Darien Solar — Plant Summary
- EIA Plant ID
- 64534
- Capacity
- 250 MW
- Primary Fuel
- Solar
- Technology
- Solar Photovoltaic
- Status
- Operating
- Location
- Rock, WI
- Operating Since
- 2025
- Generators
- 1
- Operator
- Wisconsin Electric Power Co
- Parent Company
- —
- Annual Generation
- 314,613 MWh
- Capacity Factor
- 17.1%
- Balancing Authority
- Midcontinent Independent Transmission System Operator, Inc..
- ISO/RTO
- MISO
- NERC Region
- MRO
Darien Solar
OperatingSolar
Ranked #4 of 102 Solar plants in WI#196 of 7447 nationally
250 MW Solar operating in Rock, WI — Midcontinent Independent Transmission System Operator, Inc..
EIAGEM
250 MW
Nameplate Capacity
1
Generators
unit
Solar Photovoltaic
Technology
2025
Operating Since
Location
Coordinates
42.6200, -88.7400
County
Rock, WI
Nearby Plants
- LaFayette Solar WI, LLCSolar6 MW · 19.2 km
- Lawrence Solar 1 LLCSolar2 MW · 19.4 km
- Lawrence Solar 2 LLCSolar2 MW · 19.4 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 Electric Power Co | Wisconsin Electric Power | — |
| Owner(s) | Madison Gas & Electric Co, Wisconsin Electric Power Co, Wisconsin Public Service Corp | Invenergy LLC [100%] | — |
| Status | Operating | operating | — |
Ownership Chain
About
Darien Solar is a 250 MW solar photovoltaic power plant located in Rock County, Wisconsin. The plant, which began operating in 2025, is owned and operated by Wisconsin Electric Power Co. It utilizes a single generator and fixed-tilt solar tracking technology. Darien Solar is the second-largest solar plant in Wisconsin out of 11, and ranks 119th nationally among 639 solar facilities.
The plant operates within the Midcontinent Independent Transmission System Operator (MISO) balancing authority and the Midwest Reliability Organization (MRO) NERC region. In its latest year of operation, Darien Solar generated 314,613 MWh of electricity, achieving a capacity factor of 17.1%.
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
7.1K MWh
Latest Month
314.6K MWh
Annual Generation
17.1%
Capacity Factor
Financial Data
No financial data available for this plant.
Pricing & Market Data
HIGH confidencePoint of Interconnection
Nearest Substation
West Darien · 138 kV
Substation Distance
1.934 km
Coord Source
OSM spatial
Market Position
ISO/RTO Market
MISO
LMP Node
WEC.DAR_SLR1
Pricing Hub
MICHIGAN.HUB
Location Type
Generation Node
Node Source
Curated node match
News & Articles (10)Beta
Grid·capacity addition
Developer looking to build new natural gas peaker plant in Walworth County
Online petition opposing the project has nearly 900 signatures, organizer says 400 more signed paper copies. By Joe Schulz. August 7, 2025.
WPR·7 months ago
Grid·capacity addition
Wisconsin builds on solar goals with new farm
Wisconsin continues adding more renewable energy to its grid, as the 250 MW Darien Solar Energy Center is now up and running. The project in...
Power Engineering·1 years ago
Grid·capacity addition
Wisconsin activates 250 MW solar project
Large enough to power roughly 75,000 households, the Darien Solar project is now delivering electricity to multiple utility customers.
pv magazine USA·1 years ago
Grid·capacity addition
We Energies adding more solar power to Wisconsin’s grid
MILWAUKEE — The 250-megawatt (MW) Darien Solar Energy Center is up and running — and now providing power to customers. The project in...
We Energies (operator)
We Energies News·1 years ago
Last updated 2026-03-14
View all 10 articles