(AREA) — DTE Energy Co. plans to shut down eight coal-fired units at three power plants in Michigan within the next seven years. The Detroit-based utility announced Wednesday the units being retired between 2020 and 2023 are at the River Rouge facility in the Detroit area, the St. Clair facility in St. Clair County’s East China Township and the Trenton facility in suburban Detroit. DTE says the plants together generated about 25 percent of electricity produced by the utility in 2015 or enough to power 900,000 homes. Earlier this year, DTE retired three coal generating units due to age and projected future costs. The utility says it will replace coal generating units with a mix of newer, more modern and cleaner sources of energy such as wind, natural gas and solar power.