Tennessee Code Title 65. Public Utilities and Carriers § 65-2-122

(a) The commission may establish optional services that may be purchased by regulated entities or other unregulated service providers, which are related to the exercise, administration or enforcement of jurisdiction delegated to the commission by state or federal law.

(b) The establishment of charges for services described in subsection (a) shall be cost-based.

(c) No charge for services as established in this section shall be applied to any party that does not expressly elect to use such services, and no party shall be required to elect to use such optional services as a condition of initiating any case before the commission.