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• 111. [Image] Hot Dry Rock Geothermal Energy Development Program, Annual Report, Fiscal Year 1980

  	Investigation and flow testing of the enlarged Phase I heat-extraction system at Fenton Hill continued throughout FY80. Temperature drawdown observed at that time indicated an effective fracture of approximately ...
  	Citation × Citation Citation Abstract Copy Title: Hot Dry Rock Geothermal Energy Development Program, Annual Report, Fiscal Year 1980 Author: Cremer, G.M. (comp.) Year: 1981 Investigation and flow testing of the enlarged Phase I heat-extraction system at Fenton Hill continued throughout FY80. Temperature drawdown observed at that time indicated an effective fracture of approximately 40,000 to 60,000 m/sup 2/. In May 1980, hot dry rock (HDR) technology was used to produce electricity in an interface demonstration experiment at Fenton Hill. A 60-kVA binary-cycle electrical generator was installed in the Phase I surface system and heat from about 3 kg/s of geothermal fluid at 132/sup 0/C was used to boil Freon R-114, whose vapor drove a turboalternator. A Phase II system was designed and is now being constructed at Fenton Hill that should approach commercial requirements. Borehole EE-2, the injection well, was completed on May 12, 1980. It was drilled to a vertical depth of about 4500 m, where the rock temperature is approximately 320/sup 0/C. The production well, EE-3 had been drilled to a depth of 3044 m and drilling was continuing. Environmental monitoring of Fenton Hill site continued. Development of equipment, instruments, and materials for technical support at Fenton Hill continued during FY80. Several kinds of models were also developed to understand the behavior of the Phase I system and to develop a predictive capability for future systems. Data from extensive resource investigations were collected, analyzed, and assembled into a geothermal gradient map of the US, and studies were completed on five specific areas as possible locations for HDR Experimental Site 2 Title: Hot Dry Rock Geothermal Energy Development Program, Annual Report, Fiscal Year 1980 Author: Cremer, G.M. (comp.) Year: 1981 Investigation and flow testing of the enlarged Phase I heat-extraction system at Fenton Hill continued throughout FY80. Temperature drawdown observed at that time indicated an effective fracture of approximately 40,000 to 60,000 m/sup 2/. In May 1980, hot dry rock (HDR) technology was used to produce electricity in an interface demonstration experiment at Fenton Hill. A 60-kVA binary-cycle electrical generator was installed in the Phase I surface system and heat from about 3 kg/s of geothermal fluid at 132/sup 0/C was used to boil Freon R-114, whose vapor drove a turboalternator. A Phase II system was designed and is now being constructed at Fenton Hill that should approach commercial requirements. Borehole EE-2, the injection well, was completed on May 12, 1980. It was drilled to a vertical depth of about 4500 m, where the rock temperature is approximately 320/sup 0/C. The production well, EE-3 had been drilled to a depth of 3044 m and drilling was continuing. Environmental monitoring of Fenton Hill site continued. Development of equipment, instruments, and materials for technical support at Fenton Hill continued during FY80. Several kinds of models were also developed to understand the behavior of the Phase I system and to develop a predictive capability for future systems. Data from extensive resource investigations were collected, analyzed, and assembled into a geothermal gradient map of the US, and studies were completed on five specific areas as possible locations for HDR Experimental Site 2 Close

