Recent study shows that natural gas has less GHG Emissions
Natural gas produced in the Marcellus Shale gas basin in Pennsylvania and New York is not as big a contributor to climate change as coal, according to a study of the “life cycle” greenhouse gas emissions of natural gas by researchers in Pittsburgh.
Researchers at Carnegie Mellon University weighed into a growing body of analyses about the environmental impact of a natural gas boom stretching across the Northeast. The report refutes a recent study out of Cornell University that found that extracting gas from deep shale basins results in at least as big a greenhouse gas emissions footprint as that of coal.
Opponents of gas drilling leapt on the Cornell study as evidence that gas isn’t a clean replacement for coal and has just as big an impact on global warming. Many independent analysts found that study had significant flaws. Researchers in Carnegie Mellon’s environmental engineering and business departments disagreed with Cornell in their study published earlier this month in the journal Environmental Research Letters.
The report sticks with gas’s role as a source of power generation. Gas, however, is also an ingredient at heavy industrial plants like chemical factories. Disregarding how gas is used, the industrial process of drilling for shale gas means an 11 percent increase in greenhouse gas emissions compared to average U.S. gas production.
“Green completion and capturing the gas for market that would otherwise be flared or vented could reduce the emissions associated with completion,” said the researcher team, “and thus would significantly reduce the largest source of emissions specific to Marcellus gas preproduction.”
Still, according to the study, those emissions “are not substantial contributors to the lifecycle estimates, which are dominated by the combustion emissions of the gas.”
“Marcellus shale gas production is in its infancy,” it says. “Thus, industry practice is evolving and even single well longevity is unknown. Assumptions related to production rates and ultimate recovery have considerable uncertainty.”