The EPA’s Natural Gas Problem

When U.S. President Barack Obama recently announced plans to reign in greenhouse gas emissions from the oil and gas production, the opposing drum beats from industry and environmental groups were as fast as they were relentless. The industry group America’s Natural Gas Alliance bombarded Twitter with paid advertisements stating how little their industry actually emits. Press releases from leading environmental organizations deploring the plan’s reliance on largely voluntary actions flooded email inboxes.

Opposition to any new regulation by industry, however, isn’t as lockstep as its lobbying groups would have us believe. At the same time, environmentalists’ focus on voluntary versus mandatory measures misses a much graver concern.

The White House and EPA are seeking to regulate methane emissions from the oil and gas industry.

The joint White House and U.S. Environmental Protection Agency proposal would reduce emissions of methane, the primary component of natural gas, by 40–45% from 2012 levels in the coming decade. It’s a laudable goal. While natural gas is relatively clean burning—emitting roughly half the amount of carbon dioxide per unit of energy as coal—it is an incredibly potent greenhouse gas if it escapes into the atmosphere unburned.

Methane emissions from the oil and gas sector are estimated to be equivalent to the pollution from 180 coal-fired power plants, according to studies done by the Environmental Defense Fund (EDF), an environmental organization. Yet there is a problem: despite that estimate, no one, including EDF, knows for certain how much methane the oil and gas industry actually emits.

The EPA publishes an annual inventory of U.S. Greenhouse Gas emissions, which it describes as “the most comprehensive accounting of total greenhouse gas emissions for all man-made sources in the United States.” But their estimates for the natural gas industry are, by their own admission, outdated, based on limited data, and likely significantly lower than actual emissions.

The Baseline

Getting the number right is extremely important as it will serve as the baseline for any future reductions. “The smaller the number they start with, the smaller the amount they have to reduce in coming years by regulation,” says Anthony Ingraffea, a professor of engineering at Cornell University in Ithaca, New York. “A 45% reduction on a rate that is too low will be a very small reduction. From a scientific perspective, this doesn’t amount to a hill of beans.”

Ingraffea says methane emissions are likely several times higher than what the EPA estimates. (Currently, the EPA says that up to 1.8% of the natural gas distributed and produced in the U.S. escapes to the atmosphere.) Even if Ingraffea is right, its still a small percentage, but methane’s potency as a greenhouse gas makes even a small release incredibly significant. Over 100 years, methane traps 34 times more heat in the atmosphere than carbon dioxide. If you are only looking 20 years into the future, a time frame given equal weight by the United Nation’s Intergovernmental Panel on Climate Change, methane is 86 times more potent than carbon dioxide.

After being damaged during Hurricane Ike in September 2008, a natural gas tank spews methane near Sabine Pass, Texas.

If Ingraffea is right, the amount of methane released into the atmosphere from oil and gas wells, pipelines, processing and storage facilities has a warming affect approaching that of the country’s 557 coal fired power plants. Reducing such a high rate of emissions by 40–45% would certainly help stall climate change. It would also likely be much more difficult to achieve than the cuts industry and environmental groups are currently debating.

Ingraffea first called attention to what he and others believe are EPA underestimates in 2011 when he published a highly controversial paper along with fellow Cornell professor Robert Howarth. Their research suggested the amount of methane emitted by the natural gas industry was so great that relying on natural gas was actually worse for the climate than burning coal.

Following the recent White House and EPA announcement, industry group America’s Natural Gas Alliance (ANGA) stated that they have reduced emissions by 17% since 1990 while increasing production by 37%. “We question why the administration would single out our sector for regulation, given our demonstrated reductions,” the organization wrote in a press release following the White House’s proposed policies. ANGA bases its emissions reduction on the EPA’s own figures and stands by the data. “We like to have independent third party verification, and we use the EPA’s figures for that,” says ANGA spokesman Daniel Whitten.

