Registry, engineering, and operating metrics shown on a consistent EIA basis.
| Metric | Old 300 Storage Center Fort Bend County | Hidden Lakes Reliability Project Galveston County |
|---|---|---|
| Capacity | 250 MW | 220 MW |
| Technology | Batteries | Batteries |
| Operator | Old 300 Storage Center, LLC | Evelyn Energy Storage LLC |
| Operating units | 1 | 1 |
| Latest 12-month generation | 8.6 GWh | 17.3 GWh |
| Latest complete-year capacity factor | — | — |
| National technology rank | #27 of 962 | #41 of 962 |
| 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.