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Economic and engineering studies for hydrothermal electric power plants. Final technical report, September 15, 1980-December 31, 1981

Description: Seven pre-conceptual designs of small hydrothermal power plants are presented covering resource temperature of 341/sup 0/F, 405/sup 0/F, and 515/sup 0/F and considering both flashed steam and binary cycle approaches for each temperature. These design studies are presented in six reports. A separate abstract was prepared for each report. (MHR)
Date: January 1, 1981
Creator: Pitts, D.R.
Partner: UNT Libraries Government Documents Department

Preliminary assessment of condensation behavior for hydrocarbon-vapor expansions which cross the saturation line near the critical point

Description: Previous analyses of binary cycles for conversion of geothermal energy from moderate temperature resources to electrical energy have shown potential gains in net geofluid effectiveness of on the order of 8%, resulting from selection of turbine-expansion processes whose equilibrium states pass through the two-phase region (assuming major condensation does not occur). If condensation occurs, this gain could be reduced or eliminated by the resulting loss in turbine efficiency. Experience with many fluids, however, indicates that vapor supersaturation (or subcooling) permits metastable pure-vapor states to exist at temperatures considerably below the saturation temperature at a given pressure; thus, by better understanding the condensation process, and properly structuring the cycle, substantial performance gains may be achievable. The present study assessed, qualitatively, the probability for attaining this performance gain.
Date: July 1, 1982
Creator: Demuth, O.J.
Partner: UNT Libraries Government Documents Department

Heber Geothermal Binary Demonstration Project. Final design availability assessment. Revision 1

Description: An availability assessment of the principal systems of the Heber Geothermal Power Plant has been carried out based on the final issue of the process descriptions, process flow diagrams, and the approved for design P and IDs prepared by Fluor Power Services, Inc. (FPS). The principal systems are those which contribute most to plant unavailability. The plant equivalent availability, considering forced and deferred corrective maintenance outages, was computed using a 91 state Markov model to represent the 29 principal system failure configurations and their significant combinations. The failure configurations and associated failure and repair rates were defined from system/subsystem availability assessments that were conducted using the availability assessments based on the EPRI GO methodology and availability block diagram models. The availability and unavailability ranking of the systems and major equipment is presented.
Date: February 1, 1983
Creator: Mulvihill, R.J.; Reny, D.A.; Geumlek, J.M. & Purohit, G.P.
Partner: UNT Libraries Government Documents Department

Design and operation of a geopressured-geothermal hybrid cycle power plant

Description: The following appendices are included: process flow diagram, piping and instrumentation diagram, new equipment specifications, main single line diagram, shutdown and start-up procedures, data sheets for tests, plant outages, detailed process equations, computer program and sample output, chemical analysis and scanning electron microscopy results, and management report data sheets for January 5, 1990 to May 29, 1990. (MHR)
Date: February 1, 1991
Creator: Campbell, R.G. & Hattar, M.M.
Partner: UNT Libraries Government Documents Department

Effects of vaporizer and evaporative condenser pinch points on geofluid effectiveness and cost of electricity for geothermal binary power plants

Description: A brief study was conducted in support of the DOE/DGHT Heat Cycle Research Program to investigate the influences of minimum approach temperature differences occurring in supercritical-heater/vaporizer and evaporative-condenser heat rejection systems on geothermal-electric binary power plant performance and cost of electricity. For the systems investigated optimum pinch points for minimizing cost of electricity were estimated to range from 5 to 7/sup 0/F (3 to 4/sup 0/C) for the heater vaporizer. The minimum approach of condensing temperature to wet-bulb temperature for evaporative condensers was estimated to be about 15/sup 0/F (8/sup 0/C) in order to achieve the highest plant net geofluid effectiveness, and approximately 30/sup 0/F (17/sup 0/C) to attain the minimum cost of electricity.
Date: January 1, 1984
Creator: Demuth, O.J.
Partner: UNT Libraries Government Documents Department

High geothermal energy utilization geothermal/fossil hybrid power cycle: a preliminary investigation

Description: Combining geothermal and fossil fuel energy into the so-called hybrid cycle is compared with a state-of-the-art double-flash geothermal power cycle using resources which vary from 429/sup 0/K (312/sup 0/F) to 588/sup 0/K (598/sup 0/F). It is demonstrated that a hybrid plant can compete thermodynamically with the combined output from both a fossil-fired and a geothermal plant operating separately. Economic comparison of the hybrid and double-flash cycles is outlined, and results are presented that indicate the performance of marginal hydrothermal resources may be improved enough to compete with existing power cycles on a cost basis. It is also concluded that on a site-specific basis a hybrid cycle is capable of complementing double-flash cycles at large-capacity resources, and can operate in a cycling load mode at constant geothermal fluid flow rate.
Date: November 1, 1978
Creator: Grijalva, R.L. & Sanemitsu, S.K.
Partner: UNT Libraries Government Documents Department

