Section 76.6 - NO[X] emission limitations for Group 2 boilers(a) Beginning January 1, 2000 or, for a unit subject to section 409(b) of the Act, the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2, the owner or operator of a Group 2, coal-fired boiler with a cell burner boiler, cyclone boiler, a wet bottom boiler, or a vertically fired boiler shall not discharge, or allow to be discharged, emissions of NOX to the atmosphere in excess of the following limits, except as provided in §§ 76.10 or 76.11 : (1) 0.68 lb/mmBtu of heat input on an annual average basis for cell burner boilers. The NOX emission control technology on which the emission limitation is based is plug-in combustion controls or non-plug-in combustion controls. Except as provided in § 76.5(d) , the owner or operator of a unit with a cell burner boiler that installs non-plug-in combustion controls shall comply with the emission limitation applicable to cell burner boilers.(2) 0.86 lb/mmBtu of heat input on an annual average basis for cyclone boilers with a Maximum Continuous Steam Flow at 100% of Load of greater than 1060, in thousands of lb/hr. The NOX emission control technology on which the emission limitation is based is natural gas reburning or selective catalytic reduction.(3) 0.84 lb/mmBtu of heat input on an annual average basis for wet bottom boilers, with a Maximum Continuous Steam Flow at 100% of Load of greater than 450, in thousands of lb/hr. The NOX emission control technology on which the emission limitation is based is natural gas reburning or selective catalytic reduction.(4) 0.80 lb/mmBtu of heat input on an annual average basis for vertically fired boilers. The NOX emission control technology on which the emission limitation is based is combustion controls.(b) The owner or operator shall determine the annual average NOX emission rate, in lb/mmBtu, using the methods and procedures specified in part 75 of this chapter.62 FR 67162, Dec. 19, 1996; 62 FR 3464, Jan. 23, 1997; 62 FR 32040, June 12, 1997; 64 FR 55838, Oct. 15, 1999