The natural gas industry has faced criticism from activist groups over methane emissions associated with the production, transportation and storage of the resource. However, a recent report by researchers at ICF International (ICF), commissioned by The Natural Gas Council (NGC), reviewed 75 pieces of scientific literature on U.S. methane emissions published over the past five years and concluded that methane emissions from the natural gas industry are sharply decreasing. This decline is thanks to voluntary actions from operators, equipment and infrastructure improvements, and actions taken in response to current methane emission regulations.
According to the U.S. Environmental Protection Agency’s (EPA) latest Inventory of U.S. Greenhouse Gas Emission and Sinks, methane accounted for 10.6 percent of total greenhouse gas (GHG) emissions in 2014. While natural gas is more than 95 percent methane, the Inventory shows that methane emissions from the natural gas industry only account for about 2.6 percent of all U.S. GHG emissions, and those emissions are decreasing substantially. As the EPA Inventory states:
“Those emissions [from natural gas systems] have decreased by 30.6 MMT CO2 Eq. (14.8 percent) since 1990.” (p. ES-13; emphasis added)
Such a significant decline in methane emissions from the natural gas industry is impressive, especially considering natural gas production during that same period increased over 53 percent. As the NCG points out, one of the reasons emissions are declining while production is increasing is the improvement of the natural gas infrastructure. According to the report:
“There are multiple reasons for this decline. First, equipment turnover typically results in improved performance in most sectors as newer, more efficient, and lower-emitting equipment replaces older equipment.” (p. 11)
The EPA Inventory supports this statement, asserting:
“The decrease in CH4 emissions is largely due to the decrease in emissions from transmission, storage, and distribution. The decrease in transmission and storage emissions is largely due to reduced compressor station emissions (including emissions from compressors and fugitives). The decrease in distribution emissions is largely attributed to increased use of plastic piping which has lower emissions than other pipe material, and station upgrades at metering and regulating (M&R).” (p. ES-14)
In addition to equipment and infrastructure replacement, voluntary programs employed by companies also play a role in methane emissions reduction. These include federally created programs, such as the Natural Gas STAR Program and Global Methane Initiative, as well as collaborative programs between industry, non-profit and philanthropic organizations like the Center for Sustainable Shale Development and Our Nation’s Energy Future Coalition. By partnering with these programs, natural gas operators have cut methane emissions across the board. Through the Natural Gas STAR Program alone, the EPA estimates that program partners eliminated more 1.2 trillion cubic feet of methane emissions since 1993.
Finally, actions taken in response to federal and state regulations are also contributing to the decline in methane emissions in the natural gas industry. While state regulations vary throughout the country, agencies such as the EPA and the Bureau of Land Management (BLM) have enacted national regulations on production, transportation and storage of natural gas in an attempt to decrease emissions. Some federal regulations have prompted actions that mitigate methane emissions, but often these regulations are broad, with methane reduction resulting as a byproduct. As the report mentions:
“While the regulations [from the New Source Performance Standards] do not directly address methane, the methane is contained in the same gas streams as the VOCs, so the regulations have the co-benefit of reducing methane as well as VOCs.” (p. 46-47)
Additionally, many of the ways companies meet state and federal methane emissions reduction goals are already taking place through voluntary efforts such as improving leak detection and replacing less efficient equipment. With multiple emission reduction programs and voluntary efforts in place, emissions per unit of natural gas produced continues to drop. According to the report:
“Absolute emissions declined by 15% between 1990 and 2014. Methane emissions per unit of gas produced declined by 43% over that same period.” (p. 8; emphasis added)
As this report shows, overall methane emissions in natural gas development are declining even as production has soared. Further, while actions taken in response to state and federal regulation aid in reducing emissions in the natural gas industry; technologies, practices and programs already in place are helping to ensure that methane emissions will continue to decrease.