Rankine cycle generators using geothermal fluids. Final progress report

Description: The Rankine Cycle generator was delivered and installed at Gila Hot Springs. Trial runs were made at that time, using Freon 12 as the expansion fluid. These tests showed that the boiler capacity was inadequate. It could not extract enough heat to generate sufficient volumes of Freon gas at the heat and pressure necessary to operate the system at an acceptable level. Increasing and decreasing the flow of hot water had a direct influence on efficiency, but it was not a linear relationship. Added amounts of hot water increased the power very little, but raised the water temperature at the discharge point. This implied that the heat exchange capacity of the boiler was saturated. The reverse was found in the condenser system. There was little increase in pressure of the condenser when we switched from static to run mode. Efficiency was maintained even when the cold water flow was reduced as much as 40%. The tests using Freon 12 resulted in the conclusion that the boiler volume needs to be increased and/or the configuration changed to radically increase its efficiency.
Date: January 1, 1981
Partner: UNT Libraries Government Documents Department

HGP-A wellhead generator proof-of-feasibility project

Description: The HGP-A Wellhead Generator Proof-of-Feasibility Project consists of a nominal 3 Megawatt geothermal steam turbine electric power generating facility, the first geothermal power plant in Hawaii. The plant is being constructed as a research and development project to evaluate geothermal steam as a viable resource to be considered for larger commercial electric power generating stations in Hawaii. The project facilities include a turbine building, with a contiguous service area for plant operations and maintenance, visitor center, and the power plant equipment.
Date: November 3, 1978
Partner: UNT Libraries Government Documents Department

Direct-flash-steam geothermal-power-plant assessment. Final report

Description: The objective of the project was to analyze the capacity and availability factors of an operating direct flash geothermal power plant. The analysis was to include consideration of system and component specifications, operating procedures, maintenance history, malfunctions, and outage rate. The plant studied was the 75 MW(e) geothermal power plant at Cerro Prieto, Mexico, for the years 1973 to 1979. To describe and assess the plant, the project staff reviewed documents, visited the plant, and met with staff of the operating utility. The high reliability and availability of the plant was documented and actions responsible for the good performance were identified and reported. The results are useful as guidance to US utilities considering use of hot water geothermal resources for power generation through a direct flash conversion cycle.
Date: January 1, 1982
Creator: Alt, T.E.
Partner: UNT Libraries Government Documents Department

System design verification of a hybrid geothermal/coal fired power plant

Description: This hybrid plant utilizes geothermal fluid for feedwater heating. With respect to the extraction of available work from the geothermal fluids, this cycle is approximately two times as efficient as the all geothermal plant. The System Design Verification Study presented verifies the technical and economic feasibility of the hybrid plant. This report is comprised of a conceptual design, cost estimate, and economic analysis of a one-unit 715 MW hybrid geothermal/coal fired power plant. In addition to the use of geothermal fluid for feedwater heating, its use is also investigated for additional power generation, condensate and cooling tower makeup water, coal beneficiation, air preheating, flue gas reheating and plant space heating requirements. An engineering and construction schedule for the hybrid plant is also included.
Date: September 1, 1978
Partner: UNT Libraries Government Documents Department

Geothermal commercial power plant study. Monthly progress report, September 25-October 22, 1976

Description: Efforts were concentrated on plant operating modes. The Heber plant, which was previously designed for consistant brine temperature, was reviewed and changes necessary to accomodate declining brine temperature were determined. Resultant required modifications to the computer code GEOTHM were made. The engineering, in terms of sketches and equipment lists, needed to support the capital cost estimate was determined. Attempts to use the computer program GEOTHM to develop the heat and mass balances for plants with declining geothermal fluid temperature disclosed that this code alone cannot be used for this purpose because it does not include turbine stage pressure-drop equations. It was determined that the most expedient method for obtaining the data needed for this study would be to develop a separate small computer program containing these turbine equations. With the assistance of a turbine consultant, the detailed methodology for the program was developed, and coding was started. (MHR)
Date: November 23, 1976
Partner: UNT Libraries Government Documents Department

