimentary sequence which contain hot water derived possibly from Whakarewarewa, the south dome or the Rotoatamaheke Fault.

  1. United Nations geothermal activities in developing countries

    SciTech Connect

    Beredjick, N.

    1987-07-01

    The United Nations implements technical cooperation projects in developing countries through its Department of Technical Cooperation for Development (DTCD). The DTCD is mandated to explore for and develop natural resources (water, minerals, and relevant infrastructure) and energy - both conventional and new and renewable energy sources. To date, the United Nations has been involved in over 30 geothermal exploration projects (completed or underway) in 20 developing countries: 8 in Africa (Djibouti, Ethiopia, Kenya, Madagascar); 8 in Asia (China, India, Jordan, Philippines, Thailand); 9 in Latin America (Bolivia, Chile, El Salvador, Honduras, Mexico, Nicaragua, Panama) and 6 in Europe (Greece, Romania, Turkey, Yugoslavia). Today, the DTCD has seven UNDP geothermal projects in 6 developing countries. Four of these (Bolivia, China, Honduras, and Kenya) are major exploration projects whose formulation and execution has been possible thanks to the generous contributions under cost-sharing arrangements from the government of Italy. These four projects are summarized.

  2. A Technology Roadmap for Strategic Development of Enhanced Geothermal Systems

    SciTech Connect

    Ziagos, John; Phillips, Benjamin R.; Boyd, Lauren; Jelacic, Allan; Stillman, Greg; Hass, Eric

    2013-02-13

    Realization of EGS development would make geothermal a significant contender in the renewable energy portfolio, on the order of 100+ GWe in the United States alone. While up to 90% of the geothermal power resource in the United States is thought to reside in Enhanced Geothermal Systems (EGS), hurdles to commercial development still remain. The Geothermal Technologies Office, U.S. Department of Energy (DOE), began in 2011 to outline opportunities for advancing EGS technologies on five- to 20-year timescales, with community input on the underlying technology needs that will guide research and ultimately determine commercial success for EGS. This report traces DOE's research investments, past and present, and ties them to these technology needs, forming the basis for an EGS Technology Roadmap to help guide future DOE research. This roadmap is currently open for public comment. Send your comments to geothermal@ee.doe.gov.

  3. Geothermal monitor report

    NASA Astrophysics Data System (ADS)

    1982-06-01

    Geothermal Progress Monitor Report No. 6 presents a state-by-state summary of the status of geothermal leasing, exploration, and development in major physiographic regions where geothermal resource potential has been identified. Recent state-specific activities are reported at the end of each state status report, while recent activities of a more general nature are summarized briefly in Part 2 of the report. A list of recent publications of potential interest to the geothermal community and a directory of contributors to the geothermal progress monitoring system are also included.

  4. Double-diffusive convection in geothermal systems: the salton sea, California, geothermal system as a likely candidate

    USGS Publications Warehouse

    Fournier, R.O.

    1990-01-01

    Much has been published about double-diffusive convection as a mechanism for explaining variations in composition and temperature within all-liquid natural systems. However, relatively little is known about the applicability of this phenomenon within the heterogeneous rocks of currently active geothermal systems where primary porosity may control fluid flow in some places and fractures may control it in others. The main appeal of double-diffusive convection within hydrothermal systems is-that it is a mechanism that may allow efficient transfer of heat mainly by convection, while at the same time maintaining vertical and lateral salinity gradients. The Salton Sea geothermal system exhibits the following reservoir characteristics: (1) decreasing salinity and temperature from bottom to top and center toward the sides, (2) a very high heat flow from the top of the system that seems to require a major component of convective transfer of heat within the chemically stratified main reservoir, and (3) a relatively uniform density of the reservoir fluid throughout the system at all combinations of subsurface temperature, pressure, and salinity. Double-diffusive convection can account for these characteristics very nicely whereas other previously suggested models appear to account either for the thermal structure or for the salinity variations, but not both. Hydrologists, reservoir engineers, and particularly geochemists should consider the possibility and consequences of double-diffusive convection when formulating models of hydrothermal processes, and of the response of reservoirs to testing and production. ?? 1990.

  5. Investigation of the Mount Tongariro, New Zealand, geothermal system through Self Potential mapping

    NASA Astrophysics Data System (ADS)

    Miller, C. A.

    2013-12-01

    Mount Tongariro volcano is a composite of overlapping vents active since c. 275 ka with 6 main periods of cone building. The volcano hosts an active geothermal system thought to be vapour dominated with a capping condensate layer; active surface geothermal features are present at Ketetahi, Red Crater, Central Crater and Te Maari Craters. Mount Tongariro erupted twice at Upper Te Maari Crater in 2012 after 125 years of dormancy. The first eruption (August 6th) is thought to be triggered from uncapping of the geothermal system by a landslide caused by pore pressure changes due to dyke intrusion. In response to those eruptions I undertook a combined Self Potential (SP), soil CO2 and ground temperature survey to learn more about the geothermal system, its distribution and fluid flow patterns. Analysis of SP vs. topographic gradient delineated the Ketetahi and Red Crater geothermal surface features. I propose that low pH fluids, combined with hydrothermally altered and therefore electrically conductive ground are the dominate cause of subdued SP anomalies around these features. I interpret a large positive anomaly (+1100 mV) in Oturere Valley, which has no surface geothermal activity, to result from deepening of a ground water aquifer beneath a thick electrically resistive lava flow. Subsequent modelling of SP data to estimate both water table depth, and depth to a potential current source agree with the inferred thickness of the Oturere Valley lava flow, and imply that the lava flow is a poor aquifer. Therefore underlying material hosts the aquifer. Finally I interpret a large negative (-600 mV) SP anomaly on the NE flank of North Crater as a zone of down flowing meteoric fluids, situated outside of the geothermal system. The geothermal surface features with subdued SP anomalies resulting from low pH fluids and conductive hydrothermally altered ground, map zones of weakened rock. These zones may be prone to future flank collapse, especially in areas of steep topography

  6. Geothermal wells: a forecast of drilling activity

    SciTech Connect

    Brown, G.L.; Mansure, A.J.; Miewald, J.N.

    1981-07-01

    Numbers and problems for geothermal wells expected to be drilled in the United States between 1981 and 2000 AD are forecasted. The 3800 wells forecasted for major electric power projects (totaling 6 GWe of capacity) are categorized by type (production, etc.), and by location (The Geysers, etc.). 6000 wells are forecasted for direct heat projects (totaling 0.02 Quads per year). Equations are developed for forecasting the number of wells, and data is presented. Drilling and completion problems in The Geysers, The Imperial Valley, Roosevelt Hot Springs, the Valles Caldera, northern Nevada, Klamath Falls, Reno, Alaska, and Pagosa Springs are discussed. Likely areas for near term direct heat projects are identified.

  7. San Diego Gas and Electric Company Imperial Valley geothermal activities

    NASA Technical Reports Server (NTRS)

    Hinrichs, T. C.

    1974-01-01

    San Diego Gas and Electric and its wholly owned subsidiary New Albion Resources Co. have been affiliated with Magma Power Company, Magma Energy Inc. and Chevron Oil Company for the last 2-1/2 years in carrying out geothermal research and development in the private lands of the Imperial Valley. The steps undertaken in the program are reviewed and the sequence that must be considered by companies considering geothermal research and development is emphasized. Activities at the south end of the Salton Sea and in the Heber area of Imperial Valley are leading toward development of demonstration facilities within the near future. The current status of the project is reported.

  8. Heat pump assisted geothermal heating system for Felix Spa, Romania

    SciTech Connect

    Rosca, Marcel; Maghiar, Teodor

    1996-01-24

    The paper presents a pre-feasibility type study of a proposed heat pump assisted geothermal heating system for an average hotel in Felix Spa, Romania. After a brief presentation of the geothermal reservoir, the paper gives the methodology and the results of the technical and economical calculations. The technical and economical viability of the proposed system is discussed in detail in the final part of the paper.

  9. Further Developments on the Geothermal System Scoping Model: Preprint

    SciTech Connect

    Antkowiak, M.; Sargent, R.; Geiger, J. W.

    2010-07-01

    This paper discusses further developments and refinements for the uses of the Geothermal System Scoping Model in an effort to provide a means for performing a variety of trade-off analyses of surface and subsurface parameters, sensitivity analyses, and other systems engineering studies in order to better inform R&D direction and investment for the development of geothermal power into a major contributor to the U.S. energy supply.

  10. Mantle Helium and Carbon Isotopes in Separation Creek Geothermal Springs, Three Sisters Area, Central Oregon: Evidence for Renewed Volcanic Activity or a Long Term Steady State System?

    USGS Publications Warehouse

    Van Soest, M. C.; Kennedy, B.M.; Evans, William C.; Mariner, R.H.

    2002-01-01

    Here we present the helium and carbon isotope results from the initial study of a fluid chemistry-monitoring program started in the summer of 2001 near the South Sister volcano in central Oregon. The Separation Creek area which is several miles due west of the volcano is the locus of strong crustal uplift currently occurring at a rate of 4-5 cm/yr (Wicks, et. al., 2001).Helium [RC/RA = 7.44 and 8.61 RA (RC/R A = (3He/4He)sample-. air corrected/(3He/4He)air))] and carbon (??13C = -11.59 to -9.03??? vs PDB) isotope data and CO2/3He (5 and 9 ?? 109) show that bubbling cold springs in the Separation Creek area near South Sister volcano carry a strong mantle signal, indicating the presence of fresh basaltic magma in the volcanic plumbing system. There is no evidence though, to directly relate this signal to the crustal uplift that is currently taking place in the area, which started in 1998. The geothermal system in the area is apparently much longer lived and shows no significant changes in chemistry compared to data from the early 1990s. Hot springs in the area, which are relatively far removed from the volcanic edifice, do not carry a strong mantle signal in helium isotope ratios (2.79 to 5.08 RA), unlike the cold springs, and also do not show any significant changes in helium isotope ratios compared to literature data for the same springs of over two decades ago. The cold springs of the Separation Creek area form a very diffuse but significant low temperature geothermal system, that should, due to its close vicinity to the center of up uplift, be more sensitive to changes in the deeper volcanic plumbing system than the far removed hot springs and therefore require much more study and consideration when dealing with volcano monitoring in the Cascade range or possibly with geothermal exploration in general.

  11. Design Considerations for Artificial Lifting of Enhanced Geothermal System Fluids

    SciTech Connect

    Xina Xie; K. K. Bloomfield; G. L. Mines; G. M. Shook

    2005-07-01

    This work evaluates the effect of production well pumping requirements on power generation. The amount of work that can be extracted from a geothermal fluid and the rate at which this work is converted to power increase as the reservoir temperature increases. Artificial lifting is an important issue in this process. The results presented are based on a configuration comprising one production well and one injection well, representing an enhanced geothermal system. The effects of the hydraulic conductivity of the geothermal reservoir, the flow rate, and the size of the production casing are considered in the study. Besides submersible pumps, the possibility of using lineshaft pumps is also discussed.

  12. Fluid flow processes in the Beppu geothermal system, Japan

    SciTech Connect

    Allis, R.G. ); Yusa, Y. )

    1989-01-01

    This paper reports on the Beppu geothermal system, centered beneath the late Quaternary volcanoes of Tsurumi and Garandake at the northern end of the Ryukyu volcanic arc. The deep fluid has a temperature of at least 250--300{degrees} C, and an inferred chloride concentration of 1400--1600 mg/kg. Apart from fumarolic areas near the summits of the two volcanoes, most thermal activity occurs at low elevation along the two main outflow paths towards the coast. The hot spring waters of downtown Beppu have originated from outflow along the Asamigawa Fault, with their chemistry indicating predominantly dilution of the deep fluid by groundwater. The second outflow zone towards the hot spring area of downtown Kamegawa coincides with a ridge of lavas. Here boiling, steam loss, and subsequent mixing with steam-heated groundwaters have significantly modified both the deep fluid and host rocks. The area of the geothermal system above 200{degrees} C is at least 15 km{sup 2} at sea level, and the total natural heat output is inferred to be at least 250 MW. Most of this heat output occurs as subsurface hot water outflows towards the coast due to the 1300 m of topographic relief across the system.

  13. Monitoring well systems in geothermal areas

    SciTech Connect

    Lofgren, B.E.; O'Rourke, J.; Sterrett, R.; Thackston, J.; Fain, D.

    1982-03-01

    The ability to monitor the injection of spent geothermal fluids at reasonable cost might be greatly improved by use of multiple-completion techniques. Several such techniques, identified through contact with a broad range of experts from the groundwater and petroleum industries, are evaluated relative to application in the typical geologic and hydrologic conditions of the Basin and Range Province of the Western United States. Three basic monitor well designs are suggested for collection of pressure and temperature data: Single standpipe, multiple standpipe, and closed-system piezometers. A fourth design, monitor well/injection well dual completions, is determined to be inadvisable. Also, while it is recognized that water quality data is equally important, designs to allow water sampling greatly increase costs of construction, and so such designs are not included in this review. The single standpipe piezometer is recommended for use at depths less than 152 m (500 ft); several can be clustered in one area to provide information on vertical flow conditions. At depths greater than 152 m (500 ft), the multiple-completion standpipe and closed-system piezometers are likely to be more cost effective. Unique conditions at each monitor well site may necessitate consideration of the single standpipe piezometer even for deeper completions.

  14. Geothermal heating system for the Children's Museum of Utah

    SciTech Connect

    Karlsson, T.

    1984-07-01

    The results of a study to determine the engineering and economic feasibility of using the Wasatch Hot Spring resource for space heating of the Children's Library building are presented. The Wasatch Hot Spring with a reported flow of about 63 gpm (240 l/min) at an average temperature of 104/sup 0/F is not capable of furnishing the needed heat for the Children's Museum building. The underground paths along which the thermal waters flow to their outlets at the Warm Springs Fault are not presently known. It is possible if the thermal water ascends from the deep layers of the earth along the Warm Springs Fault that increased geothermal flow at a higher temperature can be produced by drilling into the fault. Assuming that sufficient geothermal fluid quantity is produced by drilling in the area, an analysis is made of a geothermal heating system for the building based on different fluid temperatures. It is assumed that the present and planned heating systems be left intact with the gas fired boilers taking over during cold periods when the geothermal system fails to provide sufficient heat. Economic analysis shows that the geothermal system is very attractive, even for the lowest geothermal fluid temperature considered (110/sup 0/F).

  15. National Geothermal Data System: Interactive Assessment of Geothermal Energy Potential in the U.S.

    SciTech Connect

    Allison, Lee; Richard, Stephen; Clark, Ryan; Patten, Kim; Love, Diane; Coleman, Celia; Chen, Genhan; Matti, Jordan; Pape, Estelle; Musil, Leah

    2012-01-30

    Geothermal-relevant geosciences data from all 50 states (www.stategeothermaldata.org), federal agencies, national labs, and academic centers are being digitized and linked in a distributed online network via the U.S. Department of Energy-funded National Geothermal Data System (NGDS) to foster geothermal energy exploration and development through use of interactive online ‘mashups,’data integration, and applications. Emphasis is first to make as much information as possible accessible online, with a long range goal to make data interoperable through standardized services and interchange formats. An initial set of thirty geoscience data content models is in use or under development to define a standardized interchange format: aqueous chemistry, borehole temperature data, direct use feature, drill stem test, earthquake hypocenter, fault feature, geologic contact feature, geologic unit feature, thermal/hot spring description, metadata, quaternary fault, volcanic vent description, well header feature, borehole lithology log, crustal stress, gravity, heat flow/temperature gradient, permeability, and feature descriptions data like developed geothermal systems, geologic unit geothermal properties, permeability, production data, rock alteration description, rock chemistry, and thermal conductivity. Map services are also being developed for isopach maps, aquifer temperature maps, and several states are working on geothermal resource overview maps. Content models are developed preferentially from existing community use in order to encourage widespread adoption and promulgate minimum metadata quality standards. Geoscience data and maps from other NGDS participating institutions, or “nodes” (USGS, Southern Methodist University, Boise State University Geothermal Data Coalition) are being supplemented with extensive land management and land use resources from the Western Regional Partnership (15 federal agencies and 5 Western states) to provide access to a comprehensive

  16. Technical support for geopressured-geothermal well activities in Louisiana

    SciTech Connect

    Not Available

    1991-07-01

    Continuous recording microearthquake monitoring networks have been established around US Department of Energy (DOE) geopressured-geothermal design wells in southwestern Louisiana and southeastern Texas since summer 1980 to assess the effects well development may have had on subsidence and growth-fault activation. This monitoring has shown several unusual characteristics of Gulf Coast seismic activity. The observed activity is classified into two dominant types, one with identifiable body phases (type 1) and the other with only surface-wave signatures (type 2). During this reporting period no type 1 or body-wave events were reported. A total of 230 type 2 or surface-wave events were recorded. Origins of the type 2 events are still not positively understood; however, little or no evidence is available to connect them with geopressured-geothermal well activity. We continue to suspect sonic booms from military aircraft or some other human-induced source. 37 refs., 16 figs., 6 tabs.

  17. Enhanced Geothermal Systems (EGS) R&D Program

    SciTech Connect

    Entingh, Daniel J.

    1999-08-18

    The purpose of this workshop was to develop technical background facts necessary for planning continued research and development of Enhanced Geothermal Systems (EGS). EGS are geothermal reservoirs that require improvement of their permeability or fluid contents in order to achieve economic energy production. The initial focus of this R&D program is devising and testing means to extract additional economic energy from marginal volumes of hydrothermal reservoirs that are already producing commercial energy. By mid-1999, the evolution of the EGS R&D Program, begun in FY 1988 by the U.S. Department of Energy (DOE), reached the stage where considerable expertise had to be brought to bear on what technical goals should be pursued. The main purpose of this Workshop was to do that. The Workshop was sponsored by the Office of Geothermal Technologies of the Department of Energy. Its purpose and timing were endorsed by the EGS National Coordinating Committee, through which the EGS R&D Program receives guidance from members of the U.S. geothermal industry. Section 1.0 of this report documents the EGS R&D Program Review Session. There, managers and researchers described the goals and activities of the program. Recent experience with injection at The Geysers and analysis of downhole conditions at Dixie Valley highlighted this session. Section 2.0 contains a number of technical presentations that were invited or volunteered to illuminate important technical and economic facts and opportunities for research. The emphasis here was on fi.acture creation, detection, and analysis. Section 3.0 documents the initial general discussions of the participants. Important topics that emerged were: Specificity of defined projects, Optimizing cost effectiveness, Main technical areas to work on, Overlaps between EGS and Reservoir Technology R&D areas, Relationship of microseismic events to hydraulic fractures, and Defining criteria for prioritizing research thrusts. Sections 4.0 and 5.0 report

  18. STRUCTURAL CONTROLS OF THE EMERSON PASS GEOTHERMAL SYSTEM, NORTHWESTERN NEVADA: CHARACTERIZATION OF A "BLIND" SYSTEM

    SciTech Connect

    Anderson, Ryan B; Faulds, James E

    2012-12-03

    Detailed geologic analyses have elucidated the kinematics, stress state, structural controls, and past surface activity of a blind geothermal system in Emerson Pass on the Pyramid Lake Paiute Reservation, western Nevada. The Emerson Pass area resides near the boundary of the Basin and Range and Walker Lane provinces and at the western edge of a broad left step or relay ramp between the north- to north-northeast-striking, west-dipping, Fox and Lake Range normal faults. The step-over provides a structurally favorable setting for deep circulation of meteoric fluids. Strata in the area are comprised of late Miocene to Pliocene sedimentary rocks and the middle Miocene Pyramid sequence mafic to intermediate volcanic rocks, all overlying Mesozoic metasedimentary and intrusive rocks. A thermal anomaly was discovered in Emerson Pass by use of 2-m temperature surveys deployed within a structurally favorable setting and proximal to surface features indicative of geothermal activity. The 2-m temperature surveys define a north-south elongate thermal anomaly that has a maximum recorded temperature of ~60°C and resides on a north- to north-northeast-striking normal fault. Although the active geothermal system is expressed solely as a soil heat anomaly, late Pleistocene travertine and tufa mounds, chalcedonic silica/calcite veins, and silica cemented Pleistocene lacustrine gravels indicate a robust geothermal system was active at the surface in the recent past. The geothermal system is controlled primarily by the broad step-over between two major range-bounding normal faults. In detail, the system likely results from enhanced permeability generated by the intersection of two oppositely dipping, southward terminating north- to north-northwest-striking (Fox Range fault) and north-northeast-striking normal faults. Structural complexity and spatial heterogeneities of the strain and stress field have developed in the step-over region, but kinematic data suggest a west

  19. Regional and Local Controls on the Distribution of Geothermal Systems in the Great Basin, Western United States

    NASA Astrophysics Data System (ADS)

    Coolbaugh, M. F.; Blewitt, G.; Faulds, J. E.; Kreemer, C. W.

