Abstract: Geothermal Resource Investigations and Development Plans at East Mesa, California

D. A. Campbell, J. H. Howard, T. C. Hinrichs, K. E. Mathias, T. N. Narasimhan

During the past 5 years serious attention has been given to the possibility of exploiting the East Mesa, California, Known Geothermal Resource Area (KGRA). Interest initially came from the Bureau of Reclamation who, in conjunction with the University of California at Riverside, began a program to evaluate feasibility of desalting geothermal fluids to produce water needed in the southwestern United States. More recently Republic Geothermal, Inc., and Imperial Magma Co. have undertaken programs to produce electricity from the resource.

Republic operates the northern third of the KGRA and is drilling to establish the geothermal fuel supply to service a two-stage flash 48-Mw plant. Future sale of electricity has been committed to the local electric power distributor, Imperial Irrigation District.

Imperial Magma Co. operates the southern third of the KGRA and plans a 10-Mw plant using the so-called "Magmamax process," which is based on the binary-cycle concept. Imperial Magma also is drilling development wells and has constructed some hardware to be used at the plant.

The U.S. Department of Energy ("DOE"), Division of Geothermal Energy, has helped in development of this resource through a loan guarantee to Republic and by providing technical assistance to Republic, Bureau of Reclamation, and Imperial Magma as part of the DOE multiregional research-support programs such as the program at Lawrence Berkeley Laboratory.

Certain features of the resources, for example, the distribution of temperature, are well known. However, forecasts of long-term mass and heat production are based on models with assumptions that need further substantiation. For example, the deterioration of temperature with time depends on assumptions regarding recovery of heat contained in the reservoir rock as compared with fluid. Such recovery is not fully understood. Nevertheless, conservative assumptions regarding uncertainties still lead to the conclusion that the resource readily can support the needs of the phase of exploitation now under way.

AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma