Wisconsin utility Alliant Energy will spend $900 million buying 675 megawatts of utility-scale solar projects as it moves to replace uneconomic coal-fired plants with renewables.  

Alliant, which serves about 1 million customers in the Midwestern states of Wisconsin and Iowa, currently relies on renewables for about 20 percent of its generation capacity, largely wind power in Iowa, with twice as much coming from natural gas plants. 

On Tuesday Alliant said it will "acquire" six large-scale solar projects in Wisconsin from developers NextEra Energy Resources, Ranger Power and Savion, with about 35 to 40 percent of the $900 milllion investment to be raised by tax equity partners and the remainder from its Wisconsin utility. The projects, ranging from 50 megawatts up to a 200-megawatt development owned by NextEra, represent a huge leap forward for Wisconsin's solar market. The state has around 150 megawatts of installed solar today, according to Wood Mackenzie Power & Renewables.

Alliant’s solar news comes just days after it announced plans to close the remaining 380-megawatt unit of its coal-fired Edgewater Generating Station in Sheboygan by the end of 2022, a move it said will save customers “hundreds of millions of dollars in costs.” Alliant subsidiary Wisconsin Power and Light closed two other, older units at Edgewood over the past five years. 

A recent Sierra Club report found that Alliant’s Edgewater and Columbia coal plants cost ratepayers $16 million in 2019 through money-losing power sales at higher-than-market prices and could cost an additional $461 million if left operating through 2030. The environmental group is demanding that Alliant close its 1,053-megawatt Columbia plant by 2026, and replace it with clean energy alternatives. 

In 2019 Alliant established its "Clean Energy Blueprint," which aims for 30 percent renewables by 2030 on the way to an 80 percent carbon emissions cut by 2050. The blueprint includes a goal of 1 gigawatt of solar by 2023, as well as an accelerated closure of the coal plants that still made up 30 percent of its generation as of last year. 

Alliant is hoping to win regulatory approval for its solar acquisitions in the first half of 2021. 

Most Midwestern states are not known for their solar markets, but utilities across the region are increasingly staking out clean energy and decarbonization plans that move beyond onshore wind and embrace large-scale solar. Over the past few years, the active interconnection queue for Midwestern grid operator MISO has steadily shifted from wind to solar as its primary renewable resource. According to a May 2020 report from MISO, of the 68 gigawatts of projects seeking interconnection, 40.6 megawatts are solar projects.

MISO's interconnection queue has shifted sharply from wind toward solar. (Credit: MISO)

Xcel Energy, which serves Wisconsin, Colorado and smaller portions of six other states in the Midwest, is targeting 80 percent clean energy by 2030 and 100 percent clean energy by 2050. In 2018 Xcel signed large-scale wind, solar, and energy storage contracts to allow it to move ahead with early retirement plans for coal power plants in Minnesota and Colorado

Meanwhile, Northern Indiana Public Service Company (Nipsco) put out a request for proposals seeking 2.3 gigawatts of solar or solar-plus-storage to aid in its tentative plan to retire its Indiana coal fleet by 2030.

And in Michigan, utility Consumers Power is pledging to procure 5 gigawatts of solar by 2030 as part of a plan to cut carbon emissions by 90 percent and phase out all of its coal-fired power by 2040.

Unlike Xcel, Alliant has yet to invest in large-scale battery projects to allow it to store and shift its intermittent wind and solar power to provide energy to meet peak demand. It has built a 30-kilowatt-hour battery demonstration project paired with solar and electrical vehicle charging systems at its Madison headquarters, and a 42-kilowatt-hour battery system as part of a solar-backed microgrid project in Sauk City, Wisconsin.