    2005-12-01

    In the Great Basin (GB) of the western United States, geothermal systems with reservoir temperatures in excess of 150 C can be classified into two main categories (magmatic and amagmatic) according to the presence or absence of shallow magmatic heat sources. Magmatic systems are restricted to the margins of the GB where they are closely associated with Quaternary silicic volcanic rocks, whereas amagmatic systems occur over a large portion of the Great Basin interior and are not spatially associated with young silicic volcanism. A tabulation of temperature gradients for known geothermal systems in the world confirms research by others indicating that both magmatic and amagmatic systems occur within areas of high temperature gradients and high heat flow. However, high heat flow alone is not sufficient to explain the abundance of high-temperature geothermal activity in the GB interior. While the distribution of favorable host rocks likely plays a role, active crustal tectonics appears instrumental in explaining patterns of geothermal activity. At a detailed scale, Quaternary faults control the location of most geothermal systems in the GB. However, hundreds of Quaternary faults are distributed throughout the GB, and most do not host high-temperature geothermal resources. Spatial statistical analysis demonstrates that high-temperature geothermal systems (more than 150 C) are preferentially associated with NE-striking Quaternary faults, which in turn are oriented roughly perpendicular to the current direction of crustal extension in the western GB. Maps of active crustal extension rates in the GB, derived from Global Positioning System (GPS) velocity measurements and estimated slip rates on Quaternary faults, correlate well with the distribution of high-temperature geothermal systems and help explain why some faults with lower slip rates or unfavorable orientations don't host geothermal activity. Many geothermal systems in the GB occur in a broad transitional region

  20. Feasibility and Supply Analysis of U.S. Geothermal District Heating and Cooling System

    NASA Astrophysics Data System (ADS)

    He, Xiaoning

    Geothermal energy is a globally distributed sustainable energy with the advantages of a stable base load energy production with a high capacity factor and zero SOx, CO, and particulates emissions. It can provide a potential solution to the depletion of fossil fuels and air pollution problems. The geothermal district heating and cooling system is one of the most common applications of geothermal energy, and consists of geothermal wells to provide hot water from a fractured geothermal reservoir, a surface energy distribution system for hot water transmission, and heating/cooling facilities to provide water and space heating as well as air conditioning for residential and commercial buildings. To gain wider recognition for the geothermal district heating and cooling (GDHC) system, the potential to develop such a system was evaluated in the western United States, and in the state of West Virginia. The geothermal resources were categorized into identified hydrothermal resources, undiscovered hydrothermal resources, near hydrothermal enhanced geothermal system (EGS), and deep EGS. Reservoir characteristics of the first three categories were estimated individually, and their thermal potential calculated. A cost model for such a system was developed for technical performance and economic analysis at each geothermally active location. A supply curve for the system was then developed, establishing the quantity and the cost of potential geothermal energy which can be used for the GDHC system. A West Virginia University (WVU) case study was performed to compare the competiveness of a geothermal energy system to the current steam based system. An Aspen Plus model was created to simulate the year-round campus heating and cooling scenario. Five cases of varying water flow rates and temperatures were simulated to find the lowest levelized cost of heat (LCOH) for the WVU case study. The model was then used to derive a levelized cost of heat as a function of the population density

  1. The Newcastle geothermal system, Iron County, Utah

    SciTech Connect

    Blackett, R.E.; Shubat, M.A.; Bishop, C.E. ); Chapman, D.S.; Forster, C.B.; Schlinger, C.M. . Dept. of Geology and Geophysics)

    1990-03-01

    Geological, geophysical and geochemical studies contributed to conceptual hydrologic model of the blind'' (no surface expression), moderate-temperature (greater than 130{degree}C) Newcastle geothermal system, located in the Basin and Range-Colorado Plateau transition zone of southwestern Utah. Temperature gradient measurements define a thermal anomaly centered near the surface trace of the range-bounding Antelope Range fault with and elongate dissipative plume extending north into the adjacent Escalante Valley. Spontaneous potential and resistivity surveys sharply define the geometry of the dominant upflow zone (not yet explored), indicating that most of the thermal fluid issues form a short segment along the Antelope Range fault and discharges into a gently-dipping aquifer. Production wells show that this aquifer lies at a depth between 85 and 95 meter. Electrical surveys also show that some leakage of thermal fluid occurs over a 1.5 km (minimum) interval along the trace of the Antelope Range fault. Major element, oxygen and hydrogen isotopic analyses of water samples indicate that the thermal fluid is a mixture of meteoric water derived from recharge areas in the Pine Valley Mountains and cold, shallow groundwater. A northwest-southeast trending system of faults, encompassing a zone of increased fracture permeability, collects meteoric water from the recharge area, allows circulation to a depth of 3 to 5 kilometers, and intersects the northeast-striking Antelope Range fault. We postulate that mineral precipitates form a seal along the Antelope Range fault, preventing the discharge of thermal fluids into basin-fill sediments at depth, and allowing heated fluid to approach the surface. Eventually, continued mineral deposition could result in the development of hot springs at the ground surface.

  2. Geothermal systems on the island of Bali, Indonesia

    NASA Astrophysics Data System (ADS)

    Purnomo, Budi Joko; Pichler, Thomas

    2015-10-01

    This paper presents an overview of the geothermal systems on the island of Bali, Indonesia. Physicochemical data of hot springs and shallow geothermal wells were collected from four geothermal locations: Penebel, Batur, Banjar and Banyuwedang. The concentrations for the three main anions varied significantly indicating a different geothermal history. The values for Cl- ranged from 0.1 to 1000 mg/L, for HCO3- from 20 to 2200 mg/L and for SO42 - from 0.1 to 500 mg/L. Although the island of Bali is underlain by carbonate rocks, a carbonate host rock for the geothermal reservoirs could not be confirmed, because the (Ca2 + + Mg2 +)/HCO3- molar ratios were approximately 0.4, well below 1.0 and the K/Mg ratios were approaching those of a calc-alkaline rock reservoir. The HCO3- of the thermal waters correlated with Ca2 +, Mg2 +, Sr2 + and K+ indicating water-rock interaction in the presence of carbonic acid. Phase separation was inferred for the Bedugul and Banjar geothermal systems, because of relatively high B/Cl ratios. Boron isotopes were determined for selected samples with values ranging from δ11B of 1.3 to 22.5‰ (NBS 951). The heavy δ11B of + 22.5‰ together with a low B/Cl ratio indicated seawater input in the Banyuwedang geothermal system. The hydrogen and oxygen isotopic composition of the thermal water plotted along the global meteoric water line (GMWL) and close to the mean annual value for precipitation in Jakarta indicating a meteoric origin of the geothermal water. Comparison of the Si, Na/K, Na/K/Ca and Na/Li geothermometers with actual reservoir temperature measurements and physicochemical considerations led to the conclusion that the Na/Li thermometer provided most reliable results for the determination of geothermal reservoir temperatures on Bali. Using this thermometer, the following reservoir temperatures were calculated: (1) Penebel (Bedugul) from 235 to 254 °C, (2) Batur 240 °C and (3) Banjar 255 °C. Due to seawater input this thermometer

  3. Changes in thermal activity in the Rotorua geothermal field

    SciTech Connect

    Cody, A.D. ); Lumb, J.T. )

    1992-04-01

    During a period when geothermal fluid was being withdrawn for energy use at an increasing rate, the level of natural hydrothermal activity in the Rotorua geothermal field declined in an all-time low in the mid 1980s. total heatflow from a major hot-spring area fell by almost 50 percent, springs ceased their flow, and geysers displayed abnormal behavior consistent with a low aquifer pressure. since the enforced closure of bores within 1.5 km of Pohutu Geyser, sings of recovery, including a return to normal behavior of Pohutu and Waikorohihi Geysers, a resumption of activity at Kereru Geyser, and an increase in water flow from some springs are presented in this paper.

  4. Campi Flegrei Deep Drilling Project and geothermal activities in Campania Region (Southern Italy)

    NASA Astrophysics Data System (ADS)

    De Natale, Giuseppe; Troise, Claudia; Troiano, Antonio; Giulia Di Giuseppe, Maria; Mormone, Angela; Carlino, Stefano; Somma, Renato; Tramelli, Anna; Vertechi, Enrico; Sangianantoni, Agata; Piochi, Monica

    2013-04-01

    The Campanian volcanic area has a huge geothermal potential (Carlino et al., 2012), similar to the Larderello-Radicondoli-Amiata region, in Tuscany (Italy), which has been the first site in the World exploited for electric production. Recently, the Campi Flegrei Deep Drilling Project (CFDDP), sponsored by ICDP and devoted to understand and mitigate the extreme volcanic risk in the area, has also risen new interest for geothermal exploration in several areas of Italy. Following the new Italian regulations which favour and incentivise innovative pilot power plants with zero emission, several geothermal projects have started in the Campania Region, characterized by strict cooperation among large to small industries, Universities and public Research Centers. INGV department of Naples (Osservatorio Vesuviano) has the technical/scientific leadership of such initiatives. Most of such projects are coordinated in the framework of the Regional District for Energy, in which a large part is represented by geothermal resource. Leading geothermal projects in the area include 'FORIO' pilot plant project, aimed to build two small (5 MWe each one) power plants in the Ischia island and two projects aimed to build pilot power plants in the Agnano-Fuorigrotta area in the city of Naples, at the easternmost part of Campi Flegrei caldera. One of the Campi Flegrei projects, 'SCARFOGLIO', is aimed to build a 5 MWe geothermal power plant in the Agnano area, whereas the 'START' project has the goal to build a tri-generation power plant in the Fuorigrotta area, fed mainly by geothermal source improved by solar termodynamic and bio-mass. Meanwhile such projects enter the field work operational phase, the pilot hole drilling of the CFDDP project, recently completed, represents an important experience for several operational aspects, which should contitute an example to be followed by the next geothermal activities in the area. It has been furthermore a source of valuable data for geothermal

  5. [Geothermal system temperature-depth database and model for data analysis]. 5. quarterly technical progress report

    SciTech Connect

    Blackwell, D.D.

    1998-04-25

    During this first quarter of the second year of the contract activity has involved several different tasks. The author has continued to work on three tasks most intensively during this quarter: the task of implementing the data base for geothermal system temperature-depth, the maintenance of the WWW site with the heat flow and gradient data base, and finally the development of a modeling capability for analysis of the geothermal system exploration data. The author has completed the task of developing a data base template for geothermal system temperature-depth data that can be used in conjunction with the regional data base that he had already developed and is now implementing it. Progress is described.

  6. Geothermal direct applications hardware systems development and testing. 1979 summary report

    SciTech Connect

    Keller, J.G.

    1980-03-01

    Activities performed during calendar year 1979 for the hardware system development and testing task are presented. The fluidized bed technology was applied to the drying of potato by-products and to the exchange of heat to air in the space heating experiment. Geothermal water was flashed to steam and also used as the prime energy source in the steam distillation of peppermint oil. Geothermal water temperatures as low as 112.8/sup 0/C were utilized to distill alcohol from sugar beet juice, and lower temperature water provided air conditioning through an absorption air conditioning system. These experiments are discussed.

  7. Residential vertical geothermal heat pump system models: Calibration to data

    SciTech Connect

    Thornton, J.W.; McDowell, T.P.; Shonder, J.A.; Hughes, P.J.; Pahud, D.; Hellstroem, G.A.J.

    1997-12-31

    A detailed component-based simulation model of a geothermal heat pump system has been calibrated to monitored data taken from a family housing unit located at Fort Polk, Louisiana. The simulation model represents the housing unit, geothermal heat pump, ground heat exchanger, thermostat, blower, and ground-loop pump. Each of these component models was tuned to better match the measured data from the site. These tuned models were then interconnected to form the system model. The system model was then exercised in order to demonstrate its capabilities.

  8. Residential Vertical Geothermal Heat Pump System Models: Calibration to Data:

    SciTech Connect

    Thornton, Jeff W.; McDowell, T. P.; Shonder, John A; Hughes, Patrick; Pahud, D.; Hellstrom, G.

    1997-06-01

    A detailed component-based simulation model of a geothermal heat pump system has been calibrated to monitored data taken from a family housing unit located at Fort Polk, Louisiana. The simulation model represents the housing unit, geothermal heat pump, ground heat exchanger, thermostat, blower, and ground-loop pump. Each of these component models was 'tuned' to better match the measured data from the site. These tuned models were then interconnect to form the system model. The system model was then exercised in order to demonatrate its capabilities.

  9. Investigation of a fossil geothermal system, Hamblin-Cleopatra Volcano, Clark County, Nevada. Final technical report

    SciTech Connect

    Barker, D.S.

    1986-07-28

    The Hamblin-Cleopatra volcano, selected for study because erosion and fault displacement have exposed the entire volcanic succession, the intrusive core, a radial dike systems, and sedimentary and volcanic rocks that predate and postdate the volcano, was investigated to estimate the proportions of igneous materials forming lava flows, pyroclastic deposits, intrusive bodies, and reworked debris. Chemical changes in the magma throughout the active period of the volcano were documented. The geothermal system active within the pile after activity ceased was reconstructed. (ACR)

  10. Three dimensional images of geothermal systems: local earthquake P-wave velocity tomography at the Hengill and Krafla geothermal areas, Iceland, and The Geysers, California

    USGS Publications Warehouse

    Julian, B.R.; Prisk, A.; Foulger, G.R.; Evans, J.R.

    1993-01-01

    Local earthquake tomography - the use of earthquake signals to form a 3-dimensional structural image - is now a mature geophysical analysis method, particularly suited to the study of geothermal reservoirs, which are often seismically active and severely laterally inhomogeneous. Studies have been conducted of the Hengill (Iceland), Krafla (Iceland) and The Geysers (California) geothermal areas. All three systems are exploited for electricity and/or heat production, and all are highly seismically active. Tomographic studies of volumes a few km in dimension were conducted for each area using the method of Thurber (1983).

  11. Documentation of the status of international geothermal power plants and a list by country of selected geothermally active governmental and private sector entities

    NASA Astrophysics Data System (ADS)

    1992-10-01

    This report includes the printouts from the International Geothermal Power Plant Data Base and the Geothermally Active Entity Data Base. Also included are the explanation of the abbreviations used in the power plant data base, maps of geothermal installations by country, and data base questionnaires and mailing lists.

  12. Structural Controls of the Geothermal System at Gerlach, Washoe County, Nevada

    NASA Astrophysics Data System (ADS)

    Hazelwood, Lyndsay A.

    Detailed geologic mapping, spring and two-meter temperature data, and gravity and magnetic data constrain the structural controls of the high-temperature (>175°C) geothermal system at Gerlach. The system lies along the termination of a major normal fault at the southern end of the Granite Range in the southern Black Rock Desert, a known favorable setting for geothermal activity. Mapping of Quaternary deposits documents Holocene movement on the north-northeast-striking, east-dipping Gerlach fault. Dominant orientations of geothermal veins in exposed fossil geothermal systems parallel this active, terminating range-front fault, suggesting that it does provide a major control on the current geothermal system. Locally, there are two areas of geothermal upwelling with separate sets of structural controls. The two areas are expressed by outflow as two sets of springs, Great Boiling Springs and Mud Springs, as well as by separate altered bedrock fossil systems above the springs. The areas are topographically distinct (neither could represent outflow from the other), are separated by relatively lower shallow temperature measurements, and are associated with different orientations of the gravity gradient. Prominent northwest-striking fractures provide areas of enhanced permeability and parallel the secondary set of veins in the altered bedrock uphill of Great Boiling Springs. These northwest-striking veins are not observed in the area above Mud Springs, but there is an east-northeast-striking set that is not present above Great Boiling Springs. The presence of east-northeast-striking structures is supported in the gravity data. These structures could represent an ever broader-scale structural connection between the southern termination of the Gerlach fault and the northern termination of the Fox Range fault to the south.

  13. Recommendations of the workshop on advanced geothermal drilling systems

    SciTech Connect

    Glowka, D.A.

    1997-12-01

    At the request of the U.S. Department of Energy, Office of Geothermal Technologies, Sandia National Laboratories convened a group of drilling experts in Berkeley, CA, on April 15-16, 1997, to discuss advanced geothermal drilling systems. The objective of the workshop was to develop one or more conceptual designs for an advanced geothermal drilling system that meets all of the criteria necessary to drill a model geothermal well. The drilling process was divided into ten essential functions. Each function was examined, and discussions were held on the conventional methods used to accomplish each function and the problems commonly encountered. Alternative methods of performing each function were then listed and evaluated by the group. Alternative methods considered feasible or at least worth further investigation were identified, while methods considered impractical or not potentially cost-saving were eliminated from further discussion. This report summarizes the recommendations of the workshop participants. For each of the ten functions, the conventional methods, common problems, and recommended alternative technologies and methods are listed. Each recommended alternative is discussed, and a description is given of the process by which this information will be used by the U.S. DOE to develop an advanced geothermal drilling research program.

  14. A market survey of geothermal wellhead power generation systems

    NASA Technical Reports Server (NTRS)

    Leeds, M. W.

    1978-01-01

    The market potential for a portable geothermal wellhead power conversion device is assessed. Major study objectives included identifying the most promising applications for such a system, the potential impediments confronting their industrialization, and the various government actions needed to overcome these impediments. The heart of the study was a series of structured interviews with key decision-making individual in the various disciplines of the geothermal community. In addition, some technical and economic analyses of a candidate system were performed to support the feasibility of the basic concept.

  15. Structural compartmentalisation of a geothermal system, the Torre Alfina field (central Italy)

    NASA Astrophysics Data System (ADS)

    Vignaroli, Gianluca; Pinton, Annamaria; De Benedetti, Arnaldo A.; Giordano, Guido; Rossetti, Federico; Soligo, Michele; Berardi, Gabriele

    2013-11-01

    Recent surging of renewed industrial interest in the exploration of low and medium enthalpy geothermal fields makes the accurate assessment of the geothermal potential essential to minimise uncertainties during both exploration and exploitation. The Torre Alfina field is a case of abandoned, but promising, geothermal field of central Italy where the roles of the internal structural setting and of the recharge areas on the hydrothermal circulation are largely unconstrained. In this paper, field structural data integrated with geomorphic lineament analysis document the occurrence of post-orogenic deformation structures controlling the compartmentalisation of the Torre Alfina geothermal field. Strike-slip and subordinate normal fault systems (with associated network fractures) cut and dislocate the internal architecture of the reservoir and prevent its hydraulic connection with Mount Cetona, considered to be the recharge area and where hydrothermal manifestation, including travertine deposition, occurs. 230Th/234U radiometric dating of superposed travertine units gives 200, 120 and 90 ka respectively, inferred to correspond to the age of the fossil hydrothermal circulation during tectonic activity. The results have been used for illustrating a new geological conceptual model for the Torre Alfina area where the geothermal system is composed of different compartments. Tectonic structures define the main boundaries between compartments, helping the understanding of why productive and non-productive wells were found in apparently similar structural settings within the Torre Alfina field.

  16. Three-Dimensional Geologic Characterization of a Great Basin Geothermal System: Astor Pass, Nevada

    SciTech Connect

    Mayhew, Brett; Siler, Drew L; Faulds, James E

    2013-09-30

    The Great Basin, western USA, exhibits anomalously high heat flow (~75±5 mWm-2) and active faulting and extension, resulting in ~430 known geothermal systems. Recent studies have shown that steeply dipping normal faults in transtensional pull-aparts are a common structural control of these Great Basin geothermal systems. The Astor Pass blind (no surface expression) geothermal system, Nevada, lies along the boundary between the Basin and Range to the east and the Walker Lane to the west. Across this boundary, strain is transferred from dextral shear in the Walker Lane to west-northwest directed extension in the Basin and Range, resulting in a transtensional setting consisting of both northwest-striking, left-stepping dextral faults and northerly striking normal faults. Previous studies indicate that Astor Pass was controlled by the intersection of a northwest-striking dextral normal fault and north-northwest striking normal-dextral fault bounding the western side of the Terraced Hills. Drilling (to ~1200 m) has revealed fluid temperatures of ~94°C, confirming a blind geothermal system. Expanding upon previous work and employing interpretation of 2D seismic reflection data, additional detailed geologic mapping, and well cuttings analysis, a 3-dimensional geologic model of the Astor Pass geothermal system was constructed. The 3D model indicates a complex interaction/intersection area of three discrete fault zones: a northwest-striking dextral-normal fault, a north-northwest-striking normal-dextral fault, and a north-striking west-dipping normal fault. These two discrete, critically-stressed intersection areas plunge moderately to steeply to the NW-NNW and probably act as conduits for upwelling geothermal fluids.

  17. 3D characterization of the Astor Pass geothermal system, Nevada

    SciTech Connect

    Mayhew, Brett; Faulds, James E

    2013-10-19

    The Astor Pass geothermal system resides in the northwestern part of the Pyramid Lake Paiute Reservation, on the margins of the Basin and Range and Walker Lane tectonic provinces in northwestern Nevada. Seismic reflection interpretation, detailed analysis of well cuttings, stress field analysis, and construction of a 3D geologic model have been used in the characterization of the stratigraphic and structural framework of the geothermal area. The area is primarily comprised of middle Miocene Pyramid sequence volcanic and sedimentary rocks, nonconformably overlying Mesozoic metamorphic and granitic rocks. Wells drilled at Astor Pass show a ~1 km thick section of highly transmissive Miocene volcanic reservoir with temperatures of ~95°C. Seismic reflection interpretation confirms a high fault density in the geothermal area, with many possible fluid pathways penetrating into the relatively impermeable Mesozoic basement. Stress field analysis using borehole breakout data reveals a complex transtensional faulting regime with a regionally consistent west-northwest-trending least principal stress direction. Considering possible strike-slip and normal stress regimes, the stress data were utilized in a slip and dilation tendency analysis of the fault model, which suggests two promising fault areas controlling upwelling geothermal fluids. Both of these fault intersection areas show positive attributes for controlling geothermal fluids, but hydrologic tests show the ~1 km thick volcanic section is highly transmissive. Thus, focused upwellings along discrete fault conduits may be confined to the Mesozoic basement before fluids diffuse into the Miocene volcanic reservoir above. This large diffuse reservoir in the faulted Miocene volcanic rocks is capable of sustaining high pump rates. Understanding this type of system may be helpful in examining large, permeable reservoirs in deep sedimentary basins of the eastern Basin and Range and the highly fractured volcanic geothermal

  18. Description and operation of Haakon School geothermal-heating system

    SciTech Connect

    Childs, F.W.; Kirol, L.D.; Sanders, R.D.; McLatchy, M.J.

    1983-10-01

    To encourage the development of hydrothermal energy, twenty-three demonstration projects were funded. The Haakon School project is one of twelve such projects. The geothermal direct-use heating system at the Haakon School complex in Philip, South Dakota is described and information gained during approximately three heating seasons of operation is presented.

  19. Early Devonian geothermal systems in northeast Scotland: Exploration targets for epithermal gold

    SciTech Connect

    Nicholson, K. )

    1989-06-01

    Early Devonian geothermal activity is recognized in northeast Scotland by the remnants of silica sinter, a hot-spring manganese deposit, an area of steam alteration, and hydrothermal eruption breccias. At least five systems were active at this time, three of which are located on or near the intersection of major faults and lineaments. Two deposits can be dated as Early Devonian, whereas others show a spatial relation to 408 Ma Caledonian granitoids-the proposed heat sources for the geothermal systems. Fault zones active at this time provided channelways for fluids in the convecting systems. The shallow sections of these systems have been preserved in the Arndilly, Dalroy, Lecht, and Rhynie areas, which is encouraging for gold prospecting. Six targets for epithermal gold exploration are identified: the four areas named above and two areas at the intersection of major faults and lineaments.

  20. Tectonic and Structural Controls of Geothermal Activity in the Great Basin Region, Western USA

    NASA Astrophysics Data System (ADS)

    Faulds, J. E.; Hinz, N.; Kreemer, C. W.

