The Geysers, a geothermal power field located 72 miles (116 km) north of San Francisco, California, is the largest geothermal development in the world. It is also the largest producer of renewable energy in the United States, currently outputting over 750 MW.[1] The Geysers consists of 21 separate power plants that utilize steam from more than 350 producing wells. The Calpine Corporation operates and owns 19 of the 21 facilities[2]. The other two facilities are operated by the Northern California Power Agency.
Description
The Geysers geothermal development spans an area of around 30 square miles (78 km2) in Sonoma and Lake counties in California, located in the Mayacamas Mountains. Power from The Geysers provides electricity to Sonoma, Lake, Mendocino, Marin, and Napa counties. It is estimated that the development meets 60 percent of the power demand for the coastal region between the Golden Gate Bridge and the Oregon state line.[1]
Steam used at the Geysers is produced from a greywacke sandstone reservoir, that is capped by a hetrogeneous mix of low permeability rocks and underlaid by a Felsite intrusion.[3] Gravity and seismic studies suggest that the source of heat for the steam reservoir is a large magma chamber over 4 miles (7 km) beneath the ground, and greater than 8 miles (14 km) in diameter. [4]
Unlike most geothermal resources, the Geysers is a dry steam field, which means it mainly produces superheated steam. Because the power plant turbines require a vapor phase input, dry steam resources are generally preferable. Otherwise, a two-phase separator is required between the turbine and the geothermal wells to remove condensation that is produced with the steam.
History
The Geysers were first discovered in 1847 during John Fremont's survey of the Sierra Mountains and the Great Basin by William Bell Elliot. Elliot called the area "The Geysers," although the geothermal features he discovered were not technically geysers.
See also
References
- ^ a b "Calpine Corporation - The Geysers" (http). Retrieved 2007-05-16.
- ^ The Geysers (brochure), Calpine Corporation, 2004.
- ^ RESERVOIR RESPONSE TO INJECTION IN THE SOUTHEAST GEYSERS, 1991 (pdf) Steve Enedy, Kathy Enedy, John Maney, Sixteenth Workshop on Geothermal Reservoir Engineering 1991. (accessed 2007-05-16])
- ^ "Cascades Volcanic Observatory (USGS) - Clear Lake Volcanic Field, California" (http). Retrieved 2007-05-16.