Where is Mariposa Energy Project?

In Alameda 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 Mariposa Energy Project?

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

Who owns Mariposa Energy Project?

EIA-860M names Diamond Generating Corporation 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 Mariposa Energy Project LLC?

Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — Diamond Generating Corporation 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 "Mariposa Energy Project LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.

Is Mariposa Energy Project still running?

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

Mariposa Energy Project

Mariposa Energy Project is a 200 MW natural gas power plant in Alameda County, California, operated by Diamond Generating Corporation. EIA-860M lists 4 generating units here, inside CAISO. Its units entered service in 2012.

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: 199.6 MW; 199.6 MW net summer
Generating units: 4
In service: 2012
EIA plant ID: 57483

Where it is

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County: Alameda County, California
Coordinates: 37.7892, -121.6019
Balancing authority: CISO
Sector: IPP Non-CHP

Units, technology and status

Operator of record: Diamond Generating Corporation
Primary energy source: Natural gas
Technologies: Natural Gas Fired Combustion Turbine
Status: Operating

Every plant Diamond Generating Corporation reports to EIA →

Mariposa Energy Project: FAQ

Where is Mariposa Energy Project?: In Alameda 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 Mariposa Energy Project?: 200 MW of nameplate capacity across 4 units, as of the EIA-860M release for 2026-07.
Who owns Mariposa Energy Project?: EIA-860M names Diamond Generating Corporation 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 Mariposa Energy Project LLC?: Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — Diamond Generating Corporation 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 "Mariposa Energy Project LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.
Is Mariposa Energy Project still running?: EIA-860M files it as "Operating" for 2026-07. Statuses change monthly, and this page follows the monthly release.