Mammoth Pool
Mammoth Pool is a 190 MW hydroelectric power plant in Madera County, California, operated by Southern California Edison Co. EIA-860M lists 2 generating units here, inside CAISO. Its units entered service in 1960.
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
- 190 MW
- 190 MW net summer
- Generating units
- 2
- In service
- 1960
- EIA plant ID
- 344
Where it is
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- County
- Madera County, California
- Coordinates
- 37.2203, -119.338
- Balancing authority
- CISO
- Sector
- Electric Utility
Units, technology and status
- Operator of record
- Southern California Edison Co
- Primary energy source
- Hydro
- Technologies
- Conventional Hydroelectric
- Status
- Operating
Mammoth Pool: FAQ
- Where is Mammoth Pool?
- In Madera 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 Mammoth Pool?
- 190 MW of nameplate capacity across 2 units, as of the EIA-860M release for 2026-07.
- Who owns Mammoth Pool?
- EIA-860M names Southern California Edison Co 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 Mammoth Pool LLC?
- Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — Southern California Edison Co 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 "Mammoth Pool LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.
- Is Mammoth Pool still running?
- EIA-860M files it as "Operating" for 2026-07. Statuses change monthly, and this page follows the monthly release.