The state's largest utility company, WEC Energy Group, is partnering with Madison Gas and Electric on a $400 million solar and battery storage project in Kenosha County. If approved, the project would be the first and largest battery storage project among the state's largest utilities.
The Paris Solar-Battery Park would produce 200 megawatts of solar energy, which is enough to power around 60,000 homes. It would also include 110 megawatts of battery storage that would save solar power for use when the sun isn't shining, according to Brendan Conway, spokesperson for WEC Energy Group.
"During the day, it sends some energy to the grid, but also charges those batteries —110 megawatts of battery — which is equal to powering about 33,000 homes for four hours," said Conway.
WEC Energy Group, which owns We Energies and Wisconsin Public Service, submitted the proposal with MGE to the Public Service Commission on Tuesday.
The PSC authorized Invenergy to construct the 200-megawatt solar farm in the town of Paris last December. The Chicago-based developer has been seeking a buyer for the project. WEC Energy Group is proposing to purchase the solar-battery park for $360 million while MGE would fund the remaining $40 million.
If approved, WEC Energy Group would own 90 percent of the project, and MGE would own the remaining 10 percent of the energy produced and stored at the park.
"Investment in solar energy and battery storage at the Paris Solar-Battery Park is an opportunity for MGE to invest further in cost-effective clean energy and new technologies to reliably serve all our customers as we work to meet our aggressive carbon reduction goals," said Jeff Keebler, MGE chairman, president and CEO in a statement.
Both utilities said the project is an important part of efforts to reduce carbon emissions in their power mix. The two have both pledged to go carbon netural by 2050, which is in line with Gov. Tony Evers' goal for utilities to produce carbon-free electricity in the next 30 years.
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WEC Energy Group announced in November that it would retire 1,800 megawatts of fossil fuel generation, including the retirement of the 1,100-megawatt South Oak Creek coal plant in southeastern Wisconsin. The utility is devoting $2 billion to invest in 1,500 megawatts of renewable energy that would serve Wisconsin customers, including 800 megawatts of solar power and 600 megawatts of battery storage.
MGE is also transitioning away from coal, including the retirement of the 1,100-megawatt Columbia Energy Center announced earlier this month. The Madison-based utility owns a portion of the coal plant with Alliant Energy and Wisconsin Public Service.
Heather Allen, executive director of RENEW Wisconsin, called the project a "significant addition" that would give the utilities more control over electric generation.
"I think the costs have come down sufficiently that utilities can make the economic case that the value of the energy storage is good for ratepayers," said Allen. "It's good for the utility. It's good to increase grid reliability."
Tom Content, executive director of the Citizens Utility Board, agreed the project is a significant step forward for utilities.
"Certainly, having the ability to back up storage so that the power is available after the sun stops shining or if there's a sudden cloud burst and you can call on that battery right away, that's the future of the energy system," said Content.
Content said whether battery storage is cost-effective will be a question the PSC will have to consider as part of the proposal. In the meantime, he continues to work with utilities on ways customers can avoid being forced to pay twice as companies seek to recover costs from investments in coal plants that are no longer being used while building new projects.
If approved by regulators, construction would begin in 2022. The park would become operational by 2023.