Onion River
Sheboygan County, Wisconsin · EIA plant ID 65008 · Operator: Wisconsin Power & Light Co
Nameplate150MWSummer 150 MW
Generators1in service
Net generation256GWh12 mo to Aug 2026
Capacity factor20%solar units, summer MW
Heat rate—thermal plants only
First online2023
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) |
|---|---|---|---|
| 2023 | 2.9 | 2.5% | — |
| 2024 | 198.2 | 15.0% | — |
| 2025 | 255.7 | 19.5% | — |
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 |
|---|---|---|---|---|---|---|---|---|
| PV1 | Solar Photovoltaic | PV | 150 | 150 | Dec 2023 | Operating | — | coming soon |
Owner / operator
Operator: Wisconsin Power & Light Co. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| Wisconsin Power & Light Co | 100.0% | 150 MW |
Nearby plants
Within 80 km.
| Lyndon Solar WI, LLC | — | 8.5 km |
| City of Sheboygan Solar | 1 MW | 16.6 km |
| Sheboygan Falls | 347 MW | 16.9 km |
| Kohler Solar | 2 MW | 19.4 km |
| Edgewater | 414 MW | 20 km |
| Port Washington Generating Station | 1,230 MW | 24.1 km |