Researchers from the University of Texas at Austin said their
direct measurements at 190 natural gas drilling sites found
lower methane emissions than the US Environment Protection Agency has suggested in earlier estimates.
The UT measurements summary found wells generally
emitted about 20% less greenhouse gases than EPA had estimated. Proceedings of the National Academy of Sciences
published the study, “Measurements of methane emissions at
natural gas production sites in the United States” on Sept. 16.
UT chemical engineering professor David Allen and other researchers measured methane emissions from shale gas
wells completed with hydraulic fracturing. The study results
released so far involved only the gas extraction phase.
Allen said the information will help policymakers make
informed decisions. Meanwhile, more work is pending on
other possible industry sources of methane emissions, such
Sponsored by the Environmental Defense Fund (EDF)
and natural gas producers, the study concluded that methane emissions from the development of gas and associated
liquids represent 0.42% of total production.
Large oil companies contributed financing to the study.
They include Anadarko Petroleum Corp., Exxon Mobil Corp.,
Pioneer Natural Resources Co., and Royal Dutch Shell PLC.
Meanwhile, Physicians, Scientists & Engineers for
Healthy Energy called the study “fatally flawed” because of
the sample size and industry influence. But UT researchers said their methodology was sound and the research was
Trade associations last year reported in a joint study of
their own that EPA estimates on methane emissions from
unconventional gas production were too high (OGJ Online,
July 2, 2012).
The American Petroleum Institute said the UT study’s findings demonstrate industry’s successful efforts to reduce
Howard Feldman, API director of regulatory and scientific affairs, said industry will continue making progress to
reduce emissions voluntarily and in compliance with EPA’s
recent emissions standards. “Capturing methane is helping
operators deliver more natural gas to consumers, creating
a built-in incentive to continue reducing these emissions,”
He emphasized the study results help show that additional regulation on top of existing federal, state, and local regulations are not necessary.
“In fact, safe and responsible development of energy from
shale has helped the US cut carbon dioxide emission to near
20-year lows.” Feldman said.
Erica Bowman, vice-president of research and policy
analysis for America’s Natural Gas Alliance, also welcomed
the study results.
“We are continually putting into operation equipment
and practices that demonstrate our commitment to lower
emissions in the production process,” Bowman said. “We
look forward to working with stakeholders to ensure the
best science is applied in future study of this issue.”
EDF said the report marked the first of 16 methane emis-
sions studies in a comprehensive initiative. The study marks
what EDF calls “the opening chapter in this broader scien-
tific effort designed to advance the current understanding
of the climate implications of methane emissions resulting
from the US natural gas boom.”
EDF Pres. Fred Krupp acknowledged that “immediate
methane reductions are critical to slow climate change,” add-
ing, “But we don’t yet have a handle on how much is being
emitted. We need better data, and that’s what this series of
studies will deliver.”
He said new EPA wellhead emission regulations are effec-
tive. The overall research effort started last year to measure
methane emissions associated with gas production, gather-
ing lines and processing facilities, long-distance pipelines
and storage, local distribution, and commercial trucks and
Various scientific methods are being used across the various studies, including approaches that measure emissions
directly at the source and those that use airplanes or towers
Study: Methane emissions from gas
production lower than EPA estimates