Boundary

Hydro power plant · Pend Oreille County, Washington

Nameplate capacity
1,160 MW
Rank in Washington
#6
of 139 plants
In service since
1967
August 1967

Details

Primary fuel
Hydro
Technology
Conventional Hydroelectric
Operator
City of Seattle - (WA)
County
Pend Oreille County
Generating units
6
Share of state capacity
3.66%
Rank among hydro plants in Washington
#5 of 73
EIA plant code
6433

Generating units

Individual generating units at Boundary
UnitTechnologyNameplateSummerOnlineStatus
55Conventional Hydroelectric239 MW232 MW1985Operating
56Conventional Hydroelectric239 MW232 MW1986Operating
51Conventional Hydroelectric181 MW181 MW1967Operating
54Conventional Hydroelectric181 MW181 MW1967Operating
52Conventional Hydroelectric162 MW162 MW1967Operating
53Conventional Hydroelectric158 MW158 MW1967Operating

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 Washington

WanapumHydro1,220 MW
Columbia Generating StationNuclear1,200 MW
Priest RapidsHydro950 MW
WellsHydro867 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 1,160 MW solar plant and a 1,160 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 Washington power plants · What Washington actually generates