The Geysers

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 currently outputting over 750 MW. The Geysers consists of 22 separate power plants that utilize steam from more than 350 producing wells. cite web
title = Calpine Corporation - The Geysers
url = http://www.geysers.com
format = http
accessdate = 2008-06-11 ] The Calpine Corporation operates and owns 19 of the 22 facilities. The other three facilities are operated by the Northern California Power Agency and the Western GeoPower Corporation.

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.

Steam used at the Geysers is produced from a greywacke sandstone reservoir, that is capped by a heterogeneous mix of low permeability rocks and underlaid by a Felsite intrusion. [http://www.osti.gov/geothermal/servlets/purl/887486-8h0FCj/887486.pdf 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)] 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. cite web
title = Cascades Volcanic Observatory (USGS) - Clear Lake Volcanic Field, California
url = http://vulcan.wr.usgs.gov/Volcanoes/California/ClearLake/description_clear_lake.html
format = http
accessdate = 2007-05-16 ]

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 first recorded "discovery" of The Geysers was 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, but fumaroles. Soon after, in 1852, The Geysers was developed into a spa for The Geysers Resort Hotel, which attracted the likes of Ulysses S. Grant, Theodore Roosevelt, and Mark Twain.cite web
title = A History of Geothermal Energy in the United States
url = http://www1.eere.energy.gov/geothermal/history.html
format = http
accessdate = 2007-05-17 ]

ee also

*Geothermal energy in the United States
*Geothermal power

References

External links

* [http://www.prnewswire.com/cgi-bin/stories.pl?ACCT=104&STORY=/www/story/08-15-2007/0004646167&EDATE= Calpine to Increase Renewable Energy Production at The Geysers; Calpine and Santa Rosa to Expand Geysers Recharge Project]
* [http://pasadena.wr.usgs.gov/recenteqs/Maps/123-39.htm USGS map of frequent earthquakes in the Geyser area]