Q737. What is the quality of the petroleum and natural gas systems data?

A737. EPA has a multi-step data verification process, including automatic checks during data-entry, statistical analyses on completed reports, and staff review of the reported data. Based on the results of the verification process, EPA follows up with facilities to resolve any mistakes that may have occurred. Because this process is still ongoing, the data currently presented is preliminary. In addition, because of the nature of the petroleum and natural gas industry, there can be wide variation in emissions from facility to facility.

In order to provide facilities with time to adjust to the requirements of the GHGRP, EPA made available the optional use of Best Available Monitoring Methods (BAMM) for unique or unusual circumstances. Where a facility used BAMM, it was required to follow emission calculations specified by the EPA, but was allowed to use alternative methods for determining inputs to calculate emissions. In 2011, all facilities were allowed to use BAMM for sources in the petroleum and natural gas systems source category and these facilities were required to specify in their GHG annual reports when BAMM was used for an emission source.

EPA anticipates that the overall data quality will increase over time as facilities become familiar with the calculation methods and begin using more direct measurement. EPA anticipates BAMM use will decline and the Agency may have additional information to conduct verification including certain inputs to emissions equations. The Agency will also carefully review regulatory requirements, methods, and the quality of the information reported to identify areas were improvements are needed.