Development of Low-Temperature Geothermal Reservoirs for Commercial Power the U.S. Experience

Abstract

Low-temperature geothermal resources are defined herein as those with reservoir temperatures less than 200°C. This paper reviews the experien~e of the U.S. geothermal industry in the development of 19 electrical power projects in 13 different geothermal systems in the western United States with particular reference to geologic setting, reservoir temperature, generation technology and installed capacity (tabl e 1). While low-temperature geothermal systems are found in diverse geologic settings worldwide, those which have been developed for electric power generation in the U.S. are found within two physiographic provinces: the Basin and Range in Nevada and Utah and the Salton Trough in California. Magmatic heat sources are not directly associated with the majority of these systems; instead, they are found in areas devoid of Quaternary magmatism but with elev~ted crustal heat flow. The low- 398 temperature geothermal system within the Long Valley caldera in California is an exception.