Registry, engineering, and operating metrics shown on a consistent EIA basis.
| Metric | Diablo Canyon San Luis Obispo County | Helms Pumped Storage Fresno County |
|---|---|---|
| Capacity | 2,323 MW | 1,053 MW |
| Technology | Nuclear | Hydroelectric Pumped Storage |
| Operator | Pacific Gas & Electric Co. | Pacific Gas & Electric Co. |
| Operating units | 2 | 3 |
| Latest 12-month generation | 17.98 TWh | 1.06 TWh |
| Latest complete-year capacity factor | 86.3% (2025) | — |
| National technology rank | #17 of 54 | #8 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.