Tenn. Code Ann. § 65-4-107: Approval of privilege or franchise

(a) No privilege or franchise hereafter granted to any public utility by the state or by any political subdivision of the state shall be valid until approved by the commission, such approval to be given when, after hearing, the commission determines that such privilege or franchise is necessary and proper for the public convenience and properly conserves the public interest, and the commission shall have power, if it so approves, to impose such conditions as to construction, equipment, maintenance, service or operation as the public convenience and interest may reasonably require; provided, however, that nothing contained in this chapter shall be construed as applying to the laying of sidings, sidetracks, or switchouts, by any public utility, and it shall not be necessary for any such public utility to obtain a certificate of convenience from the commission for such purpose.

(b) All terms, conditions, obligations, and rights of a privilege or franchise approved by the commission for the provision of natural gas service shall remain in effect until approval of a subsequent privilege or franchise by the commission.