From Bloomberg News on Nov. 28:
By Mark Drajem
Methane released into the air after a natural gas well is tapped by hydraulic fracturing is on par with traditional drilling procedures, researchers from the Massachusetts Institute of Technology said in a report.
The findings of MITís Francis OíSullivan and Sergey Paltsev are at odds with estimates by Cornell University scientists, who concluded that natural gas produced by fracking can cause more global warming than burning coal.
Drilling companies have an economic interest in capturing the escaping gas, and in some states they are subject to regulations mandating that it be flared, not vented, the study concluded.
"When companies vent and flare methane they are losing gas that they could have captured and sold," Paltsev, the assistant director for economic research at the MIT Joint Program on the Science and Policy of Global Change, said in a statement.
Methane, a greenhouse gas linked to global warming, is the main component of natural gas. As the fracking process starts to free gas trapped in underground rock, some methane is released. The amount released can offset the global-warming benefits of natural gas over coal, Cornell University researcher Robert Howarth said in a study published last year.
When it is burned to produce electricity, natural gas emits about half the carbon dioxide, the main greenhouse gas, as coal, according to the Environmental Protection Agency. Methane is a more potent greenhouse gas, although it dissipates from the atmosphere more quickly.
The MIT study estimated actual emissions from wells that are fracked, the process in which water, sand and chemicals are shot underground to free trapped gas. Right after a well is fracked there is an initial period, called flowback, when the gas can be vented into the atmosphere or flared off.
Howarth assumed that all the gas is vented, the MIT paper said. "This is an unreasonable assumption, not least because some producing states have regulation requiring flaring as a minimum gas handling measure," Paltsev and OíSullivan said in their paper.
As a result, they conclude that those initial emissions represent 0.4 percent to 0.6 percent of a wellís estimated ultimate recovery. Howarth said those emissions could be as much as 3.2 percent.