Potential battery storage facility stirs controversy in McHenry County

Developers eyeing the construction of a battery storage facility near far northwest suburban Prairie Grove say they might come to the village with a formal proposal within the next few months.

California-based Eolian Energy is considering building a standalone energy-storage facility on about 52 acres off Behan Road. The 600-megawatt utility-scale battery energy storage system, BESS for short, would use rechargeable batteries that take in and store excess energy from the electrical grid and release it when demand is high.

An exact cost of the project has not yet been determined, but Eolian officials say the project could represent up to $700 million investment.

Since the idea was first publicly discussed with the Prairie Grove village board in December, hundreds of area residents have organized against the project, with concerns over the potential effects on safety, wildlife and the environment.

Eolian representatives provided an informational webinar for residents on Wednesday night to answer questions about the project, which is called the Monarch Grid.

The site caught Eolian’s attention because of its connection to a nearby ComEd substation and high-voltage transmission systems that transfer power to Chicago and the suburbs, Eolian Project Manager Sam Lines said.

Eolian Chief Development Officer Eric Stoutenburg said the National Electric Reliability Council identified the region as a “high risk for blackouts going forward.”

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

Eolian officials say BESS projects help stabilize electricity costs, reduce strain on aging infrastructure and provide reliable backup power. If built, the so-called Monarch Grid could support approximately 450,000 homes during peak demand.

Though much of the land Eolian is eyeing lies in unincorporated McHenry County developers want it annexed into Prairie Grove. A formal proposal to the village could be submitted “in the coming months,” Lines said.

If approved, construction could begin as early as 2028 and be completed by 2029 or 2030.

Eolian estimates the Monarch Grid would generate $5 million in tax revenue in its first year — approximately three times Prairie Grove’s annual property tax revenue, Lines said. After the first year, an average of $3.5 million is expected to be generated annually for the next 20 years.

Lines said the company has conducted multiple studies on environmental impacts through independent engineering firms.

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

Results from the studies were not shared with the public, but will be submitted with their formal proposal, Eolian officials said.

Two BESS projects are already operating in McHenry County: a 20-megawatt facility has been operating in Marengo since 2018, and another 20-megawatt facility has been operating in McHenry since 2016.

Discussions over whether there could be a data center near the possible BESS are also raising concerns among residents. Village President David Underwood said no data center developers have approached the village with a proposal or “expressed serious interest.”