Q580. For glycol dehydrators with annual average daily natural gas throughputs greater than 0 million standard cubic feet (MMscf) per day and less than 0.4 MMscf per day, can GRI-GLYCalc be used instead of Method 2 in 40 CFR 98.233(e)(2)?

A580.  The rule as amended on May 14, 2024, specifies that beginning with Reporting Year (RY) 2024, emissions from glycol dehydrators with annual average daily natural gas throughputs greater than 0 MMscf per day and less than 0.4 MMscf per day are to be reported using the requirements of either 40 CFR 98.233(e)(1), Calculation Methodology 1 (engineering calculations using simulation software), or 40 CFR 98.233(e)(2), Calculation Methodology 2 (default population-based emission factor). The rule prior to the amendments that applies for reporting years prior to RY 2024 requires the use of only Calculation Method 2 for glycol dehydrators with natural gas throughputs less than 0.4 MMscf per day. Note that the rule prior to the amendments did not explicitly exclude dehydrators with zero throughput from Calculation Methodology 2, but the EPA’s intent was that only dehydrators with throughput are subject to reporting