Geysers Unit 5-20 — United States of America

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 #497 of 10,884 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).

1,163MW installed capacity
4,351GWh reported / yr
1,243,257homes powered
1979commissioned (~47 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0000286.

Data status

Known data

FacilityGeysers Unit 5-20 WRI
CountryUnited States of America · California WRI
Coordinates38.777, -122.745 WRI
FuelGeothermal WRI
MW installed capacity1,163 MW Wikidata P2109; installed/nameplate capacity
Verification noteQuality label backfilled from existing source-backed capacity provenance on 2026-07-05; capacity value was not changed. source-verified
OwnerGeysers Power Co LLC WRI
Commissioned1979 WRI
GWh reported / yr4,351 GWh·a⁻¹ WRI

Calculated from dataset

Capacity rank in country#497 / 10884 calculated
Fuel-specific rank in country#1 / 65 calculated
Capacity vs country/fuel peers38.77× · 30 MW · n=65 calculated
Homes-powered equivalent1,243,257 calculated from reported generation
Climate14.0°C · HDD 1,786 derived from coordinates
Environmental severityC3 · 32/100 derived from coordinates

Not available

TechnologyNot available not in dataset
CO₂ emissionsnot applicable not applicable

Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.

Data provenance

Source of the capacity and fuel values:

capacity: Wikidata P2109; fuel: WRI GPPD

In context: how this plant compares

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.

Key facts

Load factor
43%, from 4,351 GWh of reported generation; the median for 60 geothermal plants in United States of America that report generation is 52%
Generation trend
4,785 GWh in 2013 and 4,351 GWh in 2019 (−9%)
Highest and lowest year
2013: 4,785 GWh; 2019: 4,351 GWh
Share of United States of America geothermal capacity
29.9% of 3,889 MW across 65 plants in this dataset
Age among peers
0 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

2013: 4,785 GWh20132014: 4,592 GWh20142015: 4,531 GWh20152016: 4,629 GWh20162017: 4,668 GWh20172018: 4,674 GWh20182019: 4,351 GWh20195k GWh

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

Owner

Operated by Geysers Power Co 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.

14.0°Cannual mean temp
1,786heating degree-days (base 18°C)
353cooling degree-days (base 18°C)
470 melevation

Monthly mean temperature

J: 7 °CJF: 8 °CFM: 10 °CMA: 12 °CAM: 16 °CMJ: 19 °CJJ: 22 °CJA: 22 °CAS: 20 °CSO: 16 °CON: 10 °CND: 7 °CD22 °C

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.

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.

C3ISO 9223 corrosivity (indicative)
32/100environmental-severity index
15.4°Cseasonal temperature swing
74 kmdistance to coast

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 #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.

Nearby power plants

Location

Coordinates 38.777, -122.745 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Geysers Unit 5-20?

Geysers Unit 5-20 is a 1,163 MW geothermal power plant in California, United States of America, commissioned in 1979.

How much electricity does Geysers Unit 5-20 generate?

Geysers Unit 5-20 generates about 4,351 GWh of electricity per year.

Who operates Geysers Unit 5-20?

Geysers Unit 5-20 is operated by Geysers Power Co LLC.

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