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Wayne Independent - Honesdale, PA
  • Study: Methane leaks make fracked gas 'dirtier' than coal, oil

  • A new Cornell University study suggests that natural gas produced using the hydraulic fracturing process contributes the same or larger amounts of greenhouse gas emissions than coal or oil.


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  • A new Cornell University study suggests that natural gas produced using the hydraulic fracturing process contributes the same or larger amounts of greenhouse gas emissions than coal or oil.
    The new study says "fugitive methane" — vented gas that escapes from flow-back and leakage — is a major contributor to the greenhouse gas footprint of shale gas.
    A final copy of the study, called Methane and the Greenhouse-Gas Footprint of Natural Gas from Shale Formations, was released Monday. It is authored by Cornell Professors Robert Howarth, Renee Santoro and Anthony Ingraffea. It will appear in the May edition of the peer-reviewed journal Climactic Change Letters.
    Howarth, a professor of ecology and environmental biology, warns that contrary to natural gas being touted as a clean-burning fuel, we should be worried about high amounts of methane gas leaking into the atmosphere.
    “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 stated in a press release. “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.”
    The warming impact of methane is 105 times more (pound for pound) than carbon dioxide, Howarth says, adding that even small leaks make a big difference.
    The report shows that roughly 3.6 to 7.9 percent of methane from shale-gas production escapes to the atmosphere in venting and leaks over the life-time of a well, causing emissions that are 30 percent more than and perhaps more than twice as great as those from conventional gas.
    Howarth said 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.
    “The higher emissions from shale gas occur at the time wells are hydraulically fractured — as methane escapes from flow-back return fluids — and during drill out following the fracturing,” according to the report.
    The report says that methane leaks from the hydraulic drilling process, as well as “fugitive emissions” — small leakages of gas — are major contributors to greenhouse gas footprint of shale gas.
    According to the report, the large greenhouse gas footprint “undercuts the logic” of it use as a bridging fuel over coming decades, if the goal is to reduce global warming.
    Howarth, Santoro and Ingraffea compared estimated emissions for shale gas, conventional gas, coal 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.
    Page 2 of 2 - 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, according to Cornell University spokesman Joe Schwartz.
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