How big is Grant County?

Grant County has a reported capacity of 300 MW. Source: EIA Form 860M.

What kind of plant is Grant County?

Grant County is a Batteries, Solar Photovoltaic facility in Grant County, WI, participating in the MISO market.

Where is Grant County located?

Grant County is in Grant County, WI, inside the MISO balancing area.

Who operates Grant County?

Grant County is operated by Wisconsin Power & Light Co according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.

How much electricity does Grant County generate?

Grant County reported 370.3 GWh over the twelve months to 2026-04. Figures are net generation as filed to EIA-923.

How does Grant County compare to other plants?

By capacity, Grant County ranks #140 of 7,234 operating plants of the same technology nationally. It ranks #2 of 116 in WI.

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Grant County

Wisconsin Power & Light Co. - Grant County - MISO

Grant County is a 200 MW solar photovoltaic facility in the Town of Potosi, Grant County, Wisconsin, using single-axis tracking on approximately 1,400 acres. A co-located 100 MW / 400 MWh lithium-ion battery energy storage system entered operation in October 2025. Wisconsin Power & Light Co. owns and operates the combined solar-plus-storage asset within the Alliant Energy system, serving the MISO market.

Website Open in grid

Aerial photograph of the Grant County battery storage installation.

Source: Alliant Energy

Grant County

MISO · Asset profile

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Grant County — 300 MW solar farm, Grant County, WI · Ask the Grid

Overview

Nameplate capacity: 300 MW
Canonical EIA plant baseline.
Registry anchor: Plant 65007
plant-65007

Structured profile

Technology: Batteries, Solar Photovoltaic
Operator: Wisconsin Power & Light Co.

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Units and generators

Operating generator records and technology attributes reported through EIA-860.

Generator	Capacity	Technology	Operation	Status
BESS1	100 MW 100 MW summer	Batteries Electricity used for energy storage · BA	Oct 2025	Operating
PV1	200 MW 200 MW summer	Solar Photovoltaic Solar · PV	May 2024	Operating

Performance

Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.

Peer context

Technology capacity: 200 MW
National rank: #140
WI rank: #2

Monthly generation

Download CSV

Latest 12 months

370.3 GWh

Reported net generation

Latest report

Apr 2026

EIA-923 monthly filing

2025 capacity factor

14.3%

Using current reported nameplate capacity

Grid and market context

Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.

Nearby substations

HIFLD infrastructure inventory

TAP136965

IN SERVICE · 138 kV

0.1 km

POTOSI

Commercial, land, and environmental record

Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.

Transactions and agreements

Project Announcement

May 26, 2020

Alliant Energy announced plans to acquire and advance 675 megawatts of solar in six Wisconsin counties, including the 200 MW Grant County Solar Project developed by NextEra Energy Resources.

Alliant Energy · NextEra Energy Resources

alliantenergy.com

Ownership Transfer

Aug 10, 2021

Ownership of the 200 MW Grant County Solar Project officially transitioned from a subsidiary of NextEra Energy Resources to Alliant Energy, following PSCW approval. Alliant Energy contracted a NextEra subsidiary to construct the project, with construction to begin in spring 2022.

Alliant Energy · NextEra Energy Resources

alliantenergy.com

Construction Start

Sep 2022

Solar project construction began, employing more than 700 workers through completion.

NextEra Energy Resources (subsidiary) · Alliant Energy

alliantenergy.com

Regulatory Approval

Aug 9, 2023

The Public Service Commission of Wisconsin approved the 100 MW Grant County Battery Project. Alliant selected FlexGen to provide battery energy storage equipment and energy management system. Construction expected to begin in early 2024, with operation expected by mid-2025.

Public Service Commission of Wisconsin · Alliant Energy · FlexGen Power Systems

alliantenergy.com

Construction Completion

May 30, 2024

Alliant Energy announced successful completion of the 200 MW Grant County Solar Project construction. Solar generator entered commercial operation in May 2024.

Alliant Energy · NextEra Energy Resources

alliantenergy.com

Related parties and identifiers

Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.

Relationship graph

Drag organizations to explore the network. Select a node to pin its details and available page link.

AssetContractorMarket / regulator

Parties and identifiers

OrganizationRoleBasis

Timeline and sources

Project milestones and public references behind the asset profile.

Project timeline

May 26, 2020
May 26, 2020
Alliant Energy announces six new solar projects in Wisconsinalliantener...
Alliant Energy announced plans to acquire and advance 675 megawatts of solar in six Wisconsin counties, including the 200 MW Grant County Solar Project developed by NextEra Energy Resources.
Aug 10, 2021
Aug 10, 2021

Reporting portfolio

EIA reporting entity

Wisconsin Power & Light Co

Entity 20856

Operating portfolio

32 plants

3 states

Reported capacity

5,775.3 MW

Batteries · Conventional Hydroelectric · Conventional Steam Coal

Largest reported plants in this portfolio
Largest reported plants	Capacity	State
Columbia (WI)	1,112 MW	WI
West Riverside Energy Center	727.6 MW	WI
Riverside Energy Center	674.9 MW	WI
Edgewater	413.7 MW	WI
South Fond Du Lac	381.6 MW	WI
Alliant Energy Neenah	371 MW	WI
Sheboygan Falls	346.8 MW	WI
Grant CountyCurrent	300 MW	WI

Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.

View full reporting portfolio

Grant County

Ask about Grant County

Grant County

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Overview

Structured profile

Related assets

Paris Solar

Wever Solar (150MW)

Units and generators

Performance

Peer context

Monthly generation

Grid and market context

Nearby substations

Commercial, land, and environmental record

Transactions and agreements

Related parties and identifiers

Relationship graph

Parties and identifiers

Timeline and sources

Project timeline

Darien Solar

Wood County

Badger Hollow I

Badger Hollow II

Reporting portfolio

Sources

Common questions about Grant County

How big is Grant County?

What kind of plant is Grant County?

Where is Grant County located?

Who operates Grant County?

How much electricity does Grant County generate?

How does Grant County compare to other plants?

Co-located assets