GLEF direct-contact heat-exchanger program. Final report

Description: A number of flash-binary cycles for the Salton Sea Known Geothermal Area have been evaluated leading to the identification of the optimum one. The brine coming from the well is separated in a flash tank producing a liquid and a vapor stream. The liquid is used in a direct contact preheater to bring the working fluid (isopentane) to the saturation point. The isopentane is then vaporized in a shell and tube heat exchanger by use of the flashed steam. The isopentane vapor is expanded in a turbine driving the generator, condensed in a surface condenser and finally returned to the preheater by the main feed pump. A review of the theoretical correlations available for the design of direct contact heat exchangers has been carried out as well as the design and fabrication of a test facility to evaluate the performance of direct contact heat exchangers under various conditions and to verify the cycle analysis. The results of the test data support the assumptions made in the system analysis and in particular, the terminal temperature differences established in the heat balance have been achieved. The column length calculation procedure has been tested and found satisfactory under the test conditions.
Date: March 1, 1980
Creator: Della Vida, P.L.; Franz, F.J. & Weinreich, R.S.
Partner: UNT Libraries Government Documents Department

500 kW direct contact pilot plant for East Mesa

Description: A 500 kW powerplant utilizing a direct contact heat exchanger (DCHX) between the geothermal brine and the isobutane working fluid is nearing completion at the East Mesa Component Test Facility. The primary purpose of the plant is to evaluate the performance potential of the direct contact system in a size much larger than the small exploratory units that have been tested to date. Thermodynamic performance of DCHX binary power systems has been demonstrated in small 10 kW research test rigs (Refs. 1, 2, and 3), however, characteristics that affect the economics and practicality of long term operation need to be evaluated. Three factors influencing plant performance and cost are: (1) the control of noncondensables that contaminate the power cycle condenser, (2) the equipment required to limit working fluid losses, and (3) the control of scaling or performance robbing deposits in critical components. These factors are not unrelated and control of one often impacts control of the other two. Operating data and research with the 500 kW pilot plant should demonstrate a solution to all three of these factors and provide design guidelines for larger plants.
Date: September 1, 1979
Creator: Nichols, K.E.
Partner: UNT Libraries Government Documents Department

Preliminary reliability and availability analysis of the Heber geothermal binary demonstration plant. Final report

Description: An assessment is presented of the reliability and availability of the Heber Geothermal Binary Demonstration Plant on the basis of preliminary design information. It also identifies and ranks components of the plant in order of their criticality to system operation and their contribution to system unavailability. The sensitivity of the various components to uncertainties of data and the potential for reliability growth are also examined. The assessment results were obtained through the adaptation and application of an existing reliability and availability methodology to the Heber plant design. These preliminary assessments were made to assist (1) in evaluating design alternatives for the plant and (2) in demonstrating that the closed-loop, multiple-fluid, binary cycle geothermal concept is competitive with the more conventional flashed steam cycle technology. The Heber Geothermal Binary Demonstration Plant Project is a cooperative effort directed toward accelerating geothermal development for power generation and establishing the binary cycle technology as a proven alternative to the flashed steam cycle for moderate temperature hydrothermal resources. The binary power plant would have a capacity of 45 MW/sub e/ net and would derive its energy from the low salinity (14,000 ppM), moderate temperature (360/sup 0/F, 182/sup 0/C) fluid from the Heber reservoir in southern California.
Date: October 1, 1981
Creator: Himpler, H.; White, J. & Witt, J.
Partner: UNT Libraries Government Documents Department

Geothermal power plant R and D: an analysis of cost-performance tradeoffs and the Heber Binary-Cycle Demonstration Project

Description: A study of advancements in power plant designs for use at geothermal resources in the low to moderate (300 to 400F) temperature range is reported. In 3 case studies, the benefits of R and D to achieve these advancements are evaluated in terms of expected increases in installed geothermal generating capacity over the next 2 decades. A parametric sensitivity study is discussed which analyzes differential power development for combinations of power plant efficiency and capitol cost. Affordable tradeoffs between plant performance and capital costs are illustrated. The independent review and analysis of the expected costs of construction, operation and maintenance of the Heber Binary Cycle Geothermal Power Demonstration Plant are described. Included in this assessment is an analysis of each of the major cost components of the project, including (1) construction cost, (2) well field development costs, (3) fluid purchase costs, and (4) well field and power plant operation and maintenance costs. The total cost of power generated from the Heber Plant (in terms of mills per kWh) is then compared to the cost of power from alternative fossil-fueled base load units. Also evaluated are the provisions of both: (a) the Cooperative Agreement between the federal government and San Diego Gas and Electric (SDG and E); and (b) the Geothermal Heat Sales Contract with Union Oil Company.
Date: June 30, 1983
Creator: Cassel, T.A.V.; Amundsen, C.B. & Blair, P.D.
Partner: UNT Libraries Government Documents Department

