New fuel for coal vs. gas debate
www.timesleader.com/news/New_fuel_for_coal_vs__gas_debate_12-27-2011.html
December 27, 2011
By Steve Mocarsky smocarsky@timesleader.com
Wilkes-based group finds natural gas has smaller greenhouse footprint.
A research group based at Wilkes University recently revised its position on whether burning coal or natural gas has a worse impact on the environment and global warming.
Based on several new studies, the Institute for Energy and Environmental Research of Northeastern Pennsylvania concluded that, contrary to findings in an April study by researchers at Cornell University, natural gas produced from Marcellus Shale wells has a lower greenhouse footprint than coal.
According to the institute essay, the use of natural gas and the other fossil fuels for energy releases greenhouse gases, especially carbon dioxide, into the atmosphere. Those gases are thought to increase global temperatures.
Studies conducted between 2000 and 2007 suggested that natural gas produces fewer greenhouse gases than coal, especially when used to generate electricity.
But a study by a team of researchers at Cornell University published in April found that extracting natural gas from shale released large quantities of methane – a far more potent greenhouse gas than carbon dioxide.
The researchers concluded that when the full life-cycle of energy extraction, delivery and use is considered, shale gas produces up to twice the greenhouse gas emissions compared to burning coal or oil – especially when viewed over a 20-year time span.
However, seven analyses released in the summer and fall of 2011 came to a different conclusion than the Cornell study. All seven found that natural gas produces 20 percent to 60 percent lower greenhouse gas emissions, especially when used for electrical generation and when viewed over a 100-year time span.
The discrepancies between the Cornell and subsequent studies appear to result primarily from the different time frames used (20-year time frame versus 100-year).
Kenneth Klemow
Wilkes professor Kenneth Klemow, one of the authors of the institute essay, was hesitant to rank as more credible either the Cornell study or a study by Carnegie-Mellon University researchers that the energy industry said disputed the Cornell study when the Carnegie-Mellon study came out in August.
Klemow had said the Carnegie-Mellon study tipped the balance more in favor of natural gas, but only “by a little bit.” While the gas industry had claimed the CMU study slam-dunked the Cornell study, Klemow said he wasn’t so sure about that.
He was sure that more research was needed and researchers needed to take more field measurements rather than rely on data from previous studies.
Klemow said last week that because of several new articles and reports that have come out in the past three months, researchers at the institute found it necessary to issue an update on the original position.
“The main message is that seven independent studies now agree that shale gas has a lower greenhouse footprint than coal. That conclusion largely contradicts the findings by a team of researchers at Cornell who published a paper last April that argued shale gas has a higher footprint than coal due to inadvertent releases of methane at gas wells,” Klemow said.
In addition to incorporating the findings of the recent studies, the institute included some graphics to illustrate key trends that have been observed. And in addition to summarizing the research to date, they say they provide “our own synthesis – especially relating to future research needs.”
“Scientists are becoming increasingly convinced that burning fossil fuels releases gases that affect our climate,” Klemow said. “Therefore, studies comparing emissions of natural gas against coal are vital if we want to have informed discussions and make wise choices.”
“While recent analyses generally show natural gas has a lower footprint than coal, the science is far from settled. More studies of methane leakage near Marcellus wells and pipelines are critically needed to give us a more accurate picture,” he said.