• 112. [Image] Geothermal Progress Monitor: Report No. 17, December 1995

  	DOE is particularly concerned with reducing the costs of geothermal power generation, especially with the abundant moderate to low-temperature resources in the US. This concern is reflected in DOE`s support ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Progress Monitor: Report No. 17, December 1995 Author: Assistant Secretary for Energy and Efficiency and Renewable Energy, Geothermal Division Year: 1995 DOE is particularly concerned with reducing the costs of geothermal power generation, especially with the abundant moderate to low-temperature resources in the US. This concern is reflected in DOE`s support of a number of energy conversion projects. Projects which focus on the costs and performance of binary cycle technology include a commercial demonstration of supersaturated turbine expansions, which earlier Studies have indicated could increase the power produced per pound of fluid. Other binary cycle projects include evaluations of the performance of various working fluid mixtures and the development and testing of advanced heat rejection systems which are desperately needed in water-short geothermal areas. DOE is also investigating the applicability of flash steam technology to low-temperature resources, as an economic alternative to binary cycle systems. A low-cost, low-pressure steam turbine, selected for a grant, will be constructed to utilize fluid discharged from a flash steam plant in Nevada. Another project addresses the efficiency of high-temperature flash plants with a demonstration of the performance of the Biphase turbine which may increase the power output of such installations with no increase in fluid flow. Perhaps the most noteworthy feature of this issue of the GPM, the 17th since its inception in 1980, is the high degree of industry participation in federally-sponsored geothermal research and development. This report describes geothermal development activities Title: Geothermal Progress Monitor: Report No. 17, December 1995 Author: Assistant Secretary for Energy and Efficiency and Renewable Energy, Geothermal Division Year: 1995 DOE is particularly concerned with reducing the costs of geothermal power generation, especially with the abundant moderate to low-temperature resources in the US. This concern is reflected in DOE`s support of a number of energy conversion projects. Projects which focus on the costs and performance of binary cycle technology include a commercial demonstration of supersaturated turbine expansions, which earlier Studies have indicated could increase the power produced per pound of fluid. Other binary cycle projects include evaluations of the performance of various working fluid mixtures and the development and testing of advanced heat rejection systems which are desperately needed in water-short geothermal areas. DOE is also investigating the applicability of flash steam technology to low-temperature resources, as an economic alternative to binary cycle systems. A low-cost, low-pressure steam turbine, selected for a grant, will be constructed to utilize fluid discharged from a flash steam plant in Nevada. Another project addresses the efficiency of high-temperature flash plants with a demonstration of the performance of the Biphase turbine which may increase the power output of such installations with no increase in fluid flow. Perhaps the most noteworthy feature of this issue of the GPM, the 17th since its inception in 1980, is the high degree of industry participation in federally-sponsored geothermal research and development. This report describes geothermal development activities Close

