Registry, engineering, and operating metrics shown on a consistent EIA basis.
| Metric | Dion R Holm Tuolumne County | Mammoth Pool Madera County |
|---|---|---|
| Capacity | 180.2 MW | 190 MW |
| Technology | Conventional Hydroelectric | Conventional Hydroelectric |
| Operator | City & County of San Francisco | Southern California Edison Co |
| Operating units | 2 | 2 |
| Latest 12-month generation | 592.5 GWh | 593.9 GWh |
| Latest complete-year capacity factor | 36.6% (2025) | 28.0% (2025) |
| National technology rank | #77 of 1,349 | #73 of 1,349 |
| 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.