Miss. Code Ann. § 77-5-257: TVA jurisdiction.

It is hereby recognized that certain corporations formed or operating under this article have entered into contracts with the Tennessee Valley Authority for the purchase of wholesale electric power and that the operations, facilities, services and rates of such corporations are thereby subject to extensive regulation by the Tennessee Valley Authority. In order to avoid the inefficiencies and confusion caused by duplicative, overlapping and conflicting jurisdiction and regulations, it is hereby declared that the Mississippi Public Service Commission and political subdivisions of the state shall not have jurisdiction over and shall not regulate those portions or aspects of a corporation’s operations, facilities, services, or rates that are regulated by the Tennessee Valley Authority. In the event of a dispute between the Mississippi Public Service Commission (commission) and the Tennessee Valley Authority (TVA) over the existence or scope of TVA’s regulatory authority, the commission shall defer to TVA’s asserted authority unless and until the commission has obtained a favorable, final, and nonappealable declaratory judgment against TVA in a court of competent jurisdiction. In any such suit, the commission shall not force a corporation(s) to incur legal fees and expenses by naming them as a party, though a corporation shall maintain the right to seek voluntary intervention under the rules of the court in which the action is pending.