1. Understanding Updates to the EPA Inventory of Greenhouse Gas Emissions from Natural Gas Systems
Gina DeFrancesco
Clean Energy Analyst | May 2019

2. The American Gas Association, founded in 1918, represents more than 200 local energy companies that deliver clean natural gas throughout the United States. There are more than 74 million residential, commercial and industrial natural gas customers in the U.S., of which 94 percent — more than 70 million customers — receive their gas from AGA members. Today, natural gas meets more than one-fourth of the United States' energy needs.

3. New Science,
New Facts
The Environmental Protection Agency (EPA) made substantial updates to its estimates of methane emissions in the Inventory of U.S. Greenhouse Gases and Sinks: 1990 – 2017 that it released in April The Inventory incorporates new data available from studies on emissions as well as its Greenhouse Gas Reporting Program (GHGRP).

4. Key Findings
Annual methane emissions from natural gas distribution systems declined 73 percent from to 2017.
The natural gas emissions rate of production from distribution systems remains less than 0.1 percent at 0.09 percent.
The industry-wide natural gas emissions as a rate of production (the “leakage rate”) is 1.3 percent – a level still well below even the most stringent thresholds for immediate climate benefits from coal to gas switching.
The EPA Inventory reveals once again that the natural gas distribution systems have a small emissions footprint shaped by a declining trend.

5. Key Findings continued
Total methane emissions from all natural gas systems have declined 15 percent from 1990 to
The ratio of methane emissions per unit of natural gas produced has declined continuously during the past two and a half decades, dropping 48 percent since 1990.
Along with natural gas systems, methane emission sources include enteric fermentation and manure management (livestock), landfills, coal mining, petroleum systems, wastewater treatment, and others. Methane emissions from all economic sectors represent 10 percent of all greenhouse gas emissions in the U.S.; methane released from natural gas systems accounts for 2.6 percent of all U.S. greenhouse gas emissions.
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 natural gas resource.

6. U.S. Greenhouse Gas Emissions (Million Metric Tons CO2e)
US GHG emissions are down 12 percent since 2005 with natural gas playing a key role in the decline
U.S. Greenhouse Gas Emissions
(Million Metric Tons CO2e)
Source: EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks:

7. Sources of Methane Emissions 2017
Source: EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks:

8. Petroleum combustion accounts for most energy-related CO2 emissions, followed by natural gas
Source: EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks:

9. Upstream natural gas systems
Source: American Gas Association Playbook 2019

10. Downstream natural gas systems
Source: American Gas Association Playbook 2019

11. Methane emissions from natural gas systems have declined 15 percent from 1990 levels
Source: EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks:

12. Methane emissions have declined even as gross natural gas withdrawals climbed 53 percent
Source: EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks:

13. Environmental Protection Agency
Methane emissions per unit of natural gas produced have declined steadily since 1990
Down 48% since 1990
Includes methane emissions from petroleum production based on the natural gas fraction of total energy content produced from oil wells.
Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks:
Environmental Protection Agency

14. Natural gas distribution emissions dropped 73 percent since 1990
Source: EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks:
Energy Information Administration

15. Sources of distribution system emissions
Source: EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks: , Annex Table 3.6-1
Environmental Protection Agency

16. Pipeline Replacement Lowers Emissions
Miles of installed main has increased 50 percent since Even with this tremendous growth, estimated methane emissions from pipeline leaks declined 76 percent. A consequence of accelerated removal of unprotected steel and cast iron pipe replaced with plastic and protected steel.
Activity Data and Emissions from EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks:

17. Summary of Revisions to Natural Gas System Methane Estimates 2015
EPA explicitly defines emissions from exploration activities; this does not represent a methodologica l change, but a separate category for presentation
Methane Emissions in 2016
Prior Inventory
New Inventory
Change
Exploration
0.7
1.2
71%
Production
106.8
108.4 1%
Onshore Production
45.4
45.1
-1%
Offshore Production
3.8 0%
Gathering, Boosting
57.7
59.5 3%
Processing
11.2
11.7 4%
Transmission, Storage
32.8
32.4
Distribution
12.0
11.9
Natural Gas Total
163.5
165.7
Petroleum Field Operations
35.4
37.7 6%
Oil and Gas Total
198.9
203.3 2%
(MMT CO2e)
Source: EPA Inventory of U.S. Greenhouse Gas Emissions and Sinks:

18. Gina DeFrancesco Clean Energy Analyst gdefrancesco@aga.org

19. TrueBlueNaturalGas.org
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