In Whatcom County, Washington (WA). The map on this page is placed at the coordinates EIA files for the plant, which locate the site rather than any individual unit.

182 MW of nameplate capacity across 4 units, as of the EIA-860M release for 2026-07.

EIA-860M names City of Seattle - (WA) as the reporting entity. That is the operator of record on the survey, which is not always the ultimate owner.

Is this the same as Diablo LLC?

Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — City of Seattle - (WA) here — not the project company that holds the asset. Project companies are commonly registered as an LLC carrying the plant's name, so a search for "Diablo LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.

Is Diablo still running?

EIA-860M files it as "Operating" for 2026-07. Statuses change monthly, and this page follows the monthly release.

Diablo

Diablo is a 182 MW hydroelectric power plant in Whatcom County, Washington, operated by City of Seattle - (WA). EIA-860M lists 4 generating units here. Its units entered service between 1936 and 1937.

As of 2026-07 (inventory dated 2026-07-31) · EIA-860M Preliminary Monthly Electric Generator Inventory · eia.gov/…/july_generator2026.xlsx · eia.gov/…/eia860m

Nameplate capacity: 182.4 MW; 182.4 MW net summer
Generating units: 4
In service: 1936–1937
EIA plant ID: 6432

Where it is

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County: Whatcom County, Washington
Coordinates: 48.7139, -121.1317
Balancing authority: SCL
Sector: Electric Utility

Units, technology and status

Operator of record: City of Seattle - (WA)
Primary energy source: Hydro
Technologies: Conventional Hydroelectric
Status: Operating

Every plant City of Seattle - (WA) reports to EIA →

Diablo: FAQ

Where is Diablo?: In Whatcom County, Washington (WA). The map on this page is placed at the coordinates EIA files for the plant, which locate the site rather than any individual unit.
How big is Diablo?: 182 MW of nameplate capacity across 4 units, as of the EIA-860M release for 2026-07.
Who owns Diablo?: EIA-860M names City of Seattle - (WA) as the reporting entity. That is the operator of record on the survey, which is not always the ultimate owner.
Is this the same as Diablo LLC?: Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — City of Seattle - (WA) here — not the project company that holds the asset. Project companies are commonly registered as an LLC carrying the plant's name, so a search for "Diablo LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.
Is Diablo still running?: EIA-860M files it as "Operating" for 2026-07. Statuses change monthly, and this page follows the monthly release.