* Effects of fractured gas produces same emissions as coal
* Fractured gas produces 30 pct more emissions than oil
* Gas industry argues no hard data to support study
By Jon Hurdle
PHILADELPHIA, March 31 Natural gas obtained by
the controversial technique of hydraulic fracturing may
contribute significantly to greenhouse gas emissions and so
should not be considered as a cleaner alternative to coal or
oil, according to a Cornell University researcher.
Although natural gas, when burned, produces only about half
of the carbon dioxide emissions of coal, that calculation omits
greenhouse gas emissions from the well-drilling,
water-trucking, pipeline-laying, and forest-felling that are
part of the production of hydraulically fractured natural gas,
Ecology Professor Robert Howarth argues in a new paper.
Combining the effects of combustion, production,
distribution, and leaked methane from hydraulically fractured
natural gas gives the fuel about the same greenhouse gas
emissions as coal and about 30 percent more than diesel or
gasoline, Howarth says in the draft paper published in
"A complete consideration of all emissions from using
natural gas seems likely to make natural gas far less
attractive than other fossil fuels in terms of the consequences
for global warming," Howarth writes.
Energy companies are scrambling to develop vast reserves of
natural gas from deep shale beds in many U.S. states including
Texas, Louisiana, and Pennsylvania. Experts say shale gas could
meet national demand for a century while helping to reduce
carbon emissions and reducing petroleum imports.
"Government and industry should not be moving ahead on the
basis of what is already misleading and incomplete
information," Howarth told Reuters. He urged a moratorium on
further development in the multibillion-dollar industry until
more is known about its greenhouse gas emissions.
The damaging nature of gas from fracturing, or "fracking",
undermines claims that it is a "transition" fuel between
carbon-intensive sources like coal, and renewables such as
solar and wind, Howarth said in the paper.
Citing preliminary data, Howarth estimates total greenhouse
gas emissions from hydraulically fractured natural gas may be
equivalent to 33 carbon grams of CO2, slightly more than 31.9
grams for coal, and well above the 20.3 grams for diesel or
The data are partly based on methane leakage of 1.5 percent
of natural gas consumed, a figure assumed by the federal
Claims by energy companies that natural gas is a cleaner
alternative to coal and oil are further undermined by leaked
methane - the principal component of natural gas -- which is
many times more potent as a greenhouse gas component than CO2,
argued Howarth, who has served on National Academy of Sciences
panels looking into climate change, and has been a Cornell
professor since 1985.
Dan Whitten, a spokesman for America's Natural Gas
Alliance, an industry group, dismissed Howarth's assertions as
preliminary and speculative and not backed by hard data and
said the professor's statement undermined its own credibility.
"We concur with the author's own assessment that this
two-page draft is 'highly uncertain', that the 'numbers should
be treated with caution', and that there is 'no rigorous
estimate' to support its conclusions," Whitten said.
"Natural gas is twice as clean as coal and is available
here in America in significant abundance today," Whitten added.
"Alongside the development of renewables, natural gas has a
key role to play in transitioning our nation to a low-carbon
Howarth acknowledged his statement contains many qualifiers
but argued that there are sufficient concerns about the
greenhouse gas emissions of hydraulically fractured natural gas
to warrant early publication.
Critics also claim that fracking contaminates ground water
with chemicals that are forced deep underground along with
water and sand to fracture the shale and release its gas.
(Editing by Marguerita Choy)