(a) Notwithstanding any other provision of this title, each municipally owned utility, electric cooperative, or electric utility in an area where customer choice is not available or the commission has delayed the implementation of full customer choice in accordance with § 39.103 shall discount charges for electric service provided to a military base.
(b) The discount under Subsection (a) is a 20 percent reduction of the base commercial rate that the municipally owned utility, electric cooperative, or electric utility would otherwise charge the military installation.

(c) An electric utility, municipally owned utility, or electric cooperative may assess a surcharge to all of the utility’s retail customers in the state to recover the difference in revenue between the revenues from the discounted rate for military bases provided under Subsection (a) and the base commercial rate. This subsection does not apply to an electric utility, municipally owned utility, or electric cooperative that was providing electric service to a military base on December 31, 2002, at a rate constituting a discount of 20 percent or more from the utility’s base commercial rate that the utility would otherwise charge the military base.
(d) Each electric utility shall file a tariff with the commission reflecting the discount required by Subsection (a) and may file a tariff reflecting the surcharge provided by Subsection (c). Not later than the 30th day after the date the commission receives the electric utility’s tariff reflecting the surcharge, the commission shall approve the tariff. A proceeding under this subsection is not a rate change for purposes of Subchapter C.
(e) An electric utility, municipally owned utility, or electric cooperative is exempt from the requirements of Subsection (a) if:
(1) the 20 percent discount would result in a reduction of revenue in an amount that is greater than one percent of the utility’s total annual revenues; or
(2) the utility:
(A) was providing electric service to a military base on December 31, 2002, at a rate constituting a discount of 20 percent or more from the utility’s base commercial rate that the utility would otherwise charge the military base; and
(B) continues to provide electric service to the military base at a rate constituting a discount of 20 percent or more from the utility’s base commercial rate that the utility would otherwise charge the military base.
(f) Each electric utility shall provide the Texas Military Preparedness Commission with the base commercial rate that the utility would otherwise charge the military base and the rate the utility is charging the military base.
(g) For the purposes of this section, the term “military base” does not include a military base:
(1) that has been closed or realigned under the Defense Base Closure and Realignment Act of 1990 (10 U.S.C. § 2687) and its subsequent amendments;
(2) that is administered by an authority established by a municipality under Chapter 379B, Local Government Code;
(3) that is operated by or for the benefit of the Texas National Guard, as defined by § 437.001, Government Code, unless the base is served by a municipally owned utility owned by a city with a population of 900,000 or more; or
(4) for which a municipally owned utility has acquired the electric distribution system under 10 U.S.C. § 2688.