Experimental study of electron beam induced removal of H/sub 2/S from geothermal fluids

Description: The treatment of geothermal steam by electron beam irradiation is a potential alternative method of H/sub 2/S removal which can be applied upstream or downstream and has no chemical requirements. The experimental work reported here examines the effectiveness of electron beam treatment of geothermal fluids. These fluids are produced by combining the constituents in a heated cell, which contains an electron beam transparent window. Irradiation of the contents and subsequent chemical analysis allows an evaluation of effectiveness. These results are used for a commercial feasibility assessment.
Date: September 1, 1983
Creator: Helfritch, D.J.; Singhvi, R.; Evans, R.D. & Reynolds, W.E.
Partner: UNT Libraries Government Documents Department

Preliminary design manual for a Geothermal Demonstration Plant at Heber, California

Description: A preliminary design of a 50 MWe Geothermal Demonstration Plant for Heber, California is presented. A site description, design basis, process design, trade-off studies to optimize plant operations, and an economic analysis of the plant are included. The plant design provides flow diagrams and equipment specifications for the energy conversion system, the cooling water system, the plant and instrument air system, the flare system, the firewater system, the electrical system, the piping system, instruments and controls, and buildings and structures.
Date: February 1, 1978
Creator: Holt, B. & Ghormley, E.L.
Partner: UNT Libraries Government Documents Department

Importance of the specific heat anomaly in the design of binary Rankine cycle power plants

Description: The transposed critical temperature (TPCT) is shown to be an extremely important thermodynamic property in the selection of working fluids and turbine states for geothermal power plants operating on a closed organic (binary) Rankine cycle. When the optimum working fluid composition and process states are determined for specified source and sink conditions, turbine inlet states consistently lie adjacent to the working fluids' TPCT line for all resource temperatures, constraints, and cost and efficiency factors investigated.
Date: May 1, 1980
Creator: Pope, W.L.; Doyle, P.A.; Fulton, R.L. & Silvester, L.F.
Partner: UNT Libraries Government Documents Department

Lawrence Berkeley Laboratory geothermal program in northern Nevada

Description: The Lawrence Berkeley Laboratory's geothermal program began with consideration of regions where fluids in the temperature range of 150 C to 230 C may be economically accessible. Three valleys, located in an area of high regional heat flow in north central Nevada, were selected for geological, geophysical, and geochemical field studies. The objective of these ongoing field activities is to select a site for a 10-MW demonstration plant. Field activities (which started in September 1973) are described. A parallel effort has been directed toward the conceptual design of a 10-MW isobutane binary plant which is planned for construction at the selected site. Design details of the plant are described. Project schedule with milestones is shown together with a cost summary of the project.
Date: September 1, 1974
Creator: Mirk, K.F. & Wollenberg, H.A.
Partner: UNT Libraries Government Documents Department

Economics of a 75-MW(e) hot-dry-rock geothermal power station based upon the design of the Phase II reservoir at Fenton Hill

Description: Based upon EE-2 and EE-3 drilling costs and the proposed Fenton Hill Phase II reservoir conditions the break-even cost of producing electricity is 4.4 cents per kWh at the bus bar. This cost is based upon a 9-well, 12-reservoir hot dry rock (HDR) system producing 75 MW(e) for 10 yr with only 20% drawdown, and an assumed annual finance charge of 17%. Only one-third of the total, potentially available heat was utilized; potential reuse of wells as well as thermal stress cracking and augmentation of heat transfer was ignored. Nearly half the bus bar cost is due to drilling expenses, which prompted a review of past costs for wells GT-2, EE-1, EE-2, and EE-3. Based on comparable depth and completion times it is shown that significant cost improvements have been accomplished in the last seven years. Despite these improvements it was assumed for this study that no further advancements in drilling technology would occur, and that even in commercially mature HDR systems, drilling problems would continue nearly unabated.
Date: February 1, 1982
Creator: Murphy, H.; Drake, R.; Tester, J. & Zyvoloski, G.
Partner: UNT Libraries Government Documents Department