• 113. [Image] Geothermal Direct Contact Heat Exchange Final Report

  	Sufficient work has been done to date to establish geothermal energy as a significant source for meeting our future energy needs. At the present time there are only a few geothermal power plants in operation; ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal Direct Contact Heat Exchange Final Report Author: Sims, A.V. Year: 1976 Sufficient work has been done to date to establish geothermal energy as a significant source for meeting our future energy needs. At the present time there are only a few geothermal power plants in operation; in the United States, The Geysers field is the only location of commercial importance. The Geysers field is a vapor dominated reservoir, producing steam that is used directly in steam turbines. Such reservoirs are comparatively rare, and represent only a small portion of the available geothermal energy. Dry rock or magma sources are a potentially much larger source of geothermal energy, but the technology for utilizing these resources has not been developed. Liquid dominated reservoirs are a major source of geothermal energy and technology is available for exploiting them. Thus, liquid dominated reservoirs are the geothermal energy resource of major interest at this time. The principal power generation processes being considered for use with liquid dominated geothermal reservoirs are the binary, the flashed steam, and the direct contact; although many variations within the general classifications are possible. The flashed steam process is probably the simplest and is suitable for use with heavy scaling brines. The capital cost for the plant is probably lowest of the three, but brine usage for unit of power produced tends to be high. The binary process appears to be more efficient, but depends on the use of shell and tube heat exchangers for transferring heat from the brine to the working fluid. The use of such exchangers is impractical for brines with heavy scaling characteristics, and in any event the cost of the exchangers is a large part of the total plant cost. The direct contact binary process offers the possibility of reduced plant cost, good efficiency, and suitability for use with scaling brines. The process is, however, the least developed of the three and presents areas of technological uncertainty. The work reported here is a preliminary investigation of some of the technical and economic aspects of the direct contact process, and was undertaken in order to evaluate the commercial potential of the process. The work consisted of laboratory tests, a conceptual design, a 50 MWe plant design, an economic study, and a pilot plant program. The laboratory tests were made to obtain enough information to develop a realistic preliminary plant design. A glass direct contact heat exchange column was designed, constructed, and operated to get information on general performance characteristics, tray efficiencies, sizing correlations, and temperature approaches. A hot water-normal hexane system was used to permit operation in a glass column at atmospheric pressure. The physical characteristics of this system are close to those proposed for the commercial plant so the answers obtained are applicable to the commercial system. Hydrocarbon stripping tests were made using a glass column and nitrogen as stripping gas in order to establish the feasibility of recovering hydrocarbon from spent hot water. The tests showed that more work is needed in this area but that hydrocarbon stripping is feasible. Solubility tests were conducted to determine the effect of temperature, and brine composition on the solubility of three hydrocarbons. This information was needed to evaluate the impact of hydrocarbon losses on the cost of power production. A computer program was developed to aid in the evaluation of various possible direct contact thermodynamic cycles. The effect of operating variables on power production was evaluated; including the effect of brine inlet temperature, operating pressure, condensing temperature and choice of working fluid. After a general investigation, an optimum cycle was found for a specific site, the Heber field. The Heber field, located in the Imperial Valley of Southern California, was chosen as representative of a medium temperature low salinity reservoir with excellent commercial potential. As part of the conceptual design, studies were made on the prevention of working fluid loss in rejected hot water and in noncondensable gases, and the elimination of particulates in expander inlet gas. The studies were used to establish practical solutions to these important design problems, at least for the preliminary design. The results of the conceptual design were used to develop a preliminary design for a 50 MWe (delivered) plant. The plant was sized for 50MWe since preliminary studies made as part of another project had established this as an economic size. An estimated capital cost was developed for the 50 MWe plant, for use in the economic study. The economic study made use of a considerable body of information developed as part of a project done for the Electric Power Research Institute by Holt/Procon, a joint venture of The Ben Holt Co. and Procon Incorporated. This information included plant and operating costs for a closed loop binary and a two-stage flashed steam process as well as costs for brine production and power transmission. The same methods and factors were used for the direct contact process. Thus, it was possible to obtain a comparison among the three processes on a consistent basis. The relative values obtained should be relatively accurate. Since the process shows promise, a pilot plant program was prepared outlining areas for future work Title: Geothermal Direct Contact Heat Exchange Final Report Author: Sims, A.V. Year: 1976 Sufficient work has been done to date to establish geothermal energy as a significant source for meeting our future energy needs. At the present time there are only a few geothermal power plants in operation; in the United States, The Geysers field is the only location of commercial importance. The Geysers field is a vapor dominated reservoir, producing steam that is used directly in steam turbines. Such reservoirs are comparatively rare, and represent only a small portion of the available geothermal energy. Dry rock or magma sources are a potentially much larger source of geothermal energy, but the technology for utilizing these resources has not been developed. Liquid dominated reservoirs are a major source of geothermal energy and technology is available for exploiting them. Thus, liquid dominated reservoirs are the geothermal energy resource of major interest at this time. The principal power generation processes being considered for use with liquid dominated geothermal reservoirs are the binary, the flashed steam, and the direct contact; although many variations within the general classifications are possible. The flashed steam process is probably the simplest and is suitable for use with heavy scaling brines. The capital cost for the plant is probably lowest of the three, but brine usage for unit of power produced tends to be high. The binary process appears to be more efficient, but depends on the use of shell and tube heat exchangers for transferring heat from the brine to the working fluid. The use of such exchangers is impractical for brines with heavy scaling characteristics, and in any event the cost of the exchangers is a large part of the total plant cost. The direct contact binary process offers the possibility of reduced plant cost, good efficiency, and suitability for use with scaling brines. The process is, however, the least developed of the three and presents areas of technological uncertainty. The work reported here is a preliminary investigation of some of the technical and economic aspects of the direct contact process, and was undertaken in order to evaluate the commercial potential of the process. The work consisted of laboratory tests, a conceptual design, a 50 MWe plant design, an economic study, and a pilot plant program. The laboratory tests were made to obtain enough information to develop a realistic preliminary plant design. A glass direct contact heat exchange column was designed, constructed, and operated to get information on general performance characteristics, tray efficiencies, sizing correlations, and temperature approaches. A hot water-normal hexane system was used to permit operation in a glass column at atmospheric pressure. The physical characteristics of this system are close to those proposed for the commercial plant so the answers obtained are applicable to the commercial system. Hydrocarbon stripping tests were made using a glass column and nitrogen as stripping gas in order to establish the feasibility of recovering hydrocarbon from spent hot water. The tests showed that more work is needed in this area but that hydrocarbon stripping is feasible. Solubility tests were conducted to determine the effect of temperature, and brine composition on the solubility of three hydrocarbons. This information was needed to evaluate the impact of hydrocarbon losses on the cost of power production. A computer program was developed to aid in the evaluation of various possible direct contact thermodynamic cycles. The effect of operating variables on power production was evaluated; including the effect of brine inlet temperature, operating pressure, condensing temperature and choice of working fluid. After a general investigation, an optimum cycle was found for a specific site, the Heber field. The Heber field, located in the Imperial Valley of Southern California, was chosen as representative of a medium temperature low salinity reservoir with excellent commercial potential. As part of the conceptual design, studies were made on the prevention of working fluid loss in rejected hot water and in noncondensable gases, and the elimination of particulates in expander inlet gas. The studies were used to establish practical solutions to these important design problems, at least for the preliminary design. The results of the conceptual design were used to develop a preliminary design for a 50 MWe (delivered) plant. The plant was sized for 50MWe since preliminary studies made as part of another project had established this as an economic size. An estimated capital cost was developed for the 50 MWe plant, for use in the economic study. The economic study made use of a considerable body of information developed as part of a project done for the Electric Power Research Institute by Holt/Procon, a joint venture of The Ben Holt Co. and Procon Incorporated. This information included plant and operating costs for a closed loop binary and a two-stage flashed steam process as well as costs for brine production and power transmission. The same methods and factors were used for the direct contact process. Thus, it was possible to obtain a comparison among the three processes on a consistent basis. The relative values obtained should be relatively accurate. Since the process shows promise, a pilot plant program was prepared outlining areas for future work Close

