River Mill

Hydro power plant in Oregon, United States of America. Approximate location 45.3, -122.35.

HydroOregonUnited States of America

River Mill is a 19 MW hydro power plant in Oregon, United States of America. It is operated by Portland General Electric Co. Based on reported annual generation of 70 GWh, it can supply roughly 20,085 homes. It ranks #3902 of 9,833 United States of America power plants by installed capacity. Commissioned in 1925, it is around 101 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).

19MW installed capacity
70GWh reported / yr
20,085homes powered
1925commissioned (~101 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0003049.

Reported generation trend

2013: 96 GWh20132014: 105 GWh20142015: 74 GWh20152016: 105 GWh20162017: 110 GWh20172018: 88 GWh20182019: 70 GWh2019110 GWh

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

Owner

Operated by Portland General 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 45.3°N — which shapes how much energy it can produce and how its output varies through the year.

10.1°Cannual mean temp
2,891heating degree-days (base 18°C)
0cooling degree-days (base 18°C)
427 melevation

Monthly mean temperature

J: 4 °CJF: 5 °CFM: 6 °CMA: 8 °CAM: 12 °CMJ: 14 °CJJ: 17 °CJA: 18 °CAS: 15 °CSO: 11 °CON: 6 °CND: 4 °CD18 °C

Heating degree-days here run 18% 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.

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 #488 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 45.3, -122.35 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Built from open public data; no personal information. Operate this site? Request a correction or removal.