(a) This section applies only to an electric utility that operates solely outside of ERCOT.
(b) In establishing the base rates of the electric utility under this subchapter or Subchapter D, the regulatory authority shall determine the utility’s revenue requirement based on, at the election of the utility:
(1) information submitted for a test year; or
(2) information submitted for a test year, updated to include information that reflects the most current actual or estimated information regarding increases and decreases in the utility’s cost of service, including expenses, capital investment, cost of capital, and sales.

(c) An electric utility that elects to provide updated information under Subsection (b)(2) must provide the information for a period ending not later than the 30th day before the date the applicable rate proceeding is filed.
(d) An electric utility that includes estimated information in the initial filing of a proceeding shall supplement the filing with actual information not later than the 45th day after the date the initial filing was made. The regulatory authority shall extend the deadline for concluding the rate proceeding for a period of time equal to the period between the date the initial filing of the proceeding was made and the date of the supplemental filing, except that the extension period may not exceed 45 days.
(e) An electric utility that makes an election under Subsection (b) is not precluded from proposing known and measurable adjustments to the utility’s historical rate information as permitted by this title and regulatory authority rules.
(f) Without limiting the availability of known and measurable adjustments described by Subsection (e), the regulatory authority shall allow an affected electric utility to make a known and measurable adjustment to include in the utility’s rates the prudent capital investment, a reasonable return on such capital investment, depreciation expense, reasonable and necessary operating expenses, and all attendant impacts, including any offsetting revenue, as determined by the regulatory authority, associated with a newly constructed or acquired natural gas-fired generation facility. The regulatory authority is required to allow the adjustment only if the facility is in service before the effective date of new rates. The adjustment may be made regardless of whether the investment is less than 10 percent of the utility’s rate base before the date of the adjustment.
(g) This section expires September 1, 2031.

For expiration of this section, see Subsection (g).
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