Gas Leaks in Fracking Disputed in Study
New York Times
16 September 2013
By Michael Wines
Drilling for shale gas through hydraulic fracturing, or fracking,
appears to cause smaller leaks of the greenhouse gas methane than
the federal government had estimated, and considerably smaller
than some critics of shale gas had feared, according to a
peer-reviewed study released on Monday.
The study, conducted by the University of Texas and sponsored by
the Environmental Defense Fund and nine petroleum companies,
bolsters the contention by advocates of fracking — and some
environmental groups as well — that shale gas is cleaner and
better than coal, at least until more renewable-energy sources are
developed. More than 500 wells were analyzed.
The Texas study concluded that while the total amount of escaped
methane from shale-gas operations was substantial — more than one
million tons annually — it was probably less than the
Environmental Protection Agency estimated in 2011.
In particular, it indicated that containment measures captured 99
percent of methane that escaped from new wells being prepared for
production, a process known as completion.
The Environmental Protection Agency has begun to require drillers
to control leaks during completions, which are believed to be one
of the major sources of methane losses at fracking wells. Although
controls will not be required until January 2015, a number of
companies already capture escaped gases at wells being prepared
“Can we control it? Thanks to new E.P.A. regulations coming
online, the answer to that is good news,” Eric Pooley, a senior
vice president at the Environmental Defense Fund, said in an
The report was published Monday in The Proceedings of the National
Academy of Sciences. With the study, which ran from May through
December of last year, the university was the first to conduct
detailed examinations of individual drilling sites. It did so with
the consent of petroleum companies, which provided about 90
percent of the financing for the study. Previous E.P.A. estimates
relied on engineering calculations, and other studies gathered
data via aircraft flights over drilling sites.
The study’s connection to the petroleum industry — among its
sponsors and financiers are Shell, Anadarko Petroleum Corporation,
Exxon Mobil and Chevron — may lead some to question its
objectivity, some outside experts said. But most said the research
and the reputations of the researchers appear solid.
“Previous studies that have gotten a lot of attention have had red
flags jumping out all over them. This one didn’t,” said Michael A.
Levi, the director of the program on energy security and climate
change at the Council on Foreign Relations. In an e-mailed
statement, Shell’s president, Marvin Odum, called the study “a
prime example of key groups — that may not have the exact same
interests — working collaboratively and taking a science-based
approach” to the methane problem.
Mr. Odum said that collecting actual emissions data, rather than
relying on estimates, would “ensure that both improvement efforts
and regulatory changes can be focused on the areas that will have
the biggest impact.”
The report comes at a time when shale-gas drilling is growing at a
breakneck pace — production, now 30 percent of all United States
natural gas, is expected to reach 50 percent by 2040 — but also
when the industry is beset by controversy.
Citizen groups accuse drillers of despoiling streams and water
supplies, and suppliers of wrecking local roads with parades of
massive trucks. Environmental groups have split sharply over
whether to support shale-gas development as a cleaner fuel that
will suffice until wind and solar power assume a greater share of
the nation’s energy supply.
The Texas study is the most comprehensive look to date at a
contentious issue in the debate over fracking: the extent to which
methane leaks during drilling and production offset the
environmental benefits of the clean-burning natural gas the wells
When burned as fuel, methane — the main component of natural gas —
is comparatively clean, producing less carbon dioxide than coal
and oil. But vented to the air, it is a short-lived but extremely
potent greenhouse gas, trapping heat at a much higher rate than
carbon dioxide, the main greenhouse gas.
Such potency means that even a small loss of methane to the air —
just 3.4 percent, scientists say — can negate its climate-changing
advantage over coal.
Some previous studies suggested that as much as 7.9 percent of all
shale gas was lost to the atmosphere, a figure that included every
stage of the gas process, from well to stove or furnace burner.
The Texas study did not examine potential losses outside the
drilling pad. But its conclusion that losses at the well were
comparatively low could remove one issue from the debate. The
Environmental Defense Fund is leading other research efforts that
should address losses elsewhere, including a look at methane leaks
in municipal gas-distribution lines.
The American Petroleum Institute hailed the study’s conclusions,
saying in a statement that its own efforts to reduce methane
emissions “are paying off.” But while E.P.A.-mandated measures
appear to have reduced emissions during well completions, the
study also concluded that leaks elsewhere in the fracking process
were higher than the E.P.A. had previously estimated.
Estimates of leaks from chemical pumps, while small, were twice
past estimates, while leaks from pneumatic controllers, or valves,
were pegged at more than 639,000 tons a year, roughly a third
greater. None of those components are currently subject to federal