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Madison Dam

Hydro power plant · Madison County, Montana

Nameplate capacity
16 MW
Rank in Montana
#48
of 73 plants
In service since
2021
December 2021

Details

Primary fuel
Hydro
Technology
Conventional Hydroelectric
Operator
NorthWestern Energy (MT Hydro)
County
Madison County
Generating units
4
Share of state capacity
0.21%
Rank among hydro plants in Montana
#16 of 23
EIA plant code
6422

Generating units

Individual generating units at Madison Dam
UnitTechnologyNameplateSummerOnlineStatus
MAD5Conventional Hydroelectric4.1 MW4.1 MW2021Operating
MAD6Conventional Hydroelectric4.1 MW4.1 MW2021Operating
MAD7Conventional Hydroelectric4.1 MW4.1 MW2022Operating
MAD8Conventional Hydroelectric4.1 MW4.1 MW2022Operating

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

Gordon Butte Wind LLCWind18 MW
HauserHydro17 MW
Turnbull HydroHydro13 MW
MysticHydro12 MW

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 16 MW solar plant and a 16 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