Study Shows that Shale Gas Is Over 50 Percent Cleaner than Coal

E&E News PM
October 25, 2011

Shale Emissions Better Than Coal—Study
Nathanial Gronewold

In the latest in a series of reports on the greenhouse gas (GHG) emissions associated with extracting natural gas through hydraulic fracturing and horizontal drilling, researchers from the University of Maryland released a report today concluding that while the GHG emissions for shale natural gas are 11 percent higher than for conventional gas, the fuel has 56 percent lower emissions than coal when used for electricity generation. This report strongly contradicts an analysis performed by Robert W. Howarth, Renee Santoro, and Anthony Ingraffea of Cornell University (published in Climate Change Letters, March 13, 2011), which suggested that GHG emissions from shale gas production would be comparable to or worse for the climate than coal. The Maryland report concludes that:

  • The fugitive emissions from the hydraulic fracturing and horizontal drilling process are very likely not substantially higher than for conventional gas;
  • The greenhouse footprint of shale gas and other unconventional gas resources is about 11% higher than that of conventional gas for electricity generation, and still 56% that of coal;
  • If the spread in future fleet efficiencies between gas and coal increases over the coming decades, this differential from coal will continue to increase;
  • Additional technologies to ensure reasonable capture of fugitive emissions may be able to reduce the disparity between shale gas and conventional gas; and
  • Any regulatory standard that classifies conventional gas as a source of ‘clean energy’ should therefore consider shale gas in this context; arguments that shale gas is more polluting than coal are largely unjustified.

At the same time, the authors of the Maryland study included cautioned that “unconventional gas technology poses other challenges” and that “[a]s a new technology, its deployment has arguably outpaced the ability of the policy and scientific communities to understand and regulate the possible environmental and health consequences of the fracking process.”