In West Virginia, business and political leaders are eager to continue expanding this practice as companies seek to tap into the vast gas reserves contained in the Marcellus Shale, a formation that stretches across 95,000 square miles from Southern New York and into Eastern Ohio.
Burning coal for electricity produces about twice the carbon dioxide as burning natural gas, but some scientists remain concerned about methane emissions that leak from gas-drilling operations, in part because methane is a more potent greenhouse gas than carbon dioxide.
Two years ago, the issue gained much more attention with the publication of a study by a team of Cornell University researchers led by ecology professor Robert Howarth. That study reported that natural gas could be just as bad - or worse - than coal for global warming, especially if the issue is examined on the short time frame in which scientists believe action is needed to curb global warming.
Since then, industry officials have harshly criticized Howarth's study, and there's been a lively debate in scientific journals about his results and about the many variables used to estimate methane emissions from the shale-gas boom across the country.
After reviewing Monday's new study, Howarth issued a statement that called the findings "good news" and said, "it suggests that the oil and gas industry - when sufficiently motivated - can produce natural gas with modestly low emissions."
Howarth said that the new study's overall methane leakage rate - 0.42 percent of total gas produced - is slightly better than the low-end of the range his team published, which was 0.6 percent to 2.8 percent of total gas produced.
But Howarth cautioned that the new study was based only on measurements at sites chosen by the companies that partnered with EDF and UT researchers on the project. Other recent studies that didn't involve industry partners and used different measurement techniques found emissions that were 10- to 20-fold higher than reported in the new paper, Howarth said.
"When measurements are made at sites the industry chooses and at times the industry allows, emissions are lower than the norm," Howarth said. "They do better when they know they are being carefully watched."
Howarth also noted that the UT-EDF paper looked only at "upstream" gas-production emissions, and not at other potential emissions as natural gas is transported to consumers.
The new study is part of a larger research effort spearheaded by EDF to measure methane emissions throughout the natural gas supply chain. Results for the studies addressing other parts of the supply chain are planned during the next 12-18 months.
"This study did not look at methane emissions from processing, transportation, or distribution of natural gas," said Paulina Jarmillo, a Carnegie Mellon University engineer who has studied the industry's emissions. "Work on measuring emissions from those stages is ongoing. We should probably wait for those numbers before saying that this study proves or disproves what others have reported for the life-cycle greenhouse emissions of natural gas."
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.