Among its myriad rules, the U.S. Environmental Protection Agency’s (EPA) Subpart W in its Greenhouse Gas Reporting Program (GHGRP) presents extra-persnickety details regarding federal emissions reporting for upstream and midstream operators.

Under Subpart W, which contains a threshold of 25,000 metric tons per year of CO2--not to be exceeded--gathering and boosting and gas transmission become more complex designations.

Subpart W is one of 29 subparts to the GHGRP. The final rule for the petroleum and natural gas systems category of the GHGRP became effective Jan. 1.

According to Vasco Roma, project leader at All4 Inc., an air quality/environmental consulting firm that hosted a recent webinar covering common reporting mistakes with the subpart, Subpart W previously only concerned itself with “production, processing and transmission compression.” But it now governs gathering and boosting, and gas transmission.

A struggle over how to define gathering/boosting and transmission lines partly drove the original exclusion of these categories. Roma noted that now, under Subpart W, gathering/boosting and transmission lines—and other facilities—are considered “their own separate facility and individually compared to the [threshold].”

Reporting of emissions from gathering/boosting and transmission lines will be due for the first time in the upcoming reporting period, Roma said, noting that the categories were added to the rule beginning with the current reporting year of 2016.

Onshore gas processing at either fractionation plants or non-fractionation plants—the latter handling less than 25 million standard cubic feet per day—involves separation of NGL or non-methane gases from natural gas.

The gas that is processed comes from production facilities, which under Subpart W, “end at the point where streams from more than one wellpad are combined,” which can be at a processing area, Roma said.

Roma said operators must evaluate equipment for each segment separately, compare it to the reporting threshold separately and prepare reports for each so-called facility separately.

He said that to his knowledge, the EPA did not levy fines for mistakes in reporting under Subpart W, but added that it is not uncommon for companies to receive comments from the EPA “indicating that reported data falls outside the expected range,” and be expected to verify that data.

Operators can prevent having to double back and recheck where their data falls if they pay attention to:

  • How their equipment is classified on an equipment-by-equipment basis;
  • Determining whether significant changes are explainable, checking to see if data exceed permit limits, and comparing data to those of peers;
  • The composition of natural gas—how much is CO2 and how much is methane? The latter, Roma said, has a higher impact on global warming, so operators must ensure the data are correct; and
  • Using actual vs. potential emissions. According to Kaitlyn Bencosme, project engineer at All4, using actual operating data is beneficial if facilities are close to the threshold. Emissions estimates are more accurate and there are fewer reported emissions. The disadvantage to actual operating data is the time and cost to gather it, she said.

Roma said that Subpart W is “a fairly technical aspect of the regulation and not something that is expected to be high on the priority list” of the new leaders at the agency and in the White House.

In recent weeks, the EPA also said it would begin dismantling the Waters of the U.S. rule, the Clean Power Plan and the U.S. Methane rule, and the agency withdrew its mandate requiring industry producers to report their emissions.

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Erin Pedigo can be reached at epedigo@hartenergy.com.