The northern Indiana utility NIPSCO has refined its long-term plans to be mostly powered by renewable energy in the next 20 years.

The northern Indiana utility NIPSCO plans to remove coal ash from five ponds at its Michigan City Generating Station which will close by 2028, but will keep a legacy coal ash pond in place as well as coal ash fill on the site.

Indiana Department of Environmental Management sent letters to utilities in December noting that it can't give approval until utilities show how the plans will control contamination.