Issue Date: July 11, 2016
Pivotal study on methane leaks from U.S. oil and natural gas wells under fire
An influential study that has shaped the climate-change-related debate over methane releases from oil and natural gas operations in the U.S. is under attack. So is the lead researcher, David T. Allen, a University of Texas, Austin, chemistry professor.
A formal complaint that environmental activists filed with the Environmental Protection Agency’s inspector general alleges that Allen committed “systematic fraud, waste, and abuse” when doing the study.
Touché Howard, another researcher, claims that Allen knowingly used a flawed instrument in the research that found U.S. oil and gas operations leaked very little methane. Howard’s accusations are the basis of the 68-page complaint, which was filed in June by NC Warn. That North Carolina environmental group was joined by 130 other organizations whose members live near oil and gas drilling and production operations.
They claim that Allen’s measurements are flawed and he deliberately covered up that fact. In turn, they say, his research has prevented EPA from requiring methane emissions reductions at oil and gas extraction sites.
NC Warn is concerned about flammable natural gas leaks, but it primarily wants to curb emissions from drilling and production of methane to blunt the climate change impacts of this gas, explains Jim Warren, NC Warn’s executive director. Methane, the primary compound in natural gas, is a powerful greenhouse gas. Over a 100-year span, it has a climate change impact 25 times as great as carbon dioxide, according to EPA.
The complaint draws attention to an unanswered question with global implications: How much methane is leaking from some 500,000 oil and natural gas drilling sites operating at some level in the U.S.? While the U.S. economy profits mightily from a glut of oil and natural gas, particularly from hydraulic fracturing, existing drilling and production operations face no national regulations. Only a handful of states have enacted or are considering enacting methane leakage limits.
Meanwhile, Warren says, “Scientists are talking about 10-foot sea-level rise and an endless string of high-temperature years, and we are seeing more fracturing operations and more methane leakage. Our goal is a zero-methane-emission standard. We want EPA to regulate methane from existing sources, not dribble along with more studies and voluntary efforts.”
EPA appears to be slowly recognizing that the amount of methane escaping from U.S. oil and gas operations is greater than once thought. Recently, EPA upped its methane emissions figures from oil and natural gas production by 34%. For oil production, EPA more than doubled its leakage assessment. The agency also took the unusual step of retroactively increasing past estimates of methane loss.
Allen’s study, released in part in 2013, is pivotal to this discussion. His University of Texas team found extremely small methane emission levels from oil and natural gas operations (Proc. Natl. Acad. Sci. USA 2013, DOI: 10.1073/pnas.1304880110). The study is the largest of its kind and has been touted by oil and gas industry advocates as demonstrating there is no need to regulate this sector.
With $18 million in funding from the Environmental Defense Fund—an environmental organization—and the oil industry, Allen was the first nonindustry researcher that oil and gas producers allowed to enter their properties and measure emissions. His research carried the stigma of industry control, but it allowed Allen, jointly with industry, to select, directly measure, and analyze methane leakage at some 190 sites.
Several studies before and after Allen’s measured methane emissions from aircraft above and mobile vans beyond companies’ property lines. Many have found significant methane losses, some as high as 6 to 12% of natural gas production. Others reported lower levels that were still well above EPA’s leakage estimate of around 0.5 to 1% of production.
Allen’s research showed leak rates of 0.42% on average, even lower that EPA’s numbers.
NC Warn’s complaint asserts that Allen’s use of a popular, portable measurement device, the Bacharach Hi Flow Sampler, resulted in flawed measurements. Furthermore, the complaint alleges that the problem was brought to Allen’s attention by an industry consultant but was ignored.
The device provides inaccurate and extremely low methane measurements from high methane leakers under certain conditions, says Howard, a retired industrial chemical engineer who invented and developed the technology in the 1990s. In 2003, Bacharach commercialized the technology in its Hi Flow Sampler. Howard’s concerns form the basis of NC Warn’s complaint.
When Howard learned of Allen’s study, he says, he warned Allen and EPA of the device’s tendency to lowball some high methane emissions rates. But they took no action.
“It is a very basic technology,” Howard explains. “It is portable, like a backpack. The operator wraps an enclosure, such as a plastic sheet, around a potentially leaking device and draws off the enclosed air with a vacuum-cleaner-like nozzle and measures its chemical makeup. When it works well, it is great, but when it doesn’t, it can underreport methane levels by a factor of 10 to 100.”
The problem is most acute when measuring natural gas leaks that contain low percentages of methane, despite high natural gas leakage rates, Howard says. In such cases, the device frequently underestimates the total methane loss, he says.
How this impacts Allen’s study, however, is unclear without a review of Allen’s raw data, which Howard says he has requested. Allen has not responded, Howard says.
Allen declined to speak with C&EN. But in a statement, Allen defends his use of the device and notes it has been an industry-standard instrument for the past 20 years.
“The instrument we used and the measurements we made were not impacted by the claimed failure. That assertion is based on the fact that we had two to three additional independent measurement systems running in parallel with the Hi Flow device. These included an optical gas imager (infrared camera) and downwind sampling and quantification of emissions from the entire site by independent investigators,” Allen’s statement says.
Allen and Howard fleshed out their disagreements in comments published last year (Environ. Sci. Technol. 2015, DOI: 10.1021/acs.est.5b00507 and 10.1021/acs.est.5b00941).
Howard is not alone in seeking Allen’s data to clear up confusion about the emissions study.
“Our goal is a zero-methane- emission standard.”
—Jim Warren, executive director, NC Warn
“I don’t know who is right, but we need to figure out what happened,” says Robert Jackson, a Stanford University professor and earth scientist who also studies methane loss. “Dave says this is not a big deal. But if Touché is correct and the study shaves off the biggest emitters, we’ve missed a lot of methane going to the atmosphere. A few percentage operations can release most of the methane and we don’t want to miss them. Dave should make the data available.”
Jackson points to an even larger problem.
“We need more bottom-up site studies like Allen’s, as well as top-down studies that measure emissions outside the property line. Allen’s is part of attempt to do that, but we should have 25 just like that,” Jackson says. “Scientists need access to oil and gas sites and resources to conduct new studies.”
Trying to fill this void are the National Oceanic & Atmospheric Administration and the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder. They have several joint studies near publication, says Thomas Ryerson, a NOAA supervisory research chemist. Researchers are using aircraft and mobile vans to measure field emissions and have characterized some 75% of U.S. oil and gas fields, he says.
They are finding large variances in methane emissions, he says. Some of the largest gas fields show low leak rates, while oil fields show the highest.
“We think there may be more methane loss during the oil and gas separation process at oil fields than processing losses at gas fields,” Ryerson says.
The team has also found varying emissions at an oil and gas field that spans the Utah and Colorado border. They recorded higher emissions on the unregulated Utah side than in Colorado, which has a host of new methane control regulations.
Despite the ongoing research, NC Warn’s Warren wants more than improved methane measurement technology.
“We are not after a ‘better meter,’ ” he says. “This is a planetary emergency. We want regulations and a buy-in from industry and EPA for zero emissions.”
- Chemical & Engineering News
- ISSN 0009-2347
- Copyright © American Chemical Society