• 114. [Image] Exploration Criteria for Low Permeability Geothermal Resources: Final Report

  	The overall project objective was to analyze low permeability geothermal systems related to high temperature plutons in the upper crust in order to ascertain those characteristics of these systems which ...
  	Citation × Citation Citation Abstract Copy Title: Exploration Criteria for Low Permeability Geothermal Resources: Final Report Author: Norton, D. Year: 1977 The overall project objective was to analyze low permeability geothermal systems related to high temperature plutons in the upper crust in order to ascertain those characteristics of these systems which could be detected by surface and shallow subsurface exploration methods. Analyses were designed to integrate data and concepts from the literature, which relate to the transport processes, together with computer simulation of idealised systems Title: Exploration Criteria for Low Permeability Geothermal Resources: Final Report Author: Norton, D. Year: 1977 The overall project objective was to analyze low permeability geothermal systems related to high temperature plutons in the upper crust in order to ascertain those characteristics of these systems which could be detected by surface and shallow subsurface exploration methods. Analyses were designed to integrate data and concepts from the literature, which relate to the transport processes, together with computer simulation of idealised systems Close

• 115. [Image] Innovation Versus Monopoly: Geothermal Energy in the West. Final Report

  	The following subjects are covered: geothermal energy and its use, electric utilities and the climate for geothermal development, the raw fuels industry and geothermal energy, and government and energy. ...
  	Citation × Citation Citation Abstract Copy Title: Innovation Versus Monopoly: Geothermal Energy in the West. Final Report Author: Bierman, S.L. Year: 1977 The following subjects are covered: geothermal energy and its use, electric utilities and the climate for geothermal development, the raw fuels industry and geothermal energy, and government and energy. The role of large petroleum companies and large public utilities is emphasized. (MHR) Title: Innovation Versus Monopoly: Geothermal Energy in the West. Final Report Author: Bierman, S.L. Year: 1977 The following subjects are covered: geothermal energy and its use, electric utilities and the climate for geothermal development, the raw fuels industry and geothermal energy, and government and energy. The role of large petroleum companies and large public utilities is emphasized. (MHR) Close

• 116. [Image] Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, November 1, 1976-March 31, 1977

  	The objective of this research is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological, ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, November 1, 1976-March 31, 1977 Author: Costain, J.K. Year: 1977 The objective of this research is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological, geochemical, and geophysical data. Detailed study of the Liberty Hill and Winnsboro plutons, South Carolina, is continuing in order to provide insight into the behavivr of uranium and thorium in unmetamorphosed granitic plutons during periods of crystallization, deuteric alteration and weathering Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, November 1, 1976-March 31, 1977 Author: Costain, J.K. Year: 1977 The objective of this research is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological, geochemical, and geophysical data. Detailed study of the Liberty Hill and Winnsboro plutons, South Carolina, is continuing in order to provide insight into the behavivr of uranium and thorium in unmetamorphosed granitic plutons during periods of crystallization, deuteric alteration and weathering Close

• 117. [Image] Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, July 1, 1977--September 30, 1977

  	The objective of this program is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological,geochemical, ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, July 1, 1977--September 30, 1977 Author: Costain, J.K. Year: 1977 The objective of this program is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological,geochemical, and geophysical data. The near-term resource assessment for Region V places primary programmatic emphasis on the confirmation of radiogenic resources in the Atlantic Coastal Plain. Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States Progress Report, July 1, 1977--September 30, 1977 Author: Costain, J.K. Year: 1977 The objective of this program is to develop and apply targeting procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological,geochemical, and geophysical data. The near-term resource assessment for Region V places primary programmatic emphasis on the confirmation of radiogenic resources in the Atlantic Coastal Plain. Close

