Registry, engineering, and operating metrics shown on a consistent EIA basis.
| Metric | Mammoth Pool Madera County | J S Eastwood Fresno County |
|---|---|---|
| Capacity | 190 MW | 199.8 MW |
| Technology | Conventional Hydroelectric | Hydroelectric Pumped Storage |
| Operator | Southern California Edison Co | Southern California Edison Co |
| Operating units | 2 | 1 |
| Latest 12-month generation | 593.9 GWh | 220.1 GWh |
| Latest complete-year capacity factor | 28.0% (2025) | — |
| National technology rank | #73 of 1,349 | #27 of 39 |
| Latest EIA report | 2026-04 | 2026-04 |
Generation comes from EIA-923. Capacity, unit counts, technology, and reporting relationships come from EIA-860. Incomplete reporting years are excluded from capacity-factor comparisons.