The company, which is already planning a 200-megawatt wind farm in Minnesota, will also buy 200 megawatts of wind power from NextEra Energy, utility spokesman Rob Crain said.
Under the deal, Alliant has also bought the development rights to a future 160-megawatt wind farm in the Green Lake area.
But in order for the deal to go forward, Wisconsin regulators must approve the Bent Tree wind farm in Minnesota, projected to cost $400 million to $450 million, Crain said.
The agreement comes as the utility company prepares for stiffer renewable energy mandates from the state Legislature and reacts to the state Public Service Commission decision last year to deny its bid to build a new coal-fired power plant in southwest Wisconsin.
The PSC expressed concern over carbon, and we listened, Crain said. While Bent Tree was already part of our plan, certainly some of the pieces that weve been able to come forward with here as part of this partnership lay the foundation for Plan B in Wisconsin.
The agreement ends NextEra's opposition to its Minnesota wind farm, and NextEra has withdrawn its involvement in that case, a company lawyer said in a filing. Terms of the deal were filed in a confidential document submitted with state regulators.