U.S. oil and gas methane emissions are 60 percent higher than EPA reports
A new study co-authored by Adam Brandt shows leakage equals $2 billion dollars in wasted natural gas — enough to supply 10 million households — and provides a roadmap for future emissions research.
A study published in the journal Science finds that the U.S. oil and gas industry emits 13 million metric tons of methane from its operations each year—nearly 60 percent more than currently estimated by the U.S. Environmental Protection Agency (EPA).
The higher overall methane leak rate underscores a growing business and environmental challenge for natural gas in an increasingly competitive, lower-carbon economy. Methane is a potent greenhouse gas, with more than 80 times the climate warming impact of carbon dioxide over a 20-year timespan. It is also the main ingredient in natural gas.
The new study estimates the current leak rate from the U.S. oil and gas system is 2.3 percent, versus the current EPA inventory estimate of 1.4 percent. Although the percentages seem small, the volume represents enough natural gas to fuel 10 million homes – lost gas worth an estimated $2 billion. The study was led by Environmental Defense Fund (EDF) researchers, with support from 19 co-authors from 15 other institutions, including Adam Brandt at Stanford's School of Earth, Energy & Environmental Sciences. They conducted new research and integrated more than half a decade of underlying research on methane emissions. This original body of science was conducted by more than 140 researchers from 40 institutions in cooperation with 50 oil and gas companies that provided site access and technical advice.
“These studies, synthesized in this Science paper, have transformed our understanding of methane emissions from natural gas systems in the United States,” said Professor David Allen, of the Cockrell School of Engineering at the University of Texas at Austin, who is a contributor to the new paper and lead author on several of the earlier studies.
What seems like small differences in equipment can add up significantly in emissions when emissions are so strongly driven by a few problem sources.
The findings reported feature measurements at over 400 well pads in six basins and scores of midstream facilities, data from component measurements, and aerial surveys covering large swaths of U.S. oil and gas infrastructure.
“This is by far the most comprehensive body of research of its kind,” said EDF Chief Scientist Steven Hamburg, who is a co-author of the paper. “Scientists have uncovered a huge problem, but also an enormous opportunity. Reducing methane emissions from the oil and gas sector is the fastest, most cost-effective way we have to slow the rate of warming today, even as the larger transition to lower-carbon energy continues.”
The International Energy Agency estimates industry can reduce its worldwide emissions by 75 percent—and that up to two-thirds of those reductions can be realized at zero net cost.
“Although we confirmed that methane emissions are substantially higher than previously thought, the good news is that our new understanding provides a cost-effective path forward to eliminate the waste of this valuable resource,” said Allen Robinson, who is a co-author, professor, and department head of mechanical engineering at Carnegie Mellon University.
Leading companies are beginning to recognize the challenge, but action to reduce emissions is only just getting started. In April, BP set its first quantitative methane target. Last month ExxonMobil committed to cut methane emissions and flared gas volumes, following an earlier announcement from its subsidiary XTO Energy that unveiled their methane reduction program. Shell, Qatar Petroleum, and a host of other producers have committed to continuously reduce methane emissions across the natural gas supply chain.
"What seems like small differences in equipment can add up significantly in emissions when emissions are so strongly driven by a few problem sources," according to a Natural Gas Initiative brief about the research co-authored by Brandt and Arvind Ravikumar, a postdoctoral researcher in Energy Resources Engineering.
Overall, EDF is calling for a 45 percent reduction in global oil and gas methane emissions by 2025 – a goal that would have the same short-term climate benefit as closing one-third of the world’s coal plants when achieved.
“It’s an impressive collection of work with implications for both mitigation and generating accurate inventory estimates,” said Eric Kort, Assistant Professor of Climate and Space Sciences at the University of Michigan, who is another of the study’s co-authors.
“Federal and state governments must take action – and many states are – but industry leadership remains crucial,” said EDF Senior Vice President Mark Brownstein. “Companies have the ability to lead through operational best practices, comprehensive methane programs, target setting, technology innovation and pilots, and constructively engaging with the regulatory process.”
EDF recently announced plans to launch MethaneSAT, a purpose-built satellite designed to measure and map human-caused methane emissions almost anywhere on earth. Due to launch in 2021, MethaneSAT will help both countries and companies track problem areas, find solutions, and monitor their progress.
EDF, the Oil and Gas Climate Initiative companies, and the UN Environment’s Climate and Clean Air Coalition are also collaborating on a set of peer-reviewed methane studies in locations across the globe, which will complement the data collected by MethaneSAT. These studies are built on the methods pioneered in the U.S.-based studies upon which the synthesis paper is based.
Funding for these studies was provided by the Heising-Simons Foundation, Bill and Susan Oberndorf, Betsy and Sam Reeves, the Robertson Foundation, TomKat Charitable Trust, and others.