Shifting Estimates

But are the EPA estimates correct, and are they sufficiently independent? To come up with its annual estimate, the EPA doesn’t make direct measurements of methane emissions each year. Rather they multiply emission factors, the volume of a gas thought to be emitted by a particular source—like a mile of pipeline or a belching cow—by the number of such sources in a given area. For the natural gas sector, emission factors are based on a limited number of measurements conducted in the early 1990s in industry-funded studies.

In 2010 the EPA increased its emissions factors for methane from the oil and natural gas sector, citing “outdated and potentially understated” emissions. The end result was a more than doubling of its annual emissions estimate from the prior year. In 2013, however, the EPA reversed course, lowering estimates for key emissions factors for methane at wells and processing facilities by 25–30%. When reached for comment, the EPA pointed me to their existing reports.

The change was not driven by better scientific understanding but by political pressure, Howarth says. “The EPA got huge pushback from industry and decreased their emissions again, and not by collecting new data.” The EPA states that the reduction in emissions factors was based on “a significant amount of new information” that the agency received about the natural gas industry.

However, a 2013 study published in the journal Geophysical Research Letters concludes that “the main driver for the 2013 reduction in production emissions was a report prepared by the oil and gas industry.” The report was a non-peer reviewed survey of oil and gas companies conducted by ANGA and the American Petroleum Institute.

The EPA’s own inspector general released a report that same year that was highly critical of the agency’s estimates of methane and other harmful gasses. “Many of EPA’s existing oil and gas production emission factors are of questionable quality because they are based on limited and/or low quality data.” The report concluded that the agency likely underestimates emissions, which “hampers [the] EPA’s ability to accurately assess risks and air quality impacts from oil and gas production activities.”


Soon after the EPA lowered its emissions estimates, a number of independent studies based on direct measurements found higher methane emissions. In November 2013, a study based on direct measurements of atmospheric methane concentrations across the United States concluded actual emissions from the oil and gas sector were 1.5 times higher than EPA estimates. The study authors noted, “the US EPA recently decreased its methane emission factors for fossil fuel extraction and processing by 25–30% but we find that [methane] data from across North America instead indicate the need for a larger adjustment of the opposite sign.”

In February 2014, a study published in the journal Science reviewed 20 years of technical literature on natural gas emissions in the U.S. and Canada and concluded that “official inventories consistently underestimate actual CH4 emissions.”

“When you actually go out and measure methane emissions directly, you tend to come back with measurements that are higher than the official inventory,” says Adam Brandt, lead author of the study and an assistant professor of energy resources engineering at Stanford University. Brandt and his colleagues did not attempt to make an estimate of their own, but stated that in a worst-case scenario total methane emissions from the oil and gas sector could be three times higher than the EPA’s estimate.

On January 22, eight days after the White House’s announcement, another study found similarly high emissions from a sector of the natural gas industry that is often overlooked. The study made direction measurements of methane emissions from natural gas pipelines and storage facilities in and around Boston, Massachusetts, and found that they were 3.9 times higher than the EPA’s estimate for the “downstream” sector, or the parts of the system which transmit, distribute, and store natural gas.

Most natural gas leaks are small, but large ones can have catastrophic consequences. The wreckage above was caused by a leak in San Bruno, California, in 2010.

Boston’s aging, leak-prone, cast-iron pipelines likely make the city more leaky than most, but the high volume of emissions—losses around the city total roughly $1 billion worth of natural gas per decade—are nonetheless surprising. The majority of methane emissions were previously believed to occur “upstream” at wells and processing facilities. Efforts to curb emissions including the recent goals set by the White House have overlooked the smaller pipelines that deliver gas to end users.

“Emissions from end users have been only a very small part of conversation on emissions from natural gas,” says lead author Kathryn McKain, an atmospheric scientist at Harvard University. “Our findings suggest that we don’t understand the underlying emission processes which is essential for creating effective policy for reducing emissions.”

