Fracking study sends alert about leakage of potent greenhouse gas
A new study finds that fracking is releasing methane, a greenhouse gas, from a Colorado field at a higher rate than estimates suggested. Researchers must determine if the field is an anomaly or part of a bigger problem.
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Prior to the latest study, the US Environmental Protection Agency and gas companies derived methane-leakage estimates by measuring emissions at a small number of wells in a field, then extending the results to the entire field, says Robert Howarth, an ecologist at Cornell University.Skip to next paragraph
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The NOAA/UC-Boulder team used atmospheric-chemistry measurements taken from a 300-foot air-sampling tower north of Denver, as well as measurements taken from an instrument-laden car.
The tower is one of several NOAA has sprinkled around the US to track greenhouse-gas emissions as well as pollutants that affect air quality. Instruments on the tower picked up pulses of methane-enriched air when winds blew from the northeast, where the gas fields – part of a broader area of production known as the Denver-Julesburg Basin – are located.
The relative abundance of methane and volatile organic compounds in a plume varies by source, a feature that allowed the team to match the methane from the northeast to gas fields.
The new results represent one study in one field, and may or may not represent what's happening elsewhere, cautions Dr. Howarth, who led a different study that came to similar conclusions about general leakage rates based on previously published estimates. The study appeared last year in the journal Climatic Change.
But the numbers available to him and his colleagues during their research were “pretty lousy,” he says. The new results represent “the first comprehensive field-based set of measurement we have” on the issue.
The NOAA/UC-Boulder team, led by ESRL scientist Gabrielle Peron, have been in the field in Utah during the past several days working with industry representatives to conduct a more detailed study of the Unita Basin, another gas field. Where the previous study identified the location of the methane, the new work aims to pinpoint individual sources in a field to help guide efforts to reduce emissions.
In April, the US EPA is slated to publish new rules on capturing rogue methane emissions. Until now, emission controls typically applied to oil and gas processing facilities, notes Meleah Geertsman, an air-quality policy specialist with the Natural Resources Defense Council in Washington.
The new rules extend the need for emissions controls to wells and other field equipment, such as compressors and pumps.
Although the new rules leave decisions on when to upgrade these to more-leak-tight versions to the exploration companies, the new rules still represent “a major step forward” in controlling emissions, she says.
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