Pit 4

Hydro power plant in California, United States of America. Approximate location 40.9864, -121.8494.

HydroCaliforniaUnited States of America

Pit 4 is a 103 MW hydro power station in California, United States of America. It is operated by Pacific Gas & Electric Co.. Based on reported annual generation of 452 GWh, it can supply roughly 129,142 homes. It ranks #1881 of 9,833 United States of America power plants by installed capacity. Commissioned in 1955, it is around 71 years old — an older, legacy facility. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 5.3% of United States of America's electricity; the national grid averages 384 gCO₂/kWh (43.0% low-carbon) (2025).

103MW installed capacity
452GWh reported / yr
129,142homes powered
1955commissioned (~71 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0000267.

Reported generation trend

2013: 349 GWh20132014: 306 GWh20142015: 230 GWh20152016: 392 GWh20162017: 375 GWh20172018: 397 GWh20182019: 452 GWh2019452 GWh

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

Owner

Operated by Pacific Gas & Electric Co.. All plants by this company →

Local climate & thermal context

This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a warm-summer Mediterranean climate (Köppen Csb) — Northern Hemisphere, latitude 41.0°N — which shapes how much energy it can produce and how its output varies through the year.

9.6°Cannual mean temp
3,121heating degree-days (base 18°C)
64cooling degree-days (base 18°C)
1,166 melevation

Monthly mean temperature

J: 1 °CJF: 3 °CFM: 5 °CMA: 8 °CAM: 12 °CMJ: 16 °CJJ: 19 °CJA: 19 °CAS: 16 °CSO: 11 °CON: 5 °CND: 2 °CD19 °C

Heating degree-days here run 27% 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: 66/100 — this site sits in the mid 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.

How it compares & nearby plants

The #179 largest hydro power plant of 1449 in United States of America by capacity.

United States of America has 1449 hydro power plants in this dataset, together about 101,657 MW of capacity.

Nearby power plants

Location

Coordinates 40.9864, -121.8494 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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