    2012-12-01

    We are conducting a thorough inventory of structural settings of geothermal systems (>400 total) in the extensional to transtensional Great Basin region of the western USA. Most of the geothermal systems in this region are not related to upper crustal magmatism and thus regional tectonic and local structural controls are the most critical factors controlling the locations of the geothermal activity. A system of NW-striking dextral faults known as the Walker Lane accommodates ~20% of the North American-Pacific plate motion in the western Great Basin and is intimately linked to N- to NNE-striking normal fault systems throughout the region. Overall, geothermal systems are concentrated in areas with the highest strain rates within or proximal to the eastern and western margins of the Great Basin, with the high temperature systems clustering in transtensional areas of highest strain rate in the northwestern Great Basin. Enhanced extension in the northwestern Great Basin probably results from the northwestward termination of the Walker Lane and the concomitant transfer of dextral shear into west-northwest directed extension, thus producing a broad transtensional region. The capacity of geothermal power plants also correlates with strain rates, with the largest (hundreds of megawatts) along the Walker Lane or San Andreas fault system, where strain rates range from 10-100 nanostrain/yr to 1,000 nanostrain/yr, respectively. Lesser systems (tens of megawatts) reside in the Basin and Range (outside the Walker Lane), where local strain rates are typically < 10 nanostrain/yr. Of the 250+ geothermal fields catalogued, step-overs or relay ramps in normal fault zones serve as the most favorable setting, hosting ~32% of the systems. Such areas have multiple, overlapping fault strands, increased fracture density, and thus enhanced permeability. Other common settings include a) intersections between normal faults and strike-slip or oblique-slip faults (27%), where multiple minor

  1. COTHERM: Geophysical Modeling of High Enthalpy Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Grab, Melchior; Maurer, Hansruedi; Greenhalgh, Stewart

    2014-05-01

    In recent years geothermal heating and electricity generation have become an attractive alternative energy resource, especially natural high enthalpy geothermal systems such as in Iceland. However, the financial risk of installing and operating geothermal power plants is still high and more needs to be known about the geothermal processes and state of the reservoir in the subsurface. A powerful tool for probing the underground system structure is provided by geophysical techniques, which are able to detect flow paths and fracture systems without drilling. It has been amply demonstrated that small-scale features can be well imaged at shallow depths, but only gross structures can be delineated for depths of several kilometers, where most high enthalpy systems are located. Therefore a major goal of our study is to improve geophysical mapping strategies by multi-method geophysical simulations and synthetic data inversions, to better resolve structures at greater depth, characterize the reservoir and monitor any changes within it. The investigation forms part of project COTHERM - COmbined hydrological, geochemical and geophysical modeling of geoTHERMal systems - in which a holistic and synergistic approach is being adopted to achieve multidisciplinary cooperation and mutual benefit. The geophysical simulations are being performed in combination with hydrothermal fluid flow modeling and chemical fluid rock interaction modeling, to provide realistic constraints on lithology, pressure, temperature and fluid conditions of the subsurface. Two sites in Iceland have been selected for the study, Krafla and Reykjanes. As a starting point for the geophysical modeling, we seek to establish petrophysical relations, connecting rock properties and reservoir conditions with geophysical parameters such as seismic wave speed, attenuation, electrical conductivity and magnetic susceptibility with a main focus on seismic properties. Therefore, we follow a comprehensive approach involving

  2. Towards the Design of Effective Engineered Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Pettitt, W.; Damjanac, B.; Detournay-Piette, C.; Cundall, P. A.; Riahi, A.; Fairhurst, C.

    2012-12-01

    Stimulation of a potential engineered geothermal systems (EGS) reservoir by fluid pressurization -and hydraulic fracturing - is affected significantly by several factors including, the in situ state of stress; pre-existing natural fractures and fracture systems in the rock mass, disposition and mechanical properties of the fractures; and rock mass permeability as influenced by the stimulation process. Little information on these critical variables is available in advance of stimulation, so that design of stimulation treatments involves considerable uncertainty. Significant advances are being made in numerical modeling for application to engineering of these and similarly complex subsurface systems. It is now possible, for example, to examine how uncertainty and lack of knowledge of various factors, such as those mentioned above, affect the overall uncertainty of an actual stimulation. Numerical modeling of fracture systems has made significant advances and is being applied by the authors to indicate the influence of the factors described above, and how associated uncertainties may affect the outcome of practical fracturing programs. It is essential that numerical studies be complemented by geophysical observations. Micro-seismic activity and P and S wave velocity changes during and after stimulation are valuable tools to assist in verifying model predictions and development of a better overall understanding of the process of hydraulic fracturing on the field scale. Fundamental studies supported by laboratory investigations can also contribute significantly to improved understanding. Results of progress to date from such studies will be discussed.

  3. Structural Controls of the Emerson Pass Geothermal System, Washoe County, Nevada

    SciTech Connect

    Anderson, Ryan B; Faulds, James E

    2012-09-30

    We have conducted a detailed geologic study to better characterize a blind geothermal system in Emerson Pass on the Pyramid Lake Paiute Tribe Reservation, western Nevada. A thermal anomaly was discovered in Emerson Pass by use of 2 m temperature surveys deployed within a structurally favorable setting and proximal to surface features indicative of geothermal activity. The anomaly lies at the western edge of a broad left step at the northeast end of Pyramid Lake between the north- to north-northeast-striking, west-dipping, Fox and Lake Range normal faults. The 2-m temperature surveys have defined a N-S elongate thermal anomaly that has a maximum recorded temperature of ~60°C and resides on a north- to north-northeaststriking fault. Travertine mounds, chalcedonic silica veins, and silica cemented Pleistocene lacustrine gravels in Emerson Pass indicate a robust geothermal system active at the surface in the recent past. Structural complexity and spatial heterogeneities of the strain and stress field have developed in the step-over region, but kinematic data suggest a WNW-trending (~280° azimuth) extension direction. The geothermal system is likely hosted in Emerson Pass as a result of enhanced permeability generated by the intersection of two oppositely dipping, southward terminating north- to north-northwest-striking (Fox Range fault) and northnortheast- striking faults.

  4. Multicomponent CO2-Brine Simulations of Fluid and Heat Transfer in Sedimentary-Basin Geothermal Systems: Expanding Geothermal Energy Opportunities

    NASA Astrophysics Data System (ADS)

    Saar, M. O.; Randolph, J. B.

    2011-12-01

    In a carbon dioxide plume geothermal (CPG) system, carbon dioxide (CO2) is pumped into existing high-permeability geologic formations that are overlain by a low-permeability caprock. The resulting CO2 plume largely displaces native formation fluid and is heated by the natural in-situ heat and background geothermal heat flux. A portion of the heated CO2 is piped to the surface to produce power and/or to provide heat for direct use before being returned to the geologic reservoir. Non-recoverable CO2 in the subsurface is geologically sequestered, serving as a CO2 sink. As such, this approach results in a geothermal power plant with a negative carbon footprint. We present results of calculations concerning geothermal power plant efficiencies and energy production rates in both traditional reservoir-based systems and engineered geothermal systems (EGS) when CO2, rather than water, is used as the subsurface working fluid. While our previous studies have examined geologic systems with established CO2 plumes, we focus here on multicomponent (CO2 + brine) systems. Numerical simulations (e.g., Randolph and Saar, Geophysical Research Letters, 2011) indicate that CPG systems provide several times the heat energy recovery of similar water-based systems. Furthermore, the CPG method results in higher geothermal heat extraction efficiencies than both water- and CO2-based EGS. Therefore, CPG should further extend the applicability of geothermal energy utilization to regions with subsurface temperatures and heat flow rates that are even lower than those that may be added due to switching from water- to CO2-based EGS. Finally, simulations at present suggest that multicomponent effects - e.g., buoyant flow as CO2 rises over denser brine - may enhance heat extraction in CPG systems compared to traditional water-based geothermal approaches.

  5. Energy Return On Investment of Engineered Geothermal Systems Data

    DOE Data Explorer

    Mansure, Chip

    2012-01-01

    The project provides an updated Energy Return on Investment (EROI) for Enhanced Geothermal Systems (EGS). Results incorporate Argonne National Laboratory's Life Cycle Assessment and base case assumptions consistent with other projects in the Analysis subprogram. EROI is a ratio of the energy delivered to the consumer to the energy consumed to build, operate, and decommission the facility. EROI is important in assessing the viability of energy alternatives. Currently EROI analyses of geothermal energy are either out-of-date, of uncertain methodology, or presented online with little supporting documentation. This data set is a collection of files documenting data used to calculate the Energy Return On Investment (EROI) of Engineered Geothermal Systems (EGS) and erratum to publications prior to the final report. Final report is available from the OSTI web site (http://www.osti.gov/geothermal/). Data in this collections includes the well designs used, input parameters for GETEM, a discussion of the energy needed to haul materials to the drill site, the baseline mud program, and a summary of the energy needed to drill each of the well designs. EROI is the ratio of the energy delivered to the customer to the energy consumed to construct, operate, and decommission the facility. Whereas efficiency is the ratio of the energy delivered to the customer to the energy extracted from the reservoir.

  6. Structural Orientations Adjacent to Some Colorado Geothermal Systems

    DOE Data Explorer

    Richard,

    2012-02-01

    Citation Information: Originator: Geothermal Development Associates, Reno, Nevada Publication Date: 2012 Title: Structural Data Edition: First Publication Information: Publication Place: Reno Nevada Publisher: Geothermal Development Associates, Reno, Nevada Description: Structural orientations (fractures, joints, faults, lineaments, bedding orientations, etc.) were collected with a standard Brunton compass during routine field examinations of geothermal phenomena in Colorado. Often multiple orientations were taken from one outcrop. Care was taken to ensure outcrops were "in place". Point data was collected with a hand-held GPS unit. The structural data is presented both as standard quadrant measurements and in format suitable for ESRI symbology Spatial Domain: Extent: Top: 4491528.924999 m Left: 207137.983196 m Right: 432462.310324 m Bottom: 4117211.772001 m Contact Information: Contact Organization: Geothermal Development Associates, Reno, Nevada Contact Person: Richard “Rick” Zehner Address: 3740 Barron Way City: Reno State: NV Postal Code: 89511 Country: USA Contact Telephone: 775-737-7806 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS’1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System 1984 (WGS ’1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  7. Multiparameter fiber optic sensing system for monitoring enhanced geothermal systems

    SciTech Connect

    Challener, William A

    2014-12-04

    The goal of this project was to design, fabricate and test an optical fiber cable which supports multiple sensing modalities for measurements in the harsh environment of enhanced geothermal systems. To accomplish this task, optical fiber was tested at both high temperatures and strains for mechanical integrity, and in the presence of hydrogen for resistance to darkening. Both single mode (SM) and multimode (MM) commercially available optical fiber were identified and selected for the cable based on the results of these tests. The cable was designed and fabricated using a tube-within-tube construction containing two MM fibers and one SM fiber, and without supporting gel that is not suitable for high temperature environments. Commercial fiber optic sensing instruments using Raman DTS (distributed temperature sensing), Brillouin DTSS (distributed temperature and strain sensing), and Raleigh COTDR (coherent optical time domain reflectometry) were selected for field testing. A microelectromechanical systems (MEMS) pressure sensor was designed, fabricated, packaged, and calibrated for high pressure measurements at high temperatures and spliced to the cable. A fiber Bragg grating (FBG) temperature sensor was also spliced to the cable. A geothermal well was selected and its temperature and pressure were logged. The cable was then deployed in the well in two separate field tests and measurements were made on these different sensing modalities. Raman DTS measurements were found to be accurate to ±5°C, even with some residual hydrogen darkening. Brillouin DTSS measurements were in good agreement with the Raman results. The Rayleigh COTDR instrument was able to detect some acoustic signatures, but was generally disappointing. The FBG sensor was used to determine the effects of hydrogen darkening, but drift over time made it unreliable as a temperature or pressure sensor. The MEMS sensor was found to be highly stable and accurate to better than its 0.1% calibration.

  8. Methanotrophic activity and diversity of methanotrophs in volcanic geothermal soils at Pantelleria (Italy)

    NASA Astrophysics Data System (ADS)

    Gagliano, A. L.; D'Alessandro, W.; Tagliavia, M.; Parello, F.; Quatrini, P.

    2014-10-01

    Volcanic and geothermal systems emit endogenous gases by widespread degassing from soils, including CH4, a greenhouse gas twenty-five times as potent as CO2. Recently, it has been demonstrated that volcanic or geothermal soils are not only a source of methane, but are also sites of methanotrophic activity. Methanotrophs are able to consume 10-40 Tg of CH4 a-1 and to trap more than 50% of the methane degassing through the soils. We report on methane microbial oxidation in the geothermally most active site of Pantelleria (Italy), Favara Grande, whose total methane emission was previously estimated at about 2.5 Mg a-1 (t a-1). Laboratory incubation experiments with three top-soil samples from Favara Grande indicated methane consumption values of up to 59.2 nmol g-1 soil d.w. h-1. One of the three sites, FAV2, where the highest oxidation rate was detected, was further analysed on a vertical soil profile, the maximum methane consumption was measured in the top-soil layer, and values greater than 6.23 nmol g-1 h-1 were still detected up to a depth of 13 cm. The highest consumption rate was measured at 37 °C, but a still detectable consumption at 80 °C (> 1.25 nmol g-1 h-1) was recorded. The soil total DNA extracted from the three samples was probed by Polymerase Chain Reaction (PCR) using standard proteobacterial primers and newly designed verrucomicrobial primers, targeting the unique methane monooxygenase gene pmoA; the presence of methanotrophs was detected at sites FAV2 and FAV3, but not at FAV1, where harsher chemical-physical conditions and negligible methane oxidation were detected. The pmoA gene libraries from the most active site (FAV2) pointed to a high diversity of gammaproteobacterial methanotrophs, distantly related to Methylocaldum-Metylococcus genera, and the presence of the newly discovered acido-thermophilic Verrucomicrobia methanotrophs. Alphaproteobacteria of the genus Methylocystis were isolated from enrichment cultures under a methane

  9. Methanotrophic activity and bacterial diversity in volcanic-geothermal soils at Pantelleria island (Italy)

    NASA Astrophysics Data System (ADS)

    Gagliano, A. L.; D'Alessandro, W.; Tagliavia, M.; Parello, F.; Quatrini, P.

    2014-04-01

    Volcanic and geothermal systems emit endogenous gases by widespread degassing from soils, including CH4, a greenhouse gas twenty-five times as potent as CO2. Recently, it has been demonstrated that volcanic/geothermal soils are source of methane, but also sites of methanotrophic activity. Methanotrophs are able to consume 10-40 Tg of CH4 a-1 and to trap more than 50% of the methane degassing through the soils. We report on methane microbial oxidation in the geothermally most active site of Pantelleria island (Italy), Favara Grande, whose total methane emission was previously estimated in about 2.5 t a-1. Laboratory incubation experiments with three top-soil samples from Favara Grande indicated methane consumption values up to 950 ng g-1 dry soil h-1. One of the three sites, FAV2, where the highest oxidation rate was detected, was further analysed on a vertical soil profile and the maximum methane consumption was measured in the top-soil layer but values > 100 ng g-1 h-1 were maintained up to a depth of 15 cm. The highest consumption rate was measured at 37 °C, but a still recognizable consumption at 80 °C (> 20 ng g-1 h-1) was recorded. In order to estimate the bacterial diversity, total soil DNA was extracted from Favara Grande and analysed using a Temporal Temperature Gradient gel Electrophoresis (TTGE) analysis of the amplified bacterial 16S rRNA gene. The three soil samples were probed by PCR using standard proteobacterial primers and newly designed verrucomicrobial primers targeting the unique methane monooxygenase gene pmoA; the presence of methanotrophs was detected in sites FAV2 and FAV3, but not in FAV1, where harsher chemical-physical conditions and negligible methane oxidation were detected. The pmoA gene libraries from the most active site FAV2 pointed out a high diversity of gammaproteobacterial methanotrophs distantly related to Methylococcus/Methylothermus genera and the presence of the newly discovered acido-thermophilic methanotrophs

  10. COTHERM: Modelling fluid-rock interactions in Icelandic geothermal systems

    NASA Astrophysics Data System (ADS)

    Thien, Bruno; Kosakowski, Georg; Kulik, Dmitrii

    2014-05-01

    Mineralogical alteration of reservoir rocks, driven by fluid circulation in natural or enhanced geothermal systems, is likely to influence the long-term performance of geothermal power generation. A key factor is the change of porosity due to dissolution of primary minerals and precipitation of secondary phases. Porosity changes will affect fluid circulation and solute transport, which, in turn, influence mineralogical alteration. This study is part of the Sinergia COTHERM project (COmbined hydrological, geochemical and geophysical modeling of geotTHERMal systems) that is an integrative research project aimed at improving our understanding of the sub-surface processes in magmatically-driven natural geothermal systems. We model the mineralogical and porosity evolution of Icelandic geothermal systems with 1D and 2D reactive transport models. These geothermal systems are typically high enthalphy systems where a magmatic pluton is located at a few kilometers depth. The shallow plutons increase the geothermal gradient and trigger the circulation of hydrothermal waters with a steam cap forming at shallow depth. We investigate two contrasting geothermal systems: Krafla, for which the water recharge consists of meteoritic water; and Reykjanes, for which the water recharge mainly consists of seawater. The initial rock composition is a fresh basalt. We use the GEM-Selektor geochemical modeling package [1] for calculation of kinetically controlled mineral equilibria between the rock and the ingression water. We consider basalt minerals dissolution kinetics according to Palandri & Kharaka [2]. Reactive surface areas are assumed to be geometric surface areas, and are corrected using a spherical-particle surface/mass relationship. For secondary minerals, we consider the partial equilibrium assuming that the primary mineral dissolution is slow, and the secondary mineral precipitation is fast. Comparison of our modeling results with the mineralogical assemblages observed in the

  11. Life-cycle analysis results for geothermal systems in comparison to other power systems: Part II.

    SciTech Connect

    Sullivan, J.L.; Clark, C.E.; Yuan, L.; Han, J.; Wang, M.

    2012-02-08

    A study has been conducted on the material demand and life-cycle energy and emissions performance of power-generating technologies in addition to those reported in Part I of this series. The additional technologies included concentrated solar power, integrated gasification combined cycle, and a fossil/renewable (termed hybrid) geothermal technology, more specifically, co-produced gas and electric power plants from geo-pressured gas and electric (GPGE) sites. For the latter, two cases were considered: gas and electricity export and electricity-only export. Also modeled were cement, steel and diesel fuel requirements for drilling geothermal wells as a function of well depth. The impact of the construction activities in the building of plants was also estimated. The results of this study are consistent with previously reported trends found in Part I of this series. Among all the technologies considered, fossil combustion-based power plants have the lowest material demand for their construction and composition. On the other hand, conventional fossil-based power technologies have the highest greenhouse gas (GHG) emissions, followed by the hybrid and then two of the renewable power systems, namely hydrothermal flash power and biomass-based combustion power. GHG emissions from U.S. geothermal flash plants were also discussed, estimates provided, and data needs identified. Of the GPGE scenarios modeled, the all-electric scenario had the highest GHG emissions. Similar trends were found for other combustion emissions.

  12. Current California legislative and regulatory activity impacting geothermal hydrothermal commercialization: a monitoring report. Report No. 1017

    SciTech Connect

    Not Available

    1980-01-20

    Four key geothermal-impacting bills presently before the California legislature are described. Two deal with state financial backing for geothermal projects. The third relates to the use of the state's share of the BLM geothermal revenues and the fourth to the protection of sensitive hot springs. The current regulatory activities of the California Energy Commission, the California Division of Oil and Gas, and the counties are discussed. (MHR)

  13. Seal/lubricant systems for geothermal drilling equipment

    SciTech Connect

    Hendrickson, R.R.; Winzenried, R.W.

    1980-07-01

    The development and testing of seals and lubricants for journal-type roller-cone rock bits for drilling into geothermal reservoirs at temperatures over 260/sup 0/C (500/sup 0/F) are described. The conditions experienced by seals and lubricants subjected to geothermal drilling are reviewed along with the basic design requirements for roller-cone bit seals and journal bearing lubricants. Two unique test facilities are described: a seal test machine which simulates pressures, temperatures, and mechanical eccentricities, and a lubricant tester capable of evaluating load-bearing ability at temperature and pressure. Three candidate elastomeric compounds demonstrated 288/sup 0/C (550/sup 0/F) capability and several others demonstrated 260/sup 0/C (500/sup 0/F) or greater capability. Successful elastomeric seal candidates were proprietary compounds based on EPDM, Kalrez, and/or Viton polymers. Three mechanical seals for reservoir temperatures over 288/sup 0/C (550/sup 0/F) are presented. Lubricant screening tests on more than 50 products are summarized, and several newly developed lubricants which meet both the compatibility and lubrication requirements are described. Several seal/lubricant systems are recommended for laboratory or field geothermal drilling tests in roller-cone drill bits. The future availability of drill bits for geothermal use is discussed, as well as the potential spinoffs of the program findings for nongeothermal roller-cone bits.

  14. Common Scientific Challenges in Carbon Sequestration and Geothermal Energy Systems

    NASA Astrophysics Data System (ADS)

    LaBonte, A.; Groat, C. G.; Schwartz, L.

    2011-12-01

    In June of 2010, DOE convened a Carbon Sequestration- Geothermal Energy--Science Joint Workshop composed of academic, industry, and government experts. Participants were charged with looking beyond needs unique to either geothermal energy or carbon storage to identify common research needs. The expectation is greater collaboration in the identified common research areas will accelerate understanding of scientific processes critical to scaling up Carbon Sequestration and Geothermal Energy Systems. The major topic areas of the workshop include: Assessment and Characterization, to aide preliminary screening for prospective sites at the regional scale and subsurface characterization to assess feasibility at the site scale, Reservoir Sustainability, such as understanding evolution of pore and fracture structure to determine storage or production capacity and integrity of the reservoir over its intended lifetime, Modeling, a key element to conceptualizing, predicting, and managing the effects of reservoir processes over a wide variety of temporal and spatial scales when subjected to perturbations, Monitoring, requiring improvements to sensors, and data collection and interpretation methods to track changes in the reservoir and seal properties, and Performance Assessment, as a critical component to both optimize economic aspects and minimize health and environmental risks of a project. Workshop outcomes detailing research to enable scale-up of both carbon sequestration and geothermal energy applications will be presented.

  15. Geothermal aquaculture project: Real Property Systems Inc. , Harney Basin, Oregon

    SciTech Connect

    Not Available

    1981-08-14

    Real Property Systems Inc., (RPS) owns two parcels in the vicinity of Harney Lake, Oregon. One parcel is 120 acres in size, the other is 200 acres. A study concludes that the 200 acre parcel has the greater potential for geothermal development. RPS is interested in an aquaculture operation that produces fresh water prawns, (Macrobrachium rosenbergii) for the market. To supply the heat necessary to maintain the ideal temperature of 82/sup 0/F desired for these prawns, a geothermal resource having a 150/sup 0/F temperature or higher, is needed. The best estimate is that 150/sup 0/F water can be found from a minimum 1090 feet depth to 2625 feet, with no absolute assurances that sufficient quantities of geothermal waters exist without drilling for the same. This study undertakes the preliminary determination of project economics so that a decision can be made whether or not to proceed with exploratory drilling. The study is based on 10 acres of ponds, with a peak requirement of 2500 gpm of 150/sup 0/F geothermal water.

  16. Evaluating Geothermal Potential in Germany by Numerical Reservoir Modeling of Engineered Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Jain, Charitra; Vogt, Christian; Clauser, Christoph

    2014-05-01

    We model hypothetical Engineered Geothermal System (EGS) reservoirs by solving coupled partial differential equations governing fluid flow and heat transport. Building on EGS's strengths of inherent modularity and storage capability, it is possible to implement multiple wells in the reservoir to extend the rock volume accessible for circulating water in order to increase the heat yield. By varying parameters like flow rates and well-separations in the subsurface, this study looks at their long-term impacts on the reservoir development. This approach allows us to experiment with different placements of the engineered fractures and propose several EGS layouts for achieving optimized heat extraction. Considering the available crystalline area and accounting for the competing land uses, this study evaluates the overall EGS potential and compares it with those of other used renewables in Germany. There is enough area to support 13450 EGS plants, each with six reversed-triplets (18 wells) and an average electric power of 35.3MWe. When operated at full capacity, these systems can collectively supply 4155TWh of electric energy in one year which would be roughly six times the electric energy produced in Germany in the year 2011. Engineered Geothermal Systems make a compelling case for contributing towards national power production in a future powered by a sustainable, decentralized energy system.

