Mich. Comp. Laws § 124.4

Sec. 4. Nothing contained in this act shall be construed to grant the right to jointly own or operate a public utility for supplying transportation, gas, light, telephone service, or electric power except as may be provided by the statutes or constitution of the state of Michigan, nor to contract to furnish municipal services outside corporate limits except in accordance with the constitutional limitations on such sales. Nothing contained in this act shall be construed as to grant to municipal corporations acting jointly any power or authority which they do not have acting singly.