Methane emissions from natural gas production — including hydraulic fracturing, or “fracking” — are lower than previously thought, according to a major new study from researchers at the University of Texas. The research was done in close coordination with the Environmental Defense Fund (EDF), a major U.S. environmental organization.
The study, published today in two parts in the journal Environmental Science & Technology, finds that methane emissions from the upstream portion of the supply chain are only 0.38 percent of production. That’s about 10 percent lower than what the same research team found in a study released in September 2013. The researchers also noted that a small number of sites accounted for the majority of emissions, suggesting that technologies already in use across the industry are effectively managing methane leakage.
The emissions rate in the study released today also corresponds with the U.S. EPA’s estimates for methane emissions, which are far lower than what anti-fracking groups frequently claim are “leaking” as a result of fracking. Earlier this year, EPA observed that methane emissions from fracking have fallen by 73 percent since just 2011. Since 1990, methane emissions from U.S. natural gas systems have declined by nearly 17 percent.
The UT/EDF study found pneumatic controllers (onsite devices that use gas pressure to control valves and other equipment) have emissions that are slightly higher than what’s reported by EPA (the study suggests these emissions are about 17 percent higher than what EPA estimated). But emissions from liquids unloading – the process of removing liquids from the well bore – were slightly lower than EPA’s estimates. The authors noted that their data “represent the most extensive set of measurements of emissions from liquid unloadings in the scientific literature.”
The overall picture shows methane emissions are slightly lower than previously thought, according to the study:
“The overall average emission rates reported in this work are lower than the previous data sets reported by Allen, et al. for the United States, and for British Columbia and Alberta.”
A chart accompanying the research shows total methane emissions of 2,185 gigagrams (Gg), or approximately 0.38 percent of total natural gas withdrawals and production in 2012, according to data from the U.S. Energy Information Administration.
Last week, Energy In Depth released a report showing declines in methane emissions in many shale basins across the country, including the Permian Basin and Eagle Ford region in Texas; major producing areas in Oklahoma; and in the Marcellus and Utica shale regions in Ohio and Pennsylvania.
Confirms Previous Studies
The UT/EDF study is only the latest in a long line of existing research and peer-reviewed papers that confirm the environmental advantages of natural gas. A brief list is below:
- National Renewable Energy Laboratory: “On a per-unit electrical output basis, harmonization reveals that median estimates of GHG emissions from shale gas-generated electricity are similar to those for conventional natural gas, with both approximately half that of the central tendency of coal.”
- U.N. IPCC: “A key development since AR4 is the rapid deployment of hydraulic fracturing and horizontal drilling technologies, which has increased and diversified the gas supply… this is an important reason for a reduction of GHG emissions in the United States.”
- Cornell Univ.: “Using more reasonable leakage rates and bases of comparison, shale gas has a GHG footprint that is half and perhaps a third that of coal.”
- Univ. of Maryland: “GHG impacts of shale gas are…only 56%that of coal.… [A]rguments that shale gas is more polluting than coal are largely unjustified.”
- Carnegie Mellon Univ.: “Natural gas from the Marcellus shale has generally lower life cycle GHG emissions than coal for production of electricity in the absence of any effective carbon capture and storage processes, by 20-50% depending upon plant efficiencies and natural gas emissions variability.”
- NOTE: Study partially funded by the Sierra Club
- Massachusetts Institute of Technology: “Although fugitive emissions from the overall natural gas sector are a proper concern, it is incorrect to suggest that shale gas-related hydraulic fracturing has substantially altered the overall GHG intensityof natural gas production.”
- NOTE: Coauthor is a lead author of the IPCC’s Fifth Assessment Report
- National Energy Technology Laboratory(U.S. DOE): “Natural gas-fired baseload power production has life cycle greenhouse gas emissions 42 to 53 percent lower than those for coal-fired baseload electricity, after accounting for a wide range of variability and compared across different assumptions of climate impact timing.”
- Joint Institute for Strategic Energy Analysis/NREL: “Based on analysis of more than 16,000 sources of air-pollutant emissions reported in a state inventory of upstream and midstream natural gas industry, life cycle greenhouse gas emissions associated with electricity generated from Barnett Shale gas extracted in 2009 were found to be very similar to conventional natural gas and less than half thoseof coal-fired electricity generation.”
- AEA Technology(for the European Commission): “In our analysis, emissions from shale gas generation are significantly lower (41% to 49%) than emissions from electricity generated from coal. This is on the basis of methane having a 100 year GWP of 25. This finding is consistent [with] most other studies into the GHG emissions arising from shale gas.”
- Worldwatch Institute: “[W]e conclude that on average, U.S. natural gas-fired electricity generation still emitted 47 percent less GHGsthan coal from source to use using the IPCC’s 100-year global warming potential for methane of 25.”
- The Breakthrough Institute: “The climate benefits of natural gas are real and are significant. Recent lifecycle assessments studies confirm that natural gas has just half as much global warming potentialas coal.”
The head of the U.S. EPA has also said, “Responsible development of natural gas is an important part of our work to curb climate change.”
A Rebuke to Anti-Fracking Advocacy
The findings from the UT/EDF study cast more doubt upon the claims of groups that oppose fracking, who have made “methane leaks” a key component of their advocacy against U.S. oil and natural gas development.
Last year, Gasland filmmaker Josh Fox wrote that President Obama “does not have the right information on fracked gas,” alleging that “methane is leaking like crazy” from oil and natural gas production activities. Food & Water Watch, one of the most aggressive anti-fracking groups in the country, claimed last month that natural gas is “proving to be more of a ‘gangplank’ to climate chaos,” based upon claims of high methane leakage rates. The group linked to a 2013 op-ed by Cornell University activist Tony Ingraffea, whose claims were refuted by climate scientists just days after his column was published.
Al Gore has also criticized fracking, based upon assumptions of high methane emissions.
Most scientists, however, have found that natural gas will retain its environmental and climate advantages if methane emissions are kept under two to three percent of total production. The U.S. EPA’s data, which are largely corroborated by today’s UT/EDF study, suggest a leakage rate of only about 1.5 percent.
Methane a Fixable Problem
Although the research does show methane emissions on the right trajectory, the study also finds that a “small subset of natural gas wells are responsible for the majority of methane emissions,” according to the press release associated with the report. That means most wells and their associated equipment have been effectively designed to mitigate or even eliminate emissions.
As the authors noted regarding pneumatic controllers:
“…the measurements reported in this work had large numbers of devices for which no emissions were detected during the sampling period” (p. 14; emphasis added).
The finding that a “small subset” of sites is responsible for most emissions meshes with what EDF President Fred Krupp said earlier this year, when he noted that “we have the technology” to reduce methane emissions. “This is essentially a data acquisition and management problem — the kind that we know we can solve,” Krupp wrote in an op-ed for the New York Times, co-authored by Michael Bloomberg.
The UT study was funded in part by EDF and several energy companies who agreed to participate in the research, and who provided access to the well sites for direct measurements. According to the study, the sites where measurements occurred were not selected by the companies, but rather chosen at random by the researchers themselves.