  17. STRUCTURAL CONTROLS OF THE EMERSON PASS GEOTHERMAL SYSTEM, NORTHWESTERN NEVADA: CHARACTERIZATION OF A "BLIND" SYSTEM

    SciTech Connect

    Anderson, Ryan B; Faulds, James E

    2013-10-27

    The Pyramid Lake area is favorable for geothermal development due to the tectonic setting of the region. The Walker Lane belt, a dextral shear zone that accommodates ~20% relative motion between the Pacific and North American plates, terminates northwestward in northeast California. NW-directed dextral shear is transferred to WNW extension accommodated by N-to -NNE striking normal faults of the Basin and Range. As a consequence, enhanced dilation occurs on favorably oriented faults generating high geothermal potential in the northwestern Great Basin. The NW-striking right-lateral Pyramid Lake fault, a major structure of the northern Walker Lane, terminates at the southern end of Pyramid Lake and transfers strain to the NNE-striking down to the west Lake Range fault, resulting in high geothermal potential. Known geothermal systems in the area have not been developed due to cultural considerations of the Pyramid Lake Paiute Tribe. Therefore, exploration has been focused on discovering blind geothermal systems elsewhere on the reservation by identifying structurally favorable settings and indicators of past geothermal activity. One promising area is the northeast end of Pyramid Lake, where a broad left step between the west-dipping range-bounding faults of the Lake and Fox Ranges has led to the formation of a broad, faulted relay ramp. Furthermore, tufa mounds, mineralized veins, and altered Miocene rocks occur proximal to a thermal anomaly discovered by a 2-m shallow temperature survey at the north end of the step-over in Emerson Pass. Detailed geologic mapping has revealed a system of mainly NNE-striking down to the west normal faults. However, there are three notable exceptions to this generality, including 1) a prominent NW-striking apparent right-lateral fault, 2) a NW-striking down to the south fault which juxtaposes the base of the mid-Miocene Pyramid sequence against younger late Tertiary sedimentary rocks, and 3) a NNE-striking down to the east normal fault

  18. Community Geothermal Technology Program: Bottom heating system using geothermal power for propagation. Final report, Phases 1 and 2

    SciTech Connect

    Downing, J.C.

    1990-01-01

    The objective is to develop and study a bottom-heating system in a greenhouse utilizing geothermal energy to aid germination and speed growth of palms. Source of heat was geothermal brine from HGP-A well. The project was successful; the heat made a dramatic difference with certain varieties, such as Areca catechu (betelnut) with 82% germination with heat, zero without. For other varieties, germination rates were much closer. Quality of seed is important. Tabs, figs.

  19. Engineered Geothermal Systems Energy Return On Energy Investment

    SciTech Connect

    Mansure, A J

    2012-12-10

    Energy Return On Investment (EROI) is an important figure of merit for assessing the viability of energy alternatives. Too often comparisons of energy systems use efficiency when EROI would be more appropriate. For geothermal electric power generation, EROI is determined by the electricity delivered to the consumer compared to the energy consumed to construct, operate, and decommission the facility. Critical factors in determining the EROI of Engineered Geothermal Systems (EGS) are examined in this work. These include the input energy embodied into the system. Embodied energy includes the energy contained in the materials, as well as, that consumed in each stage of manufacturing from mining the raw materials to assembling the finished system. Also critical are the system boundaries and value of the energy heat is not as valuable as electrical energy. The EROI of an EGS depends upon a number of factors that are currently unknown, for example what will be typical EGS well productivity, as well as, reservoir depth, temperature, and temperature decline rate. Thus the approach developed is to consider these factors as parameters determining EROI as a function of number of wells needed. Since the energy needed to construct a geothermal well is a function of depth, results are provided as a function of well depth. Parametric determination of EGS EROI is calculated using existing information on EGS and US Department of Energy (DOE) targets and is compared to the minimum EROI an energy production system should have to be an asset rather than a liability.

  20. Environmental impacts of open loop geothermal system on groundwater

    NASA Astrophysics Data System (ADS)

    Kwon, Koo-Sang; Park, Youngyun; Yun, Sang Woong; Lee, Jin-Yong

    2013-04-01

    Application of renewable energies such as sunlight, wind, rain, tides, waves and geothermal heat has gradually increased to reduce emission of CO2 which is supplied from combustion of fossil fuel. The geothermal energy of various renewable energies has benefit to be used to cooling and heating systems and has good energy efficiency compared with other renewable energies. However, open loop system of geothermal heat pump system has possibility that various environmental problems are induced because the system directly uses groundwater to exchange heat. This study was performed to collect data from many documents such as papers and reports and to summarize environmental impacts for application of open loop system. The environmental impacts are classified into change of hydrogeological factors such as water temperature, redox condition, EC, change of microbial species, well contamination and depletion of groundwater. The change of hydrogeological factors can induce new geological processes such as dissolution and precipitation of some minerals. For examples, increase of water temperature can change pH and Eh. These variations can change saturation index of some minerals. Therefore, dissolution and precipitation of some minerals such as quartz and carbonate species and compounds including Fe and Mn can induce a collapse and a clogging of well. The well contamination and depletion of groundwater can reduce available groundwater resources. These environmental impacts will be different in each region because hydrogeological properties and scale, operation period and kind of the system. Therefore, appropriate responses will be considered for each environmental impact. Also, sufficient study will be conducted to reduce the environmental impacts and to improve geothermal energy efficiency during the period that a open loop system is operated. This work was supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning

  1. Natural analogs for enhanced heat recovery from geothermal systems

    SciTech Connect

    Nielson, Dennis L.

    1996-01-24

    High-temperature hydrothermal systems are physically and chemically zoned with depth. The energy input is from a magmatic zone, intruded by igneous bodies, that may also contribute variable amounts of magmatic fluid to the system. The heat source is directly overlain by a section of rocks, that due to their elevated temperature, respond to stress in a ductile fashion. The ductile zone is, in turn, overlain by a section of rocks that respond to stress in a brittle fashion, where water is able to circulate through fractures (the geothermal reservoir) and will be termed the hydrothermal circulation zone. Ancient and modern high-temperature geothermal systems show a predictable sequence of evolutionary events affecting these stratified zones. Metamorphic core complexes are uplifts, formed in highly extended terrains, that expose fossil brittle-ductile transition zones. Formerly ductile rocks have had brittle fractures superimposed on them, and meteoric hydrothermal systems are associated with the brittle fracturing. Porphyry copper deposits typically evolve from magmatic to meteoric hydrothermal systems. At the Larderello geothermal system, the brittle- ductile transition has been mapped using reflection seismology, and the zone has been penetrated by the San Pompeo 2 well where temperatures >420°C were encountered. Although neo-granitic dikes have been penetrated by drilling in the Larderello area, the brittle- ductile transition is largely above the inferred plutonic heat source. In the Geysers system, in contrast, the present steam system has been superimposed on young plutonic rocks and the inferred brittle-ductile transition is present at a depth of about 4.7 km within the plutonic rocks. As hydrothermal reservoirs are depleted, or surface facilities are restricted by environmental considerations, interest will turn to the deeper portions of known systems. Japan already has an aggressive program to develop Deep-seated and Magma-Ambient resources. This program, as

  2. Direct utilization of geothermal heat in cascade application to aquaculture and greenhouse systems at Navarro College. Final report, March 1, 1979-September 30, 1984

    SciTech Connect

    Smith, K.

    1984-09-01

    This final report documents the Navarro College geothermal use project, which is one of nineteen direct-use geothermal projects funded principally by DOE. The six-year project encompassed a broad range of technical, institutional, and economic activities including: resource and environmental assessment; well drilling and completion; system design, construction, and monitoring; economic analysis; and public awareness programs. Some of the project conclusions are that: (1) the 130/sup 0/F Central Texas geothermal resource can support additional geothermal development; (2) private sector economic incentives currently exist which encourage commercial development of this geothermal resource; (3) potential uses for this geothermal resource include water and space heating, aquacultural and agricultural heating uses, and fruit and vegetable dehydration; (4) high maintenance costs arising from the geofluids' scaling and corrosion characteristics can be avoided through proper analysis and design.

  3. Thermally conductive cementitious grout for geothermal heat pump systems

    DOEpatents

    Allan, Marita

    2001-01-01

    A thermally conductive cement-sand grout for use with a geothermal heat pump system. The cement sand grout contains cement, silica sand, a superplasticizer, water and optionally bentonite. The present invention also includes a method of filling boreholes used for geothermal heat pump systems with the thermally conductive cement-sand grout. The cement-sand grout has improved thermal conductivity over neat cement and bentonite grouts, which allows shallower bore holes to be used to provide an equivalent heat transfer capacity. In addition, the cement-sand grouts of the present invention also provide improved bond strengths and decreased permeabilities. The cement-sand grouts can also contain blast furnace slag, fly ash, a thermoplastic air entraining agent, latex, a shrinkage reducing admixture, calcium oxide and combinations thereof.

  4. 3D Geological Model for "LUSI" - a Deep Geothermal System

    NASA Astrophysics Data System (ADS)

    Sohrabi, Reza; Jansen, Gunnar; Mazzini, Adriano; Galvan, Boris; Miller, Stephen A.

    2016-04-01

    Geothermal applications require the correct simulation of flow and heat transport processes in porous media, and many of these media, like deep volcanic hydrothermal systems, host a certain degree of fracturing. This work aims to understand the heat and fluid transport within a new-born sedimentary hosted geothermal system, termed Lusi, that began erupting in 2006 in East Java, Indonesia. Our goal is to develop conceptual and numerical models capable of simulating multiphase flow within large-scale fractured reservoirs such as the Lusi region, with fractures of arbitrary size, orientation and shape. Additionally, these models can also address a number of other applications, including Enhanced Geothermal Systems (EGS), CO2 sequestration (Carbon Capture and Storage CCS), and nuclear waste isolation. Fractured systems are ubiquitous, with a wide-range of lengths and scales, making difficult the development of a general model that can easily handle this complexity. We are developing a flexible continuum approach with an efficient, accurate numerical simulator based on an appropriate 3D geological model representing the structure of the deep geothermal reservoir. Using previous studies, borehole information and seismic data obtained in the framework of the Lusi Lab project (ERC grant n°308126), we present here the first 3D geological model of Lusi. This model is calculated using implicit 3D potential field or multi-potential fields, depending on the geological context and complexity. This method is based on geological pile containing the geological history of the area and relationship between geological bodies allowing automatic computation of intersections and volume reconstruction. Based on the 3D geological model, we developed a new mesh algorithm to create hexahedral octree meshes to transfer the structural geological information for 3D numerical simulations to quantify Thermal-Hydraulic-Mechanical-Chemical (THMC) physical processes.

  5. Seismic tomography and dynamics of geothermal and natural hydrothermal systems in the south of Bandung, Indonesia

    NASA Astrophysics Data System (ADS)

    Jousset, Philippe; Sule, Rachmat; Diningrat, Wahyuddin; Syahbana, Devy; Schuck, Nicole; Akbar, Fanini; Kusnadi, Yosep; Hendryana, Andri; Nugraha, Andri; Ryannugroho, Riskiray; Jaya, Makki; Erbas, Kemal; Bruhn, David; Pratomo, Bambang

    2015-04-01

    The structure and the dynamics of geothermal reservoirs and hydrothermal systems allows us to better assess geothermal resources in the south of Bandung. A large variety of intense surface manifestations like geysers, hot-steaming grounds, hot water pools, and active volcanoes suggest an intimate coupling between volcanic, tectonic and hydrothermal processes in this area. We deployed a geophysical network around geothermal areas starting with a network of 30 seismic stations including high-dynamic broadband Güralp and Trillium sensors (0.008 - 100 Hz) and 4 short-period (1 Hz) sensors from October 2012 to December 2013. We extended the network in June 2013 with 16 short-period seismometers. Finally, we deployed a geodetic network including a continuously recording gravity meter, a GPS station and tilt-meters. We describe the set-up of the seismic and geodetic networks and we discuss observations and results. The earthquakes locations were estimated using a non-linear algorithm, and revealed at least 3 seismic clusters. We perform joint inversion of hypo-center and velocity tomography and we look at seismic focal mechanisms. We develop seismic ambient noise tomography. We discuss the resulting seismic pattern within the area and relate the structure to the distribution of hydrothermal systems. We aim at searching possible structural and dynamical links between different hydrothermal systems. In addition, we discuss possible dynamical implications of this complex volcanic systems from temporal variations of inferred parameters. The integration of those results allows us achieving a better understanding of the structures and the dynamics of those geothermal reservoirs. This approach contributes to the sustainable and optimal exploitation of the geothermal resource in Indonesia.

  6. Vertical arrays for fracture mapping in geothermal systems

    SciTech Connect

    Albright, J.N.; Rutledge, J.T.; Fairbanks, T.D.; Thomson, J.C.; Stevenson, M.A.

    1998-12-01

    In collaboration with UNOCAL Geothermal Operations, Los Alamos National Laboratory assessed the feasibility of using vertical arrays of borehole seismic sensors for mapping of microseismicity in The Geysers geothermal field. Seismicity which arises from minute displacements along fracture or fault surfaces has been shown in studies of seismically active oil reservoirs to be useful in identifying fractures affected by and possibly contributing to production. Use of retrievable borehole seismic packages at The Geysers was found to reduce the threshold for detection of microearthquakes by an estimated 2--3 orders of magnitude in comparison to surface-based sensors. These studies led to the design, materials selection, fabrication, and installation of a permanent array of geophones intended for long term seismic monitoring and mapping of fractures in the vicinity of the array at The Geysers.

  7. Geothermal district heating system feasibility analysis, Thermopolis, Wyoming

    SciTech Connect

    Goering, S.W.; Garing, K.L.; Coury, G.; Mickley, M.C.

    1982-04-26

    The purpose of this study is to determine the technical and economic feasibility of constructing and operating a district heating system to serve the residential, commercial, and public sectors in Thermopolis. The project geothermal resource assessment, based on reviews of existing information and data, indicated that substantial hot water resources likely exist in the Rose Dome region 10 miles northeast of Thermopolis, and with quantities capable of supporting the proposed geothermal uses. Preliminary engineering designs were developed to serve the space heating and hot water heating demands for buildings in the Thermopolis-East Thermopolis town service area. The heating district design is based on indirect geothermal heat supply and includes production wells, transmission lines, heat exchanger units, and the closed loop distribution and collection system necessary to serve the individual customers. Three options are presented for disposal of the cooled waters-reinjection, river disposal, and agricultural reuse. The preliminary engineering effort indicates the proposed system is technically feasible. The design is sized to serve 1545 residences, 190 businesses, and 24 public buildings. The peak design meets a demand of 128.2 million Btu at production rates of 6400 gpm.

  8. High Temperature Components of Magma-Related Geothermal Systems: An Experimental and Theoretical Approach

    SciTech Connect

    Philip A. Candela; Philip M. Piccoli

    2004-03-15

    This summarizes select components of a multi-faceted study of high temperature magmatic fluid behavior in shallow, silicic, volcano-plutonic geothermal systems. This work built on a foundation provided by DOE-supported advances made in our lab in understanding the physics and chemistry of the addition of HCI and other chlorides into the high temperature regions of geothermal systems. The emphasis of this project was to produce a model of the bolatile contributions from felsic magmatic systems to geothermal systems

  9. Geothermal Energy.

    ERIC Educational Resources Information Center

    Bufe, Charles Glenn

    1983-01-01

    Major activities, programs, and conferences in geothermal energy during 1982 are highlighted. These include first comprehensive national assessment of U.S. low-temperature geothermal resources (conducted by U.S. Geological Survey and Department of Energy), map production by U.S. Geological Survey, geothermal plant production, and others. (JN)

  10. Middlesex Community College Geothermal Project

    SciTech Connect

    Klein, Jessie; Spaziani, Gina

    2013-03-29

    The purpose of the project was to install a geothermal system in the trustees house on the Bedford campus of Middlesex Community College. In partnership with the environmental science faculty, learning activities for environmental science courses were developed to explain geothermal energy and more specifically the newly installed system to Middlesex students. A real-time monitoring system highlights the energy use and generation.

  11. Geology of the Beowawe geothermal system, Eureka and Lander Counties, Nevada

    SciTech Connect

    Struhsacker, E.M.

    1980-07-01

    A geologic study is described undertaken to evaluate the nature of structural and stratigraphic controls within the Beowawe geothermal system, Eureka and Lander Counties, Nevada. This study includes geologic mapping at a scale of 1:24,000 and lithologic logs of deep Chevron wells. Two major normal fault systems control the configuration of the Beowawe geothermal system. Active hot springs and sinter deposits lie along the Malpais Fault zone at the base of the Malpais Rim. The Malpais Rim is one of several east-northeast-striking, fault-bounded cuestas in north central Nevada. A steeply inclined scarp slope faces northwest towards Whirlwind Valley. The general inclination of the volcanic rocks on the Malpais dip slope is 5/sup 0/ to 10/sup 0/ southeast.

  12. Completion Design Considerations for a Horizontal Enhanced Geothermal System

    SciTech Connect

    Olson, Jeffrey; Eustes, Alfred; Fleckenstein, William; Eker, Erdinc; Baker, Reed; Augustine, Chad

    2015-09-02

    The petroleum industry has had considerable success in recent decades in developing unconventional shale plays using horizontal drilling and multi-zonal isolation and stimulation techniques to fracture tight formations to enable the commercial production of oil and gas. Similar well completions could be used in Enhanced Geothermal Systems (EGS) to create multiple fractures from horizontal wells. This study assesses whether well completion techniques used in the unconventional shale industry to create multi-stage fractures can be applied to an enhanced geothermal system, with a focus on the completion of the EGS injection well. This study assumes an Enhanced Geothermal System (EGS) consisting of a central horizontal injection well flanked on each side by horizontal production wells, connected to the injection well by multiple fractures. The focus is on the design and completion of the horizontal well. For the purpose of developing design criteria, a reservoir temperature of 200 degrees C (392 degrees F) and an injection well flow rate of 87,000 barrels per day (160 kg/s), corresponding to production well flow rates of 43,500 barrels per day (80 kg/s) is assumed. The analysis found that 9-5/8 inches 53.5 pounds per foot (ppf) P110 casing string with premium connections meets all design criteria for the horizontal section of injection well. A P110 grade is fairly common and is often used in horizontal sections of shale development wells in petroleum operations. Next, several zonal isolation systems commonly used in the shale gas industry were evaluated. Three techniques were evaluated -- a 'plug and perf' design, a 'sand and perf' design, and a 'packer and port' design. A plug and perf system utilizes a cemented casing throughout the length of the injector wellbore. The sand and perf system is identical to the plug and perf system, but replaces packers with sand placed in the casing after stimulation to screen out the stimulated perforated zones and provide zonal

  13. Geothermal energy program overview

    NASA Astrophysics Data System (ADS)

    1991-12-01

    The mission of the Geothermal Energy Program is to develop the science and technology necessary for tapping our nation's tremendous heat energy sources contained within the Earth. Geothermal energy is a domestic energy source that can produce clean, reliable, cost-effective heat and electricity for our nation's energy needs. Geothermal energy - the heat of the Earth - is one of our nation's most abundant energy resources. In fact, geothermal energy represents nearly 40 percent of the total U.S. energy resource base and already provides an important contribution to our nation's energy needs. Geothermal energy systems can provide clean, reliable, cost-effective energy for our nation's industries, businesses, and homes in the form of heat and electricity. The U.S. Department of Energy's (DOE) Geothermal Energy Program sponsors research aimed at developing the science and technology necessary for utilizing this resource more fully. Geothermal energy originates from the Earth's interior. The hottest fluids and rocks at accessible depths are associated with recent volcanic activity in the western states. In some places, heat comes to the surface as natural hot water or steam, which have been used since prehistoric times for cooking and bathing. Today, wells convey the heat from deep in the Earth to electric generators, factories, farms, and homes. The competitiveness of power generation with lower quality hydrothermal fluids, geopressured brines, hot dry rock, and magma (the four types of geothermal energy), still depends on the technical advancements sought by DOE's Geothermal Energy Program.

  14. Geothermal Energy Program overview

    SciTech Connect

    Not Available

    1991-12-01

    The mission of the Geothermal Energy Program is to develop the science and technology necessary for tapping our nation's tremendous heat energy sources contained with the Earth. Geothermal energy is a domestic energy source that can produce clean, reliable, cost- effective heat and electricity for our nation's energy needs. Geothermal energy -- the heat of the Earth -- is one of our nation's most abundant energy resources. In fact, geothermal energy represents nearly 40% of the total US energy resource base and already provides an important contribution to our nation's energy needs. Geothermal energy systems can provide clean, reliable, cost-effective energy for our nation's industries, businesses, and homes in the form of heat and electricity. The US Department of Energy's (DOE) Geothermal Energy Program sponsors research aimed at developing the science and technology necessary for utilizing this resource more fully. Geothermal energy originates from the Earth's interior. The hottest fluids and rocks at accessible depths are associated with recent volcanic activity in the western states. In some places, heat comes to the surface as natural hot water or steam, which have been used since prehistoric times for cooking and bathing. Today, wells convey the heat from deep in the Earth to electric generators, factories, farms, and homes. The competitiveness of power generation with lower quality hydrothermal fluids, geopressured brines, hot dry rock, and magma ( the four types of geothermal energy) still depends on the technical advancements sought by DOE's Geothermal Energy Program.

  15. Natural analogs for enhanced heat recovery from geothermal systems

    SciTech Connect

    Nielson, D.L.

    1996-12-31

    High-temperature hydrothermal systems are physically and chemically zoned with depth. The energy input is from a magmatic zone, intruded by igneous bodies, that may also contribute variable amounts of magmatic fluid to the system. The heat source is directly overlain by a section of rocks, that due to their elevated temperature, respond to stress in a ductile fashion. The ductile zone is, in turn, overlain by a section of rocks that respond to stress in a brittle fashion, where water is able to circulate through fractures (the geothermal reservoir) and will be termed the hydrothermal circulation zone. Ancient and modern high-temperature geothermal systems show a predictable sequence of evolutionary events affecting these stratified zones. Metamorphic core complexes are uplifts, formed in highly extended terrains, that expose fossil brittle-ductile transition zones. Formerly ductile rocks have had brittle fractures superimposed on them, and meteoric hydrothermal systems are associated with the brittle fracturing. Porphyry copper deposits typically evolve from magmatic to meteoric hydrothermal systems. At the Larderello geothermal system, the brittle-ductile transition has been mapped using reflection seismology, and the zone has been penetrated by the San Pompeo 2 well where temperatures >420{degrees}C were encountered. Although neo-granitic dikes have been penetrated by drilling in the Larderello area, the brittle-ductile transition is largely above the inferred plutonic heat source. In the Geysers system, in contrast, the present steam system has been superimposed on young plutonic rocks and the inferred brittle-ductile transition is present at a depth of about 4.7 km within the plutonic rocks. As hydrothermal reservoirs are depleted, or surface facilities are restricted by environmental considerations, interest will turn to the deeper portions of known systems. Japan already has an aggressive program to develop Deep-Seated and Magma-Ambient resources.

