Michigan Compiled Laws, Chapter 460. Public Utilities § 460.505

Sec. 5. In determining the question of public convenience and necessity the commission shall take into consideration the service being rendered by the utility then serving such territory, the investment in such utility, the benefit, if any, to the public in the matter of rates and such other matters as shall be proper and equitable in determining whether or not public convenience and necessity requires the applying utility to serve the territory. Every certificate of public convenience and necessity issued by the commission, under the authority hereby granted, shall describe in detail the territory in which said applicant shall operate and it shall not operate in or serve any other territory under the authority of said certificate.