The Boston study was one of 16 recent or ongoing studies coordinated by EDF to try to determine just how much methane is actually being emitted from the industry as a whole. Seven studies, focusing on different aspects of oil and gas industry infrastructure, have been published thus far. Two of the studies, including the recent Boston study, have found significantly higher emission rates. One study, conducted in close collaboration with industry, found lower emissions. EDF says it hopes to have all studies completed by the end of 2015. The EPA told me it will take the studies into account for possible changes in its current methane emission factors.

Fraction of a Percent

EDF is simultaneously working with industry to try to reduce methane emissions. A recent study commissioned by the environmental organization concluded the US oil and gas industry could cut methane emissions by 40% from projected 2018 levels at a cost of less than one cent per thousand cubic feet of natural gas, which today sells for about $5. The reductions could be achieved with existing emissions-control technologies and policies.

“We are talking about one third or one fourth of a percent of the price of gas to meet these goals,” says Steven Hamburg chief scientist for EDF. The 40–45% reduction goal recently announced by the White House is nearly identical to the level of cuts analyzed by EDF. To achieve the reduction the White House proposes mandatory changes in new oil and gas infrastructure as well as voluntary measures for existing infrastructure.

Thomas Pyle, president of the Institute for Energy Research, an industry organization, says industry is already reducing its methane emissions and doesn’t need additional rules. “It’s like regulating ice cream producers not to spill any ice cream during the ice cream making process,” he says. “It is self-evident for producers to want to capture this product with little or no emissions and make money from it.”

Unlike making ice cream, however, natural gas producers often vent their product intentionally as part of the production process. One of the biggest sources of methane emissions in natural gas production is gas that is purposely vented from pneumatic devices which use pressurized methane to open and close valves and operate pumps. They typically release or “bleed” small amounts of gas during their operation.

Such equipment is widely used throughout natural gas extraction, processing, and transmission process. A recent study by Natural Resources Defense Council (NRDC) estimates natural gas driven pneumatic equipment vents 1.6–1.9 million metric tons of methane each year. The figure accounts for nearly one-third of all methane lost by the natural gas industry, as estimated by the EPA.

A natural gas distribution facility

“Low-bleed” or “zero-bleed” controllers are available, though they are more expensive. The latter use compressed air or electricity to operate instead of pressurized natural gas, or they capture methane that would otherwise be vented and reuse it. “Time and time again we see that we can operate this equipment without emissions or with very low emissions,” Hamburg says. Increased monitoring and repair of unintended leaks at natural gas facilities could reduce an additional third of the industry’s methane emissions according to the NRDC study.

Environmentalist organizations have come out in strong opposition to the lack of mandatory regulations for existing infrastructure, which will account for nearly 90% of methane emissions in 2018 according to a recent EDF report.

While industry groups oppose mandatory regulations on new infrastructure, at least one industry leader isn’t concerned. “I don’t believe the new regulations will hurt us at all,” says Mark Boling an executive vice president at Houston-based Southwestern Energy Company, the nation’s fourth largest producer of natural gas.

Boling says leak monitoring and repair programs his company initiated starting in late 2013 will pay for themselves in 12 to 18 months through reduced methane emissions. Additionally, he says the company has also replaced a number of pneumatic devices with zero-bleed solar powered electric pumps. Southwestern Energy is now testing air compressors powered by fuel cells to replace additional methane-bleeding equipment Boling says. In November, Southwestern Energy launched ONE Future, a coalition of companies from across the natural gas industry. Their goal is to lower the industry’s methane emissions below one percent.

Based on the EPA emissions rate of 1.8% and fixes identified by EDF and NRDC, their goal seems attainable. But what if the actual emissions rate is significantly higher, as Howarth and Ingraffea have long argued and recent studies seem to suggest? “We can sit here and debate whose numbers are right, ‘Is it 4%? 8%? Whatever,’ ” Boling says. “But there are cost effective opportunities out there to reduce emissions, and we need to step up and do it.”