  16. Feasibility study of sedimentary enhanced geothermal systems using reservoir simulation

    NASA Astrophysics Data System (ADS)

    Cho, Jae Kyoung

    investigated. Especially, water density, viscosity and rock heat capacity play a significant role in reservoir performance. The Permian Lyons formation in the Denver Basin is selected for this preliminary study. Well log data around the area of interest are collected and borehole temperature data are analyzed to estimate the geothermal potential of the target area and it follows that the target formation has a geothermal gradient as high as 72 °C/km. Based on the well log data, hypothetical reservoir simulation models are build and tested to access the hydraulic and thermal performance. It turns out that the target formation is marginally or sub-marginally commercial in terms of its formation conductivity. Therefore, the target formation may require reservoir stimulation for commercially viable power generation. Lastly, reservoir simulation models with average petrophysical properties obtained from the well log analysis of the target formation are built. In order to account for overburden and underburden heat transfer for confined reservoirs, low permeability layers representing shale cap/bed rocks are attached to the top and bottom of the reservoir layers. The dual permeability concept is applied to the reservoir layers to model induced fracture networks by reservoir stimulation. The simulation models are tested by changing fracture conductivity and shape factor. The results show that a balance between hydraulic and thermal performance should be achieved to meet the target flow rate and sustainability of 30 years' uninterrupted operation of geothermal electricity power generation. Ineffective reservoir stimulation could result in failing to create a producing reservoir with appropriate productivity index or causing premature thermal breakthrough or short-circuiting which advances the end of geothermal systems. Therefore, Enhanced Geothermal Systems (EGS) should be engineered to secure producing performance and operational sustainability simultaneously.

  17. Off peak geothermal heat pump storage system

    SciTech Connect

    Drake, M.S.

    1986-03-01

    The basic design of a system installed in the Columbus, Ohio Zoo is described. The distribution system is described in detail. The control system is microprocessor controlled, with about 50 monitoring points. Preliminary evaluations have indicated that the system can operate with an overall coefficient of performance in excess of 3.5. 1 figure.

  18. Detection by infrared thermography and modelling of an icecapped geothermal system in Kerguelen archipelago

    NASA Astrophysics Data System (ADS)

    Ballestracci, Regis; Nougier, Jacques

    1984-03-01

    In order to investigate the geothermal fields in the volcanic islands of Kerguelen (South Indian Ocean), and taking account of the difficult field and meteorological conditions, an infrared survey was conducted by a helicopter-borne thermocamera on the slopes of the recent volcano of the Rallier du Baty peninsula where fumaroles were previously found. Four active zones were observed. Fumaroles and hot water springs are located near the limits of the icecap which covers all the upper part of the peninsula. Joint infrared and normal TV imageries have been largely sufficient to obtain detailed surveys of these active zones. A tentative model of the icecapped geothermal system has been drawn, the main feature being that the supply of convective heat from the recent and still warm magmatic chamber is too low and local for melting all the icecap but remains high enough to insure its slow fusion and the discharge of steam and hot water at its periphery.

  19. Hydrocarbon anomaly in soil gas as near-surface expressions of upflows and outflows in geothermal systems

    SciTech Connect

    Ong, H.L.; Higashihara, M.; Klusman, R.W.; Voorhees, K.J.; Pudjianto, R.; Ong, J

    1996-01-24

    A variety of hydrocarbons, C1 - C12, have been found in volcanic gases (fumarolic) and in geothermal waters and gases. The hydrocarbons are thought to have come from products of pyrolysis of kerogen in sedimentary rocks or they could be fed into the geothermal system by the recharging waters which may contain dissolved hydrocarbons or hydrocarbons extracted by the waters from the rocks. In the hot geothermal zone, 300°+ C, many of these hydrocarbons are in their critical state. It is thought that they move upwards due to buoyancy and flux up with the upflowing geothermal fluids in the upflow zones together with the magmatic gases. Permeability which could be provided by faults, fissures, mini and micro fractures are thought to provide pathways for the upward flux. A sensitive technique (Petrex) utilizing passive integrative adsorption of the hydrocarbons in soil gas on activated charcoal followed by desorption and analysis of the hydrocarbons by direct introduction mass spectrometry allows mapping of the anomalous areas. Surveys for geothermal resources conducted in Japan and in Indonesia show that the hydrocarbon anomaly occur over known fields and over areas strongly suspected of geothermal potential. The hydrocarbons found and identified were n-paraffins (C7-C9) and aromatics (C7-C8). Detection of permeable, i.e. active or open faults, parts of older faults which have been reactivated, e.g. by younger intersecting faults, and the area surrounding these faulted and permeable region is possible. The mechanism leading to the appearance of the hydrocarbon in the soil gas over upflow zones of the geothermal reservoir is proposed. The paraffins seems to be better pathfinders for the location of upflows than the aromatics. However the aromatics may, under certain circumstances, give better indications of the direction of the outflow of the geothermal system. It is thought that an upflow zone can be

  20. Validation of hydrogeochemical codes using the New Zealand geothermal system

    SciTech Connect

    Glassley, W.

    1992-12-01

    Evaluation of the performance of a nuclear waste repository requires that numerous parameters be evaluated over a broad range of conditions using codes. The capabilities of these codes must be demonstrated using complex natural systems in which the processes of interest have already occurred or are occurring. We have initiated such a test of geochemical and hydrological simulation codes, using the geothermal areas of the Taupo Volcanic Zone, New Zealand. Areas that have been evolving for a few tens to a few tens of thousands of years are of particular interest. This effort will help determine the extent to which simplified modeling approaches can be used in performance assessment calculations. To guide the selection of natural systems, we are attempting to map potential repository regions dominated by equilibrium processes and those dominated by kinetically controlled processes. To do so, fluid velocities and temperatures were computed using the V-TOUGH code assuming an equivalent continuum, dual porosity model. These results were then used to compare advective fluid flow rate with silica dissolution/precipitation rates, using Damkoehler numbers. Only the first 5000 years of repository operation were considered. The results identify a migrating envelope of kinetically dominated activity several meters wide in the vicinity of waste packages that contrasts with other parts of the repository. The Lake Rotokawa region, New Zealand, has been used in our first test effort, since it contains environments that are examples of kinetic and equilibrium processes. The results of tests involving equilibrium processes show excellent correspondence between simulated and observed mineral alteration sequences, although discrepancies in some mineral parageneses demonstrate that operator decisions in conducting simulations must be considered an integral part of validation efforts.

  1. Earthquake swarm activity highlights crustal faulting associated with the Waimangu-Rotomahana-Mt Tarawera geothermal field, Taupo Volcanic Zone

    NASA Astrophysics Data System (ADS)

    Bannister, Stephen; Sherburn, Steven; Bourguignon, Sandra

    2016-03-01

    The Waimangu-Rotomahana-Mt.Tarawera geothermal field (WRTGF) in the Taupo Volcanic Zone, New Zealand, experiences frequent but sporadic earthquake swarms with durations of less than 1 day. Here we examine detailed locations of the seismic activity using precise double-difference relative location techniques. We utilize a combination of cross-correlation-derived arrival times and catalogue-based arrival times from 582 earthquakes recorded in the area between 2004 and 2015 for the relocation analysis. The new earthquake locations highlight a ~ 6 km long NE-SW lineation, which we infer to represent a sub-surface fault that extends along the northern side of Waimangu geothermal system and the north-western end of Lake Rotomahana. We suggest that this structural feature acts as a permeable pathway for aqueous fluid and CO2 release up to the surface geothermal field and Lake Rotomahana, from a deeper magmatic source.

  2. Sperry Low Temperature Geothermal Conversion System, Phase 1 and Phase II. Final report. Volume III. Systems description

    SciTech Connect

    Matthews, H.B.

    1984-01-01

    The major fraction of hydrothermal resources that have the prospect of being economically useful for the generation of electricity are in the 300/sup 0/F to 425/sup 0/F temperature range. Cost-effective conversion of the geothermal energy to electricity requires the conception and reduction to practice of new ideas to improve conversion efficiency, enhance brine flow, reduce plant costs, increase plant availability, and shorten the time between investment and return. The problems addressed during past activities are those inherent in the geothermal environment, in the binary fluid cycle, in the difficulty of efficiently converting the energy of a low-temperature resource, and in geothermal economics. Explained in detail in this document, some of these problems are: the energy expended by the down-hole pump; the difficulty in designing reliable down-hole equipment; fouling of heat-exchanger surfaces by geothermal fluids; the unavailability of condenser cooling water at most geothermal sites; the large portion of the available energy used by the feed pump in a binary system; the pinch effect - a loss in available energy in transferring heat from water to an organic fluid; flow losses in fluids that carry only a small amount of useful energy to begin with; high heat-exchanger costs - the lower the temperature interval of the cycle, the higher the heat exchanger costs in $/kW (actually, more than inversely proportional); the complexity and cost of the many auxiliary elements of proposed geothermal plants; and the unfortunate cash flow vs. investment curve caused by the many years of investment required to bring a field into production before any income is realized.

  3. Thermal Infrared Remote Sensing of the Yellowstone Geothermal System

    NASA Astrophysics Data System (ADS)

    Vaughan, R. G.; Keszthelyi, L. P.; Heasler, H.; Jaworowski, C.; Lowenstern, J. B.; Schneider, D. J.

    2009-12-01

    The Yellowstone National Park (YNP) geothermal system is one of the largest in the world, with thousands of individual thermal features ranging in size from a few centimeters to tens of meters across, (e.g., fumaroles, geysers, mud pots and hot spring pools). Together, large concentrations of these thermal features make up dozens of distinct thermal areas, characterized by sparse vegetation, hydrothermally altered rocks, and usually either sinter, travertine, or acid sulfate alteration. The temperature of these thermal features generally ranges from ~30 to ~93 oC, which is the boiling temperature of water at the elevation of Yellowstone. In-situ temperature measurements of various thermal features are sparse in both space and time, but they show a dynamic time-temperature relationship. For example, as geysers erupt and send pulses of warm water down slope, the warm water cools rapidly and is then followed by another pulse of warm water, on time scales of minutes. The total heat flux from the Park’s thermal features has been indirectly estimated from chemical analysis of Cl- flux in water flowing from Yellowstone’s rivers. We are working to provide a more direct measurement, as well as estimates of time variability, of the total heat flux using satellite multispectral thermal infrared (TIR) remote sensing data. Over the last 10 years, NASA’s orbiting ASTER and MODIS instruments have acquired hundreds and thousands of multispectral TIR images, respectively, over the YNP area. Compared with some volcanoes, Yellowstone is a relatively low-temperature geothermal system, with low thermal contrast to the non-geothermal surrounding areas; therefore we are refining existing techniques to extract surface temperature and thermal flux information. This task is complicated by issues such as, during the day, solar heated surfaces may be warmer than nearby geothermal features; and there is some topographic (elevation) influence on surface temperatures, even at night. Still

  4. Process Control System of the Mutnovskaya Geothermal Power Plant

    SciTech Connect

    Idzon, O. M.; Ivanov, V. V.; Ilyushin, V. V.; Nikol'skii, A. I.

    2004-01-15

    The experience of creating software and algorithms for automatic process control at the Mutnovskaya geothermal power plant (GTPP) on the basis of the Teleperm ME automation system is presented. The heat cycle and special features of the heat flow diagram of the power plant are briefly described. The engineering solutions used, the structure of the system, and the principles of process control at the Mutnovskaya GTPP are considered. Special attention is devoted to the turbine regulator that consists of several regulating units because of the great number of problems solved by control valves; each regulating unit solves control problems depending on the mode of operation of the power generating set.

  5. Coupled reactive flow modeling with declining reactivity in fractured geothermal systems

    NASA Astrophysics Data System (ADS)

    Palguta, J.; Williams, C. F.; Ingebritsen, S.; Hickman, S.; Sonnenthal, E. L.

    2011-12-01

    mineral precipitation controls primary mineral dissolution. The two-dimensional models also allow us to consider the importance of diffusion in controlling reaction behavior. We conclude that mathematically linking reactivity loss to declining surface area may be a viable way to obtain more accurate predictions of the spatial and temporal changes of key geothermal system properties (e.g., permeability, mineral compositions, and solute concentrations) over extended periods of time. Our findings suggest that modeling approaches that do not incorporate a mechanism for rapid changes in reactive surface area may over predict the rate of fracture permeability decay. Consequently, this work also implies that some fraction of the increased permeability resulting from fracture formation and reactivation in tectonically active geothermal systems may be maintained over significant time intervals. Therefore, the models provide a potential framework for predicting the long-term behavior of natural geothermal systems.

  6. I/S and C/S mixed layers, some indicators of recent physical-chemical changes in active geothermal systems: The case study of Chipilapa (El Salvador)

    SciTech Connect

    Beaufort, D.; Papapanagiotou, P.; patrier, P.; Fouillac, A.M.; Traineau, H.

    1996-01-24

    I/S and C/S mixed layers from the geothermal field of Chipilapa (El Salvador) have been studied in details in order to reevaluate their potential use as indicator of the thermodynamic conditions in which they were formed. It is funded that overprinting of clay bearing alteration stages is common. For a given alteration stage, the spatial variation of I/S and C/S mixed layer ininerals is controlled by kinetics of mixed layer transformation and not only by temperature. Clay geo-thermometers cannot give reliable results because the present crystal-chemical states of the I/S and C/S mixed layers is not their initial state, it was aquired during the overall hydrothermal history which post dated the nucleation of smectitic clay material at high temperature. Occurrences of smectites or smectite-rich mixed layers at high temperature in reservoirs is a promising guide for reconstruct the zones in which boiling or mixing of non isotherinal fluids occurred very recently or still presently.

  7. Opportunities for support of geothermal energy activities from Petroleum Violation Escrow funds

    SciTech Connect

    Not Available

    1988-06-01

    The purpose of this document is to provide a reference for the geothermal community regarding the extent to which Petroleum Violation Escrow (PVE) funds might be employed by states to fund research, development, demonstration and applications pertaining to geothermal energy resources. The document highlights the background and status of the PVE funds being disbursed through state energy agencies and summarizes the types of energy-related activities being conducted with these funds and the process used to select and approve these activities. These funds provides a mechanism for expanding the contribution of geothermal technologies to domestic energy conservation and security.

  8. Thermal history of the Acoculco geothermal system, eastern Mexico: Insights from numerical modeling and radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Canet, Carles; Trillaud, Frederic; Prol-Ledesma, Rosa María; González-Hernández, Galia; Peláez, Berenice; Hernández-Cruz, Berenice; Sánchez-Córdova, María M.

    2015-10-01

    Acoculco is a geothermal prospective area hosted by a volcanic caldera complex in the eastern Trans-Mexican Volcanic Belt. Surface manifestations are scarce and consist of gas discharges (CO2-rich) and acid-sulfate springs of low temperature, whereas hydrothermal explosive activity is profusely manifested by meter-scale craters and mounds of hydrothermal debris and breccias. Silicic alteration extends for several square kilometers around the zone with gas manifestations and explosive features, affecting surficial volcanic rocks, primarily tuffs and breccias. In the subsurface, an argillic alteration zone (ammonium illite) extends down to a depth of ∼ 600 m, and underneath it a propylitic zone (epidote-calcite-chlorite) occurs down to ∼ 1000 m. Thermal logs from an exploratory borehole (EAC-1, drilled in 1995 down to 1810 m) showed a conductive heat transfer regime under high geothermal gradient (∼ 140 °C/1000 m). In contrast, the thermal profile established from temperatures of homogenization of fluid inclusions-measured on core samples from the same drill hole-suggests that convection occurred in the past through the upper ~ 1400 m of the geothermal system. A drop in permeability due to the precipitation of alteration minerals would have triggered the cessation of the convective heat transfer regime to give place to a conductive one. With the purpose of determining when the transition of heat transfer regime occurred, we developed a 1D model that simulates the time-depth distribution of temperature. According to our numerical simulations, this transition happened ca. 7000 years ago; this date is very recent compared to the lifespan of the geothermal system. In addition, radiocarbon chronology indicates that the hydrothermal explosive activity postdates the end of the convective heat transfer regime, having dated at least three explosive events, at 4867-5295, 1049-1417 and 543-709 y cal. BP. Therefore, hydrothermal explosions arise from the self-sealing of

  9. National Geothermal Data System: State Geological Survey Contributions to Date

    NASA Astrophysics Data System (ADS)

    Patten, K.; Allison, M. L.; Richard, S. M.; Clark, R.; Love, D.; Coleman, C.; Caudill, C.; Matti, J.; Musil, L.; Day, J.; Chen, G.

    2012-12-01

    In collaboration with the Association of American State Geologists the Arizona Geological Survey is leading the effort to bring legacy geothermal data to the U.S. Department of Energy's National Geothermal Data System (NGDS). NGDS is a national, sustainable, distributed, interoperable network of data and service (application) providers entering its final stages of development. Once completed the geothermal industry, the public, and policy makers will have access to consistent and reliable data, which in turn, reduces the amount of staff time devoted to finding, retrieving, integrating, and verifying information. With easier access to information, the high cost and risk of geothermal power projects (especially exploration drilling) is reduced. This presentation focuses on the scientific and data integration methodology as well as State Geological Survey contributions to date. The NGDS is built using the U.S. Geoscience Information Network (USGIN) data integration framework to promote interoperability across the Earth sciences community and with other emerging data integration and networking efforts. Core to the USGIN concept is that of data provenance; by allowing data providers to maintain and house their data. After concluding the second year of the project, we have nearly 800 datasets representing over 2 million data points from the state geological surveys. A new AASG specific search catalog based on popular internet search formats enables end users to more easily find and identify geothermal resources in a specific region. Sixteen states, including a consortium of Great Basin states, have initiated new field data collection for submission to the NGDS. The new field data includes data from at least 21 newly drilled thermal gradient holes in previously unexplored areas. Most of the datasets provided to the NGDS are being portrayed as Open Geospatial Consortium (OGC) Web Map Services (WMS) and Web Feature Services (WFS), meaning that the data is compatible with a

  10. Beneficial effects of groundwater entry into liquid-dominated geothermal systems

    SciTech Connect

    Lippmann, M.J. ); Truesdell, A.H. )

    1990-04-01

    In all active liquid-dominated geothermal systems there is continuous circulation of mass and transfer of heat, otherwise they would slowly cool and fade away. In the natural state these systems are in dynamic equilibrium with the surrounding colder groundwater aquifers. The ascending geothermal fluids cool conductively, boil, or mix with groundwaters, and ultimately may discharge at the surface as fumaroles or hot springs. With the start of fluid production and the lowering of reservoir pressure, the natural equilibrium is disrupted and cooler groundwater tends to enter the reservoir. Improperly constructed or damaged wells, and wells located near the margins of the geothermal system, exhibit temperature reductions (and possibly scaling from mixing of chemically distinct fluids) as the cooler-water moves into the reservoir. These negative effects, especially in peripheral wells are, however, compensated by the maintenance of reservoir pressure and a reduction in reservoir boiling that might result in mineral precipitation in the formation pores and fractures. The positive effect of cold groundwater entry on the behavior of liquid-dominated system is illustrated by using simple reservoir models. The simulation results show that even though groundwater influx into the reservoir causes cooling of fluids produced from wells located near the cold-water recharge area, it also reduces pressure drawdown and boiling in the exploited zone, and sweeps the heat stored in the reservoir rocks toward production wells, thus increasing the productive life of the wells and field. 9 refs.

  11. Prediction of reinjection effects on the Cerro Prieto geothermal system

    SciTech Connect

    Tsang, C.F.; Mangold, D.C.; Doughty, C.; Lippmann, M.J.

    1982-08-10

    The response of the Cerro Prieto geothermal field to different reinjection schemes is predicted using a two-dimensional vertical reservoir model with single- or two-phase flow. The advance of cold fronts and pressure changes in the system associated with the inection operations are computed, taking into consideration the geologic characteristics of the field. The effects of well location, depth, and rates of injection are analyzed. Results indicate that significant pressure maintenance effects may be realized in a carefully designed reinjection operation.

  12. Long-term predictions of minewater geothermal systems heat resources

    NASA Astrophysics Data System (ADS)

    Harcout-Menou, Virginie; de ridder, fjo; laenen, ben; ferket, helga

    2014-05-01

    Abandoned underground mines usually flood due to the natural rise of the water table. In most cases the process is relatively slow giving the mine water time to equilibrate thermally with the the surrounding rock massif. Typical mine water temperature is too low to be used for direct heating, but is well suited to be combined with heat pumps. For example, heat extracted from the mine can be used during winter for space heating, while the process could be reversed during summer to provide space cooling. Altough not yet widely spread, the use of low temperature geothermal energy from abandoned mines has already been implemented in the Netherlands, Spain, USA, Germany and the UK. Reliable reservoir modelling is crucial to predict how geothermal minewater systems will react to predefined exploitation schemes and to define the energy potential and development strategy of a large-scale geothermal - cold/heat storage mine water systems. However, most numerical reservoir modelling software are developed for typical environments, such as porous media (a.o. many codes developed for petroleum reservoirs or groundwater formations) and cannot be applied to mine systems. Indeed, mines are atypical environments that encompass different types of flow, namely porous media flow, fracture flow and open pipe flow usually described with different modelling codes. Ideally, 3D models accounting for the subsurface geometry, geology, hydrogeology, thermal aspects and flooding history of the mine as well as long-term effects of heat extraction should be used. A new modelling approach is proposed here to predict the long-term behaviour of Minewater geothermal systems in a reactive and reliable manner. The simulation method integrates concepts for heat and mass transport through various media (e.g., back-filled areas, fractured rock, fault zones). As a base, the standard software EPANET2 (Rossman 1999; 2000) was used. Additional equations for describing heat flow through the mine (both

  13. Geothermal pump down-hole energy regeneration system

    DOEpatents

    Matthews, Hugh B.

    1982-01-01

    Geothermal deep well energy extraction apparatus is provided of the general kind in which solute-bearing hot water is pumped to the earth's surface from a subterranean location by utilizing thermal energy extracted from the hot water for operating a turbine motor for driving an electrical power generator at the earth 3 s surface, the solute bearing water being returned into the earth by a reinjection well. Efficiency of operation of the total system is increased by an arrangement of coaxial conduits for greatly reducing the flow of heat from the rising brine into the rising exhaust of the down-well turbine motor.

  14. Geothermal tomorrow 2008

    SciTech Connect

    None, None

    2009-01-18

    Contributors from the Geothermal Technologies Program and the geothermal community highlight the current status and activities of the Program and the development of the global resource of geothermal energy.

  15. Geothermal progress monitor report No. 6

    SciTech Connect

    Not Available

    1982-06-01

    Geothermal Progress Monitor Report No. 6 presents a state-by-state summary of the status of geothermal leasing, exploration, and development in major physiographic regions where geothermal resource potential has been identified. Recent state-specific activities are reported at the end of each state status report, while recent activities of a more general nature are summarized briefly in Part II of the report. A list of recent publications of potential interest to the geothermal community and a directory of contributors to the geothermal progress monitoring system are also included.

  16. A New Concept for Geothermal Energy Extraction: The Radiator - Enhanced Geothermal System

    NASA Astrophysics Data System (ADS)

    Hilpert, M.; Geiser, P.; Marsh, B. D.; Malin, P. E.; Moore, S.

