Geothermal power plants in the United States
Geothermal units in the 2025 EIA-860 data total 4,049 MW of nameplate capacity, 0.3% of the US fleet. It is the main source at 66 plants; California has the most, with 2,936 MW. More of today’s geothermal capacity came online in 1985 than in any other year (398 MW). The oldest unit still working went into service in 1971 at Geysers Unit 5-20, California.
When today’s geothermal capacity was built
Above the line: capacity still operable in 2025, by the year each unit came online. Below: geothermal capacity retired in each year, including plants that have closed completely (EIA’s retired-generator file).
States with the most geothermal capacity
Largest units
The single biggest geothermal generator is unit U13 at Geysers Unit 5-20, rated at 140 MW.
| Plant | State | Unit size | Online |
|---|---|---|---|
| Geysers Unit 5-20 | California | 140 MW | 1980 |
| Geysers Unit 5-20 | California | 124 MW | 1980 |
| Geysers Unit 5-20 | California | 124 MW | 1985 |
| Geysers Unit 5-20 | California | 124 MW | 1982 |
| Geysers Unit 5-20 | California | 124 MW | 1983 |
| Geysers Unit 5-20 | California | 124 MW | 1985 |
| Geysers Unit 5-20 | California | 119 MW | 1975 |
| Geysers Unit 5-20 | California | 119 MW | 1979 |
The 25 largest geothermal plants
| Rank | Plant | State | Runs on | Capacity | First unit | Operator |
|---|---|---|---|---|---|---|
| 1 | Geysers Unit 5-20 | California | Geothermal | 1,236 MW | 1971 | Geysers Power Co LLC |
| 2 | Calistoga Power Plant | California | Geothermal | 176 MW | 1984 | Geysers Power Co LLC |
| 3 | Geothermal 1 | California | Geothermal | 110 MW | 1983 | Northern California Power Agny |
| 4 | Geothermal 2 | California | Geothermal | 110 MW | 1985 | Northern California Power Agny |
| 5 | McGinness Hills | Nevada | Geothermal | 104 MW | 2012 | Ormat Nevada Inc |
| 6 | McGinness Hills 3 | Nevada | Geothermal | 98.8 MW | 2018 | Ormat Nevada Inc |
| 7 | Coso Finance Partners | California | Geothermal | 92.2 MW | 1987 | Coso Operating Co LLC |
| 8 | Heber Geothermal | California | Geothermal | 91.5 MW | 2006 | ORCAL Geothermal, Inc |
| 9 | Coso Energy Developers | California | Geothermal | 90 MW | 1988 | Coso Operating Co LLC |
| 10 | Coso Power Developers | California | Geothermal | 90 MW | 1989 | Coso Operating Co LLC |
| 11 | North Brawley Geothermal Plant | California | Geothermal | 80 MW | 2009 | Ormat Nevada Inc |
| 12 | Sonoma California Geothermal | California | Geothermal | 78 MW | 1983 | Geysers Power Co LLC |
| 13 | Tungsten Mountain | Nevada | Geothermal | 74.8 MW | 2017 | Tungsten Mountain |
| 14 | Second Imperial Geothermal | California | Geothermal | 74.5 MW | 2006 | ORCAL Geothermal, Inc |
| 15 | Dixie Valley | Nevada | Geothermal | 70.9 MW | 1988 | Ormat Nevada Inc |
| 16 | Stillwater Facility | Nevada | Geothermal | 69.2 MW | 2009 | Ormat Stillwater LLC |
| 17 | Patua Acquisition Project, LLC | Nevada | Geothermal | 58.6 MW | 2013 | Patua Acquisition Company, LLC |
| 18 | Salton Sea Power LLC - Unit 5 | California | Geothermal | 58.3 MW | 2000 | CalEnergy Operating Corporation |
| 19 | Bottle Rock Power | California | Geothermal | 55 MW | 1985 | Mayacma Geothermal |
| 20 | John L. Featherstone Plant | California | Geothermal | 55 MW | 2012 | Hudson Ranch Power I LLC |
| 21 | Salton Sea Power Gen Co - Unit 3 | California | Geothermal | 53.9 MW | 1989 | CalEnergy Operating Corporation |
| 22 | Puna Geothermal Venture I | Hawaii | Geothermal | 51 MW | 1992 | Puna Geothermal Venture |
| 23 | Salton Sea Power Gen Co - Unit 4 | California | Geothermal | 47.5 MW | 1996 | CalEnergy Operating Corporation |
| 24 | Ormesa III | California | Geothermal | 45.6 MW | 1989 | Ormat Nevada Inc |
| 25 | CE Leathers | California | Geothermal | 45.5 MW | 1989 | CalEnergy Operating Corporation |