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U.S. Department of Energy Energy Efficiency and Renewable Energy

Costs of Geothermal Power

Wells can be drilled a mile or more deep into underground reservoirs to tap steam and very hot water that drive turbines and electric generators. Because of economies of scale in resource development and power generation, geothermal power plants supply electricity directly to the grid, typically operating as baseload plants with capacity factors above 90%.

This trend graph compares the capital cost in dollars per kilowatt for flashed steam, binary, and hot dry rock power systems, starting in 1995 with projections to 2020. Flashed steam is the cheapest, starting at 1,400 dollars per kilowatt in 1995 and decreasing gradually to 1,200 dollars per kilowatt in 2005 and 1,100 dollars per kilowatt in 2020. Binary systems follow the same trend at a higher price, starting at 2,100 dollars per kilowatt in 1995, decreasing to 1,900 dollars per kilowatt in 2005, and to 1,700 dollars per kilowatt in 2020. Hot dry rock systems are the most expensive, starting at 5,500 dollars per kilowatt in 1995 and dropping to 4,800 dollars per kilowatt in 2005 and 3,200 dollars per kilowatt in 2020. This trend graph shows the cost of geothermal energy starting at 9.8 cents per kilowatt-hour in 1995, dropping to 2.9 cents per kilowatt-hour in 2005, then gradually decreasing to 2.2 cents per kilowatt-hour in 2020.