Understanding Updates to the EPA Inventory of Greenhouse Gases

Report June 17, 2020

Understanding Updates to the EPA Inventory of Greenhouse Gases




The Environmental Protection Agency (EPA) made further updates to its estimates of methane emissions in its Inventory of US Greenhouse Gas Emissions and Sinks: 1990-2018. The Inventory incorporates new data available from studies on emissions as well as the EPA’s own Greenhouse Gas Reporting Program (GHGRP).

The Inventory reveals once again that natural gas distribution systems have a small emissions footprint shaped by a declining trend. Distribution systems owned and operated by local natural gas utilities emit 0.08 percent of produced natural gas. These annual emissions declined 73 percent from 1990 to 2018, even as natural gas utility companies added more than 769,000 miles of pipeline to serve 20 million more customers.

This exceptional record can be traced to gas utilities continuing to make safety their top priority and remaining deeply committed to systematically upgrading infrastructure through risk-based integrity management programs. As companies and the country continue to modernize the natural gas infrastructure base and connect homes and businesses, there will be new opportunities to achieve low-cost carbon emissions reductions by leveraging this existing infrastructure and the nation’s abundant natural gas resource.

Key Findings:

  • Annual methane emissions from natural gas distribution systems declined 73 percent from 1990 to 2018.
  • The natural gas emissions rate of production from distribution systems remains less than 0.1 percent, now at 0.08 percent.
  • Industry-wide natural gas emissions as a rate of production (the “leakage rate”) are now 1.0 percent—a level well below the most stringent thresholds for immediate climate benefits achieved through coal to natural gas switching.
  • Total methane emissions from natural gas systems have declined 24 percent since 1990 to 2018.
  • Methane emissions from natural gas production for year-end 2017 were revised down 24 percent estimates compared with the prior EPA Inventory. Recalculations based on updated data and methods resulted in an 82 percent reduction in estimated methane emissions from offshore production and a 39 percent reduction from methane emissions from gathering and boosting stations.
  • Methane emissions from natural gas stationary combustion accounted for 13.3 and 33.3 percent of the direct fossil fuel (natural gas, coal, fuel oil, and wood) methane emissions from the residential and commercial sectors, respectively, in 2018.

For more information, contact:

Gina DeFrancesco, Clean Energy Analyst, Energy Analysis

gdefrancesco@aga.org, (202) 824-7127