Published on July 28th, 2014 | by Sandy Dechert7
Do Fugitive Emissions Of Methane Create A Fossil Fuel Tossup?
July 28th, 2014 by Sandy Dechert
A longer version of this article, with commentary, was released in one of our sister publications, Planetsave, on Sunday, July 27.
Scientific American has raised an issue that’s been puzzling environmental and climate scientists since the beginnings of the natural gas boom in the United States. With ClimateWire, the nation’s most reputable lay science journal published a review of two articles last week by Stefan Schwietzke, a researcher at the National Oceanic and Atmospheric Administration’s Earth Systems Research Laboratory in Boulder, Colorado, in Environmental Science & Technology and Sustainable Chemistry and Engineering. One of the papers begins:
“The amount of methane emissions released by the natural gas (NG) industry is a critical and uncertain value for various industry and policy decisions, such as for determining the climate implications of using NG over coal.”
Concerned about a possibly freewheeling decision to phase out coal for power in favor of America’s bountiful natural gas reserves, which emit only half the carbon dioxide of coal energy, Schwietzke’s team went after some concrete data on fugitive emissions of methane from leaks at gas drilling wellheads and through pipelines and processing infrastructure. His researchers worked out the methodology seen at right.
They recalculated previous inventories from the Environmental Protection Agency, Intergovernmental Panel on Climate Change, and other sources to pin down oilfield and coal emissions with more certainty. They then made natural gas calculations and put the results through a custom atmospheric computer model. And guess what? The researchers concluded that “further emissions reductions by the NG industry may be needed to ensure climate benefits over coal during the next few decades.”
It turns out that fugitive emissions of methane from gas drilling and production are probably more harmful to the world’s climate than previously thought. Much more harmful. Until now, scientists had lowballed the potential for fugitive emissions of methane from gas drilling. EPA’s current estimate of emissions, set at 1.2% mostly on the basis of petroleum company estimates, was much lower than the range of averages computed by the new study (2–4%). Three percent is the generally accepted tipping point. Outlier results from some sites measured even higher, with Utah’s Uinta basin drilling apparently the most dangerous, at almost 10%. The Europe-based Emissions Database for Global Atmospheric Research (EDGAR) had also underestimated methane production. The disparity between bottom lines appears to stem from this prior failure to accurately gauge fugitive emission rates for methane. (More details are in the Planetsave article if you are interested.)
Schwietzke’s results were published last week in two respected and peer-reviewed scientific journals: Environmental Science & Technology and Sustainable Chemistry and Engineering. They go a long way toward confirming previous independent findings by David Allen of the University of Texas, Robert Howarth at Cornell, and Scot Miller from Harvard.
Petroleum geologists and engineers have known about the technology to tap the nation’s deep shale natural gas potential for decades. They back-burnered it because petroleum prices hadn’t gone high enough to meet expenses, but now that oil has gone up and up and become scarcer, it’s possible to justify the costly and disruptive hydraulic fracturing needed to go after deep-shale gas.
When the economics appeared to work out, oil and gas companies leapt right onto fracking. President Obama leapt right after them with the “transitional (bridge) fuel” idea. Suddenly, the American financial forecast looked a lot brighter. The President has started backpedaling on the greenhouse gas issue a bit since the National Climate Assessment and other studies earlier this year began clarifying the emissions scenarios.
Now that he appears to know the real score on fracking and fugitive emissions, however, perhaps we can expect further efforts on renewables. After all, they’re cheaper and farther along in development than carbon capture and storage.
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