Methane leaks erode green credentials of natural gas, Losses of up to 9% show need for broader data on US gas industry’s environmental impact by Jeff Tollefson, January 2, 2013, Nature, doi:10.1038/493012a
Scientists are once again reporting alarmingly high methane emissions from an oil and gas field, underscoring questions about the environmental benefits of the boom in natural-gas production that is transforming the US energy system. The researchers, who hold joint appointments with the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado in Boulder, first sparked concern in February 2012 with a study1 suggesting that up to 4% of the methane produced at a field near Denver was escaping into the atmosphere. If methane — a potent greenhouse gas — is leaking from fields across the country at similar rates, it could be offsetting much of the climate benefit of the ongoing shift from coal- to gas-fired plants for electricity generation. Industry officials and some scientists contested the claim, but at an American Geophysical Union (AGU) meeting in San Francisco, California, last month, the research team reported new Colorado data that support the earlier work, as well as preliminary results from a field study in the Uinta Basin of Utah suggesting even higher rates of methane leakage — an eye-popping 9% of the total production. That figure is nearly double the cumulative loss rates estimated from industry data — which are already higher in Utah than in Colorado. “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, who led the aerial component of the study as head of the aircraft programme at NOAA’s Earth System Research Laboratory in Boulder.
Pétron and her colleagues have a defence of the Colorado study in press3, and at the AGU meeting she discussed a new study of the Denver–Julesburg Basin conducted with scientists at Picarro, a gas-analyser manufacturer based in Santa Clara, California. That study relies on carbon isotopes to differentiate between industrial emissions and methane from cows and feedlots, and the preliminary results line up with their earlier findings. A great deal rides on getting the number right. A study4 published in April by scientists at the EDF and Princeton University in New Jersey suggests that shifting to natural gas from coal-fired generators has immediate climatic benefits as long as the cumulative leakage rate from natural-gas production is below 3.2%; the benefits accumulate over time and are even larger if the gas plants replace older coal plants. By comparison, the authors note that the latest estimates from the US Environmental Protection Agency (EPA) suggest that 2.4% of total natural-gas production was lost to leakage in 2009. To see if that number holds up, the NOAA scientists are also taking part in a comprehensive assessment of US natural-gas emissions, conducted by the University of Texas at Austin and the EDF, with various industry partners. The initiative will analyse emissions from the production, gathering, processing, long-distance transmission and local distribution of natural gas, and will gather data on the use of natural gas in the transportation sector. In addition to scouring through industry data, the scientists are collecting field measurements at facilities across the country. The researchers expect to submit the first of these studies for publication by February, and say that the others will be complete within a year. In April, the EPA issued standards intended to reduce air pollution from hydraulic-fracturing operations — now standard within the oil and gas industry — and advocates say that more can be done, at the state and national levels, to reduce methane emissions. “There are clearly opportunities to reduce leakage,” says Hamburg.
Bridge To Nowhere? NOAA Confirms High Methane Leakage Rate Up To 9% From Gas Fields, Gutting Climate Benefit by Joe Romm, January 2, 2013, Think Progress
Researchers with the National Oceanic and Atmospheric Administration (NOAA) have reconfirmed earlier findings of high rates of methane leakage from natural gas fields. If these findings are replicated elsewhere, they would utterly vitiate the climate benefit of natural gas, even when used to switch off coal.
Indeed, if the previous findings — of 4% methane leakage over a Colorado gas field — were a bombshell, then the new measurements reported by the journal Nature are thermonuclear:
… the research team reported new Colorado data that support the earlier work, as well as preliminary results from a field study in the Uinta Basin of Utah suggesting even higher rates of methane leakage — an eye-popping 9% of the total production. That figure is nearly double the cumulative loss rates estimated from industry data — which are already higher in Utah than in Colorado.
Leakage of 4%, let alone 9%, would call into question the value of unconventional gas as any sort of bridge fuel. Colm Sweeney, the head of the aircraft program at NOAA’s Earth System Research Laboratory, who led the study’s aerial component, told Nature:
“We were expecting to see high methane levels, but I don’t think anybody really comprehended the true magnitude of what we would see.”
The industry has tended kept most of the data secret while downplaying the leakage issue. The Environmental Defense Fund (EDF) is working with the industry to develop credible leakage numbers in a variety of locations. The earlier NOAA findings were called into question by Michael Levi of the Council on Foreign Relations. The NOAA researchers “have a defence of the Colorado study in press,” Nature notes. Right now, fracking would seem to be a bridge to nowhere. [Emphasis added]
[Both NOAA studies address upstream/midstream emissions only; transmission, storage, and distribution losses need to be added]