Foothill Feeder

Hydro power plant in California, United States of America. Approximate location 34.5148, -118.6092.

HydroCaliforniaUnited States of America

Foothill Feeder is a 9 MW hydro power plant in California, United States of America. It is operated by Metropolitan Water District of S CA. Based on reported annual generation of 44 GWh, it can supply roughly 12,657 homes. It ranks #4814 of 9,833 United States of America power plants by installed capacity. Commissioned in 1981, it is around 45 years old — long-established. 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).

9MW installed capacity
44GWh reported / yr
12,657homes powered
1981commissioned (~45 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0006645.

Reported generation trend

2013: 60 GWh20132014: 25 GWh20142015: 0 GWh20152016: 27 GWh20162017: 53 GWh20172018: 48 GWh20182019: 44 GWh201960 GWh

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

Owner

Operated by Metropolitan Water District of S CA. 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 34.5°N — which shapes how much energy it can produce and how its output varies through the year.

17.2°Cannual mean temp
992heating degree-days (base 18°C)
716cooling degree-days (base 18°C)
467 melevation

Monthly mean temperature

J: 11 °CJF: 12 °CFM: 13 °CMA: 15 °CAM: 18 °CMJ: 21 °CJJ: 25 °CJA: 25 °CAS: 23 °CSO: 19 °CON: 14 °CND: 11 °CD25 °C

Heating degree-days here run 60% 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: 26/100 — this site sits in the bottom 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 #677 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 34.5148, -118.6092 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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