SURPRISE? Not. Natural Gas mining is dirtier than coal, Cornell study says

[Hans Laetz, Newsgroup Editor]

Natural Gas Stature Undercut
Gas lobby fires back

Ken Silverstein | Apr 13, 2011


Natural gas’ stature may get undercut. A new study says it is
responsible for a lot more greenhouse gas emissions than either coal
or oil.



The analysis by Cornell University says that the total greenhouse
gases over 20 years as a result of exploring for shale are at least 20
percent greater -- possibly as much as double -- when compared to
those of coal. That’s because natural gas is composed mostly of
methane, which may have the ability to dissipate but is still capable
of trapping more heat than carbon dioxide.



“The large greenhouse gas footprint of shale gas undercuts the logic
of its use as a bridging fuel over coming decades, if the goal is to
reduce global warming,” says Robert Horvath, a Cornell University
ecology professor and lead author of the study. “We do not intend that
our study be used to justify the continued use of either oil or coal,
but rather to demonstrate that substituting shale gas for these other
fossil fuels may not have the desired effect of mitigating climate
warming.”



After the Japanese nuclear accident, the natural gas lobby has
positioned itself as the wonder boy. But this most recent study cast a
pall over that and all at a time when the U.S. Energy Information
Administration is saying that natural gas will increase its market
from roughly 20 percent today to 45 percent by 2035.
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That’s largely attributable to the expected growth of the shale-gas
sector. Those deposits are extracted by pumping a concoction of
chemicals a mile underground to loosen the gas from the rocks where it
is embedded. Critics, who have been arguing that such “fracking” is
polluting the ground water, now have a powerful new point -- that the
gas is not as pollution-friendly as its supporters have claimed.



The conventional wisdom is that natural gas releases about half the
emissions as coal, and specifically carbon dioxide. The Cornell
professor is casting doubt on that conclusion -- using research from
the U.S. Environmental Protection Agency and the Council of Scientific
Society Presidents. The former says leakage from distribution lines is
more than previously thought while the latter warns that shale-gas may
aggravate rather than mitigate global warming.


“Very little is known about the greenhouse gas footprint of
unconventional gas,” writes Horvath.



Firing Back



The natural gas industry has been quick to fire back. One of its main
contentions is that the Cornell study does not consider that methane
emissions are also released during the production of coal. Energy
InDepth goes on to say that the study’s assumptions are faulty and
notes two shortcomings:



The first is that the 20-year time horizon it uses to make its
calculations do not coincide with the more accepted 100-year time
frame by scientists under the United Nation’s framework. The second
one is that the estimated methane releases from shale exploration are
vastly overstated -- 320 percent greater than what the UN’s scientists
had assumed.



The reason that the shorter time frame used by Cornell’s ecologist is
erroneous, the organization says, is because of methane’s ability to
dissipate. After 100 years, the natural gas lobby says that the
methane is “long gone.” Carbon dioxide, by comparison, is still around
after 100 years.



Similar concerns are echoed by the environmental group Worldwatch
Institute, which says that the same life cycle assessment is needed
for both gas and coal. The group has previously said that natural gas
can be an effective bridge fuel until green energy sources are full
developed.



“The study’s conclusions rely almost entirely on the application of a
Global Warming Potential factor that’s 45 percent higher for natural
gas than the one cited by the UN’s Intergovernmental Panel on Climate
Change (IPCC) in 2007,” says Energy InDepth.



The Cornell study is unlikely to derail the future of shale-gas. But
it will give new ammo to its critics, who will use it bring about new
rules to make the exploration process safer.