Mill Creek 3 — United States of America
Hydro power plant in California, United States of America. Approximate location 34.088, -117.0395.
HydroCaliforniaUnited States of America
Mill Creek 3 is a 3 MW hydro power plant in California, United States of America. It is operated by Southern California Edison Co. Based on reported annual generation of 11 GWh, it can supply roughly 3.0k homes. It ranks #8189 of 10,884 United States of America power plants by installed capacity. Commissioned in 1903, it is around 123 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).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0007147.
Data status
Known data
Calculated from dataset
Not available
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 3 MW, Mill Creek 3 is below the median hydro plant in United States of America (8 MW). Hydropower converts the energy of falling or flowing water into electricity; output depends on rainfall and reservoir level, and large dams also provide grid balancing and storage.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
Key facts
- Load factor
- 40%, from 11 GWh of reported generation; the median for 1342 hydro plants in United States of America that report generation is 42%
- Generation trend
- 6 GWh in 2013 and 11 GWh in 2019 (+83%)
- Highest and lowest year
- 2017: 14 GWh; 2014: 5 GWh
- Share of United States of America hydro capacity
- less than 0.1% of 102,513 MW across 1,449 plants in this dataset
- Age among peers
- 5 of 1,444 dated hydro 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 Southern California Edison 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 hot-summer Mediterranean climate (Köppen Csa) — Northern Hemisphere, latitude 34.1°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 17% 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: 59/100 — 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 #1064 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 102,513 MW of capacity.
Nearby power plants
- Santa Ana 3 · Hydro · 3.1 MW · California
- Santa Ana 1 · Hydro · 3.2 MW · California
- Crafton Hills College Solar Farm · Solar · 1.3 MW · California
- Solar Photovoltaic Project #22 · Solar · 2 MW · California
- Solar Photovoltaic Project #07 · Solar · 2.5 MW · California
- Solar Photovoltaic Project #48 · Solar · 5 MW · California
Location
Coordinates 34.088, -117.0395 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Frequently asked questions
What type of power plant is Mill Creek 3?
Mill Creek 3 is a 3 MW hydro power plant in California, United States of America, commissioned in 1903.
How much electricity does Mill Creek 3 generate?
Mill Creek 3 generates about 11 GWh of electricity per year.
Who operates Mill Creek 3?
Mill Creek 3 is operated by Southern California Edison Co.