Michigan's Attorney General is opposing the sale of the Palisades nuclear plant, near South Haven.
Mike Cox says if the sale does not go through, ratepayers would have to pay at least $62 million more for electricity.
He is also questioning whether the sale would deplete funding needed to decommission the plant and pay for cleanup.
A New Orleans-based utility holding company wants to buy Palisades Nuclear for $380 million.
It is currently owned by CMS Energy out of Jackson.