Twelvemile Solar 1
Mayes County, Oklahoma · EIA plant ID 68088 · Operator: Leeward Asset Management, LLC
Nameplate152MWSummer 152 MW
Generators1in service
Net generation139GWh12 mo to Aug 2026
Capacity factor21%solar units, summer MW
Heat rate—thermal plants only
First online2026
The 12-month figures include preliminary EIA-923 months, which EIA revises. Final data runs through Dec 2025.
Monthly net generation
EIA-923, all units at the plant. Net of station use; storage can go negative.
FinalPreliminary
Capacity factor by year
Net MWh ÷ (summer MW × hours), solar units. Each year uses that year's EIA-860 ratings; the hollow dot is the latest 12 months.
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 |
|---|---|---|---|---|---|---|---|---|
| TS1 | Solar Photovoltaic | PV | 152 | 152 | Mar 2026 | Operating | — | coming soon |
| TS12 | Solar Photovoltaic | PV | 152 | 152 | planned Mar 2026 | not_current | — | coming soon |
Owner / operator
Operator: Leeward Asset Management, LLC. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| Leeward Asset Management, LLC | 100.0% | 152 MW |
Nearby plants
Within 80 km.
| Saltbranch Solar 1 | 73 MW | 0 km |
| Twelvemile Solar 3 | — | 0 km |
| Twelvemile Solar 2 | 52 MW | 0 km |
| Saltbranch 2 | 73 MW | 0 km |
| Markham | 128 MW | 11.9 km |
| Chouteau | 1,070 MW | 12.9 km |