Methane Leaks Can Make Fracking Gas ‘Dirtier’ than Coal Or Oil
4/11/2011 - Cornell University - Newswise — ITHACA, N.Y. –
Extracting natural gas from the Marcellus Shale could do more to
aggravate global warming than mining coal, according to a Cornell
study published in the May issue of the peer-reviewed journal
Climatic Change Letters.
While natural gas has been touted as a clean-burning fuel that
produces less carbon dioxide than coal, ecologist Robert Howarth
warns that we should be more concerned about methane leaking into
the atmosphere during hydraulic fracturing.
Natural gas is mostly methane, which is a much more potent
greenhouse gas, especially in the short term, with 105 times more
warming impact, pound for pound, than carbon dioxide, Howarth said,
adding that even small leaks make a big difference.
that as much as 8 percent of the methane in shale gas leaks into the
air during the lifetime of a hydraulic shale gas well – up to twice
what escapes from conventional gas production.
“The take-home message of our study is that if you do an integration
of 20 years following the development of the gas, shale gas is worse
than conventional gas and is, in fact, worse than coal and worse
than oil,” Howarth said.
“We are not advocating for more coal or
oil, but rather to move to a truly green, renewable future as
quickly as possible. We need to look at the true environmental
consequences of shale gas.”
Howarth, a professor of ecology and environmental biology,
Tony Ingraffea, professor of engineering, and Renee Santoro, a research
technician in ecology and evolutionary biology, analyzed data from
published sources, industry reports and even PowerPoint
presentations from the Environmental Protection Agency.
They compared estimated emissions for shale gas, conventional gas,
coal (surface-mined and deep-mined) and diesel oil, taking into
account direct emissions of CO2 during combustion, indirect
emissions of CO2 necessary to develop and use the energy source and
methane emissions, which were converted to equivalent value of CO2
for global warming potential.
The study is the first peer-reviewed paper on methane emissions from
shale gas, and one of the few exploring the greenhouse gas
footprints of conventional gas drilling.
Most studies have used EPA
emission estimates from 1996, which were updated in November 2010
when it was determined that greenhouse gas emissions of various
fuels are higher than previously believed.
“We are highlighting unconventional gas because it is a contemporary
problem for us in upstate New York, and because there is a big
difference between developing gas from an unconventional well and a
conventional well, for the mere reason that unconventional wells are
bigger,” Ingraffea said.
He noted that the hydraulic fracturing process lends itself to more
leakage because it takes more time to drill the well, requires more
venting and produces more flowback waste, he said.
“We do not intend for you to accept what we’ve reported on today as
the definitive scientific study in regards to this question.
clearly not,” he added. “What we’re hoping to do with this study is
to stimulate the science that should have been done before.
opinion, corporate business plans superseded national energy