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.
As of 2023, some 15,000 geothermal wells (mostly hydrothermal) operated worldwide.
History
Archaeological evidence documents that geothermal resources have been in use in the US for more than 10,000 years. Paleo-Indians first used geothermal hot springs for warmth, cleansing, and minerals.
Pacific Gas and Electric opened the US' first commercial geothermal power plant at The Geysers in California in September 1960, initially producing eleven megawatts of net power. The Geysers system grew into the world's largest, with an output of 750 MW. It exploits the largest dry steam field, north of San Francisco. The original turbine lasted for more than 30 years.
Near Several small power plants were built during the late 1980s in the Basin and Range geologic province in Nevada, southeastern Oregon, southwestern Idaho, Arizona and western Utah. is now an area of rapid geothermal development.
In the Salton Sea, as of 2001, 15 geothermal plants were producing electricity. Hudson Ranch I geothermal plant, a 50 MW plant opened in May 2012. A second similar plant was to open in 2013.
The most significant development catalyst is the Energy Policy Act of 2005. This Act made new geothermal plants eligible for the full federal production tax credit, previously available only to wind power projects and certain kinds of biomass. It also authorized and directed increased funding for research by the Department of Energy, and enabled the Bureau of Land Management to address its backlog of geothermal leases and permits.
In April 2008, exploratory drilling began at Newberry Volcano in Oregon. As of August 2008, 103 new projects were under way in 13 US states. When developed, these projects could potentially supply up to 3,979 MW of power, meeting the needs of about 4 million homes. The DOE Geothermal Technologies Program (part of the American Recovery and Reinvestment Act of 2009) allowed the USDOE to fund research in Enhanced Geothermal Systems (EGS) to learn more about the fracture systems in geothermal reservoirs and better predict the results of reservoir stimulation.
In 2009, investment bank Credit Suisse calculated that geothermal power costs 3.6 cents per kilowatt-hour, versus 5.5 cents per kilowatt-hour for coal, if geothermal receives subsidized loans.
A report released in late May 2019 by the Department of Energy suggests that US geothermal power capacity could increase by more than twenty-six times by 2050, reaching a capacity of 60 GW, thanks to accelerated technological development and adoption. The report documented the benefits of geothermal power for residential and industrial heating. Energy Secretary Rick Perry announced his Department had provided funding for a $140-million research facility at the University of Utah on man-made geothermal energy.
In 2018, due to volcanic activity the Puna Geothermal Venture in Hawaii had to be closed and was inundated by lava flows. It reopened in November 2020.
The Department of Energy (DOE), launched the Frontier Observatory for Research in Geothermal Energy (FORGE).
Production
With 3,676 MW of installed geothermal capacity as of 2019, the US remains the world leader with about 25% of the online capacity total. The future outlook for expanded production from conventional and enhanced geothermal systems is positive as new technologies promise increased growth in locations previously not considered.
By state
Installed geothermal capacity in megawatts (MW) by state as of February 2012: