Bottle Rock Power — United States of America

Bottle Rock Power is a 55 MW geothermal power plant in California, United States of America. It is operated by Bottle Rock Power LLC. Based on its capacity (estimated), it can supply roughly 103k homes (estimated). It ranks #3520 of 10,884 United States of America power plants by installed capacity. Commissioned in 1985, it is around 41 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 USA0000902.

Data provenance

Source of the capacity and fuel values:

capacity: Wikidata P2109; fuel: WRI GPPD

In context: how this plant compares

At 55 MW, Bottle Rock Power 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.

Key facts

Generation trend

73 GWh in 2013 and 17 GWh in 2015 (−76%)

Highest and lowest year

2013: 73 GWh; 2015: 17 GWh

Share of United States of America geothermal capacity

1.4% of 3,889 MW across 65 plants in this dataset

Age among peers

5 of 65 dated geothermal plants in United States of America are older

Calculated from the capacity and generation records in this dataset (WRI Global Power Plant Database (CC BY 4.0)).

Reported generation trend

Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).

Owner

Operated by Bottle Rock Power LLC.

Local climate & thermal context

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 21% 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: 42/100 — 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.

Site climate & environmental severity

This site sits in a moderately corrosive environment (estimated ISO 9223 class C3 — Medium), with humidity / wetness the leading environmental stress.

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.

How it compares & nearby plants

The #19 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.

Nearby power plants

• Sonoma California Geothermal · Geothermal · 78 MW · California
• Calistoga Power Plant · Geothermal · 176.4 MW · California
• Geysers Unit 5-20 · Geothermal · 1,163 MW · California
• Aidlin Geothermal Power Plant · Geothermal · 25 MW · California
• Geothermal 1 · Geothermal · 110 MW · California
• Geothermal 2 · Geothermal · 110 MW · California

Location

Coordinates 38.8348, -122.7677 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions