Grand Coulee

Hydro power plant in Washington, United States of America. Approximate location 47.9575, -118.9773.

HydroWashingtonUnited States of America

Grand Coulee is a 6,809 MW hydro power station in Washington, United States of America. It is operated by U S Bureau of Reclamation. Based on reported annual generation of 16,639 GWh, it can supply roughly 4,754,114 homes. It ranks #1 of 9,833 United States of America power plants by installed capacity. Commissioned in 1967, it is around 59 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).

6,809MW installed capacity
16,639GWh reported / yr
4,754,114homes powered
1967commissioned (~59 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0006163.

Reported generation trend

2013: 21,073 GWh20132014: 20,262 GWh20142015: 18,879 GWh20152016: 19,012 GWh20162017: 20,984 GWh20172018: 21,043 GWh20182019: 16,639 GWh201921k GWh

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

Owner

Operated by U S Bureau of Reclamation. 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 cold semi-arid steppe climate (Köppen BSk) — Northern Hemisphere, latitude 48.0°N — which shapes how much energy it can produce and how its output varies through the year.

8.6°Cannual mean temp
3,566heating degree-days (base 18°C)
157cooling degree-days (base 18°C)
662 melevation

Monthly mean temperature

J: -3 °CJF: 0 °CFM: 4 °CMA: 8 °CAM: 13 °CMJ: 17 °CJJ: 21 °CJA: 20 °CAS: 15 °CSO: 9 °CON: 2 °CND: -3 °CD21 °C

Heating degree-days here run 45% 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: 77/100 — this site sits in the top 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 #1 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 47.9575, -118.9773 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.