Willow Rock Energy Storage CenterPlanned
Kern County, California · EIA plant ID 70492 · Operator: GEM A-CAES LLC
500 MW planned (Battery), first expected Jul 2030 · EIA-860M
Nameplate—MWSummer — MW
Generators0in service
Net generation—GWh12 mo
Capacity factor—not meaningful for storage
Heat rate—thermal plants only
First online—
Capacity factor by year
Net MWh ÷ (summer MW × hours), primary-fuel units. Each year uses that year's EIA-860 ratings; the hollow dot is the latest 12 months.
No capacity factor available.
Heat rate by year
Electric fuel MMBtu × 1000 ÷ net MWh (Btu/kWh, HHV), fossil units only; CT + CA counted as one combined-cycle block.
Heat rate applies to fuel-burning (thermal) units only.
Generators
EIA-860 (annual) with EIA-860M updates through Sep 2026. EIA-923 reports generation by plant, prime mover and fuel, not by unit, so unit-level output isn't shown.
| Gen ID | Technology | Prime mover | Nameplate MW | Summer MW | Online | Status | Planned retirement | OEM / model |
|---|---|---|---|---|---|---|---|---|
| WRES1 | — | CE | 125 | 125 | planned Jul 2030 | Planned | — | coming soon |
| WRES2 | — | CE | 125 | 125 | planned Jul 2030 | Planned | — | coming soon |
| WRES3 | — | CE | 125 | 125 | planned Jul 2030 | Planned | — | coming soon |
| WRES4 | — | CE | 125 | 125 | planned Jul 2030 | Planned | — | coming soon |
Owner / operator
Operator: GEM A-CAES LLC. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
Nearby plants
Within 80 km.
| Edwards Sanborn E2 | 258 MW | 4.1 km |
| Edwards Sanborn E3 | 38 MW | 4.7 km |
| Edwards Sanborn E1A | 293 MW | 6.3 km |
| Sanborn BESS 4 | 47 MW | 6.8 km |
| Edwards Sanborn E4 | 249 MW | 7.2 km |
| RE Rosamond Two LLC | 20 MW | 7.5 km |