New Warnings About Methane Emissions

Concerns about the methane problem associated with the U.S. natural gas boom are mounting with each study released. This week scientists with the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado (UC) at Boulder published a new paper on methane leakage in the journal Geophysical Research Letters. It reports an alarmingly high level of methane emissions in the Uintah Basin of Utah — 6.2 to 11.7 percent of total production for an area about 1,000 square miles. Findings are based on readings from airplane flights that measured methane in the air on a single day and estimated the proportion of those emissions that came from the oil and gas infrastructure —production, gathering systems, processing and transmission of the gas out of the region. 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.

This follows two other regional studies conducted by scientists at the same organizations. One released last May in the Journal of Geophysical Research reported a 17 percent methane leak rate for the Los Angeles Basin, which has received quite a bit of attention although, as I’ll explain below, the figure can be misleading.  The second study, conducted over the Denver-Julesburg Basin in 2008, found 4 percent of the methane produced at an oil and gas field near Denver at that time was escaping into the atmosphere. Taken together, these studies are troubling. They should be regarded as alarm bells ringing in our ears. Action by policymakers and industry is needed now.

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.

Though Environmental Defense Fund was not involved in any of these studies, we can offer some important context based on our own experience doing research on this critical issue.

Methane emissions can occur from natural gas produced both from oil and gas wells. In order to get a clear understanding of the problem, it is necessary to pay careful attention to the details of each study.  In the Los Angeles study, for example, the authors report a 17 percent leakage for the oil and gas industry, but fail to highlight that the vast majority of total hydrocarbon production in the basin is oil. This led some to the mistaken conclusion that 17 percent leakage applies to the natural gas industry as a whole.

Certainly, this finding still indicates more should be done to better control methane emissions associated with oil production in the Los Angeles Basin.  But it also points to a limitation with methane leak rates: Percentages quoted are not comparable between basins. Regional differences matter.

Further, oil and gas production in the Los Angeles Basin study only accounted for 8 percent of the region’s total methane emissions, compared to 48 percent from natural gas distribution and geologic seeps. The Los Angeles study underscores the importance of looking at the total picture when assessing sources and remedies of methane pollution.

The Uintah study is a slightly different story.  In this case, the basin is made up predominantly of natural gas producing wells, but the overflight captured more than just production activities.  Emissions from gathering, processing, and other various ancillary activities taking place in the basin were also captured in the overflight, with no way to attribute the high emissions among these various elements of the natural gas supply chain.

In other words, there is as of yet no data to tell us whether the emissions are coming from production, gathering, processing or other activities.  We know that industry-wide, the production process known as well completions (the process after hydraulic fracturing when a well is cleared of fluids and sands) may contribute about 10 percent of the total methane emissions if operators are not using “green completion” technologies that capture emissions for sales or beneficial reuse. Under recently enacted federal regulations, which EDF fought to adopt, green completions will be required nationally for any new hydraulically fractured natural gas well starting January 2015. There’s no data on whether operators in the Uintah were using green completions at the time of the study, but there is reason to suspect they were not. The Uintah study authors cite a U.S. Government Accountability Office report that notes higher rates of methane flaring and venting at the time of the study than in surrounding production basins.

More investigative work is needed before we can claim to understand what is driving these apparently large emissions. We don’t know everything we need to about the production and distribution practices employed in the Uintah Basin when this research took place, but there is no reason for the public to remain in the dark.  Producers, gathering and processing companies, and pipeline companies in the Uintah Basin must provide citizens with a clear accounting of what they were doing at the time these measurements were made, what they are currently doing and what they will do to end polluting practices and reduce methane pollution.  Likewise, federal and state regulators governing air rules in Utah need to take a hard look at their regulatory and enforcement practices, and provide evidence to assure the public that they are employing necessary procedures to prevent air pollution from the oil and gas infrastructure.  The evidence would suggest they are lagging. It appears there is a lot of work to do in Utah, and companies and regulators alike should not waste a moment in getting after it – including steps to routinely survey emissions in active basins to measure progress over time.

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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3 Comments

  1. Posted August 6, 2013 at 12:14 am | Permalink

    This caveat seems to substantially undercut the study's significance without a lot more cross-checking:

    "However, we also note that we have no specific knowledge (via emissions estimates from other days) as to the extent of day-to-day variability of emissions in this basin and would caution against any extrapolation of this data."

    • Posted August 6, 2013 at 10:45 am | Permalink

      Pinpointing of emission sources is key to determine both responsibility and corrective actions that can be taken to mitigate the emissions. Are the emissions from wellhead christmas trees, casing defects, gathering line leakage, flowback or geological leakage (methane that makes its way to the surface caused by hydraulic fracturing) or some other unknown source? We can easily pinpoint emission sources with adequate access. The top down measuring approach is simple but the results may raise more questions than answers….

  2. Posted August 7, 2013 at 6:03 pm | Permalink

    This analysis provides direction to looking for answers, but the original study underscores the need to take action immediately. Based on calculations at Cornell, leakage rates this high in the field which does not measure distant pipeline, city delivery, and other sources makes natural gas production via hydraulic fracturing to be an extreme cause of climate change–even more so than coal. We need to applaud NOAA and the University of Colorado for undertaking this study, but now we must take action. Any and all methods to reduce leakage in the field should be sought. In addition, given costs, it's time to further put funding and incentives into finding heating and electricity efficiencies in all we do.