Coso Volcanic Field - Geothermal Power

Geothermal Power

The Coso Volcanic Field is also well known as a geothermal area. Fumaroles are present along faults bounding the rhyolite-capped horst and locally within the rhyolite field. A multi-disciplinary program of geothermal assessment carried out in the 1970s defined a potential resource of 650 megawatts electric with a nominal life span of 30 years. Judged by the youthfulness of the rhyolite lavas and by a zone of low seismic velocity crust roughly beneath the rhyolite, a magma body may be the source of thermal energy for the geothermal system.

Commercial power development began in the 1980s. Located within the Naval Air Weapons Station China Lake Station near Ridgecrest, California, power plants at the Coso Geothermal was operated by Caithness Energy, LLC (Reno, Nevada)and sold in 2006. It currently produces 270 MW from four geothermal power plants. More than 100 wells have been drilled throughout the field, with production depths from 2,000 to 12,000 feet (610 to 3,700 m), and temperatures from 200° to 350°C. Coso began generating electricity in 1987. Since then, improvements have resulted in more efficient use of the resource. (Source: Geothermal Resources Council Bulletin)