Mammoth Pool — Plant Summary
- EIA Plant ID
- 344
- Capacity
- 190 MW
- Primary Fuel
- Hydro
- Technology
- Conventional Hydroelectric
- Status
- Operating
- Location
- Madera, CA
- Operating Since
- 1960
- Generators
- 2
- Operator
- Southern California Edison Co
- Parent Company
- Edison International
- Annual Generation
- 465,889 MWh
- Capacity Factor
- 27.9%
- Balancing Authority
- California Independent System Operator
- ISO/RTO
- CAISO
- NERC Region
- WECC
Mammoth Pool
OperatingHydro
Ranked #15 of 247 Hydro plants in CA#99 of 1454 nationally
190 MW Hydro operating in Madera, CA — California Independent System Operator
EIAGEMWD
190 MW
Nameplate Capacity
2
Generators
units
Conventional Hydroelectric
Technology
1960
Operating Since
Location
Coordinates
37.2203, -119.3380
County
Madera, CA
Nearby Plants
- Big Creek 8Hydro75 MW · 1.4 km
- Big Creek 2Hydro66.6 MW · 3.6 km
- Big Creek 2AHydro110 MW · 3.6 km
Ownership & Operator
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Southern California Edison Co | Southern California Edison | — |
| Owner(s) | Southern California Edison Co | Edison International | — |
| Status | Operating | operating | — |
Ownership Chain
About
Mammoth Pool Dam is a hydroelectric dam located on the San Joaquin River in the southern Sierra Nevada mountain range of California, about 45 miles (72 km) northeast of Fresno. It forms Mammoth Pool Reservoir and lies within the Sierra National Forest. The dam and reservoir were named after a large natural pool in the river that was once located above the present dam site.
Read more on WikipediaMammoth Pool is a 190 MW conventional hydroelectric power plant located in Madera County, California. The plant began operating in 1960 and has two generators. It is owned by Edison International and operated by Southern California Edison Co. The primary fuel source is water (WAT). The plant operates within the California Independent System Operator (CAISO) balancing authority and the Western Electricity Coordinating Council (WECC) NERC region.
In the latest year of reported generation, Mammoth Pool produced 465,889 MWh of electricity, resulting in a capacity factor of 27.9%. According to available data, the installed cost of the plant was $383.51 per kW. Mammoth Pool is ranked as the 15th largest hydroelectric plant out of 42 in California, and 99th out of 194 nationally. News reports indicate that the plant has been mentioned in the news 10 times, with 8 articles related to hazards.
Generated from EIA, GEM, and public data sources
Engineering & Generators
Grid Context
NERC Region
WECC
Balancing Authority
California Independent System Operator
Grid Voltage
220 kV
Regulatory Status
RE
Entity Type
Investor-Owned Utility
Sector
Electric Utility
Generation
35.8K MWh
Latest Month
465.9K MWh
Annual Generation
27.9%
Capacity Factor
Jan 2023 – Dec 2025
Financial DataBeta
Source: FERC Form 1HIGH
$411/kW
Installed Cost
$12.9/MWh
Operating Cost
Southern California Edison Company
Reporting Utility
Cumulative Installed Cost
Per-Unit Cost Trends
Pricing & Market Data
HIGH confidenceMarket Position
ISO/RTO Market
CAISO
LMP Node
MAMOTH2G_7_B1
Pricing Hub
TH_ZP26_GEN-APND
Location Type
Pricing Node
Node Source
Curated node match
News & Articles (10)Beta
General
Central California fishing report Nov. 12: Delta stripers and sturgeon biting
Weekly Central California fishing report covering Fresno, Millerton Lake, Don Pedro, Isabella and more with lake conditions, trout plants...
Fresno Bee·4 months ago
General
Central California fishing report Nov. 12: Delta stripers and sturgeon biting
Weekly Central California fishing report covering Fresno, Millerton Lake, Don Pedro, Isabella and more with lake conditions, trout plants...
Fresno Bee·4 months ago
General
Central California fishing report Nov. 12: Delta stripers and sturgeon biting
Weekly Central California fishing report covering Fresno, Millerton Lake, Don Pedro, Isabella and more with lake conditions, trout plants...
Fresno Bee·4 months ago
General
Central California fishing report Nov. 12: Delta stripers and sturgeon biting
Weekly Central California fishing report covering Fresno, Millerton Lake, Don Pedro, Isabella and more with lake conditions, trout plants...
Fresno Bee·4 months ago
Last updated 2026-03-26
View all 10 articles