    2014-12-01

    Enhanced Geothermal Systems (EGS) in hot dry rock frequently underperform or fail due to insufficient reservoir characterization and poorly controlled permeability stimulation. Our new EGS design is based on the concept of a cooling radiator of an internal combustion engine, which we call the Radiator EGS (RAD-EGS). Within a hot sedimentary aquifer, we propose to construct vertically extensive heat exchanger vanes, which consist of rubblized zones of high permeability and which emulate a hydrothermal system. A "crows-foot" lateral drilling pattern at multiple levels is used to form a vertical array that includes S1 and Shmax. To create the radiator, we propose to use propellant fracing. System cool-down is delayed by regional background flow and induced upward flow of the coolant which initially heats the rock. Tomographic Fracture Imaging is used to image and control the permeability field changes. Preliminary heat transfer calculations suggest that the RAD-EGS will allow for commercial electricity production for at least several tens of years.

  17. Parametric Analysis of the Factors Controlling the Costs of Sedimentary Geothermal Systems - Preliminary Results (Poster)

    SciTech Connect

    Augustine, C.

    2013-10-01

    Parametric analysis of the factors controlling the costs of sedimentary geothermal systems was carried out using a modified version of the Geothermal Electricity Technology Evaluation Model (GETEM). The sedimentary system modeled assumed production from and injection into a single sedimentary formation.

  18. 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)

  19. Development of geothermal logging systems in the United States

    SciTech Connect

    Lysne, P.

    1994-04-01

    Logging technologies developed for hydrocarbon resource evaluation have not migrated into geothermal applications even though data so obtained would strengthen reservoir characterization efforts. Two causative issues have impeded progress: (1) there is a general lack of vetted, high-temperature instrumentation, and (2) the interpretation of log data generated in a geothermal formation is in its infancy. Memory-logging tools provide a path around the first obstacle by providing quality data at a low cost. These tools feature on-board computers that process and store data, and newer systems may be programmed to make decisions. Since memory tools are completely self-contained, they are readily deployed using the slick line found on most drilling locations. They have proven to be rugged, and a minimum training program is required for operator personnel. Present tools measure properties such as temperature and pressure, and the development of noise, deviation, and fluid conductivity logs based on existing hardware is relatively easy. A more complex geochemical tool aimed at a quantitative analysis of (potassium, uranium and thorium) is in the calibration phase, and it is expandable into all nuclear measurements common in the hydrocarbon industry. A fluid sampling tool is in the design phase. All tools are designed for operation at conditions exceeding 400 C, and for deployment in the slim holes produced by mining-coring operations. Partnerships are being formed between the geothermal industry and scientific drilling programs to define and develop inversion algorithms relating raw tool data to more pertinent information. These cooperative efforts depend upon quality guidelines such as those under development within the international Ocean Drilling Program.

  20. Assessing the role of ancient and active geothermal systems in oil-reservoir evolution in the eastern Basin and Range province, western USA. Annual progress report, June 1, 1992--May 31, 1993

    SciTech Connect

    Hulen, J.B.

    1993-07-01

    Results of our research on the oil fields of the Basin and Range province of the western USA continue to support the following concept: Convecting, moderate-temperature geothermal systems in this region have fostered and in some cases critically influenced the generation, migration, and entrapment of oil. At one Basin-Range field (Grant Canyon), oil-bearing and aqueous fluid inclusions in late-stage hydrothermal quartz were entrapped at temperatures comparable to those now prevailing at reservoir depths (120--130{degrees}C); apparent salinities of the aqueous varieties match closely the actual salinity of the modern, dilute oil-field waters. The inclusion-bearing quartz has the oxygen-isotopic signature for precipitation of the mineral at contemporary temperatures from modern reservoir waters. Measured and fluid-inclusion temperatures define near-coincident isothermal profiles through the oil-reservoir interval, a phenomenon suggesting ongoing heat and mass transfer. These findings are consistent with a model whereby a still-active, convectively circulating, meteoric-hydrothermal system: (1) enhanced porosity in the reservoir rock through dissolution of carbonate; (2) hydrothermally sealed reservoir margins; (3) transported oil to the reservoirs from a deep source of unknown size and configuration; and (4) possibly accelerated source-rock maturation through an increase in the local thermal budget. Grant Canyon and other Basin-Range oil fields are similar to the oil-bearing, Carlin-type, sediment-hosted, disseminated gold deposits of the nearby Alligator Ridge district. The oil fields could represent either weakly mineralized analogues of these deposits, or perhaps an incipient phase in their evolution.

  1. Geologic and preliminary reservoir data on the Los Humeros Geothermal System, Puebla, Mexico

    SciTech Connect

    Ferriz, H.

    1982-01-01

    Exploratory drilling has confirmed the existence of a geothermal system in the Los Humeros volcanic center, located 180 km east of Mexico City. Volcanic activity in the area began with the eruption of andesites, followed by two major caldera-forming pyroclastic eruptions. The younger Los Potreros caldera is nested inside the older Los Humeros caldera. At later stages, basaltic andesite, dacite, and olivine basalt lavas erupted along the ring-fracture zones of both calderas. Geologic interpretation of structural, geophysical, and drilling data suggests that: (1) the water-dominated geothermal reservoir is hosted by the earliest andesitic volcanic pile, is bounded by the ring-fracture zone of the Los Potreros caldera, and is capped by the products of the oldest caldera-forming eruption; (2) permeability within the andesitic pile is provided by faults and fractures related to intracaldera uplift; (3) the geothermal system has potential for a large influx of meteoric water through portions of the ring-fracture zones of both calderas; and (4) volcanic centers with similar magmatic and structural conditions can be found in the eastern Cascades, USA.

  2. Prospecting for a Blind Geothermal System Utilizing Geologic and Geophysical Data, Seven Troughs Range, Northwestern Nevada

    NASA Astrophysics Data System (ADS)

    Forson, Corina

    To aid in the discovery and evaluation of blind resources, it is important to utilize geologic, geophysical, and geochemical techniques to find the required elements (e.g., heat source, fluid to transport the heat, and permeability in a reservoir) for geothermal energy production. Based on a regional low resistivity anomaly discovered through a reconnaissance magnetotelluric (MT) survey, detailed geologic mapping, structural analysis, and a 2 m temperature survey were conducted to delineate the most likely areas for blind geothermal activity in the Seven Troughs Range, Nevada. The Seven Troughs Range resides in the northwestern Basin and Range province 190 km northeast of Reno and 50 km northwest of Lovelock in western Nevada. There is no known geothermal system in the area. Mesozoic metasedimentary strata and intrusions dominate the northern and southern parts of the range but are nonconformably overlain by a thick sequence (~ 1.5 km) of Oligocene to Miocene volcanic and volcaniclastic rocks and Quaternary sediments in the central part of the range. The southern part of the range consists of a basement horst block bounded by two major range-front faults, with Holocene fault scarps marking the more prominent fault on the east side of the range. In contrast, several gently to moderately west-tilted fault blocks, with good exposures of the Tertiary volcanic strata and bounded by a series of steeply east-dipping normal faults, characterize the central part of the range. Kinematic analysis of faults in the range and regional relations indicate a west-northwest-trending extension direction. Accordingly, slip and dilation tendency analyses suggest that north-northeast striking faults are the most favorably oriented for reactivation and fluid flow under the current stress field. Two areas in the Seven Troughs Range have a favorable structural setting for generating permeability and channeling geothermal fluids to the near surface: 1) A major right step in the range

  3. A novel heat flux study of a geothermally active lake - Lake Rotomahana, New Zealand

    NASA Astrophysics Data System (ADS)

    Tivey, Maurice A.; de Ronde, Cornel E. J.; Tontini, Fabio Caratori; Walker, Sharon L.; Fornari, Daniel J.

    2016-03-01

    A new technique for measuring conductive heat flux in a lake was adapted from the marine environment to allow for multiple measurements to be made in areas where bottom sediment cover is sparse, or even absent. This thermal blanket technique, pioneered in the deep ocean for use in volcanic mid-ocean rift environments, was recently used in the geothermally active Lake Rotomahana, New Zealand. Heat flow from the lake floor propagates into the 0.5 m diameter blanket and establishes a thermal gradient across the known blanket thickness and thereby provides an estimate of the conductive heat flux of the underlying terrain. This approach allows conductive heat flux to be measured over a spatially dense set of stations in a relatively short period of time. We used 10 blankets and deployed them for 1 day each to complete 110 stations over an 11-day program in the 6 × 3 km lake. Results show that Lake Rotomahana has a total conductive heat flux of about 47 MW averaging 6 W/m2 over the geothermally active lake. The western half of the lake has two main areas of high heat flux; 1) a high heat flux area averaging 21.3 W/m2 along the western shoreline, which is likely the location of the pre-existing geothermal system that fed the famous Pink Terraces, mostly destroyed during the 1886 eruption 2) a region southwest of Patiti Island with a heat flux averaging 13.1 W/m2 that appears to be related to the explosive rift that formed the lake in the 1886 Tarawera eruption. A small rise in bottom water temperature over the survey period of 0.01 °C/day suggests the total thermal output of the lake is ~ 112-132 MW and when compared to the conductive heat output suggests that 18-42% of the total thermal energy is by conductive heat transfer.

  4. Three-Dimensional Geologic Characterization of Geothermal Systems: Astor Pass, Nevada, USA

    SciTech Connect

    Siler, Drew L; Mayhew, Brett; Faulds, James E

    2012-09-30

    Geothermal systems in the Great Basin, USA, are controlled by a variety of fault intersection and fault interaction areas. Understanding the specific geometry of the structures most conducive to geothermal circulation is crucial in order to both mitigate the costs of geothermal exploration (especially drilling) and to identify blind geothermal systems (no surface expression). Astor Pass, Nevada, one such blind geothermal system, lies near the boundary between two distinct structural domains, the Walker Lane and the Basin and Range, and exhibits characteristics of each setting. Both northwest-striking, left-stepping dextral faults of the Walker Lane and kinematically linked northerly striking normal faults associated with the Basin and Range are present at Astor Pass. Previous studies identified a blind geothermal system controlled by the intersection of northwest-striking dextral and north-northwest-striking normal faults. Wells drilled into the southwestern quadrant of the fault intersection yielded 94˚C fluids, with geothermometers suggesting significantly higher maximum temperatures. Additional data, including reprocessed 2D seismic data and petrologic analysis of well cuttings, were integrated with existing and reinterpreted geologic maps and cross-sections to aid construction of a 3D geologic model. This comprehensive 3D integration of multiple data sets allows characterization of the structural setting of the Astor Pass blind geothermal system at a level of detail beyond what independent data interpretation can provide. Our analysis indicates that the blind geothermal system is controlled by two north- to northwest-plunging fault intersections.

  5. A geochemical reconnaissance of the Alid volcanic center and geothermal system, Danakil depression, Eritrea

    USGS Publications Warehouse

    Lowenstern, J. B.; Janik, C.J.; Fournier, R.O.; Tesfai, T.; Duffield, W.A.; Clynne, M.A.; Smith, James G.; Woldegiorgis, L.; Weldemariam, K.; Kahsai, G.

    1999-01-01

    Geological and geochemical studies indicate that a high-temperature geothermal system underlies the Alid volcanic center in the northern Danakil depression of Eritrea. Alid is a very late-Pleistocene structural dome formed by shallow intrusion of rhyolitic magma, some of which vented as lavas and pyroclastic flows. Fumaroles and boiling pools distributed widely over an area of ~10 km2 on the northern half of Alid suggest that an active hydrothermal system underlies much of that part of the mountain. Geothermometers indicate that the fumarolic gases are derived from a geothermal system with temperatures >225??C. The isotopic composition of condensed fumarolic steam is consistent with these temperatures and implies that the source water is derived primarily from either lowland meteoric waters or fossil Red Sea water, or both. Some gases vented from the system (CO2, H2S and He) are largely magmatic in origin. Permeability beneath the volcanic center may be high, given the amount of intrusion-related deformation and the active normal faulting within the Danakil depression.Geological and geochemical studies indicate that a high-temperature geothermal system underlies the Alid volcanic center in the northern Danakil depression of Eritrea. Alid is a very late-Pleistocene structural dome formed by shallow intrusion of rhyolitic magma, some of which vented as lavas and pyroclastic flows. Fumaroles and boiling pools distributed widely over an area of approx. 10 km2 on the northern half of Alid suggest that an active hydrothermal system underlies much of that part of the mountain. Geothermometers indicate that the fumarolic gases are derived from a geothermal system with temperatures >225??C. The isotopic composition of condensed fumarolic steam is consistent with these temperatures and implies that the source water is derived primarily from either lowland meteoric waters or fossil Red Sea water, or both. Some gases vented from the system (CO2, H2S and He) are largely

  6. Outstanding Issues in the Assessment of Enhanced Geothermal Systems Resources

    NASA Astrophysics Data System (ADS)

    Williams, C.; Deangelo, J.

    2010-12-01

    The successful implementation of Enhanced Geothermal Systems (EGS) technology has the potential to dramatically expand both the magnitude and spatial extent of geothermal energy production, and the U.S. Geological Survey (USGS) has been working to develop a comprehensive EGS resource assessment for the United States. However, a number of outstanding scientific and technical issues must be resolved in order to ensure the accuracy and reliability of this assessment. Among these are determining those conditions under which it is possible to replicate the high average permeability (approximately 10-15 to 10-13 m2) characteristic of natural hydrothermal reservoirs, evaluating the likely heterogeneity of fracture permeability within EGS reservoirs and its influence on the geothermal recovery factor, Rg, which is defined as the ratio of produced thermal energy to the thermal energy contained in the stimulated volume comprising the reservoir, and improving estimates of temperature in the upper crust to better quantify the thermal energy available at those depths viable for EGS reservoir creation. Models for the development of fracture permeability from the shear slip along pre-existing natural fractures induced by hydraulic stimulation indicate that production from EGS reservoirs will be sensitive to the influence of effective stress and rock properties on the processes of shear fracture formation and closure. Calibration of model parameters with results from EGS field experiments and demonstration projects suggests that sufficient permeability may be difficult to attain through shear stimulation at depths greater than approximately 6 km, particularly in regions characterized by high normal stress on pre-existing faults and fractures. In addition, the expected heterogeneity of fracture permeability within EGS reservoirs may limit Rg to values on the order of 0.05 to 0.1, which is at the lower end of the observed range for producing natural geothermal reservoirs. Although

  7. Enhanced Geothermal Systems (EGS) well construction technology evaluation report.

    SciTech Connect

    Capuano, Louis, Jr.; Huh, Michael; Swanson, Robert; Raymond, David Wayne; Finger, John Travis; Mansure, Arthur James; Polsky, Yarom; Knudsen, Steven Dell

    2008-12-01

    Electricity production from geothermal resources is currently based on the exploitation of hydrothermal reservoirs. Hydrothermal reservoirs possess three ingredients critical to present day commercial extraction of subsurface heat: high temperature, in-situ fluid and high permeability. Relative to the total subsurface heat resource available, hydrothermal resources are geographically and quantitatively limited. A 2006 DOE sponsored study led by MIT entitled 'The Future of Geothermal Energy' estimates the thermal resource underlying the United States at depths between 3 km and 10 km to be on the order of 14 million EJ. For comparison purposes, total U.S. energy consumption in 2005 was 100 EJ. The overwhelming majority of this resource is present in geological formations which lack either in-situ fluid, permeability or both. Economical extraction of the heat in non-hydrothermal situations is termed Enhanced or Engineered Geothermal Systems (EGS). The technologies and processes required for EGS are currently in a developmental stage. Accessing the vast thermal resource between 3 km and 10 km in particular requires a significant extension of current hydrothermal practice, where wells rarely reach 3 km in depth. This report provides an assessment of well construction technology for EGS with two primary objectives: (1) Determining the ability of existing technologies to develop EGS wells. (2) Identifying critical well construction research lines and development technologies that are likely to enhance prospects for EGS viability and improve overall economics. Towards these ends, a methodology is followed in which a case study is developed to systematically and quantitatively evaluate EGS well construction technology needs. A baseline EGS well specification is first formulated. The steps, tasks and tools involved in the construction of this prospective baseline EGS well are then explicitly defined by a geothermal drilling contractor in terms of sequence, time and cost. A

  8. Hydrothermal fluids circulation and travertine deposition in an active tectonic setting: Insights from the Kamara geothermal area (western Anatolia, Turkey)

    NASA Astrophysics Data System (ADS)

    Brogi, Andrea; Alçiçek, M. Cihat; Yalçıner, Cahit Çağlar; Capezzuoli, Enrico; Liotta, Domenico; Meccheri, Marco; Rimondi, Valentina; Ruggieri, Giovanni; Gandin, Anna; Boschi, Chiara; Büyüksaraç, Aydin; Alçiçek, Hülya; Bülbül, Ali; Baykara, Mehmet Oruç; Shen, Chuan-Chou

    2016-06-01

    Coexistence of thermal springs, travertine deposits and tectonic activity is a recurring feature for most geothermal areas. Although such a certainty, their relationships are debated mainly addressing on the role of the tectonic activity in triggering and controlling fluids flow and travertine deposition. In this paper, we present the results of an integrated study carried out in a geothermal area located in western Anatolia (Turkey), nearby the well-known Pamukkale area (Denizli Basin). Our study focused on the relationships among hydrothermal fluids circulation, travertine deposition and tectonic activity, with particular emphasis on the role of faults in controlling fluids upwelling, thermal springs location and deposition of travertine masses. New field mapping and structural/kinematics analyses allowed us to recognize two main faults systems (NW- and NE-trending), framed in the Neogene-Quaternary extensional tectonic evolution of western Anatolia. A geo-radar (GPR) prospection was also provided in a key-area, permitting us to reconstruct a buried fault zone and its relationships with the development of a fissure-ridge travertine deposit (Kamara fissure-ridge). The integration among structural and geophysical studies, fluids inclusion, geochemical, isotopic data and 230 Th/238 U radiometric age determination on travertine deposits, depict the characteristics of the geothermal fluids and their pathway, up to the surface. Hydrological and seismological data have been also taken in account to investigate the relation between local seismicity and fluid upwelling. As a main conclusion we found strict relationships among tectonic activity, earthquakes occurrence, and variation of the physical/chemical features of the hydrothermal fluids, presently exploited at depth, or flowing out in thermal springs. In the same way, we underline the tectonic role in controlling the travertine deposition, making travertine (mainly banded travertine) a useful proxy to reconstruct the

  9. Geothermal activity in the subglacial Katla caldera, Iceland, 1999-2005, studied with radar altimetry

    NASA Astrophysics Data System (ADS)

    Guđmundsson, Magnús T.; Höganadóttir, Pórdís; Kristinsson, Arnór Bergur; Guđbjörnsson, Snaebjörn

    The Katla caldera is located under the Mýrdalsjökull ice cap and is one of the most hazardous volcanoes in Iceland due to major jökulhlaups that accompany eruptions. Subglacial geothermal activity is manifested in several 10-50 m deep depressions (ice cauldrons) within and at the caldera rim and the total geothermal heat output is of the order of a few hundred megawatts. A shortlived but powerful pulse in geothermal heat output took place in 1999, probably including a minor subglacial eruption, when new ice cauldrons formed in three places and an unexpected jökulhlaup occurred. Following these events, a comprehensive monitoring program was set up for Katla, including ice surface elevation profiling from aircraft, to monitor variations in geothermal heat and detect signs of subglacial water accumulation. A radar altimeter coupled with a kinematic GPS is used, achieving an absolute elevation accuracy of 3 m and internal consistency of 1-2 m. Profiles across the caldera are flown twice a year. An annual accumulation-ablation cycle in surface elevation with amplitude of 5-10 m is observed. By removing this cycle from the data, changes due to subglacial geothermal activity are obtained. After the events in 1999, a decline in geothermal activity was observed. In 2001-03 some ice cauldrons expanded and deepened by 10-15 m, indicating renewed increase in geothermal activity. This trend is also apparent for 2003-05. The increase in geothermal poweramounts to a few tens of megawatts. It is likely that the increased thermal output is related to increased seismicity and caused by magma inflow.

  10. Summary of geothermal exploration activity in the State of Washington from 1978 to 1983. Final report

    SciTech Connect

    Korosec, M.A.

    1984-01-01

    Project activity is summarized with references to the publications produced. Project findings are reported as they relate to specific geothermal resource target areas. Some major projects of the goethermal exploration program are: thermal and mineral spring chemistry, heat flow drilling, temperature gradient measurements, Cascade Range regional gravity, geohydrology study of the Yakima area, low temperature geothermal resources, geology, geochemistry of Cascade Mountains volcanic rocks, and soil mercury studies. (MHR)

  11. Electronic Submersible Pump (ESP) Technology and Limitations with Respect to Geothermal Systems (Fact Sheet)

    SciTech Connect

    Not Available

    2014-09-01

    The current state of geothermal technology has limitations that hinder the expansion of utility scale power. One limitation that has been discussed by the current industry is the limitation of Electric Submersible Pump (ESP) technology. With the exception of a few geothermal fields artificial lift technology is dominated by line shaft pump (LSP) technology. LSP's utilize a pump near or below reservoir depth, which is attached to a power shaft that is attached to a motor above ground. The primary difference between an LSP and an ESP is that an ESP motor is attached directly to the pump which eliminates the power shaft. This configuration requires that the motor is submersed in the geothermal resource. ESP technology is widely used in oil production. However, the operating conditions in an oil field vary significantly from a geothermal system. One of the most notable differences when discussing artificial lift is that geothermal systems operate at significantly higher flow rates and with the potential addition of Enhanced Geothermal Systems (EGS) even greater depths. The depths and flow rates associated with geothermal systems require extreme horsepower ratings. Geothermal systems also operate in a variety of conditions including but not limited to; high temperature, high salinity, high concentrations of total dissolved solids (TDS), and non-condensable gases.

  12. Modeling studies of geothermal systems with a free water surface

    SciTech Connect

    Bodvarsson, G.S.; Pruess, K.

    1983-12-01

    A numerical simulator was developed for the modeling of air-steam-water systems. The simulator was applied to various problems involving injection into or production from a geothermal reservoir in hydraulic communication with a shallow free-surface aquifer. First, a one-dimensional column problem is considered and the water level movement during exploitation is studied using different capillary pressure functions. Second, a two-dimensional radial model is used to study and compare reservoir depletion for cases with and without a free-surface aquifer. Finally, the contamination of a shallow free-surface aquifer due to cold water injection is investigated. The primary aim of these studies is to obtain an understanding of the response of a reservoir in hydraulic communication with a unconfined aquifer during exploitation or injection and to determine under which circumstances conventional modeling techniques (fully saturated systems) can be applied to such systems.

  13. Marketing the Klamath Falls Geothermal District Heating system

    SciTech Connect

    Rafferty, K.

    1993-06-01

    The new marketing strategy for the Klamath Falls system has concentrated on offering the customer an attractive and easy to understand rate structure, reduced retrofit cost and complexity for his building along with an attractive package of financing and tax credits. Initial retrofit costs and life-cycle cost analysis have been conducted on 22 buildings to date. For some, the retrofit costs are simply too high for the conversion to make sense at current geothermal rates. For many, however, the prospects are good. At this writing, two new customers are now connected and operating with 5 to 8 more buildings committed to connect this construction season after line extensions are completed. This represents nearly a 60% increase in the number of buildings connected to the system and a 40% increase in system revenue.

