Mich. Comp. Laws § 460.1177

Sec. 177. (1) An electric meter provided by a utility must be used to determine the amount of the customer's inflow and outflow electricity in each pricing period. Eligible customers shall pay only the incremental cost above that for meters provided by the electric utility to similarly situated, nongenerating customers. (2) A distributed generation customer shall be credited by the customer's supplier of electric generation service for the outflow during the billing period. The credit must appear on the bill for the following billing period and be limited to the total charges on that bill. Any excess bill credits not used to offset inflow charges in the next billing period will be carried forward to subsequent billing periods.