New warning on greenhouse impacts of natural gas

August 6, 2013 by Ken Ward Jr.


We’ve written before on this blog (see here, here, here, here and here) about the ongoing scientific debate over the impact that methane emissions from the natural gas industry could have on global warming, and on the potential for natural gas to help deal with that problem or, at least, serve as a “bridge” to a cleaner energy future based on renewables.

Now, there’s anther significant study out that adds to the discussion. The study itself provides a possible warning about natural gas emissions, but the report is already getting some criticism from both industry and environmental groups.

Here’s the press release from the University of Colorado Boulder:

On a perfect winter day in Utah’s Uintah County in 2012, scientists from the Cooperative Institute for Research in Environmental Sciences (CIRES) and colleagues at the National Oceanic and Atmospheric Administration (NOAA) tested out a new way to measure methane emissions from a natural gas production field.

Their results, accepted for publication in Geophysical Research Letters, constitute a proof-of-concept that could help both researchers and regulators better determine how much of the greenhouse gas and other air pollutants leak from oil and gas fields. The measurements show that on one February day in the Uintah Basin, the natural gas field leaked 6 to 12 percent of the methane produced, on average, on February days.

And from that release, here’s the paper’s central conclusion:

The team determined that methane emissions from the oil and natural gas fields in Uintah County totaled about 55,000 kg (more than 120,000 lbs) an hour on the day of the flight. That emission rate is about 6 to 12 percent of the average hourly natural gas production in Uintah County during the month of February.

A recent federal report estimated that methane’s leak rate, nationally, is less than 1 percent of production; another report noted that emissions in the Uintah (“Uinta”) Basin, which produces about 1 percent of total U.S. natural gas, may have higher emissions than typical for western gas fields. The Environmental Protection Agency’s Office of Inspector General has called for better emissions data from the natural gas sector, and this paper is one of the first published since. 

The industry group Energy In Depth has criticized the paper  noting it’s based on just one day’s worth of data, and commenting:

Some will see the publication of NOAA’s latest research as a reason to gin up fear about methane leaks from natural gas (and probably another excuse to write a story with “fracking” in the headline). But those of us who actually pay attention to details, data, and the growing consensus within the scientific community know better.


Also weighing in was Michael Levi of the Council on Foreign Relations, who provided a nuanced discussion of the paper here. And the Environmental Defense Fund also had a write-up on the study, including in it a mention of the uncertainty of the estimates presented:

The authors calculated the uncertainty of their measurements, finding a 68 percent chance the leak rate is between 6.2 and 11.7 percent, and a 95 percent chance it is between 3.5 and 14 percent.

EDF scientist Steven Hamburg explained by way of background:

Any amount of methane lost from the natural gas supply chain should be eliminated whenever possible. That’s because methane retains heat much more effectively relative to carbon dioxide: Over the first 20 years, an ounce of methane traps in heat 72 times more efficiently. Even small amounts vented or released as “fugitives” – unintentional methane leaked as gas moves from the field to your doorstep – can reduce or eliminate the climate advantage we think we’re getting when we substitute natural gas for coal or oil.
That said, in order to understand how to reduce the leaks we must recognize that each study offers a snapshot of emissions at a specific time, across a specific basin. Different industry sources make up the emissions profile in these areas, including distinct amounts of oil and gas production, and varying components of the natural gas supply chain (production, gathering, processing and local distribution). By comparison, the latest estimates from the U.S. Environmental Protection Agency suggest that 1.5 percent of total U.S. natural gas production was lost to venting or leakage in 2011. We have a lot of work to do to understand the apparent disparities between different estimates and studies.

… As to what these studies mean for our nation as a whole, one need is additional data — a comprehensive and consistent look at methane emissions at various locations across the country — in order to properly characterize methane across the U.S. natural gas supply system. That’s why EDF, along with close to 100 academic, research and industry partners, is working on a series of 16 studies to directly measure methane emissions across the supply chain. Together, these sixteen studies will provide the most complete national picture of methane emissions to date.
The first study, led by the University of Texas and involving nine natural gas producers, will be published in the coming weeks. The UT study is not based on emissions from a single location but on measurements from diverse regions with data collected at the actual source. Direct measurements in the UT study focus on methane lost at the well pad and other natural gas production points, and will provide insights into how effectively specific industry practices can contain methane emissions. But it won’t offer a complete picture of methane emissions across all of the natural gas system. We’ll need the entire series of studies, a project that will continue through 2014, before we can draw comprehensive conclusions about the scope of the problem and the full range of options for minimizing methane emissions.
The Uintah and Los Angeles studies tell us that methane emissions appear to be a serious problem in some regions. Additional data will tell us more about where emissions are occurring and what can be done to reduce them. But we know enough to get started fixing the problem. There is no reason to wait.

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