Hydro power plant in Washington, United States of America. Approximate location 45.9567, -122.5544.
HydroWashingtonUnited States of America
Merwin is a 136 MW hydro power station in Washington, United States of America. It is operated by PacifiCorp. Based on reported annual generation of 337 GWh, it can supply roughly 96,285 homes. It ranks #1625 of 9,833 United States of America power plants by installed capacity. Commissioned in 1946, it is around 80 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 USA0003847.
Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).
Operated by PacifiCorp. All plants by this company →
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 46.0°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 20% 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: 61/100 — 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.
The #137 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.
Coordinates 45.9567, -122.5544 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
