Figure: 30 TAC §117.123(b)(1)

Where:

Cap_30day        =          the NO_X 30-day rolling average emission cap in pounds per day;

i                    =          each emission unit in the emission cap;

N                    =          the total number of emission units in the emission cap;

H_i                   =     (A)  for compliance with §117.105(a) - (d) of this title.  The actual historical average of the daily heat input for each unit included in the source cap, in million British thermal units per day (MMBtu/day), as certified to the executive director, for a 24 consecutive month period between January 1, 1990, and June 9, 1993, plus one standard deviation of the average daily heat input for that period.  All sources included in the source cap must use the same 24 consecutive month period.  If sufficient historical data are not available for this calculation, the executive director may approve another method for calculating H_i; and

                              (B)  for compliance with §117.105(e) or §117.110 of this title.  The actual historical average of the daily heat input for each unit included in the source cap, in MMBtu/day, as certified to the executive director, for a 24 consecutive month period between January 1, 1997, and December 31, 1999.  All sources included in the source cap must use the same 24 consecutive month period.  If sufficient historical data are not available for this calculation, the executive director and United States Environmental Protection Agency may approve another method for calculating H_i.  For sources complying with the lean-burn engine emission specifications in §117.105(e) of this title, the owner or operator may combine the source cap with sources complying with §117.105(a) - (d) of this title, using the 1997 - 1999 heat input baseline described earlier for the sources complying with §117.105(a) - (d) of this title; and

R_i                    =          (A)  for compliance with §117.105(a) - (d) of this title.

                              (i)  for emission units subject to the federal New Source Review requirements of 40 Code of Federal Regulations (CFR) §§51.165(a), 51.166, or 52.21, or to the requirements of Chapter 116 of this title (relating to Control of Air Pollution by Permits for New Construction or Modification) that implements these federal requirements, or emission units that have been subject to a New Source Performance Standard requirement of 40 CFR Part 60 prior to June 9, 1993, R_i is the lowest of the actual emission rate or all applicable federally enforceable NO_X emission limitations as of June 9, 1993, in pounds per million British thermal units (lb/MMBtu), that apply to emission unit i in the absence of trading.  All calculations of emission rates must presume that emission controls in effect on June 9, 1993, are in effect for the two-year period used in calculating the actual heat input; and

                              (ii)  for all other emission units, R_i is the lowest of the reasonably available control technology (RACT) limit of §117.105(b) - (d) or §117.115(f) of this title or the best available control technology NO_X limit for any unit subject to a permit issued in accordance with Chapter 116 of this title, in lb/MMBtu, that applies to emission unit i in the absence of trading; and

          (B)  for compliance with §117.105(e) or §117.110 of this title, the lowest of:

                                    (i)  the appropriate specification of §§117.105(e), 117.110, or 117.115(f) of this title;

                                    (ii)  any permit NO_X emission limit for any unit subject to a permit issued in accordance with Chapter 116 of this title, in lb/MMBtu, that applies to emission unit i in the absence of trading, in effect on September 10, 1993; and

                                    (iii)  the actual emission rate as of the dates specified in clause (ii) of this figure.  All calculations of emission rates must presume that emission controls in effect on the dates specified in clause (ii) of this figure are in effect for the two-year period used in calculating the actual heat input.