New survey of US methane leaksThis image, produced by NASA, shows methane concentrations over the Un

New survey of US methane leaksThis image, produced by NASA, shows methane concentrations over the United States between 2003 and 2009. Methane is pulled out of the ground and burned as natural gas, but if it leaks into the upper part of the atmosphere it is also a strong greenhouse gas that contributes to climate change. In the years 2003-2009, new drilling techniques were developed in the United States that released methane from reservoirs that were previously inaccessible. The basic technique involves drilling holes into gas rich units and pumping sand and fluid into these units at high pressure; the pressure fractures the ground and the sand holds open the fractures, allowing gas to flow out.If methane is used as an energy source instead of coal, there is a possible economic and environmental benefit as each molecule of methane has far more energy than the same mass of coal and burning it releases far fewer pollutants, including far less CO2. However, because of how methane atoms interact with infrared light, methane is also a far more potent greenhouse gas than CO2, so small methane leaks can totally swamp the environmental benefits of natural gas over coal. Therefore, monitoring the amount of methane that leaks out of the drilling and transportation operations is hugely important.The research shown in this image from a few years ago showed a couple of methane leak hotspots, including a large one associated with drilling in Colorado. Although they did not prepare as pretty of an image as this one, a new study was just published updating these results and characterizing leaks from other gas fields.In 2015, a P-3 aircraft operated by the National Oceanographic and Atmospheric Adminstration (NOAA) sampled the gas plumes above these drilling sites. They measured the atmospheric chemistry, the isotopic composition of gases, and other gases like ethane that can leak out associated with the methane. They matched gases measured in the atmosphere to the composition actually measured in wells in the units, to make sure they were measuring the methane actually leaking out of the ground.In some cases, like the bullseye on this plot, their measurements suggest substantial progress. The methane measured leaking from Colorado has declined dramatically since this image was published; nearly 40% lower than what was observed in this time period. This reduction could be due to better procedures, or it could be due to there simply being less drilling now due to the drop in gas prices.However, other areas showed higher leak rates. This area in Colorado, the Hayensville Shale in Arkansas, and the Eagle Ford shale in Texas all showed leaks that were comparable to 2-3% of the total methane gas produced. These leak rates are high enough that any benefit to using methane instead of coal is almost certainly lost.However, that wasn’t nearly the worst. In North Dakota, the Bakken formation is also being used as a gas source. The amount of natural gas measured in the air above this formation implied that 5.4% of the produced natural gas from this formation was leaking to the atmosphere during the measurement period.Overall there has been improvement in gas leaks in many areas. In fact, there should be improvement in gas leaks – gas that leaks to the atmosphere can’t be sold, if it’s leaking it’s literally money leaking into the sky. The previous administration made a point of working with gas producers to help them cut their gas release rates, but so far it still is not enough. The leak rates in some fields are approaching the levels we need (<1%), but as the Bakken formation shows, there needs to be a continued effort from industry to cut down on leaks and that effort has a long way to go.-JBBImage credit: https://www.jpl.nasa.gov/news/news.php?release=2014-348Original paper:https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JD028622 -- source link

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