Yellowtail

Hydro power plant in Montana, United States of America. Approximate location 45.3074, -107.9575.

HydroMontanaUnited States of America

Yellowtail is a 269 MW hydro power station in Montana, United States of America. It is operated by U S Bureau of Reclamation. Based on reported annual generation of 914 GWh, it can supply roughly 261,142 homes. It ranks #1036 of 9,833 United States of America power plants by installed capacity. Commissioned in 1966, it is around 60 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).

269MW installed capacity
914GWh reported / yr
261,142homes powered
1966commissioned (~60 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0002204.

Reported generation trend

2013: 471 GWh20132014: 1,096 GWh20142015: 744 GWh20152016: 690 GWh20162017: 1,124 GWh20172018: 1,059 GWh20182019: 914 GWh20191k 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 45.3°N — which shapes how much energy it can produce and how its output varies through the year.

7.4°Cannual mean temp
3,996heating degree-days (base 18°C)
132cooling degree-days (base 18°C)
1,372 melevation

Monthly mean temperature

J: -5 °CJF: -2 °CFM: 1 °CMA: 6 °CAM: 11 °CMJ: 16 °CJJ: 20 °CJA: 20 °CAS: 14 °CSO: 8 °CON: 1 °CND: -3 °CD20 °C

Heating degree-days here run 63% 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: 84/100 — 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 #72 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 45.3074, -107.9575 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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