(a) Emission specifications. No person shall allow the discharge into the atmosphere nitrogen oxides (NOX ) emissions in excess of the following emission specifications, in accordance with the applicable schedule in §117.9010 of this title (relating to Compliance Schedule for Bexar County Ozone Nonattainment Area Major Sources), except as provided in subsection (c) of this section:
  (1) stationary gas turbines, 0.55 pound per million British thermal unit (lb/MMBtu);
  (2) duct burners used in turbine exhaust ducts, 0.55 lb/MMBtu; and
  (3) gas-fired lean-burn stationary reciprocating internal combustion engines, 0.5 gram per horsepower-hour.
(b) NOX averaging time. The emission specifications in subsection (a) of this section apply on:
  (1) a block one-hour average, in the units of the applicable standard; or
  (2) if the unit is operated with a NOX continuous emissions monitoring system (CEMS) or predictive emissions monitoring system (PEMS) under §117.240 of this title (relating to Continuous Demonstration of Compliance), a rolling 30-day average, in the units of the applicable standard.
(c) Compliance flexibility. An owner or operator may use §117.9800 of this title (relating to Use of Emission Credits for Compliance) to comply with the NOX emission specifications of this section.
(d) Prohibition of circumvention.
  (1) The maximum rated capacity used to determine the applicability of the emission specifications in this section and the initial compliance demonstration, monitoring, testing requirements, and control plan requirements in §§117.235, 117.240, and 117.252 of this title (relating to Initial Demonstration of Compliance; Continuous Demonstration of Compliance; and Control Plan Procedures for Reasonably Available Control Technology) must be the greater of the following:
    (A) the maximum rated capacity as of December 31, 2019;
    (B) the maximum rated capacity after December 31, 2019; or
    (C) the maximum rated capacity authorized by a permit issued under Chapter 116 of this title (relating to Control of Air Pollution by Permits for New Construction or Modification) after December 31, 2019.
  (2) A unit's classification is determined by the most specific classification applicable to the unit as of December 31, 2019. For example, a unit that is classified as a gas-fired lean-burn stationary reciprocating internal combustion engine as of December 31, 2019, but subsequently is authorized to operate as a dual-fuel engine, is classified as a gas-fired lean-burn stationary reciprocating internal combustion engine for the purposes of this chapter.
  (3) A source that met the definition of major source on December 31, 2019, is always classified as a major source for purposes of this chapter. A source that did not meet the definition of major source (i.e., was a minor source, or did not yet exist) on December 31, 2019, but becomes a major source at any time after December 31, 2019, is from that time forward always classified as a major source for purposes of this chapter.

Source Note: The provisions of this §117.205 adopted to be effective May 16, 2024, 49 TexReg 3347