A bridge to nowhere?
Early into the new year, researchers measuring methane leaks from natural gas fields in Utah found that far more of the climate-forcing gas was being emitted than they thought (methane is 20 times more potent than carbon dioxide in trapping heat). Preliminary results from that research, in the Uinta Basin, show that 9 percent of the total methane produced there is being leaked to the atmosphere.
To put that percentage into context, in order for natural gas operations (from well to city) to produce less climate impact than the life cycle carbon emissions of a new coal-fired power plant, leakage from natural gas operations needs to be under 3.2 percent. Given that, 9 percent is a little crazy.
Uinta gas field, viewed from above. Image courtesy Flickr user SkyTruth.
"We were expecting to see high methane levels, but I don’t think anybody really comprehended the true magnitude of what we would see," says Colm Sweeney, part of the research team and a scientist at NOAA's Earth Systems Laboratory in Boulder.
These high leakage numbers (a 4 percent rate was found in a Colorado gas field last year, and a Cornell study last year also called into question natural gas's climate benefits, although the leak measuring methodology has been questioned by other researchers [PDF]) are problematic if natural gas is supposed to be a clean energy bridge to renewables. Models created by the Environmental Defense Fund show that natural gas does have potential to lower carbon emissions significantly, especially if it is part of a switch to a natural gas-renewable mix, but those models assume a 2.8 percent leak rate or lower. Natural gas power plants are also viewed as a key part of switching to renewables, because those plants can come online quickly, relative to coal plants, helping to keep the energy supply constant when used in concert with variable sources like wind and solar.
Another new study looking at methane escapes in cities also brought some bad news, finding that pipelines are leaking in many places. The team, led by Boston University researcher Nathan Phillips, used a cool new piece of monitoring technology from a California-based company, Picarro, that lets researchers mount a methane detector on a car and drive around, finding leaks. The monitor also uses isotope detectors to determine what source the leaks come from, differentiating between pipeline leaks and other sources, like swamps or leaking landfills. The researchers on that study found 3,356 methane leaks coming from fossil fuel sources.
Upper image: Methane leaks (3356 yellow spikes > 2.5 ppm) mapped on Boston's 785 road miles (red) surveyed in this study. Lower image: Leaks around Beacon Hill and the Massachusetts State House. Sample values of methane concentrations (ppm) are shown for each panel. From Mapping urban pipeline leaks: Methane leaks across Boston.
While Phillips says they don't yet know the magnitude of those leaks, he told Andrew Revkin at the Times' Dot Earth blog he expected most were small, but there were likely a few really large ones, which not only waste gas, but also pose an explosion risk.
Another study looking at methane leaks from a number of natural gas fields, led by the University of Texas, Austin and in cooperation with Environmental Defense Fund and many of the nation's largest natural gas producers, is set for completion this month. The size and scope of this study make its results particularly interesting, because it will provide a better sense of leakages in a number of gas fields, versus the more localized studies in Utah and Colorado. Stay tuned.
Stephanie Paige Ogburn is the online editor at High Country News.
