Geothermal energy was first used for electric power production in the United States in 1960. The Geysers in Sonoma and Lake counties, California was developed into the largest geothermal steam electrical plant in the world, at 1,517 megawatts. Other geothermal steam fields operate in the western US and Alaska. Geothermal power can be dispatchable to follow the demands of changing loads. Its environmental impact includes hydrogen sulfide emissions, corrosive or saline chemicals discharged in waste water, possible seismic effects from injection into rock formations, waste heat and noise.
