Geothermal power plant in California, United States of America. Approximate location 38.777, -122.745.
GeothermalCaliforniaUnited States of America
Geysers Unit 5-20 is a 1,163 MW geothermal power station in California, United States of America. It is operated by Geysers Power Co LLC. Based on reported annual generation of 4,351 GWh, it can supply roughly 1.2 million homes. It ranks #552 of 10,938 United States of America power plants by installed capacity. Commissioned in 1979, it is around 47 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, geothermal supplies about 0.4% of United States of America's electricity; the national grid averages 384 gCO₂/kWh (43.0% low-carbon) (2025).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0000286.
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
The capacity and/or fuel fields on this page include a source-backed provenance label from GEM, an official registry, Wikidata, OSM, or a cross-source match.
capacity: Wikidata P2109 nameplate capacity; fuel: WRI source-record fuel
At 1,163 MW, Geysers Unit 5-20 is well above the median geothermal plant in United States of America (30 MW). Geothermal plants tap underground heat to raise steam for a turbine; they provide steady, low-carbon baseload but are limited to geologically active regions.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).
Operated by Geysers Power Co LLC.
This geothermal plant taps underground heat to raise steam that drives a turbine. It sits in a warm-summer Mediterranean climate (Köppen Csb) — Northern Hemisphere, latitude 38.8°N — which shapes how much energy it can produce and how its output varies through the year.
Monthly mean temperature
Heating degree-days here run 27% below the median power plant in this dataset — a proxy for how much extra energy heated equipment must replace through its surfaces in winter.
Climate heat-demand index: 39/100 — this site sits in the mid third of the power plants we cover by heating degree-days.
Climate normals: WorldClim 2.1 (1970–2000 monthly normals, 10 arc-min, CC BY 4.0); zone: Köppen-Geiger world climate classification (Kottek et al. 2006, 0.5° grid). Degree-days & heat-demand index computed by PowerAtlas — a modelled heat-demand proxy, not a measured site figure.
For a plant’s outdoor hardware — heat-recovery steam generators (HRSG), expansion joints, valves, flanges and their insulation — the local climate sets how fast unprotected steel and coatings degrade. This site sits in a moderately corrosive environment (estimated ISO 9223 class C3 — Medium), with humidity / wetness the leading environmental stress.
Higher environmental severity is exactly where protective removable insulation pays back most: a sheltered micro-climate slows corrosion, UV and thermal-cycling damage and extends outdoor hardware service life. This is an indicative site-climate context — not a condition assessment of any specific plant or operator.
Indicative estimate via the ISO 9223:2012 informative method (atmospheric corrosivity from temperature, time-of-wetness and airborne salinity), using WorldClim climate normals, the Köppen-Geiger class and coast distance. Indicative, not a measured corrosion rate.
The #1 largest geothermal power plant of 65 in United States of America by capacity.
United States of America has 65 geothermal power plants in this dataset, together about 3,889 MW of capacity.
Coordinates 38.777, -122.745 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Geysers Unit 5-20 is a 1,163 MW source-record geothermal power plant in California, United States of America, commissioned in 1979.
Geysers Unit 5-20 generates about 4,351 GWh of electricity per year.
Its output is enough to supply roughly 1,243,257 homes.
Geysers Unit 5-20 is operated by Geysers Power Co LLC.
