Geothermal energy in the United States in the context of Lake County, California

Geothermal power is electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation is currently used in 26 countries, while geothermal heating is in use in 70 countries.

As of 2019, worldwide geothermal power capacity amounts to 15.4 gigawatts (GW), of which 23.9% (3.68 GW) are installed in the United States. International markets grew at an average annual rate of 5 percent over the three years to 2015, and global geothermal power capacity is expected to reach 14.5–17.6 GW by 2020. Based on current geologic knowledge and technology the Geothermal Energy Association (GEA) publicly discloses, the GEA estimates that only 6.9% of total global potential has been tapped so far, while the IPCC reported geothermal power potential to be in the range of 35 GW to 2 TW. Countries generating more than 15 percent of their electricity from geothermal sources include El Salvador, Kenya, the Philippines, Iceland, New Zealand, and Costa Rica. Indonesia has an estimated potential of 29 GW of geothermal energy resources, the largest in the world; in 2017, its installed capacity was 1.8 GW.

Geothermal power in Indonesia is an increasingly significant source of renewable energy. As a result of its volcanic geology, it is often reported that Indonesia has 40% of the world's potential geothermal resources, estimated at 28,000 megawatts (MW).

With 2,356 MW of installed capacity as of year-end 2022, this puts Indonesia in second place in the world after the United States in utilizing geothermal power, superseding the Philippines. In 2007, geothermal energy represented 1.9% of the country's total energy supply and 3.7% of its electric power.