California is scheduled to have another geothermal power plant on line by next August. As a new joint venture of Pacific Lighting Energy Systems and the Mammouth Binary Power Company, the new $12.5 million facility will be built at Casa Diable Hot Springs near Mammouth Lakes, Calif. The plant is expected to turn out about 7,000 kilowatt hours of electricity (enough power for the needs of about 10,000 people). It will sell its energy production for redistribution to Southern California Edison Company.
This new geothermal project will add one more unit to the state's already successful earth-energy projects. Of those existing, the best known is Union Oil's development at the Geysers, 90 miles north of San Francisco. This plant, where underground dry steam or vapor is used to activate turbines, is regarded as the largest geothermal undertaking in the world.
As a successful commercial venture, the Geysers plant converts enough energy to serve about 1 million homeowners at prices competitive with other norms of energy production.
More recently brought on-stream in California early this year was a second Imperial Valley geothermal plant on the Salton Sea, 170 miles southeast of Los Angeles. This unit and one opened at Brawley in 1980 are operated from underground saline-laced hot water that is converted into steam. Each of the Imperial Valley units have capacities of 10,000 k.w.h.
While geothermal power at present represents only a small segment of alternative energy sources, its potential, industry experts say, could become significant. Already sizable projects - using technology developed in oil-field prospecting - have become successful in the Philippines, and major geothermal drilling is taking place in Japan and Indonesia.