NOAA Study: Bakken Methane Emissions Much Lower than Previously Thought

On the same day the Obama administration finalized methane regulations on new and modified oil and gas infrastructure, a new National Oceanic and Atmospheric Administration (NOAA) study was released illustrating one of the reasons the rules have been highly criticized.

The study finds methane emissions from the Bakken region are lower than previously believed. And not only are they significantly lower than a 2014 satellite study  that anti-fracking activists touted, they are also far lower than previous EPA estimates, according to the researchers’ own assessment and EID research.

From the NOAA press release on the study:

“The Bakken oil and gas field is leaking a lot of methane, but less than some satellites report, and less than the latest Environmental Protection Agency inventory for petroleum systems, according to the researchers’ calculations.”

The researchers claimed that their data were only “slightly lower” than EPA’s but the researchers appear to be making that statement using 2013 EPA methane emission estimates, which were the latest available at the time the study was conducted. But the EPA has since release drastically upwardly-revised methane emissions data for 2014 – and when that latest data are used, the EPA’s overestimation is more pronounced: EPA’s latest estimates are 1.625 mmt CO2 eq. more than the NOAA study.

The math works like this: The study finds that annual methane emissions in the Bakken are 275,000 tons, which equates to 6.875 million metric tons CO2 equivalent. The researchers calculated the Bakken’s share of the 2013 nationwide inventory data based on the percentage of national production from the Bakken (12.5 percent in 2014), finding their emission estimate was lower than EPA’s.

EPA only reports petroleum system emissions at the national level. The EPA is now claiming methane emissions for petroleum systems were 68.1 mmt CO2 eq. in 2014. Assuming for a moment the latter figure is correct, one can apply the researchers’ proportional calculations (12.5 percent) and find 8.5 mmt CO2 eq. of that 68.1 mmt is attributable to the Bakken.

So this study, conducted by the same researchers responsible for a recent ethane-focused study that hinted previous methane emissions from the Bakken shale may have been exaggerated, confirms that is indeed the case.

This fact further calls EPA’s highly questionable upward revisions of methane emissions in its latest Greenhouse Gas Inventory into question, considering they have been used to justify their new regulation on oil and natural gas systems. In case you missed it, EPA data had previously consistently shown methane emissions plummeting as natural gas and oil production has soared. EPA’s revisions were most drastic in the petroleum sector, as emissions from petroleum systems increased 2 ½ times from previous estimates.  But as EID reported recently, EPA made a number of dubious assumptions, including the fact that the agency assumed that smaller sources emit the same amount of methane as larger sources.  In other words, new study confirms what many have suspected: EPA’s new data – which is based on some faulty new methodology – are very likely exaggerated.

Previous estimates of Bakken methane emissions have also been based on a recent satellite study, which found suspiciously high emission rates, and as EID noted had no way to account for the fact that several areas of the United States, with absolutely no oil and gas production, had increasing methane emissions, while areas with oil and gas development had lower emissions. That study has long been trotted out by fracking opponents as evidence the Bakken is largely responsible for assumed increases in U.S. methane emissions from petroleum systems. The NOAA researchers noted the satellite study “warrants further examination” and concludes, “We conclude the exceptionally high atmospheric loss rate of CH4 reported by Schneising et al. [2014] for 2009–2011 is inconsistent with our airborne data from May 2014.”

Data inconsistent with previous studies?

Early headlines have focused on the 275,000 tons of emissions per year found in the NOAA study but that figure seems to contradict a finding made in the researchers’ previous study. That ethane-focused study the same researchers released last month claimed to find 250,000 tons of annual ethane emissions in the Bakken and stated that the ratio of ethane to methane detected was 5:2, according to a Washington Post article:

“They found that the ratio of ethane to methane produced by the Bakken was much higher than what has been observed in many other shale oil and gas fields in the United States — an observation that could have big implications for future methane assessments, which are important for climate scientists.

“In many oil and gas fields, methane is often the primary natural gas present — sometimes accounting for up to 90 percent or more of the gas that is released during extraction. Ethane often tends to be present in smaller proportions.  In the Bakken, however, the researchers found that ethane accounted for nearly 50 percent of all the natural gas composition, while methane was closer to 20 percent.”

So applying the simple math here, considering the researchers found methane emissions are roughly 30 percent less than ethane emissions in the Bakken, one would think their methane estimate would be closer to 175,000 tons than 275,000 tons annually.

This is an inconsistency that requires explanation. Nevertheless, the research still clearly indicates that methane emissions in the Bakken are much lower than the alarmists have claimed – and as North Dakota Department of Health Environmental Health Section chief Dave Glatt told The Associated Press the problem is not “widespread.”

As this study shows, past methane emission estimates from the Bakken were very likely exaggerated.  Considering EPA’s recent drastic upward revision of methane emissions has already raised eyebrows for making unfounded assumptions – this study further calls the agency’s methods into question on the day that it unveiled its new methane regulations on the oil and gas industry.

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