McNary

Hydro power plant in Oregon, United States of America. Approximate location 45.9402, -119.2988.

HydroOregonUnited States of America

McNary is a 990 MW hydro power station in Oregon, United States of America. It is operated by USACE Northwestern Division. Based on reported annual generation of 4,474 GWh, it can supply roughly 1,278,400 homes. It ranks #319 of 9,833 United States of America power plants by installed capacity. Commissioned in 1955, it is around 71 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).

990MW installed capacity
4,474GWh reported / yr
1,278,400homes powered
1955commissioned (~71 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0003084.

Reported generation trend

2013: 5,270 GWh20132014: 5,364 GWh20142015: 5,150 GWh20152016: 5,628 GWh20162017: 5,709 GWh20172018: 5,682 GWh20182019: 4,474 GWh20196k GWh

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

Owner

Operated by USACE Northwestern Division. 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 45.9°N — which shapes how much energy it can produce and how its output varies through the year.

11.8°Cannual mean temp
2,607heating degree-days (base 18°C)
344cooling degree-days (base 18°C)
176 melevation

Monthly mean temperature

J: 1 °CJF: 4 °CFM: 8 °CMA: 12 °CAM: 16 °CMJ: 20 °CJJ: 23 °CJA: 23 °CAS: 18 °CSO: 12 °CON: 6 °CND: 1 °CD23 °C

Heating degree-days here run 6% 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: 52/100 — 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 #22 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 45.9402, -119.2988 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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