In Butte County, California (CA). 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 Thermalito?

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

EIA-860M names California Dept. of Water Resources 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 Thermalito LLC?

Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — California Dept. of Water Resources 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 "Thermalito LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.

Is Thermalito still running?

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

Thermalito

Thermalito is a 115 MW pumped storage hydro plant in Butte County, California, operated by California Dept. of Water Resources. EIA-860M lists 4 generating units here, inside CAISO. Its units entered service in 1968.

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: 115.1 MW; 115.1 MW net summer
Generating units: 4
In service: 1968
EIA plant ID: 438

Where it is

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County: Butte County, California
Coordinates: 39.5149, -121.6301
Balancing authority: CISO
Sector: Electric Utility

Units, technology and status

Operator of record: California Dept. of Water Resources
Primary energy source: Pumped storage
Technologies: Conventional Hydroelectric, Hydroelectric Pumped Storage
Status: Operating

This site runs on more than one energy source. EIA-860M capacity splits: Pumped storage 83 MW, Hydro 33 MW. It is filed here under Pumped storage, the source with the most capacity.

Every plant California Dept. of Water Resources reports to EIA →

Thermalito: FAQ

Where is Thermalito?: In Butte County, California (CA). 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 Thermalito?: 115 MW of nameplate capacity across 4 units, as of the EIA-860M release for 2026-07.
Who owns Thermalito?: EIA-860M names California Dept. of Water Resources 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 Thermalito LLC?: Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — California Dept. of Water Resources 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 "Thermalito LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.
Is Thermalito still running?: EIA-860M files it as "Operating" for 2026-07. Statuses change monthly, and this page follows the monthly release.