Registry, engineering, and operating metrics shown on a consistent EIA basis.
| Metric | W R Gianelli Merced County | ONeill Merced County |
|---|---|---|
| Capacity | 424 MW | 25.2 MW |
| Technology | Hydroelectric Pumped Storage | Hydroelectric Pumped Storage |
| Operator | California Dept. of Water Resources | U S Bureau of Reclamation |
| Operating units | 8 | 6 |
| Latest 12-month generation | 258.7 GWh | 2.6 GWh |
| Latest complete-year capacity factor | — | — |
| National technology rank | #15 of 39 | #38 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.