Developers Eye Massive Battery Storage Facility in McHenry County

Eolian Energy considers $700 million investment for 600-megawatt utility-scale battery project near Prairie Grove

Mar. 15, 2026 at 8:34pm

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California-based Eolian Energy is considering building a standalone 600-megawatt utility-scale battery energy storage system on 52 acres near the village of Prairie Grove in McHenry County, Illinois. The $700 million project, called the Monarch Grid, would help stabilize electricity costs, reduce strain on aging infrastructure, and provide reliable backup power to the region. However, the proposal has stirred controversy among hundreds of local residents who have organized against the project due to concerns over safety, wildlife, and environmental impacts.

Why it matters

The Monarch Grid project highlights the growing need for large-scale energy storage solutions to support the electrical grid as renewable energy sources become more prevalent. While battery storage facilities can help improve grid reliability, their construction often faces community opposition due to concerns about potential risks and impacts.

The details

Eolian Energy says the Monarch Grid site was selected due to its proximity to a ComEd substation and high-voltage transmission lines that transfer power to Chicago and the suburbs. The company claims the project could support up to 450,000 homes during peak demand and generate $5 million in tax revenue for Prairie Grove in the first year, three times the village's current property tax revenue. However, residents have organized against the proposal, citing concerns about safety, wildlife, and the environment that have not been fully addressed by the developer.

  • Eolian Energy first discussed the Monarch Grid proposal with the Prairie Grove village board in December 2026.
  • Eolian held an informational webinar for residents on March 15, 2026 to answer questions about the project.
  • Eolian plans to submit a formal proposal to the village 'in the coming months'.
  • If approved, construction could begin as early as 2028 and be completed by 2029 or 2030.

The players

Eolian Energy

A California-based energy company that is considering building the 600-megawatt Monarch Grid battery storage facility near Prairie Grove.

Sam Lines

Eolian Energy's Project Manager for the Monarch Grid proposal.

Eric Stoutenburg

Eolian Energy's Chief Development Officer, who says the region has been identified as 'high risk for blackouts going forward'.

David Underwood

The President of the Village of Prairie Grove, who stated that no data center developers have approached the village with a proposal.

Prairie Grove residents

Hundreds of local residents who have organized against the Monarch Grid project due to concerns over safety, wildlife, and environmental impacts.

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What they’re saying

“We're trying to build infrastructure ahead of the problem, and the problem has been well defined.”

— Eric Stoutenburg, Chief Development Officer, Eolian Energy

“All of those came up about as clean as you can expect. The project, as it's operating, will not impose any environmental danger to the local environment here, including the adjacent conservation district here.”

— Sam Lines, Project Manager, Eolian Energy

What’s next

The judge in the case will decide on Tuesday whether or not to allow Walker Reed Quinn out on bail.

The takeaway

This case highlights growing concerns in the community about repeat offenders released on bail, raising questions about bail reform, public safety on SF streets, and if any special laws to govern autonomous vehicles in residential and commercial areas.