Alliant Energy has reached a deal with consumer and environmental advocates to raise gas and electricity rates next year as the utility begins phasing out its coal fleet. If approved by regulators, the new rates would add about $8.50 a month to the typical residential electricity bill and about $5 a month to the average gas bill. Electric rates would not change in 2023, though there could be an adjustment to gas costs.

Alliant says the rate hike is needed to cover the cost of investing nearly $1 billion in solar generation to replace two coal-fired plants, a plan the company projects will save up to $2 billion over the next four decades. While its 475,000 ratepayers will be asked to pay off the remaining $500 million balance on the Edgewater coal plant in Sheboygan, scheduled to close next year, debt restructuring will slightly lower the company's profit on that investment.