Geothermal power plant in California, United States of America. Approximate location 37.6464, -118.9092.
GeothermalCaliforniaUnited States of America
Mammoth Pacific II is a 15 MW geothermal power plant in California, United States of America. It is operated by Ormat Nevada Inc. Based on reported annual generation of 69 GWh, it can supply roughly 19,600 homes. It ranks #4128 of 9,833 United States of America power plants by installed capacity. Commissioned in 1991, it is around 35 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 USA0010481.
Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).
Operated by Ormat Nevada Inc. All plants by this company →
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 37.6°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 83% above 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: 90/100 — this site sits in the top third of the power plants we cover by heating degree-days.
In colder climates, uninsulated hot equipment (boilers, turbines, valves, steam lines) loses proportionally more heat to ambient air — exactly the loss Inzonex modular insulation is designed to cut.
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.
The #55 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 37.6464, -118.9092 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
