Ever since the technique known as fracking unleashed massive reserves of natural gas in the U.S., the environmental cost of gas as an energy source has been a hot topic. Today, a new study out from the University of Texas aims to shed some light on the subject.
Supporters of natural gas power say it’s better than coal when it comes to climate change, since burning it produces less carbon dioxide. However, opponents say the methane that escapes into the atmosphere when gas is extracted from the ground might cancel out that benefit. Methane is a greenhouse gas many times more potent than CO2.
The report from UT concludes that a small share of wells produce much of the methane that leaks out during the gas production.
It also identifies certain pieces of equipment that contribute to the problem. It suggests that tighter scrutiny or regulation of wells may help reduce those emissions.
Lead researcher David Allen with UT's Cockrell School of Engineering says it’s similar to the way older, poorly operating cars are responsible for more than their fair share of air pollution.
"We need to be thinking about how do we find those vehicles that have the really high emissions and then get them fixed,” Allen says.
The study found that wells with certain kinds of pneumatic devices and plunger lifts created more methane emissions. It also illustrated a correlation between higher emissions and the geographic location of wells, the reservoir pressure of wells and the age of a well. Often these factors contribute to the need to removed liquid from wells, something that leads to the venting of emissions into the air.
“As wells get older and the amount of well pressure decreases, yes you would expect that it would then be more likely that you would need to do these unloadings,” said Allen.
The research is not likely to end debate over the impacts of natural gas production on global warming. It only looked at so called “upstream” impact of natural gas at the well site, and aims to identify the cause of much, but not all, emissions.
But some environmentalists hope it will allow regulators to significantly reign in greenhouse gas pollution from gas production.
The study was conducted with participation from some energy companies the Environmental Defense Fund, which has already pointed to the findings as a reason for creating a “national methane policy.”
The research is out today in the journal Environmental Science & Technology.
Below you can watch a video from the Cockrell School of Engineering explaining the extraction process used in hydraulic fracturing.