Studies Duel Over Natural Gas Climate Impact
Morgantown Dominion Post
20 January 2012
By Associated Press
ALBANY, N.Y. — Two groups of scientists at Cornell University are
dueling over whether natural gas from shale is better or worse
than coal when it comes to global climate change.
It’s a significant question because proponents of shale gas
development using the controversial practice of high-volume
hydraulic fracturing argue that natural gas is a cleaner-burning
“bridge fuel” from the age of coal to an era of wind, solar and
other sustainable energy sources.
The U.S. Energy Information Administration projects that
unconventional gas, mainly from shale, will supply nearly half of
U.S. gas production by 2035. One of the core benefits of tapping
vast shale gas reserves such as the Marcellus shale beneath
southern New York, Pennsylvania, Ohio and West Virginia, is the
belief that it produces less greenhouse gas than coal.
Opponents of shale development cite potential damage to health and
the environment, especially water supplies, from hydraulic
fracturing, or “fracking,” which injects a well with chemically
treated water to stimulate production. They also have seized on
the greenhouse gas study published by Cornell’s Robert Howarth in
the journal Climatic Change last spring.
In that study, and in a follow-up released Thursday, Howarth said
methane leakage at the well, along aging pipelines and at other
points give shale gas development a worse greenhouse gas footprint
than that of coal. He estimated that as much as 8 percent of
methane from shale gas production escapes into the atmosphere,
where it is a far more potent greenhouse gas than carbon dioxide.
Howarth and colleagues Renee Santoro and Anthony Ingraffea wrote
that the greenhouse gas footprint of shale gas is “perhaps more
than twice as great” as coal when you compare the two energy
sources over a 20-year time frame, and comparable to coal over a
100-year time frame.
That flies in the face of previous estimates that the greenhouse
gas impact of natural gas is about half that of coal.
Cornell colleague Anthony Cathles countered the Howarth study in
the same journal this month, challenging Howarth’s calculations
and conclusions. He noted that natural gas is widely considered to
be cleaner than coal because it doesn’t produce hazardous
by-products such as sulfur, mercury, ash and particulates, and it
provides twice the energy per unit of weight when it’s burned.