Tex. Tax Code § 11.315

(a) In this section, "energy storage system" means a device capable of storing energy to be discharged at a later time, including a chemical, mechanical, or thermal storage device.

(b) A person is entitled to an exemption from taxation by a taxing unit of an energy storage system owned by the person if:

(1) the exemption is adopted by the governing body of the taxing unit in the manner provided by law for official action by the governing body; and

(2) the energy storage system:

(A) is used, constructed, acquired, or installed wholly or partly to meet or exceed 40 C.F.R. Section 50.11 or any other rules or regulations adopted by any environmental protection agency of the United States, this state, or a political subdivision of this state for the prevention, monitoring, control, or reduction of air pollution;

(B) is located in:

(i) an area designated as a nonattainment area within the meaning of Section 107(d) of the federal Clean Air Act (42 U.S.C. Section 7407); and

(ii) a municipality with a population of at least 150,000 adjacent to a municipality with a population of more than two million;

(C) has a capacity of at least 10 megawatts; and

(D) is installed on or after January 1, 2014.

(c) Once authorized, an exemption adopted under this section may be repealed by the governing body of a taxing unit in the manner provided by law for official action by the governing body.