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Yellowtail

Hydro power plant · Big Horn County, Montana

Nameplate capacity
278 MW
Rank in Montana
#6
of 73 plants
In service since
1966
August 1966

Details

Primary fuel
Hydro
Technology
Conventional Hydroelectric
Operator
U S Bureau of Reclamation
County
Big Horn County
Generating units
4
Share of state capacity
3.63%
Rank among hydro plants in Montana
#4 of 23
EIA plant code
2204

Generating units

Individual generating units at Yellowtail
UnitTechnologyNameplateSummerOnlineStatus
1Conventional Hydroelectric72 MW72 MW1966Operating
3Conventional Hydroelectric72 MW72 MW1966Operating
4Conventional Hydroelectric72 MW72 MW1966Operating
2Conventional Hydroelectric63 MW72 MW1966Operating

Nameplate is the maximum rated output; summer capacity is what the unit can reliably deliver on a hot day, which is typically lower.

Similarly sized plants in Montana

About this data

From EIA’s inventory of operable generators, May 2026 release. Capacity is nameplate — the maximum rated output of the equipment, not what the plant actually generates over a year, which depends on how often it runs. A 278 MW solar plant and a 278 MW nuclear plant have the same entry here and produce very different amounts of electricity.

“In service since” is the earliest in-service date among the units still listed, so a site rebuilt around newer equipment can read as younger than the site itself. All Montana power plants · What Montana actually generates