  14. Boron isotope variations in geothermal systems on Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Purnomo, Budi Joko; Pichler, Thomas; You, Chen-Feng

    2016-02-01

    This paper presents δ11B data for hot springs, hot acid crater lakes, geothermal brines and a steam vent from Java, Indonesia. The processes that produce a large range of the δ11B values were investigated, including the possible input of seawater as well as the contrast δ11B compositions of acid sulfate and acid chloride crater lakes. The δ11B values of hot springs ranged from - 2.4 to + 28.7‰ and acid crater lakes ranged from + 0.6 to + 34.9‰. The δ11B and Cl/B values in waters from the Parangtritis and Krakal geothermal systems confirmed seawater input. The δ11B values of acid sulfate crater lakes ranged from + 5.5 to + 34.9‰ and were higher than the δ11B of + 0.6‰ of the acid chloride crater lake. The heavier δ11B in the acid sulfate crater lakes was caused by a combination of vapor phase addition and further enrichment due to evaporation and B adsorption onto clay minerals. In contrast, the light δ11B of the acid chloride crater lake was a result of acid water-rocks interaction. The correlations of δ11B composition with δ18O and δ2H indicated that the B isotope corresponded to their groundwater mixing sources, but not for J21 (Segaran) and J48 (Cikundul) that underwent 11B isotope enrichment by B adsorption into minerals.

  15. Geobotanical characterization of a geothermal system using hyperspectral imagery: Long Valley Caldera, CA

    SciTech Connect

    Carter, M R; Cochran, S A; Martini, B A; Pickles, W L; Potts, D C; Priest, R E; Silver, E A; Wayne, B A; White, W T

    1998-12-01

    We have analyzed hyperspectral Airborne Visible-Infrared Imaging System (AVIRIS) imagery taken in September of 1992 in Long Valley Caldera, CA, a geothermally active region expressed surficially by hot springs and fumaroles. Geological and vegetation mapping are attempted through spectral classification of imagery. Particular hot spring areas in the caldera are targeted for analysis. The data is analyzed for unique geobotanical patterns in the vicinity of hot springs as well as gross identification of dominant plant and mineral species. Spectra used for the classifications come from a vegetation spectral library created for plant species found to be associated with geothermal processes. This library takes into account the seasonality of vegetation by including spectra for species on a monthly basis. Geological spectra are taken from JPL and USGS mineral libraries. Preliminary classifications of hot spring areas indicate some success in mineral identification and less successful vegetation species identification. The small spatial extent of individual plants demands either sub-pixel analysis or increased spatial resolution of imagery. Future work will also include preliminary analysis of a hyperspectral thermal imagery dataset and a multitemporal air photo dataset. The combination of these remotely sensed datasets for Long Valley will yield a valuable product for geothermal exploration efforts in other regions.

  16. Laboratory testing and modeling to evaluate perfluorocarbon compounds as tracers in geothermal systems

    SciTech Connect

    Reimus, Paul W

    2011-01-21

    The thermal stability and adsorption characteristics of three perfluorinated hydrocarbon compounds were evaluated under geothermal conditions to determine the potential to use these compounds as conservative or thermally-degrading tracers in Engineered (or Enhanced) Geothermal Systems (EGS). The three compounds tested were perfluorodimethyl-cyclobutane (PDCB), perfluoromethylcyclohexane (PMCH), and perfluorotrimethylcyclohexane (PTCH), which are collectively referred to as perfluorinated tracers, or PFTs. Two sets of duplicate tests were conducted in batch mode in gold-bag reactors, with one pair of reactors charged with a synthetic geothermal brine containing the PFTs and a second pair was charged with the brine-PFT mixture plus a mineral assemblage chosen to be representative of activated fractures in an EGS reservoir. A fifth reactor was charged with deionized water containing the three PFTs. The experiments were conducted at {approx}100 bar, with temperatures ranging from 230 C to 300 C. Semi-analytical and numerical modeling was also conducted to show how the PFTs could be used in conjunction with other tracers to interrogate surface area to volume ratios and temperature profiles in EGS reservoirs. Both single-well and cross-hole tracer tests are simulated to illustrate how different suites of tracers could be used to accomplish these objectives. The single-well tests are especially attractive for EGS applications because they allow the effectiveness of a stimulation to be evaluated without drilling a second well.

  17. Screening for heat transport by groundwater in closed geothermal systems.

    PubMed

    Ferguson, Grant

    2015-01-01

    Heat transfer due to groundwater flow can significantly affect closed geothermal systems. Here, a screening method is developed, based on Peclet numbers for these systems and Darcy's law. Conduction-only conditions should not be expected where specific discharges exceed 10(-8)  m/s. Constraints on hydraulic gradients allow for preliminary screening for advection based on rock or soil types. Identification of materials with very low hydraulic conductivity, such as shale and intact igneous and metamorphic rock, allow for analysis with considering conduction only. Variability in known hydraulic conductivity allows for the possibility of advection in most other rocks and soil types. Further screening relies on refinement of estimates of hydraulic gradients and hydraulic conductivity through site investigations and modeling until the presence or absence of conduction can be confirmed. PMID:24438345

  18. Thermal and chemical evolution of The Geysers geothermal system, California

    SciTech Connect

    Moore, J.N.

    1992-01-01

    Fluid inclusions and mineral assemblages provide a reward of the thermal and chemical changes that occurred during the evolution of The Geysers geothermal system. The data document the presence of an extensive liquid dominated geothermal system that developed in response to felsite intrusion and its evolution to a vapor-dominated regime. Temperatures within the early liquid-dominated system ranged from 175 C at a distance of 7200 feet from the felsite to more than 350 C near the contact while salinities varied from 5 equivalent weight percent NaCl (at a distance of 5500 feet) to more than 26 weight percent NaCl. As temperatures around the felsite declined, the liquid-dominated system collapsed upon itself. Downward migration of the low salinity waters resulted in dilution of the fluids present in regions now occupied by the caprock and normal vapor-dominated reservoir. In contrast, dilution was minor in rocks now hosting the high-temperature vapor-dominated reservoir. This suggests that low permeabilities are the primary reason for the development of the high-temperature reservoir. Boiling within the caprock produced late-stage veins of calcite and quartz. As the fluid boiled off, condensate was trapped as low salinity fluid inclusions. Within the main body of the reservoir, a liquid phase with salinities of up to 7 equivalent weight percent NaCl persisted to temperatures between 250 and 270 C. However, except for the presence of vapor-rich inclusions, little evidence of boiling within the reservoir rocks was preserved.

  19. Phase relations and adiabats in boiling seafloor geothermal systems

    NASA Astrophysics Data System (ADS)

    Bischoff, James L.; Pitzer, Kenneth S.

    1985-11-01

    Observations of large salinity variations and vent temperatures in the range of 380-400°C suggest that boiling or two-phase separation may be occurring in some seafloor geothermal systems. Consideration of flow rates and the relatively small differences in density between vapors and liquids at the supercritical pressures at depth in these systems suggests that boiling is occurring under closed-system conditions. Salinity and temperature of boiling vents can be used to estimate the pressure-temperature point in the subsurface at which liquid seawater first reached the two-phase boundary. Data are reviewed to construct phase diagrams of coexisting brines and vapors in the two-phase region at pressures corresponding to those of the seafloor geothermal systems. A method is developed for calculating the enthalpy and entropy of the coexisting mixtures, and results are used to construct adiabats from the seafloor to the P-T two-phase boundary. Results for seafloor vents discharging at 2300 m below sea level indicate that a 385°C vent is composed of a brine (7% NaCl equivalent) in equilibrium with a vapor (0.1% NaCl). Brine constitutes 45% by weight of the mixture, and the fluid first boiled at approximately 1 km below the seafloor at 415°C, 330 bar. A 400°C vent is primarily vapor (88 wt.%, 0.044% NaCl) with a small amount of brine (26% NaCl) and first boiled at 2.9 km below the seafloor at 500°C, 520 bar. These results show that adiabatic decompression in the two-phase region results in dramatic cooling of the fluid mixture when there is a large fraction of vapor.

  20. Modeling Self-Potential Effects During Reservoir Stimulation in Enhanced Geothermal Systems.

    NASA Astrophysics Data System (ADS)

    Troiano, Antonio; Giulia Di Giuseppe, Maria; Monetti, Alessio; Patella, Domenico; Troise, Claudia; De Natale, Giuseppe

    2015-04-01

    Geothermal systems represent a large resource that can provide, with a reasonable investment, a very high and cost-effective power generating capacity. Considering also the very low environmental impact, their development represents, in the next decades, an enormous perspective. Despite its unquestionable potential, geothermal exploitation has long been perceived as limited, mainly because of the dependence from strict site-related conditions, mainly related to the reservoir rock's permeability and to the high thermal gradient, implying the presence of large amounts of hot fluids at reasonable depth. Many of such limitations can be overcome using Enhanced Geothermal Systems technology (EGS), where massive fluid injection is performed to increase the rock permeability by fracturing. This is a powerful method to exploit hot rocks with low natural permeability, otherwise not exploitable. Numerical procedures have already been presented in literature reproducing thermodynamic evolution and stress changes of systems where fluids are injected. However, stimulated fluid flow in geothermal reservoirs can produce also surface Self-Potential (SP) anomalies of several mV. A commonly accepted interpretation involves the activation of electrokinetic processes. Since the induced seismicity risk is generally correlated to fluid circulation stimulated in an area exceeding the well of several hundreds of meters, the wellbore pressure values can be totally uncorrelated to seismic hazard. However, SP anomalies, being generated from pressure gradients in the whole area where fluids flow, has an interesting potential as induced earthquake precursor. In this work, SP anomalies observed above the Soultz-sous-Forets (Alsace, France) geothermal reservoir while injecting cold water have been modeled, considering a source related to the fluid flow induced by the well stimulation process. In particular, the retrieved changes of pressure due to well stimulation in the EGS system have been used

  1. Geochemical exploration of a promissory Enhanced Geothermal System (EGS): the Acoculco caldera, Mexico.

    NASA Astrophysics Data System (ADS)

    Peiffer, Loic; Romero, Ruben Bernard; Pérez-Zarate, Daniel; Guevara, Mirna; Santoyo Gutiérrez, Edgar

    2014-05-01

    The Acoculco caldera (Puebla, Mexico) has been identified by the Mexican Federal Electricity Company (in Spanish 'Comisión Federal de Electricidad', CFE) as a potential Enhanced Geothermal System (EGS) candidate. Two exploration wells were drilled and promising temperatures of ~300° C have been measured at a depth of 2000 m with a geothermal gradient of 11oC/100m, which is three times higher than the baseline gradient measured within the Trans-Mexican Volcanic Belt. As usually observed in Hot Dry Rock systems, thermal manifestations in surface are scarce and consist in low-temperature bubbling springs and soil degassing. The goals of this study were to identify the origin of these fluids, to estimate the soil degassing rate and to explore new areas for a future detailed exploration and drilling activities. Water and gas samples were collected for chemical and isotopic analysis (δ18O, δD, 3He/4He, 13C, 15N) and a multi-gas (CO2, CH4, H2S) soil survey was carried out using the accumulation chamber method. Springs' compositions indicate a meteoric origin and the dissolution of CO2 and H2S-rich gases, while gas compositions reveal a MORB-type origin mixed with some arc-type contribution. Gas geothermometry results are similar to temperatures measured during well drilling (260° C-300° C). Amongst all measured CO2 fluxes, only 5% (mean: 5543 g m-2 day-1) show typical geothermal values, while the remaining fluxes are low and correspond to biogenic degassing (mean: 18 g m-2 day-1). The low degassing rate of the geothermal system is a consequence of the intense hydrothermal alteration observed in the upper 800 m of the system which acts as an impermeable caprock. Highest measured CO2 fluxes (above > 600 g m-2 day-1) have corresponding CH4/CO2 flux ratios similar to mass ratios of sampled gases, which suggest an advective fluid transport. To represent field conditions, a numerical model was also applied to simulate the migration of CO2 towards the surface through a

  2. The application of unmanned aerial systems (UAS) in geophysical investigations of geothermal systems

    NASA Astrophysics Data System (ADS)

    Glen, J. M.; Egger, A. E.; Ippolito, C.; Phelps, G. A.; Berthold, R.; Lee, R.; Spritzer, J. M.; Tchernychev, M.

    2012-12-01

    Investigations of geothermal systems typically involve ground-based geological and geophysical studies in order to map structures that control and facilitate fluid flow. The spatial extent of ground-based investigations can be limited, however, by surficial hot springs, dense foliage, and roadless or private lands. This can result in data gaps in key areas, particularly around active hydrothermal springs. Manned aircraft can provide access to these areas and can yield broad and uniform data coverage, but high-resolution surveys are costly and relatively inflexible to changes in the survey specifications that may arise as data are collected. Unmanned aerial systems (UAS) are well suited for conducting these surveys, but until recently, various factors (scientific instrumentation requirements, platform limitations, and size of the survey area) have required the use of large UAS platforms, rendering unmanned aerial surveys unsuitable for most investigations. We have developed and tested a new cesium magnetometer system to collect magnetic data using two different small-platform UAS that overcomes many of the challenges described above. We are deploying this new system in Surprise Valley, CA, to study the area's active geothermal field. Surprise Valley is ideally suited to testing UAS due to its low population density, accessible airspace, and broad playa that provides ample opportunity to safely land the aircraft. In combination with gravity and topographic data, magnetic data are particularly useful for identifying buried, intra-basin structures, especially in areas such as Surprise Valley where highly magnetic, dense mafic volcanic rocks are interbedded with and faulted against less magnetic, less dense sedimentary rock. While high-resolution gravity data must be collected at point locations on the ground, high-resolution magnetic data can be obtained by UAS that provide continuous coverage. Once acquired, the magnetic data obtained by the UAS will be combined with

  3. Federal Assistance Program Quarterly Project Progress Report. Geothermal Energy Program: Information Dissemination, Public Outreach, and Technical Analysis Activities. Reporting Period: January 1 - March 31, 2001 [Final report

    SciTech Connect

    Lund, John W.

    2002-03-22

    The final report of the accomplishments of the geothermal energy program: information dissemination, public outreach and technical analysis activities by the project team consisting of the Geo-Heat Center, Geothermal Resources Council, Geothermal Education Office, Geothermal Energy Association and the Washington State University Energy Program.

  4. Warren Estates-Manzanita Estates Reno, Nevada residential geothermal district heating system

    SciTech Connect

    McKay, F.; McKay, G.; McKay, S.; Flynn, T.

    1995-12-31

    Warren Estates-Manzanita Estates is the largest privately-owned and operated residential geothermal district heating system in the State of Nevada. The system has operated for ten years and presently services 95 homes. Geothermal energy is used to heat homes, domestic water, spas, swimming pools, and greenhouses. Four homes have installed driveway deicing systems using geothermal energy. This paper briefly describes the geothermal resource, wells, system engineering, operation, applications, and economics. The accompanying posters illustrate the geothermal area, system design, and various applications. The resource is part of the Moana geothermal field, located in southwest Reno. Excluding the Warren-Manzanita Estates, the well-known Moana field supports nearly 300 geothermal wells that supply fluids to individual residences, several motels, a garden nursery, a few churches, and a municipal swimming pool. The Warren-Manzanita Estates is ideally suited for residential district space heating because the resource is shallow, moderate-temperature, and chemically benign. The primary reservoir rock is the Kate Peak andesite, a Tertiary volcanic lahar that has excellent permeability within the narrow fault zones that bisect the property. The Kate Peak formation is overlain by impermeable Tertiary lake sediments and alluvium. Two production wells, each about 240 m deep, are completed near the center of the residential development at the intersection of two fault zones. Geothermal fluids are pumped at a rate of 15 to 25 l/s (260-400 gpm) from one of two wells at a temperature of 95{degrees}C (202{degrees}F) to two flat-plate heat exchangers. The heat exchangers transfer energy from the geothermal fluids to a second fluid, much like a binary geothermal power plant.

  5. High Fluoride and Geothermal Activities In Continental Rift Zones, Ethiopia

    NASA Astrophysics Data System (ADS)

    Weldesenbet, S. F.; Wohnlich, S.

    2012-12-01

    The Central Main Ethiopian Rift basin is a continental rift system characterized by volcano-tectonic depression endowed with huge geothermal resource and associated natural geochemical changes on groundwater quality. Chemical composition of groundwater in the study area showed a well defined trend along flow from the highland and escarpment to the rift floor aquifer. The low TDS (< 500mg/l) Ca-Mg-HCO3 dominated water at recharge area in the highlands and escarpments evolve progressively into Ca-Na-HCO3 and Na-Ca-HCO3 type waters along the rift ward groundwater flow paths. These waters finally appear as moderate TDS (mean 960mg/l) Na-HCO3 type and as high TDS (> 1000 mg/l) Na-HCO3-Cl type in volcano-lacustrine aquifers of the rift floor. High concentrations of fluoride (up to 97.2 mg/l) and arsenic (up to 98μg/l) are recognized feature of groundwaters which occur mostly in the vicinity of the geothermal fields and the rift lakes in the basin. Fluoride and arsenic content of dry volcaniclastic sediments close to these areas are in the range 666-2586mg/kg and 10-13mg/kg respectively. The relationship between fluoride and calcium concentrations in groundwaters showed negative correlation. Near-equilibrium state attained between the mineral fluorite (CaF2) and the majority of fluoride-rich (>30mg/l) thermal groundwater and shallow cold groundwater. This indicated that the equilibrium condition control the high concentration of fluoride in the groundwaters. Whereas undersaturation state of fluorite in some relatively low-fluoride (<30mg/l) thermal waters indicated a dilution by cold waters. Laboratory batch leaching experiments showed that fast dissolution of fluoride from the sediment samples suddenly leached into the interacting water at the first one hour and then remain stable throughout the experiment. The concentrations of leached fluoride from the hot spring deposits, the lacustrine sediments, and the pyroclastic rock are usually low (1% of the total or less than

  6. Fluoride and Geothermal Activities In Continental Rift Zones, Ethiopia

    NASA Astrophysics Data System (ADS)

    Weldesenbet, S. F.

    2012-12-01

    The Central Main Ethiopian Rift basin is a continental rift system characterized by volcano-tectonic depression endowed with huge geothermal resource and associated natural geochemical changes on groundwater quality. Chemical composition of groundwater in the study area showed a well defined trend along flow from the highland and escarpment to the rift floor aquifer. The low TDS (< 500mg/l) Ca-Mg-HCO3 dominated water at recharge area in the highlands and escarpments evolve progressively into Ca-Na-HCO3 and Na-Ca-HCO3 type waters along the rift ward groundwater flow paths. These waters finally appear as moderate TDS (mean 960mg/l) Na-HCO3 type and as high TDS (> 1000 mg/l) Na-HCO3-Cl type in volcano-lacustrine aquifers of the rift floor. High concentrations of fluoride (up to 97.2 mg/l) and arsenic (up to 98μg/l) are recognized feature of groundwaters which occur mostly in the vicinity of the geothermal fields and the rift lakes in the basin. Fluoride and arsenic content of dry volcaniclastic sediments close to these areas are in the range 666-2586mg/kg and 10-13mg/kg respectively. The relationship between fluoride and calcium concentrations in groundwaters showed negative correlation. Near-equilibrium state attained between the mineral fluorite (CaF2) and the majority of fluoride-rich (>30mg/l) thermal groundwater and shallow cold groundwater. This indicated that the equilibrium condition control the high concentration of fluoride in the groundwaters. Whereas undersaturation state of fluorite in some relatively low-fluoride (<30mg/l) thermal waters indicated a dilution by cold waters. Laboratory batch leaching experiments showed that fast dissolution of fluoride from the sediment samples suddenly leached into the interacting water at the first one hour and then remain stable throughout the experiment. The concentrations of leached fluoride from the hot spring deposits, the lacustrine sediments, and the pyroclastic rock are usually low (1% of the total or less than

  7. Geopressured-geothermal well activities in Louisiana. Annual report, 1 January 1991--31 December 1991

    SciTech Connect

    John, C.J.

    1992-10-01

    Since September 1978, microseismic networks have operated continuously around US Department of Energy (DOE) geopressured-geothermal well sites to monitor any microearthquake activity in the well vicinity. Microseismic monitoring is necessary before flow testing at a well site to establish the level of local background seismicity. Once flow testing has begun, well development may affect ground elevations and/or may activate growth faults, which are characteristic of the coastal region of southern Louisiana and southeastern Texas where these geopressured-geothermal wells are located. The microseismic networks are designed to detest small-scale local earthquakes indicative of such fault activation. Even after flow testing has ceased, monitoring continues to assess any microearthquake activity delayed by the time dependence of stress migration within the earth. Current monitoring shows no microseismicity in the geopressured-geothermal prospect areas before, during, or after flow testing.

  8. Characterization of a deep geothermal reservoir in an active volcanic area

    NASA Astrophysics Data System (ADS)

    Brehme, M.; Kamah, Y.; Koestono, H.; Zimmermann, G.; Regenspurg, S.; Erbaş, K.; Wiegand, B.; Sauter, M.

