It's the third consecutive year that the Michigan Public Service Commission has asked for a five-year assessment. Chairman Sally Talberg says the information is important because regulators must ensure there are sources of electricity to meet demand.
She says there have been "unprecedented power plant retirements" in Michigan and the region.
Public comment on the utility reports must be filed by May 12. The Public Service Commission wants its staff to file a report reviewing the data by June 30.