Mich. Comp. Laws § 486.352

Sec. 2. Any company or corporation heretofore organized and doing business under and by virtue of the general laws of this state, and operating a waterworks system in any city, town or village in this state, the population whereof shall not exceed 25,000 inhabitants, according to the last official census preceding the filing of its amended articles of association so as to show the added purpose, have the right to erect, purchase, own and operate a plant or plants, in addition to its waterworks system and plant, to produce and supply electricity as mentioned in section 1 hereof.