From Energy in Depth:
Bombshell Study Confirms Low Methane Leakage from Shale Gas
Posted by: Steve Everley
For years, critics of hydraulic fracturing have alleged that “methane leaks” from development are not only astronomically high, but also make natural gas from shale a climate “disaster” and “gang-plank.” But a new, highly anticipated report from the University of Texas and the Environmental Defense Fund might put that theory to rest – at last, and for good.
The UT-EDF study released today looked at 190 onshore natural gas production sites in the United States. During completion activities (including hydraulic fracturing), the authors found that emissions were “nearly 50 times lower than previously estimated by the Environmental Protection Agency.” Based on its findings, the researchers estimate that total annual methane emissions are “comparable” to EPA’s estimates.
The UT-EDF study’s findings (along with data from the latest EPA Greenhouse Gas Inventory) suggest a leakage rate of only about 1.5 percent, if not less than that. That rate is comfortably below the threshold required for shale to maintain its obvious and significant climate benefits.
In 2011, a few activist-researchers from Cornell University (Howarth, Ingraffea, et. al.) released a study purporting to show high levels of methane “leakage” from natural gas systems, including wells that had been hydraulically fractured. The Cornell study suggested as much as 7.9 percent of natural gas developed from shale was leaking into the atmosphere.
Granted, the Cornell study was inherently flawed and directly underwritten by folks ideologically opposed to shale development. But that study (along with a few limited and deeply flawed assessments from researchers at the National Oceanic and Atmospheric Administration) gave opponents an opening to suggest a new form of environmental harm from hydraulic fracturing. The press, meanwhile, latched on to how “industry” says leaks are low, but “some scientists” say leakage is much higher. All of a sudden, it was now a “debate.”
Fast forward to today. We know that experts at the U.S. Department of Energy, MIT, the University of Maryland -- and even high-ranking officials in the Obama administration -- have all either disputed the types of conclusions in the Howarth report or released their own studies showing a low leakage rate. The EPA’s most recent data on greenhouse gas emissions from natural gas systems suggest a rate of below two percent. Even a study underwritten by the anti-gas Sierra Club found that the Howarth paper was “biased” and “wrong.”
But there was one major point of agreement: the need for more data. All of these reports added to the growing body of knowledge on this subject, but most folks still agreed that a study underway by the Environmental Defense Fund and the University of Texas would provide an unprecedented and perhaps definitive data set on methane emissions. Its findings, whatever they may be, would set the bar for understanding the reality of natural gas development in the United States – especially as it occurs increasingly in shale and other tight reservoirs across the country.
The first part of that EDF study, released today, confirms the consensus around which the scientific community had already rallied with regard to methane leakage rates from natural gas systems.
The report made the following conclusions:
· Emissions associated with preparing a gas well for production were lower than previously estimated;
· Emissions associated with routine production (i.e. pneumatic devices and other equipment) might be higher than previously estimated;
· Emissions measured at wells during completion were varied, but the average emissions were almost 50 times lower than EPA’s estimates; and
· Methane emissions from natural gas production (incorporating all sources measured in the study) are between 757 gigagrams (Gg) and 1,157 Gg, comparable to the EPA estimate of approximately 1,200 Gg.
· When scaled to a nationwide estimate, total emissions are approximately 2,300 Gg, compared with EPA’s estimate of 2,545 Gg.
While some of the individual measurements for particular segments did come in a little higher, other areas returned emissions numbers far lower than previously thought – as much as 97 percent lower than EPA’s estimates, in the case of hydraulically fractured well completions. Thus, the overall emissions profile is not only low, but actually less than what even the Environmental Protection Agency had estimated.
In addition to offering a clear rebuke to the Howarth/Ingraffea theory of “high leakage,” the UT-EDF paper suggests that the leakage threshold cited by critics as the point beyond which shale loses its climate advantage is not being crossed – and it’s not even close.
In two separate pieces, Joe Romm from Climate Progress has cited a 2011 paper from Tom Wigley that established a two percent leakage rate threshold. Romm’s argument has been that available research suggests emissions are higher than two percent, making shale a net negative in terms of greenhouse gas (GHG) emissions. Here’s one relevant excerpt of Wigley’s research that Romm highlighted in 2011:
“[U]nless leakage rates for new methane can be kept below 2%, substituting gas for coal is not an effective means for reducing the magnitude of future climate change.”
Last month, Romm wrote about NOAA’s limited findings on methane emissions in Utah, claiming the results, if confirmed, would “utterly vitiate the direct climate benefit of natural gas.” Romm again cited the Wigley study to establish the leakage rate threshold of two percent.
EPA’s latest data on greenhouse gas emissions in the United States show a leakage rate of only about 1.5 percent, and the UT-EDF report released today shows that for at least one major component of the supply chain, methane emissions are equal to if not less than what EPA calculated. Will critics acknowledge that this latest research may “utterly vitiate” their own arguments?
It’s worth emphasizing that the study’s findings are limited to the areas sampled, so extrapolating its findings to arrive at a nationwide conclusion may not be appropriate. The authors themselves stress this point in the study. But it is also easily the most comprehensive study performed on this issue to date, giving its conclusions significant weight in answering the “methane leak” question.
Put differently: Based on the best information available to us today, shale has a clear benefit when it comes to greenhouse gas emissions.
It should also be noted that the study provides critical insight into areas where leakage that is occurring can be most effectively reduced. Thus, the report is not only welcome news for those interested in protecting the environment, but also can serve as a roadmap the industry can use as it continues to invest in and deploy technologies that reduce emissions.
The activist fear-mongering about methane emissions has been exposed as fraudulent by the most comprehensive research on the subject to date, including data that incorporates the first-ever direct measurements of methane emissions from various segments of the production process. Perhaps now we can all come together, take a deep breath, and recognize the clear economic and environmental benefits of natural gas from shale.
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