A new U.S. Environmental Protection Agency (EPA) study released last week indicates the agency may be greatly exaggerating oil and natural gas system methane emissions.
By using a combination of extractive air sampling and remote optical gas imaging (OGI) tools to analyze 80 pneumatic control systems across eight well pads, the study found oil and gas methane emissions in Utah’s Uinta Basin are “significantly lower” than previously thought.
In fact, EPA researchers found methane emissions from intermittent bleed devices were 97 percent lower than the standard emission factor for intermittent pneumatic control devices EPA uses for estimates in its Greenhouse Gas Inventory(GHGI). The researchers wrote,
“The average IPC emission rate estimate of 0.32 scf/h was significantly lower than the GHG Inventory IPC emission factor of 13.5 scf/h per device.”
This is relevant on a national scale considering the EPA’s latest inventory reported 45 percent of oil and gas system methane emissions in 2015 were attributable to pneumatic controllers. The researchers acknowledge the significance of this finding by noting pneumatic devices are the “most significant sources of CH4 in ONG production field operations.”
And as EID has pointed out numerous times, EPA has used faulty methodology the past two years to calculate national oil and gas production segment pneumatic device counts. This is in partly due to the fact that starting in 2016, the agency started extrapolating leakage rate data from larger facilities that report to the Greenhouse Gas Reporting program onto these smaller wells under the false assumption that smaller wells have similar equipment counts and emission profiles.
This led to exaggerated equipment counts — particularly for pneumatic controllers, starting with the 2016 GHGI — and exaggerated emission estimates. For example, reported methane emissions from pneumatic controllers more than doubled in the 2016 GHGI compared to the 2015 GHGI for both natural gas and petroleum systems.
Fortunately, since the purpose of the study was to “improve information on a variety of factors affecting well pad PC emission characterization,” it appears the new data will be used by EPA to improve its methodology for calculating pneumatic controller emissions. As Western Energy Alliance’s Ryan Streams said,
“The Uinta Basin pneumatic controller study is the latest in a series that have consistently demonstrated emissions from this type of equipment are much lower than previous EPA estimates. We’re pleased to see research supporting what industry has been suggesting for some time now.
“We’re hopeful that EPA will take this study along with the growing body of scientific evidence as an opportunity to revisit its emission factors for pneumatic controllers.”
The EPA study also finds that emissions of volatile organic compounds (VOCs) are lower than previously believed, further confirming a 2016 report also found that VOC emissions were about half of previous estimates.
In the interest of full disclosure, EID notes this study was published by Scientific Research Publishing, an open access journal which recently published a deeply flawed and inflammatory study claiming fracking has increased infant mortality rates in Pennsylvania. However, in sharp contrast to that study — which didn’t bother to take actual measurements to support its topline finding or consider other potential contributing factors — this EPA-funded study took direct measurements to come to these conclusions.
Furthermore, it was primarily funded by an EPA Regional Applied Research Effort (RARE) internal project grant issued during the Obama administration.