Geothermal Developments at San Diego Gas & Electric
In 1972, the first well flow tests were conducted by NARCO and Magma Power to determine reservoir characteristics such as mass flow, temperature, stability, and mineral content of geothermal brine from the exploration wells. The results of these tests were encouraging. Brine temperatures were relatively hot, and salinity was less than previously experienced. Results were sufficient to justify further testing of the process design to determine an appropriate energy conversion cycle for a power plant. Both the flash cycle and binary cycle were considered. In the binary cycle, geothermal heat is transferred from hot brine to a secondary working fluid by means of heat exchangers. The heated secondary fluid expands to drive a turbine-generator. The flash cycle was rejected because the high measured noncondensible gas content of the brines seriously reduced the cycle efficiency. The reduced salinity was expected to result in reduced scaling characteristics. For these reasons the binary cycle was selected for initial design and field testing. In 1973, a series of field tests was conducted to support the design of the binary conversion cycle. Unfortunately, a rapid decline in heat exchanger performance resulting from scaling demonstrated a need to reevaluate the cycle design. A flash/binary process was chosen as the basis for facility design modifications and additional field testing. Design modifications were to use as much of the original design as possible in order to minimize cost. In March of 1974, SDG&E resumed field testing at Niland using reduced size models of the new flash/binary design. The 1974 test program confirmed the decision to modify the design, construction, and operation of the GLEF in a four-stage, flash/binary cycle configuration. In May of 1975, the design was completed and construction of the GLEF began. Startup operations were initiated and in June 1976 the facility was dedicated. In the fall of 1976 while debugging and initial operation was being accomplished, a test program was developed to provide additional basic information necessary for the design of a commercial flash/binary geothermal plant. The primary objective of the program was to develop binary heat exchanger heat design data under a variety of conditions.
- Research Organization:
- San Diego Gas & Electric, San Diego, CA
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC03-76ET28443
- OSTI ID:
- 892092
- Report Number(s):
- EPRI-TC-80-907-15; TRN: US200701%%3
- Resource Relation:
- Conference: Proceedings of the Fourth Annual Geothermal Conference and Workshop, Conference Proceedings, December 1980
- Country of Publication:
- United States
- Language:
- English
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Geothermal Loop Experimental Facility. Quarterly report, April-June 1979
Geothermal Loop Experimental Facility. Quarterly report, April--June 1978