Dion R Holm

Hydro power plant in California, United States of America. Approximate location 37.8966, -119.9675.

HydroCaliforniaUnited States of America

Dion R Holm is a 157 MW hydro power station in California, United States of America. It is operated by City & County of San Francisco. Based on reported annual generation of 608 GWh, it can supply roughly 173,800 homes. It ranks #1479 of 9,833 United States of America power plants by installed capacity. Commissioned in 1960, it is around 66 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).

157MW installed capacity
608GWh reported / yr
173,800homes powered
1960commissioned (~66 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0000380.

Reported generation trend

2013: 503 GWh20132014: 429 GWh20142015: 602 GWh20152016: 648 GWh20162017: 924 GWh20172018: 248 GWh20182019: 608 GWh2019924 GWh

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

Owner

Operated by City & County of San Francisco. 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 37.9°N — which shapes how much energy it can produce and how its output varies through the year.

12.3°Cannual mean temp
2,347heating degree-days (base 18°C)
264cooling degree-days (base 18°C)
1,252 melevation

Monthly mean temperature

J: 5 °CJF: 6 °CFM: 6 °CMA: 9 °CAM: 13 °CMJ: 18 °CJJ: 22 °CJA: 22 °CAS: 19 °CSO: 14 °CON: 8 °CND: 5 °CD22 °C

Heating degree-days here run 5% 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: 48/100 — 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 #123 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 37.8966, -119.9675 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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