New Study Finds Low Methane Leakage Rates in Top Producing Shale Regions
Researchers from the Cooperative Institute for Research in Environmental Sciences (CIRES) in Boulder, Colorado and the National Oceanic and Atmospheric Administration (NOAA) released a report this week, which finds that methane leakage rates from three major shale developing regions in the United States are in line with federal estimates at 1.1 percent of production. These leakage rates are well below the threshold for natural gas to maintain its climate benefits. The report also supports research that Energy In Depth released last year showing how methane emissions have declined in some of the largest producing oil and gas basins nationwide.
The researchers’ measurements come from five flights from a NOAA research aircraft over the Haynesville shale region in Texas/northwestern Louisiana, the Fayetteville shale region in Arkansas, and the northeastern Pennsylvania portion of the Marcellus shale region in the summer of 2013 – a year of booming natural gas production. As the report notes, the northeastern portion of the Marcellus shale region “accounted for the majority of Marcellus shale gas production that year.” Here’s exactly what the researchers found in each region:
“We calculate emission rates from the horizontal CH4 flux in the planetary boundary layer downwind of each region after subtracting the CH4 flux entering the region upwind. We find one-day CH4 emissions of (8.0 ± 2.7) × 107 g/hr from the Haynesville region, (3.9 ± 1.8) × 107 g/hr from the Fayetteville region, and (1.5 ± 0.6) × 107 g/hr from the Marcellus region in northeastern Pennsylvania. Finally, we compare the CH4 emissions to the total volume of natural gas extracted from each region to derive a loss rate from production operations of 1.0–2.1% from the Haynesville region, 1.0–2.8% from the Fayetteville region, and 0.18–0.41% from the Marcellus region in northeastern Pennsylvania.” (emphasis added)
The report goes on to say:
“The climate impact of CH4 loss from shale gas production depends upon the total leakage from all production regions. The regions investigated in this work represented over half of the U.S. shale gas production in 2013, and we find generally lower loss rates than those reported in earlier studies of regions that made smaller contributions to total production. Hence, the national average CH4 loss rate from shale gas production may be lower than values extrapolated from the earlier studies.” (emphasis added)
The lead author of the study, Jeff Peisch of CIRES, also pointed to the importance of this rate for these specific regions, explaining,
“The gas fields we studied for this paper produced about 20 percent of the natural gas in the United States, and more than half the shale gas, so this moves us closer to understanding methane leaks from U.S. natural gas production.”
The report comes to this important conclusion:
“The production-weighted loss rate from the Haynesville, Fayetteville, and Marcellus study regions is 1.1%, which is similar to a loss rate calculated using the 2012 EPA GHG inventory and 2012 EIA natural gas production data.”
In other words, not only are the leakage rates of these three shale producing areas around 1 percent, they also represent over half of the United States’ total shale gas production. That’s not all: the region with the lowest leakage rates – the Marcellus in northeastern Pennsylvania – also had the most natural gas production of the three shale regions. This is something that the report highlights:
“Natural gas production from the Marcellus shale has increased steadily since early 2010. By June 2013, production from the entire Marcellus shale formation was over 2.6 × 108 m3. We estimate the total CH (9.2 billion cubic feet) per day, which made it the largest shale gas producing play in the U.S. The northeastern Pennsylvania portion of the Marcellus shale play accounted for approximately 70% of the total Marcellus production, as discussed in more detail below. In June 2013, the northeastern Pennsylvania portion of the Marcellus shale play accounted for approximately 8.0% of U.S. natural gas production and 22.5% of U.S. unconventional shale gas production.”
According to data from the Energy Information Administration (EIA), in 2013, production in the Marcellus shale went up by 45.92 percent. In that same year, according to this report, its methane emissions were exceedingly low, between 0.18–0.41 percent of production.
EID has noted on a number of occasions that one of the drawbacks of measurements from flyovers in aircrafts is that there is often uncertainty as to where exactly the methane is coming from. That is, evaluating what percentage of the methane is from oil and gas production versus other sources, such as agriculture, coal production, or natural petroleum seeps, often involves uncertain modeling exercises and hypothesizing. Even taking other sources of methane into account, the researchers still found exceedingly low methane leakage rates. In fact, they argue that, around the Fayetteville shale, these could very well be over-estimates. From the report:
“The CH4 loss rate calculated for the Western Arkoma region, 6–20%, is most likely an overestimate. Emissions from livestock, point sources not related to the oil and gas industry, and a plume of unknown origin may account for one third of the CH4 emissions in this region, which interferes with our assumption that all CH4 emissions in a region come from the oil and gas industry. However, the high calculated loss rate does indicate that CH4 emissions from inactive wells may be a significant source of CH4.”
The reason for these low methane emission rates? The researchers surmise that new technologies and drilling efficiency have played a large role:
“Both improved technology and the exploration of new regions may play a role in this increased production efficiency. For example, the new-well gas production per rig was approximately a factor of 1.75 greater in the Marcellus region than in the Haynesville region for June and July 2013 (http://www.eia.gov/petroleum/drilling/), which may partly explain the lower loss rate found in the northeastern Pennsylvania portion of the Marcellus region.”
This latest study certainly bolsters data from the Environmental Protection Agency (EPA), which show that as natural gas production has soared across the United States, methane emissions have been dramatically reduced.
These findings are also in line with a recent report by researchers at the University of Texas and the Environmental Defense Fund (EDF), which finds that methane emissions from the upstream portion of the supply chain are only 0.38 percent of production. That’s about 10 percent lower than what the same research team found in a study released in September 2013. Studies by the National Renewable Energy Laboratory, U.N. IPCC, Massachusetts Institute of Technology, and many others have also found that methane emissions are low and natural gas has clear climate benefits. As EPA administrator Gina McCarthy has said, “Responsible development of natural gas is an important part of our work to curb climate change.”
This latest study is also yet another big rebuke to anti-fracking activists who have long maintained that methane leaks are a climate “disaster” or “gang-plank to more warming.” On the contrary, perhaps Joost de Gouw, NOAA researcher and co-author of the latest report, put it best when he said,
“It is good news that our atmospheric measurements are close to the EPA estimates. If leak rates are too high, natural gas does not compare favorably with one alternative, coal, in terms of climate impact. Where leak rates are low, the comparison favors natural gas.”
Yes, it is very good news, indeed.