Tennessee Code Title 6. Cities and Towns § 6-54-109

(1) Any corporation chartered or authorized to build or operate, or operating, a street railway, whether by steam, electricity, or otherwise;

(2) Any corporation chartered or authorized to manufacture or furnish, or furnishing gas, electricity, or other substance for the lighting of the streets or public places of any town or city, or for the use or consumption by the inhabitants of such town or city; or

(3) Any corporation chartered or authorized to supply, or supplying, any town or city or the inhabitants thereof with water;

to acquire the franchises or property of any similar corporation carrying on its operations with any city or town, or partly in such city or town and in the territory adjacent to same, by consolidation, purchase, lease or other mode, except only by and with the permission and consent, expressed officially in writing, of the municipal government of the city or town in which the corporation whose franchises or property is being acquired carries on its business, wholly or in part, and then only upon such terms and conditions as the municipal government may prescribe; provided, that such terms and conditions shall not violate any law.