Darien Solar
Rock County, Wisconsin · EIA plant ID 64534 · Operator: Wisconsin Electric Power Co
Nameplate250MWSummer 250 MW
Generators1in service
Net generation362GWh12 mo to Aug 2026
Capacity factor17%solar units, summer MW
Heat rate—thermal plants only
First online2025
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.
Annual data table
| Year | Net GWh | Capacity factor | Heat rate (Btu/kWh) |
|---|---|---|---|
| 2025 | 314.6 | 17.1% | — |
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 |
|---|---|---|---|---|---|---|---|---|
| 1 | Solar Photovoltaic | PV | 250 | 250 | Mar 2025 | Operating | — | coming soon |
Owner / operator
Operator: Wisconsin Electric Power Co. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| Wisconsin Electric Power Co | 75.0% | 188 MW |
| Wisconsin Public Service Corp | 15.0% | 38 MW |
| Madison Gas & Electric Co | 10.0% | 25 MW |
Nearby plants
Within 80 km.
| Foundry Ridge Energy Center LLC | — | 4.3 km |
| Spring Brook Solar WI, LLC | 6 MW | 18.5 km |
| LaFayette Solar WI, LLC | 6 MW | 19.2 km |
| Lawrence Solar 2 LLC | 2 MW | 19.4 km |
| Lawrence Solar 1 LLC | 2 MW | 19.4 km |
| Lobelia 1 | 2 MW | 20.5 km |