    2012-04-01

    In this study an integrated methodological approach to characterize a complex deep geothermal reservoir located in an active volcanic setting in Indonesia is presented. The methods applied include hydraulic and hydrogeochemical (incl. isotope tracer) techniques to model groundwater flow, heat transport, and hydro-geochemical properties of the reservoir. 3D geological and hydraulic models of the area were constructed based on deep drill profiles, collected fluid and rock samples, and mapping of geological structures. First results show that the geothermal reservoir is composed of major geological units such as altered andesite, basalt, breccia, and tuff layers. Several tectonic faults crosscut the geological units into individual blocks and reservoirs and influence hydraulic pathways in multiple ways. Hot water and steam are produced by nine wells. Fluids are reinjected into the reservoir through one injection well. Currently, a geothermal plant produces 60 MWe from steam withdrawn. Temperatures of the geothermal system range between 250 and 350 °C (Koestono et al. 2010). Based on the chemical composition of fluids from the production wells (concentration of major ions and physicochemical parameters) at least two different hydro-geochemical reservoirs could be identified. The deep reservoir with a moderate pH of 5 is marked by total silica concentrations up to 350 mg/L and high chloride concentrations of 430 mg/L. For the shallow reservoir, highly acidic conditions with pH values of 2.9 are analysed for water, while steam shows pH values around 4. Furthermore, high chloride (1550 mg/L), total silica (460 mg/L), and sulphate concentrations (1600 mg/L) are characteristic for the shallow reservoir. According to Giggenbach (1988) and Nicholson (1993) the water can be classified into sulphate-rich waters and neutral chloride-waters. Sulphate-rich water is expected to occur near to the heat source while chloride-rich waters discharge near the outflow zone. Surface

  9. Life-cycle analysis results of geothermal systems in comparison to other power systems.

    SciTech Connect

    Sullivan, J. L.; Clark, C. E.; Han, J.; Wang, M.; Energy Systems

    2010-10-11

    A life-cycle energy and greenhouse gas emissions analysis has been conducted with Argonne National Laboratory's expanded Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model for geothermal power-generating technologies, including enhanced geothermal, hydrothermal flash, and hydrothermal binary technologies. As a basis of comparison, a similar analysis has been conducted for other power-generating systems, including coal, natural gas combined cycle, nuclear, hydroelectric, wind, photovoltaic, and biomass by expanding the GREET model to include power plant construction for these latter systems with literature data. In this way, the GREET model has been expanded to include plant construction, as well as the usual fuel production and consumption stages of power plant life cycles. For the plant construction phase, on a per-megawatt (MW) output basis, conventional power plants in general are found to require less steel and concrete than renewable power systems. With the exception of the concrete requirements for gravity dam hydroelectric, enhanced geothermal and hydrothermal binary used more of these materials per MW than other renewable power-generation systems. Energy and greenhouse gas (GHG) ratios for the infrastructure and other life-cycle stages have also been developed in this study per kilowatt-hour (kWh) of electricity output by taking into account both plant capacity and plant lifetime. Generally, energy burdens per energy output associated with plant infrastructure are higher for renewable systems than conventional ones. GHG emissions per kWh of electricity output for plant construction follow a similar trend. Although some of the renewable systems have GHG emissions during plant operation, they are much smaller than those emitted by fossil fuel thermoelectric systems. Binary geothermal systems have virtually insignificant GHG emissions compared to fossil systems. Taking into account plant construction and operation, the GREET

  10. High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems

    SciTech Connect

    Turnquist, Norman; Qi, Xuele; Raminosoa, Tsarafidy; Salas, Ken; Samudrala, Omprakash; Shah, Manoj; Van Dam, Jeremy; Yin, Weijun; Zia, Jalal

    2013-12-20

    This report summarizes the progress made during the April 01, 2010 – December 30, 2013 period under Cooperative Agreement DE-EE0002752 for the U.S. Department of Energy entitled “High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems.” The overall objective of this program is to advance the technology for well fluids lifting systems to meet the foreseeable pressure, temperature, and longevity needs of the Enhanced Geothermal Systems (EGS) industry for the coming ten years. In this program, lifting system requirements for EGS wells were established via consultation with industry experts and site visits. A number of artificial lift technologies were evaluated with regard to their applicability to EGS applications; it was determined that a system based on electric submersible pump (ESP) technology was best suited to EGS. Technical barriers were identified and a component-level technology development program was undertaken to address each barrier, with the most challenging being the development of a power-dense, small diameter motor that can operate reliably in a 300°C environment for up to three years. Some of the targeted individual component technologies include permanent magnet motor construction, high-temperature insulation, dielectrics, bearings, seals, thrust washers, and pump impellers/diffusers. Advances were also made in thermal management of electric motors. In addition to the overall system design for a full-scale EGS application, a subscale prototype was designed and fabricated. Like the full-scale design, the subscale prototype features a novel “flow-through-the-bore” permanent magnet electric motor that combines the use of high temperature materials with an internal cooling scheme that limits peak internal temperatures to <330°C. While the full-scale high-volume multi-stage pump is designed to lift up to 80 kg/s of process water, the subscale prototype is based on a production design that can pump 20 kg/s and has been modified

  11. Locating an active fault zone in Coso geothermal field by analyzing seismic guided waves from microearthquake data

    SciTech Connect

    SGP-TR-150-16

    1995-01-26

    Active fault systems usually provide high-permeability channels for hydrothermal outflow in geothermal fields. Locating such fault systems is of a vital importance to plan geothermal production and injection drilling, since an active fault zone often acts as a fracture-extensive low-velocity wave guide to seismic waves. We have located an active fault zone in the Coso geothermal field, California, by identifying and analyzing a fault-zone trapped Rayleigh-type guided wave from microearthquake data. The wavelet transform is employed to characterize guided-wave's velocity-frequency dispersion, and numerical methods are used to simulate the guided-wave propagation. The modeling calculation suggests that the fault zone is {approx} 200m wide, and has a P wave velocity of 4.80 km/s and a S wave velocity of 3.00 km/s, which is sandwiched between two half spaces with relatively higher velocities (P wave velocity 5.60 km/s, and S wave velocity 3.20 km/s). zones having vertical or nearly vertical dipping fault planes.

  12. Coniform stromatolites from geothermal systems, North Island, New Zealand

    USGS Publications Warehouse

    Jones, B.; Renaut, R.W.; Rosen, Michael R.; Ansdell, K.M.

    2002-01-01

    Coniform stromatolites are found in several sites in the Tokaanu and Whakarewarewa geothermal areas of North Island, New Zealand. At Tokaanu, silicification of these stromatolites is taking place in Kirihoro, a shallow hot springfed pool. At Whakarewarewa, subfossil silicified coniform stromatolites are found on the floor of "Waikite Pool" on the discharge apron below Waikite Geyser, and in an old sinter succession at Te Anarata. The microbes in the coniform stromatolites from Tokaanu, Waikite Pool, and Te Anarata have been well preserved through rapid silicification. Nevertheless, subtle differences in the silicification style induced morphological variations that commonly mask or alter morphological features needed for identification of the microbes in terms of extant taxa. The coniform stromatolites in the New Zealand hotspring pools are distinctive because (1) they are formed of upward tapering (i.e., conical) columns, (2) neighboring columns commonly are linked by vertical sheets or bridges, (3) internally, they are formed of alternating high- and low-porosity laminae that have a conical vertical profile, and (4) Phormidium form more than 90% of the biota. As such, they are comparable to modern coniform mats and stromatolites found in the geothermal systems of Yellowstone National Park and ice-covered lakes in Antarctica. Formation of the coniform stromatolites is restricted to pools that are characterized by low current energy and a microflora that is dominated by Phormidium. These delicate and intricate stromatolites could not form in areas characterized by fast flowing water or a diverse microflora. Thus, it appears that the distribution of these distinctive stromatolites is controlled by biological constraints that are superimposed on environmental needs.

  13. Characterization of hot dry rock geothermal energy extraction systems

    SciTech Connect

    Albright, J.N.; Newton, C.A.

    1981-01-01

    The engineering of heat exchange systems by which geothermal heat can be efficiently extracted from hot impermeable rocks is studied. The system currently under investigation at Fenton Hill, New Mexico consists of a network of large fractures created through the hydraulic pressurization of a well penetrating hot basement rocks and subsequently intersected by a second well drilled to form a flow-thru system. Cool water pumped into the fractures through one well, once heated in the reservoir, returns to the surface through the second well, is cooled, and then recirculated. While much is known about the performance parameters of the fracture network from short-term flow tests, little is understood concerning the spatial dimensions and geometrical relationship of individual fractures comprising the network. Ultimately, the success one has in estimating the long-term performance of such a system where commercialization is an issue, and in engineering future systems with optimal performance, depends on the success in characterizing the flow-thru fracture networks. To date only nonconventional application of oil field logging techniques and acoustic emissions studies have been used in the characterization of the fracture network.

  14. Geothermal system at 21°N, East Pacific Rise: physical limits on geothermal fluid and role of adiabatic expansion

    USGS Publications Warehouse

    Bischoff, J.L.

    1980-01-01

    Pressure-volume-temperature relations for water at the depth of the magma chamber at 21°N on the East Pacific Rise suggest that the maximum subsurface temperature of the geothermal fluid is about 420°C. Both the chemistry of the discharging fluid and thermal balance considerations indicate that the effective water/rock ratios in the geothermal system are between 7 and 16. Such low ratios preclude effective metal transport at temperatures below 350°C, but metal solubilization at 400°C and above is effective even at such low ratios. It is proposed that the 420°C fluid ascends essentially adiabatically and in the process expands, cools, and precipitates metal sulfides within the upper few hundred meters of the sea floor and on the sea floor itself.

  15. National Geothermal Data System: Case Studies on Exploration and Development of Potential Geothermal Sites Through Distributed Data Sharing

    SciTech Connect

    Anderson, Arlene; Allison, Lee; Richard, Steve; Caudill-Daugherty, Christy; Patten, Kim

    2014-09-29

    The NGDS released version 1 of the system on April 30, 2014 using the US Geoscience Information Network (USGIN) as its data integration platform. NGDS supports the 2013 Open Data Policy, and as such, the launch was featured at the 2014 Energy Datapalooza. Currently, the NGDS features a comprehensive user interface for searching and accessing nearly 41,000 documents and more than 9 million data points shared by scores of data providers across the U.S. The NGDS supports distributed data sharing, permitting the data owners to maintain the raw data that is made available to the consumer. Researchers and industry have been utilizing the NGDS as a mechanism for promoting geothermal development across the country, from hydrothermal to ground source heat pump applications. Case studies in geothermal research and exploration from across the country are highlighted.

  16. Geothermal Energy.

    ERIC Educational Resources Information Center

    Nemzer, Marilyn; Page, Deborah

    This curriculum unit describes geothermal energy in the context of the world's energy needs. It addresses renewable and nonrenewable energy sources with an in-depth study of geothermal energy--its geology, its history, and its many uses. Included are integrated activities involving science, as well as math, social studies, and language arts.…

  17. Importance of Hydrogeological Conditions on Open-loop Geothermal System

    NASA Astrophysics Data System (ADS)

    Park, D.; Bae, G.; Kim, S.; Lee, K.

    2013-12-01

    The open-loop geothermal system has been known as an eco-friendly, energy-saving, and cost-efficient alternative for the cooling and heating of buildings with directly using the relatively stable temperature of groundwater. Thus, hydrogeological properties of aquifer, such as hydraulic conductivity and storage, must be important in the system application. The study site is located near Han-river, Korea, and because of the well-developed alluvium it might be a typical site appropriate to this system requiring an amount of groundwater. In this study, the first objective of numerical experiments was to find the best distributions of pumping and injection wells suitable to the hydrogeological conditions of the site for the efficient and sustainable system operation. The aquifer has a gravel layer at 15m depth below the ground surface and the river and the agricultural field, which may be a potential contaminant source, are located at the west and east sides, respectively. Under the general conditions that the regional groundwater flows from the east to the river, the locally reversed well distribution, locating the pumping well at upgradient and the injection well at downgradient of the regional flow, was most sustainable. The gravel layer with high hydraulic conductivity caused a little drawdown despite of an amount of pumping and allowed to stably reinject the used groundwater in all the cases, but it provided a passage transferring the injected heat to the pumping well quickly, particularly in the cases locating the injection well at the upgradient. This thermal interference was more severe in the cases of the short distance between the wells. The high conductive layer is also a reason that the seasonal role conversion of wells for the aquifer thermal energy storage was ineffective in this site. Furthermore, the well distribution vertical to the regional groundwater flow was stable, but not best, and, thus, it may be a good choice in the conditions that the regional

  18. Geothermal Prospector: Supporting Geothermal Analysis Through Spatial Data Visualization and Querying Tools

    SciTech Connect

    Getman, Daniel; Anderson, Arlene; Augustine, Chad

    2015-09-02

    Determining opportunities for geothermal energy can involve a significant investment in data collection and analysis. Analysts within a variety of industry and research domains collect and use these data; however, determining the existence and availability of data needed for a specific analysis activity can be challenging and represents one of the initial barriers to geothermal development [2]. This paper describes the motivating factors involved in designing and building the Geothermal Prospector application, how it can be used to reduce risks and costs related to geothermal exploration, and where it fits within the larger collection of tools that is the National Geothermal Data System (NGDS) [5].

  19. National Geothermal Data System State Contributions by Data Type (Appendix A1-b)

    SciTech Connect

    Love, Diane

    2015-12-20

    Multipaged spreadsheet listing an inventory of data submissions to the State contributions to the National Geothermal Data System project by services, by state, by metadata compilations, metadata, and map count, including a summary of information.

  20. Method for inhibiting silica precipitation and scaling in geothermal flow systems

    DOEpatents

    Harrar, J.E.; Lorensen, L.E.; Locke, F.E.

    1980-06-13

    A method for inhibiting silica scaling and precipitation in geothermal flow systems by on-line injection of low concentrations of cationic nitrogen-containing compounds, particularly polymeric imines, polymeric amines, and quaternary ammonium compounds is described.

  1. Method for inhibiting silica precipitation and scaling in geothermal flow systems

    DOEpatents

    Harrar, Jackson E.; Lorensen, Lyman E.; Locke, Frank E.

    1982-01-01

    A method for inhibiting silica scaling and precipitation in geothermal flow systems by on-line injection of low concentrations of cationic nitrogen-containing compounds, particularly polymeric imines, polymeric amines, and quaternary ammonium compounds.

  2. Design, fabrication, delivery, operation and maintenance of a geothermal power conversion system

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The design, fabrication, delivery, operation and maintenance of an Hydrothermal Power Company 1250 KVA geothermal power conversion system using a helical screw expander as the prime mover is described. Hydrostatic and acceptance testing are discussed.

  3. Clay alteration of volcaniclastic material in a submarine geothermal system, Bay of Plenty, New Zealand

    NASA Astrophysics Data System (ADS)

    Hocking, Michael W. A.; Hannington, Mark D.; Percival, Jeanne B.; Stoffers, Peter; Schwarz-Schampera, Ulrich; de Ronde, C. E. J.

    2010-04-01

    The Calypso Hydrothermal Vent Field (CHVF) is located along an offshore extension of the Taupo Volcanic Zone (TVZ), an area of abundant volcanism and geothermal activity on the North Island of New Zealand. The field occurs within a northeast-trending submarine depression on the continental shelf approximately 10-15 km southwest of the White Island volcano in the Bay of Plenty. The graben has been partially filled by tephra from regional subaerial volcanic eruptions, and active hydrothermal venting occurs at several locations along its length. The vents occur at water depths of 160 to 190 m and have temperatures up to 201 °C. Recovered samples from the vent field include variably cemented and veined volcaniclastic sediments containing an assemblage of clay minerals, amorphous silica, barite, As-Sb-Hg sulfides, and abundant native sulfur. The volcanic glass has been altered primarily to montmorillonite and mixed-layer illite-montmorillonite; illite, and possibly minor talc and mixed-layer chlorite-smectite or chlorite-vermiculite are also present. A hydrothermal versus diagenetic origin for the smectite is indicated by the presence of both illite and mixed-layer clays and by the correlation between the abundance of clay minerals and the abundance of native sulfur in the samples. The mineralization and alteration of the volcanic host rocks are similar to that observed in near-neutral pH geothermal systems on land in the TVZ (e.g., Broadlands-Ohaaki). However, the clay minerals in the CHVF have a higher concentration of Mg in the dioctahedral layer and a higher interlayer Na content than clay minerals from Broadlands-Ohaaki, reflecting the higher concentrations of Mg and Na in seawater compared to meteoric water. Minerals formed at very low pH (e.g., kaolinite and alunite), typical of steam-heated acid-sulfate type alteration in the TVZ geothermal environment, were not found. Mixing with seawater likely prevented the formation of such low-pH mineral assemblages. The

  4. Federal Geothermal Research Program Update - Fiscal Year 2004

    SciTech Connect

    Patrick Laney

    2005-03-01

    The Department of Energy (DOE) and its predecessors have conducted research and development (R&D) in geothermal energy since 1971. The Geothermal Technologies Program (GTP) works in partnership with industry to establish geothermal energy as an economically competitive contributor to the U.S. energy supply. Geothermal energy production, a $1.5 billion a year industry, generates electricity or provides heat for direct use applications. The technologies developed by the Geothermal Technologies Program will provide the Nation with new sources of electricity that are highly reliable and cost competitive and do not add to America's air pollution or the emission of greenhouse gases. Geothermal electricity generation is not subject to fuel price volatility and supply disruptions from changes in global energy markets. Geothermal energy systems use a domestic and renewable source of energy. The Geothermal Technologies Program develops innovative technologies to find, access, and use the Nation's geothermal resources. These efforts include emphasis on Enhanced Geothermal Systems (EGS) with continued R&D on geophysical and geochemical exploration technologies, improved drilling systems, and more efficient heat exchangers and condensers. The Geothermal Technologies Program is balanced between short-term goals of greater interest to industry, and long-term goals of importance to national energy interests. The program's research and development activities are expected to increase the number of new domestic geothermal fields, increase the success rate of geothermal well drilling, and reduce the costs of constructing and operating geothermal power plants. These improvements will increase the quantity of economically viable geothermal resources, leading in turn to an increased number of geothermal power facilities serving more energy demand. These new geothermal projects will take advantage of geothermal resources in locations where development is not currently possible or

  5. Federal Geothermal Research Program Update Fiscal Year 2004

    SciTech Connect

    Not Available

    2005-03-01

    The Department of Energy (DOE) and its predecessors have conducted research and development (R&D) in geothermal energy since 1971. The Geothermal Technologies Program (GTP) works in partnership with industry to establish geothermal energy as an economically competitive contributor to the U.S. energy supply. Geothermal energy production, a $1.5 billion a year industry, generates electricity or provides heat for direct use applications. The technologies developed by the Geothermal Technologies Program will provide the Nation with new sources of electricity that are highly reliable and cost competitive and do not add to America's air pollution or the emission of greenhouse gases. Geothermal electricity generation is not subject to fuel price volatility and supply disruptions from changes in global energy markets. Geothermal energy systems use a domestic and renewable source of energy. The Geothermal Technologies Program develops innovative technologies to find, access, and use the Nation's geothermal resources. These efforts include emphasis on Enhanced Geothermal Systems (EGS) with continued R&D on geophysical and geochemical exploration technologies, improved drilling systems, and more efficient heat exchangers and condensers. The Geothermal Technologies Program is balanced between short-term goals of greater interest to industry, and long-term goals of importance to national energy interests. The program's research and development activities are expected to increase the number of new domestic geothermal fields, increase the success rate of geothermal well drilling, and reduce the costs of constructing and operating geothermal power plants. These improvements will increase the quantity of economically viable geothermal resources, leading in turn to an increased number of geothermal power facilities serving more energy demand. These new geothermal projects will take advantage of geothermal resources in locations where development is not currently possible or

  6. Systems study of drilling for installation of geothermal heat pumps

    SciTech Connect

    Finger, J.T.; Sullivan, W.N.; Jacobson, R.D.; Pierce, K.G.

    1997-09-01

    Geothermal, or ground-source, heat pumps (GHP) are much more efficient than air-source units such as conventional air conditioners. A major obstacle to their use is the relatively high initial cost of installing the heat-exchange loops into the ground. In an effort to identify drivers which influence installation cost, a number of site visits were made during 1996 to assess the state-of-the-art in drilling for GHP loop installation. As an aid to quantifying the effect of various drilling-process improvements, we constructed a spread-sheet based on estimated time and material costs for all the activities required in a typical loop-field installation. By substituting different (improved) values into specific activity costs, the effect on total project costs can be easily seen. This report contains brief descriptions of the site visits, key points learned during the visits, copies of the spread-sheet, recommendations for further work, and sample results from sensitivity analysis using the spread-sheet.

  7. Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations

    DOE Data Explorer

    Buscheck, Thomas A.

    2012-01-01

    Active Management of Integrated Geothermal–CO2 Storage Reservoirs in Sedimentary Formations: An Approach to Improve Energy Recovery and Mitigate Risk: FY1 Final Report The purpose of phase 1 is to determine the feasibility of integrating geologic CO2 storage (GCS) with geothermal energy production. Phase 1 includes reservoir analyses to determine injector/producer well schemes that balance the generation of economically useful flow rates at the producers with the need to manage reservoir overpressure to reduce the risks associated with overpressure, such as induced seismicity and CO2 leakage to overlying aquifers. Based on a range of well schemes, techno-economic analyses of the levelized cost of electricity (LCOE) are conducted to determine the economic benefits of integrating GCS with geothermal energy production. In addition to considering CO2 injection, reservoir analyses are conducted for nitrogen (N2) injection to investigate the potential benefits of incorporating N2 injection with integrated geothermal-GCS, as well as the use of N2 injection as a potential pressure-support and working-fluid option. Phase 1 includes preliminary environmental risk assessments of integrated geothermal-GCS, with the focus on managing reservoir overpressure. Phase 1 also includes an economic survey of pipeline costs, which will be applied in Phase 2 to the analysis of CO2 conveyance costs for techno-economics analyses of integrated geothermal-GCS reservoir sites. Phase 1 also includes a geospatial GIS survey of potential integrated geothermal-GCS reservoir sites, which will be used in Phase 2 to conduct sweet-spot analyses that determine where promising geothermal resources are co-located in sedimentary settings conducive to safe CO2 storage, as well as being in adequate proximity to large stationary CO2 sources.

  8. Torbett-Hutchings-Smith Memorial Hospital geothermal-system demonstration at Marlin, Texas. Final design report

    SciTech Connect

    Not Available

    1980-09-17

    The final design and economics of the Torbett-Hutchings-Smith (THS) Memorial Hospital geothermal heating system at Marlin, Texas are outlined. A brief description of the existing heating system, an overview of the geothermal retrofit, and the results of an economic analysis are included. It is estimated that the geothermal heating system will displace approximately 84 percent of the hospital's average annual natural gas consumption. In summer conditions, approximately 45 gpm of geothermal fluid will be utilized at a wellhead temperature of 139/sup 0/F. In peak demand winter conditions, approximately 160 gpm will be utilized at a wellhead temperature of 148/sup 0/F. The geothermal fluid temperature drop across the system will range from about 5/sup 0/F in summer to over 45/sup 0/F during winter. Total capital costs for the system are estimated to be $673,000, including the production well, a geothermal equipment room, engineering and architectural costs, and all equipment. The average annual natural gas savings are expected to be $28,200 while average annual operating and maintenance costs are estimated to be $7750. A before tax life cycle economic analysis of the THS system shows the breakeven period (BEP) of 29 years falling slightly below the 30 year expected life. This BEP is significantly influenced by the developmental nature of this project and by its lack of tax incentives.

  9. Enhanced Geothermal Systems (EGS) R&D Program: Monitoring EGS-Related Research

    SciTech Connect

    McLarty, Lynn; Entingh, Daniel; Carwile, Clifton

    2000-09-29

    This report reviews technologies that could be applicable to Enhanced Geothermal Systems development. EGS covers the spectrum of geothermal resources from hydrothermal to hot dry rock. We monitored recent and ongoing research, as reported in the technical literature, that would be useful in expanding current and future geothermal fields. The literature review was supplemented by input obtained through contacts with researchers throughout the United States. Technologies are emerging that have exceptional promise for finding fractures in nonhomogeneous rock, especially during and after episodes of stimulation to enhance natural permeability.

  10. Enhanced Geothermal System Development of the AmeriCulture Leasehold in the Animas Valley

    SciTech Connect

    Duchane, David V; Seawright, Gary L; Sewright, Damon E; Brown, Don; Witcher, James c.; Nichols, Kenneth E.

    2001-03-02

    Working under the grant with AmeriCulture, Inc., and its team of geothermal experts, assembled a plan to apply enhanced geothermal systems (EGS) techniques to increase both the temperature and flow rate of the geothermal waters on its leasehold. AmeriCulture operates a commercial aquaculture facility that will benefit from the larger quantities of thermal energy and low cost electric power that EGS technology can provide. The project brought together a team of specialists that, as a group, provided the full range of expertise required to successfully develop and implement the project.