• 118. [Image] Development of drilling foams for geothermal applications

  	The use of foam drilling fluids in geothermal applications is addressed. A description of foams - what they are, how they are used, their properties, equipment required to use them, the advantages and ...
  	Citation × Citation Citation Abstract Copy Title: Development of drilling foams for geothermal applications Author: McDonald, W.J. Year: 1980 The use of foam drilling fluids in geothermal applications is addressed. A description of foams - what they are, how they are used, their properties, equipment required to use them, the advantages and disadvantages of foams, etc. - is presented. Geothermal applications are discussed. Results of industry interviews presented indicate significant potential for foams, but also indicate significant technical problems to be solved to achieve this potential. Testing procedures and results of tests on representative foams provide a basis for work to develop high-temperature foams; SAND-79-7122 Title: Development of drilling foams for geothermal applications Author: McDonald, W.J. Year: 1980 The use of foam drilling fluids in geothermal applications is addressed. A description of foams - what they are, how they are used, their properties, equipment required to use them, the advantages and disadvantages of foams, etc. - is presented. Geothermal applications are discussed. Results of industry interviews presented indicate significant potential for foams, but also indicate significant technical problems to be solved to achieve this potential. Testing procedures and results of tests on representative foams provide a basis for work to develop high-temperature foams; SAND-79-7122 Close

• 119. [Image] Analysis of a Radial-Outflow Reaction Turbine Concept for Geothermal Application

  	The radial-outflow reaction turbine, a pure-reaction turbine designed to improve the conversion efficiency of geothermal energy into electrical power is described. It also has potential as a total-flow ...
  	Citation × Citation Citation Abstract Copy Title: Analysis of a Radial-Outflow Reaction Turbine Concept for Geothermal Application Author: House, P.A. Year: 1978 The radial-outflow reaction turbine, a pure-reaction turbine designed to improve the conversion efficiency of geothermal energy into electrical power is described. It also has potential as a total-flow turbine for low-temperature water. The principle of incomplete expansion can be used to obtain a reduction in turbine size when the turbine exhausts into a low-pressure condenser. And, by adding this turbine to single- and two-stage flashed-steam systems, the conversion efficiency of systems utilizing low- and high-energy wellhead sources, respectively can be improved. The Appendix outlines the analysis of the radial-outflow reaction turbine and leads to an expression for engine efficiency Title: Analysis of a Radial-Outflow Reaction Turbine Concept for Geothermal Application Author: House, P.A. Year: 1978 The radial-outflow reaction turbine, a pure-reaction turbine designed to improve the conversion efficiency of geothermal energy into electrical power is described. It also has potential as a total-flow turbine for low-temperature water. The principle of incomplete expansion can be used to obtain a reduction in turbine size when the turbine exhausts into a low-pressure condenser. And, by adding this turbine to single- and two-stage flashed-steam systems, the conversion efficiency of systems utilizing low- and high-energy wellhead sources, respectively can be improved. The Appendix outlines the analysis of the radial-outflow reaction turbine and leads to an expression for engine efficiency Close

• 120. [Image] The Transient Cylindrical Probe Method for Determination of Thermal Parameters of Earth Materials

  	The transient cylindrical probe method has been used widely to measure the thermal conductivity of earth materials. The efficiency of the method is dependent on basic mathematical analysis as well as ...
  	Citation × Citation Citation Abstract Copy Title: The Transient Cylindrical Probe Method for Determination of Thermal Parameters of Earth Materials Author: Kristiansen, J. I. Year: 1982 The transient cylindrical probe method has been used widely to measure the thermal conductivity of earth materials. The efficiency of the method is dependent on basic mathematical analysis as well as treatment of experimental data. It is considered that the introduction of new and effective techniques will improve the method Title: The Transient Cylindrical Probe Method for Determination of Thermal Parameters of Earth Materials Author: Kristiansen, J. I. Year: 1982 The transient cylindrical probe method has been used widely to measure the thermal conductivity of earth materials. The efficiency of the method is dependent on basic mathematical analysis as well as treatment of experimental data. It is considered that the introduction of new and effective techniques will improve the method Close