(a) Unless the utility commission establishes alternate rate methodologies in accordance with § 13.183(c), the utility commission may not prescribe any rate that will yield more than a fair return on the invested capital used and useful in rendering service to the public. The governing body of a municipality exercising its original jurisdiction over rates and services may use alternate ratemaking methodologies established by ordinance or by utility commission rule in accordance with § 13.183(c). Unless the municipal regulatory authority uses alternate ratemaking methodologies established by ordinance or by utility commission rule in accordance with § 13.183(c), it may not prescribe any rate that will yield more than a fair return on the invested capital used and useful in rendering service to the public.
(b) In fixing a reasonable return on invested capital, the regulatory authority shall consider, in addition to other applicable factors, the efforts and achievements of the utility in the conservation of resources, the quality of the utility’s services, the efficiency of the utility’s operations, and the quality of the utility’s management.

(c) In any proceeding involving any proposed change of rates, the burden of proof shall be on the utility to show that the proposed change, if proposed by the utility, or that the existing rate, if it is proposed to reduce the rate, is just and reasonable.