(a) Reasonably Available Control Technology (RACT) emission specifications for wood-fired boilers. For units located in the Dallas-Fort Worth eight-hour ozone nonattainment area, no person shall allow the discharge into the atmosphere nitrogen oxides (NOX ) emissions in excess of 0.12 pounds per million British thermal units (lb/MMBtu) for wood-fired boilers, in accordance with the applicable schedule in §117.9030(a) of this title (relating to Compliance Schedule for Dallas-Fort Worth Eight-Hour Ozone Nonattainment Area Major Sources), except as provided in subsection (e) of this section.
(b) Emission specifications for RACT in Wise County. For units located in Wise County, no person shall allow the discharge into the atmosphere NOX emissions in excess of the following emission specifications, in accordance with the applicable schedule in §117.9030(a) of this title, except as provided in subsection (e) of this section:
  (1) process heaters with a maximum rated capacity equal to or greater than 40 million British thermal units per hour (MMBtu/hr), 0.10 lb/MMBtu (or alternatively, 82 parts per million by volume (ppmv), at 3.0% oxygen (O2), dry basis);
  (2) stationary, reciprocating internal combustion engines:
    (A) gas-fired rich-burn engines, 0.50 grams per horsepower-hour (g/hp-hr); and
    (B) gas-fired lean-burn engines:
      (i) White Superior four-cycle units that have been placed into service, modified, reconstructed, or relocated:
        (I) before June 1, 2015, 12.0 g/hp-hr; and
        (II) on or after June 1, 2015, 2.0 g/hp-hr;
      (ii) Clark two-cycle units that have been placed into service, modified, reconstructed, or relocated:
        (I) before June 1, 2015, 12.0 g/hp-hr; and
        (II) on or after June 1, 2015, 2.0 g/hp-hr;
      (iii) Fairbanks Morse MEP two-cycle units that have been placed into service, modified, reconstructed, or relocated:
        (I) before June 1, 2015, 4.0 g/hp-hr; and
        (II) on or after June 1, 2015, 2.0 g/hp-hr; and
      (iv) all others, 2.0 g/hp-hr; and
  (3) stationary gas turbines:
    (A) with a horsepower (hp) rating of less than 10,000 hp, 0.55 lb/MMBtu; and
    (B) with a hp rating of 10,000 hp or greater, 0.15 lb/MMBtu.
(c) NOX averaging time. The emission specifications of subsections (a) and (b) of this section apply:
  (1) if the unit is operated with a NOX continuous emissions monitoring system (CEMS) or predictive emissions monitoring system (PEMS) under §117.440 of this title (relating to Continuous Demonstration of Compliance), either as:
    (A) a rolling 30-day average, in the units of the applicable standard;
    (B) a block one-hour average, in the units of the applicable standard, or alternatively;
    (C) a block one-hour average, in pounds per hour, for boilers and process heaters, calculated as the product of the boiler's or process heater's maximum rated capacity and its applicable specification in lb/MMBtu; and
  (2) if the unit is not operated with a NOX CEMS or PEMS under §117.440 of this title, a block one-hour average, in the units of the applicable standard. Alternatively for boilers and process heaters, the emission specification may be applied in pounds per hour, as specified in paragraph (1)(C) of this subsection.
(d) Related emissions. No person shall allow the discharge into the atmosphere from any unit subject to NOX emission specifications in subsection (a) or (b) of this section, emissions in excess of the following, except as provided in §117.425 of this title (relating to Alternative Case Specific Specifications) or paragraph (3) of this subsection.
  (1) Carbon monoxide (CO) emissions must not exceed 400 ppmv at 3.0% O2, dry basis (or alternatively, 3.0 g/hp-hr for stationary internal combustion engines; or 775 ppmv at 7.0% O2, dry basis for wood fuel-fired boilers or process heaters):
    (A) on a rolling 24-hour averaging period, for units equipped with CEMS or PEMS for CO; and
    (B) on a block one-hour averaging period, for units not equipped with CEMS or PEMS for CO.
  (2) For units that inject urea or ammonia into the exhaust stream for NOX control, ammonia emissions must not exceed 10 ppmv at 3.0% O2, dry, for boilers and process heaters; 15% O2, dry, for stationary gas turbines and gas-fired lean-burn engines; and 3.0% O2, dry, for all other units, based on:
    (A) a block one-hour averaging period for units not equipped with a CEMS or PEMS for ammonia; and
    (B) a rolling 24-hour averaging period for units equipped with CEMS or PEMS for ammonia.
  (3) The correction of CO emissions to 3.0% O2, dry basis, in paragraph (1) of this subsection does not apply to boilers and process heaters operating at less than 10% of maximum load and with stack O2 in excess of 15% (i.e., hot-standby mode).
(e) Compliance flexibility.
  (1) An owner or operator may use any of the following alternative methods to comply with the NOX emission specifications of this section:
    (A) §117.423 of this title (relating to Source Cap); or
    (B) §117.9800 of this title (relating to Use of Emission Credits for Compliance).
  (2) Section 117.425 of this title is not an applicable method of compliance with the NOX emission specifications of this section.
  (3) An owner or operator may petition the executive director for an alternative to the CO or ammonia specifications of this section in accordance with §117.425 of this title.
(f) 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 final control plan in §§117.435, 117.440, and 117.452 of this title (relating to Initial Demonstration of Compliance; Continuous Demonstration of Compliance; and Final Control Plan Procedures for Reasonably Available Control Technology) must be the greater of the following:
    (A) the maximum rated capacity as of December 31, 2012;
    (B) the maximum rated capacity after December 31, 2012; 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, 2012.
  (2) A unit's classification is determined by the most specific classification applicable to the unit as of December 31, 2012. For example, a unit that is classified as a stationary gas-fired engine as of December 31, 2012, but subsequently is authorized to operate as a dual-fuel engine, is classified as a stationary gas-fired engine for the purposes of this chapter.
  (3) A source that met the definition of major source on December 31, 2012, 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, 2012, but becomes a major source at any time after December 31, 2012, is from that time forward always classified as a major source for purposes of this chapter.

Source Note: The provisions of this §117.405 adopted to be effective June 25, 2015, 40 TexReg 3965