Onion River — Plant Summary
- EIA Plant ID
- 65008
- Capacity
- 150 MW
- Primary Fuel
- Solar
- Technology
- Solar Photovoltaic
- Status
- Operating
- Location
- Sheboygan, WI
- Operating Since
- 2023
- Generators
- 1
- Operator
- Wisconsin Power & Light Co
- Parent Company
- Alliant Energy
- Annual Generation
- 255,689 MWh
- Capacity Factor
- 19.4%
- Balancing Authority
- Midcontinent Independent Transmission System Operator, Inc..
- ISO/RTO
- MISO
- NERC Region
- MRO
Onion River
OperatingSolar
Ranked #10 of 102 Solar plants in WI#491 of 7447 nationally
150 MW Solar operating in Sheboygan, WI — Midcontinent Independent Transmission System Operator, Inc..
EIAGEM
150 MW
Nameplate Capacity
1
Generators
unit
Solar Photovoltaic
Technology
2023
Operating Since
Location
Coordinates
43.6002, -87.8966
County
Sheboygan, WI
Nearby Plants
- City of Sheboygan SolarSolar0.9 MW · 16.6 km
- Sheboygan FallsNatural Gas346.8 MW · 16.9 km
- Kohler SolarSolar2.3 MW · 19.5 km
Ownership & Operator
Owner data does not fully agree across sources.
EIA typically reports the operating utility, while GEM resolves to the financial owner or parent corporation. Both can be correct.
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Wisconsin Power & Light Co | Wisconsin Power and Light | — |
| Owner(s) | Wisconsin Power & Light Co | Alliant Energy | — |
| Status | Operating | operating | — |
Ownership Chain
About
Onion River is a 150 MW solar photovoltaic power plant located in Sheboygan County, Wisconsin. The plant, which began operating in 2023, utilizes single-axis tracking technology. It is owned by Alliant Energy and operated by Wisconsin Power & Light Co. Onion River is connected to the Midcontinent Independent Transmission System Operator (MISO) balancing authority.
The plant's latest annual generation was 255,689 MWh, resulting in a capacity factor of 19.4%. Onion River is the 7th largest solar plant in Wisconsin (out of 11) and ranks 359th nationally (out of 639). The installed cost of the plant was $1,515 per kW, according to FERC data.
Generated from EIA, GEM, and public data sources
Engineering & Generators
Grid Context
NERC Region
MRO
Balancing Authority
Midcontinent Independent Transmission System Operator, Inc..
Grid Voltage
138 kV
Regulatory Status
RE
Entity Type
Investor-Owned Utility
Sector
Electric Utility
Generation
7.5K MWh
Latest Month
255.7K MWh
Annual Generation
19.4%
Capacity Factor
Financial DataBeta
Source: FERC Form 1HIGH
$1,512/kW
Installed Cost
$0.6/MWh
Operating Cost
Wisconsin Power and Light Company
Reporting Utility
Annual Capital & Operating Expenses
Cumulative Installed Cost
Per-Unit Cost Trends
Pricing & Market Data
HIGH confidenceMarket Position
ISO/RTO Market
MISO
LMP Node
ALTE.ONIONRIV
Pricing Hub
MICHIGAN.HUB
Location Type
Generation Node
Node Source
EIA-860 direct report
News & Articles (9)Beta
Industry·corporate
Construction in Motion on Alliant Energy's Solar in Wisconsin
The projects are included in the company's Clean Energy Blueprint, a plan for cost-effectively accelerating its transition to renewable energy while...
Alliant Energy (operator)
CSRwire·2 weeks ago
Grid·capacity addition
Sheboygan's Onion River Solar Project is now in service. Here's the impact it's expected to have.
Alliant Energy's solar farm has a capacity to power 40000 homes in the Sheboygan area.
Alliant Energy (operator)
The Sheboygan Press·2 years ago
Grid·capacity addition
Alliant Energy triples its solar generating capacity with completion of six new sites.
Already the state's largest owner-operator of solar installations in Wisconsin, Alliant's five new sites triple the power it gets from the...
Alliant (operator)
Milwaukee Journal Sentinel·2 years ago
Deals·project finance
Alliant's $200M Sheboygan County solar project is nearly complete. Here's how many homes it will power.
TOWN OF HOLLAND – Alliant Energy projects construction on the $200 million Onion River Solar Project will finish this fall.
Alliant Energy (operator)
The Sheboygan Press·2 years ago
Last updated 2026-03-14
View all 9 articles