The provisions of this section apply separately for calculating emission credits for NOX, NOX + NMHC, or PM.

(a) [Reserved]

(b) For each participating family, calculate positive or negative emission credits relative to the otherwise applicable emission standard. Calculate positive emission credits for a family that has an FEL below the standard. Calculate negative emission credits for a family that has an FEL above the standard. Sum your positive and negative credits for the model year before rounding. Round the sum of emission credits to the nearest kilogram (kg), using consistent units throughout the following equation:

Emission credits (kg) = (Std−FEL) · Volume · AvgPR · UL · 10− 3 Eq. 1039.705-1 Where: Std = the emission standard, in grams per kilowatt-hour, that applies under subpart B of this part for engines not participating in the ABT program of this subpart (the “otherwise applicable standard”). FEL = the family emission limit for the engine family, in grams per kilowatt-hour. Volume = the number of engines eligible to participate in the averaging, banking, and trading program within the given engine family during the model year, as described in paragraph (c) of this section. AvgPR = the average value of maximum engine power values for the engine configurations within an engine family, calculated on a sales-weighted basis, in kilowatts. UL = the useful life for the given engine family, in hours.

(c) As described in § 1039.730, compliance with the requirements of this subpart is determined at the end of the model year based on actual U.S.-directed production volumes. Do not include any of the following engines to calculate emission credits:

(1) Engines with a permanent exemption under subpart G of this part or under 40 CFR part 1068.

(2) Exported engines.

(3) Engines not subject to the requirements of this part, such as those excluded under § 1039.5.

(4) Engines in families that include only stationary engines, except for engines in families certified to standards that are identical to standards applicable under this part 1039 to nonroad engines of the same type for the same model year.

(5) Any other engines, where we indicate elsewhere in this part 1039 that they are not to be included in the calculations of this subpart.

[69 FR 39213, June 29, 2004, as amended at 71 FR 39185, July 11, 2006; 72 FR 53133, Sept. 18, 2007; 75 FR 22992, Apr. 30, 2010; 81 FR 74139, Oct. 25, 2016; 89 FR 29794, Apr. 22, 2024]