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Chief Joseph

Hydro power plant · Douglas County, Washington

Nameplate capacity

2,456 MW

Rank in Washington

of 139 plants

In service since

1955

September 1955

Details

Primary fuel: Hydro
Technology: Conventional Hydroelectric
Operator: USACE Northwestern Division
County: Douglas County
Generating units: 27
Share of state capacity: 7.75%
Rank among hydro plants in Washington: #2 of 73
EIA plant code: 3921

Generating units

Individual generating units at Chief Joseph
Unit	Technology	Nameplate	Summer	Online	Status
17	Conventional Hydroelectric	95 MW	95 MW	1977	Operating
18	Conventional Hydroelectric	95 MW	95 MW	1977	Operating
19	Conventional Hydroelectric	95 MW	95 MW	1977	Out of service but expected to return to service in next calendar year
20	Conventional Hydroelectric	95 MW	95 MW	1978	Operating
21	Conventional Hydroelectric	95 MW	95 MW	1978	Operating
22	Conventional Hydroelectric	95 MW	95 MW	1978	Operating
23	Conventional Hydroelectric	95 MW	95 MW	1978	Operating
24	Conventional Hydroelectric	95 MW	95 MW	1979	Operating
25	Conventional Hydroelectric	95 MW	95 MW	1979	Operating
26	Conventional Hydroelectric	95 MW	95 MW	1979	Operating
27	Conventional Hydroelectric	95 MW	95 MW	1979	Operating
1	Conventional Hydroelectric	88 MW	88 MW	1958	Operating
10	Conventional Hydroelectric	88 MW	88 MW	1955	Out of service but expected to return to service in next calendar year
11	Conventional Hydroelectric	88 MW	88 MW	1955	Out of service but expected to return to service in next calendar year
12	Conventional Hydroelectric	88 MW	88 MW	1955	Out of service but expected to return to service in next calendar year
13	Conventional Hydroelectric	88 MW	88 MW	1957	Out of service but expected to return to service in next calendar year
14	Conventional Hydroelectric	88 MW	88 MW	1957	Operating
15	Conventional Hydroelectric	88 MW	88 MW	1957	Operating
16	Conventional Hydroelectric	88 MW	88 MW	1957	Operating
2	Conventional Hydroelectric	88 MW	88 MW	1958	Operating
3	Conventional Hydroelectric	88 MW	88 MW	1958	Operating
4	Conventional Hydroelectric	88 MW	88 MW	1958	Operating
5	Conventional Hydroelectric	88 MW	88 MW	1957	Operating
6	Conventional Hydroelectric	88 MW	88 MW	1956	Operating
7	Conventional Hydroelectric	88 MW	88 MW	1956	Out of service and NOT expected to return to service in next calendar year
8	Conventional Hydroelectric	88 MW	88 MW	1956	Out of service and NOT expected to return to service in next calendar year
9	Conventional Hydroelectric	88 MW	88 MW	1955	Out of service but expected to return to service in next calendar year

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

Grand Coulee	Hydro	6,809 MW
Rocky Reach	Hydro	1,349 MW
Wanapum	Hydro	1,220 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 2,456 MW solar plant and a 2,456 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