O'Brien Solar Fields
Solar power plant · Dane County, Wisconsin
Nameplate capacity
22 MW
Rank in Wisconsin
#81
of 278 plants
In service since
2021
May 2021
Details
- Primary fuel
- Solar
- Technology
- Solar Photovoltaic
- Operator
- Madison Gas & Electric Co
- County
- Dane County
- Generating units
- 3
- Share of state capacity
- 0.11%
- Rank among solar plants in Wisconsin
- #21 of 115
- EIA plant code
- 64590
Generating units
| Unit | Technology | Nameplate | Summer | Online | Status |
|---|---|---|---|---|---|
| OBSFN | Solar Photovoltaic | 8.3 MW | 8.3 MW | 2021 | Operating |
| OBSFS | Solar Photovoltaic | 8.3 MW | 8.3 MW | 2021 | Operating |
| OBSFW | Solar Photovoltaic | 5.5 MW | 5.5 MW | 2021 | Operating |
Nameplate is the maximum rated output; summer capacity is what the unit can reliably deliver on a hot day, which is typically lower.
Similarly sized plants in Wisconsin
| Mosinee Mill | Other | 23 MW |
| St Croix Falls | Hydro | 23 MW |
| Chippewa Falls | Hydro | 22 MW |
| Rhinelander Mill | Natural gas | 21 MW |
About this data
From EIA’s inventory of operable generators, May 2026 release. Capacity is nameplate — the maximum rated output of the equipment, not what the plant actually generates over a year, which depends on how often it runs. A 22 MW solar plant and a 22 MW nuclear plant have the same entry here and produce very different amounts of electricity.
“In service since” is the earliest in-service date among the units still listed, so a site rebuilt around newer equipment can read as younger than the site itself. All Wisconsin power plants · What Wisconsin actually generates