EDF Methane Paper: Constructive, But Premature?

There’s a useful expression in the carpentry trade: Measure twice, cut once. It suggests there’s value in patience. Mistakes are almost guaranteed when you rush to judgment, so it’s well worth taking the time to size things up properly before making a decision – or a declaration.

Unfortunately, as we continue to see, this common sense approach to building a house has been largely abandoned by those attempting to build a case in opposition to shale development  – with some in the academic community lending their names to papers and projects that have less to do with informing a discussion than generating sensational headlines in the press.  Not every shale critic caves under the pressure to chase headlines instead of hard facts, but they are few and far between.

Here at EID, we’ve always considered the Environmental Defense Fund (EDF) to be one of the few remaining constructive critics out there – folks who accept the premise that natural gas can help our country achieve key objectives in both the energy and environmental spheres, but who, like most Americans, want to ensure that the process needed to deliver on that promise and potential is done right.

Unfortunately, that’s also why we were somewhat disappointed to read through EDF’s recent paper on the use of natural gas in cars, trucks and power plants. The authors had a chance to call out EPA and others for playing fast-and-loose with the facts on methane emission estimates, but they didn’t take it. To their credit, the authors at least warn that those estimates aren’t very good:

“There is a need for the natural gas industry and science community to help obtain better emissions data…” (EDF paper, p. 1)

“Despite recent changes to EPA’s methodology for estimating [methane] leakage from natural gas systems, the actual magnitude remains uncertain and estimates could change as methods are refined. Ensuring a high degree of confidence in the climate benefits of natural gas fuel-switching pathways will require better data than are available today.” (EDF paper, p. 4)

“[T]he paper does not draw hard and fast conclusions about the future implications of any kind of fuel shifting, nor does it answer the question of whether natural gas generation or natural gas-powered vehicles will be better or worse for the climate.” (EDF press release)

But in the end, it’s hard to get press to cover warnings about poor data quality (take it from me as a former reporter), so the authors decided it was necessary to play along and make some guesses of their own. Here’s their take on the carbon footprint of vehicles that run on compressed natural gas:

“Given EPA’s current estimates of [methane] leakage from natural gas production and delivery infrastructure, in addition to a modest [methane] contribution from the vehicle itself (for which few empirical data are available), CNG-fueled vehicles are not a viable mitigation strategy for climate change.” (EDF paper p.2)

For the record, CNG is widely recognized as a low-carbon fuel. The Department of Energy’s Alternative Fuels and Advanced Vehicles Data Center says CNG is 26% less carbon-intensive than gasoline.

So why do the authors of the EDF paper reach a different conclusion?

Let’s start with the EPA’s estimate for methane leakage, which the authors rely on even while doubting its accuracy. The EPA arbitrarily doubled this estimate last year, guessing that 2.4 percent of natural gas – comprised mostly of methane – is lost during production, transmission and distribution. Worse still, the agency uses the flawed estimate as the basis for new greenhouse gas regulations targeting the industry. But nobody believes 2.4 percent is a good number, not even EPA:

“These estimates based mostly on emissions factors available from two major studies … conducted in the early and late 1990s respectively.” (EPA, p. 7-8)

“[F]urther work is needed to improve the methodological approach and transparency of the new data.” (EPA p. 2)

Secretary of Energy Steven Chu’s Advisory Board has also criticized the accuracy of EPA’s estimate:

“Currently, there is great uncertainty about the scale of methane emissions.” (SEAB subcommittee report, p. 17)

In fact, according to independent analysts at IHS CERA, it’s time for the EPA to go back to the drawing board:

“[I]ts estimates of methane emissions are dramatically overstated and it would be unwise to use them as a basis for policymaking. … [T]he estimates are not credible…” (IHS CERA report, p. 3)

A study by URS Corp. found the level of overstatement is huge, more than 10 times too high:

“It appears that the EPA’s [completion estimate] for unconventional fractured wells is potentially overestimated by 1200%. … The current EPA overestimate is frequently cited in studies and reports, leading to inaccurate conclusions about industry emissions and increasing the potential for federal or state governmental agencies to rely upon the inaccurate data in their decision making.” (URS Corp. report, p. 4-5)

And the authors of the EDF paper sound yet another alarm about how the EPA has inflated its methane leakage estimate, even as they use that same suspect number to develop their own conclusions:

“EPA’s reported uncertainty appears small considering that its current value is double the prior estimate, which was itself twice as high as the previously accepted amount.” (EDF paper p.1)

Wait a second. According to EDF, the EPA’s current methane leakage estimate is now roughly four times higher than was previously accepted? No wonder the authors have doubts about its accuracy.

Unfortunately, the EPA’s numbers aren’t the only ones in the EDF paper that exaggerate methane leakage from natural gas wellsites. The authors also cite a study of 250 Barnett Shale wells in Fort Worth, Texas, to support their conclusions. But the authors concede the results of the study are skewed, because high leak rates at a handful of sites outweighed many more with near-zero leak rates, driving up the average for all the sites:

“Our analysis … revealed a highly skewed distribution of emissions, with 10% of well sites accounting for nearly 70% of emissions … [L]eak rates calculated based on operator-reported, daily gas production data at these well sites ranged from 0% to 5%…” (EDF paper p.3)

One of the paper’s authors, Steven Hamburg, was good enough to speak with EID about all this prior to the report’s release. When asked about the information used in the paper, he said “it’s far too limited to draw robust conclusions.” Hamburg said the intention behind the paper was to create a model that could be used in the future, once there’s real data instead of estimates, to perform detailed calculations on the carbon footprint of natural gas. EDF is gathering new information on gas wells today and plans to build “a very large data set” within the next couple of years. Hamburg also noted that the EPA’s estimates will be replaced in a few months with emissions data from oil and gas companies under the agency’s mandatory greenhouse gas reporting rule.

Hamburg said the debate over methane emissions needs to be informed with better data, because right now it’s “he said, she said, they said, we said” and every time a new study is published, it’s really just the author’s “best guess.”

That’s a welcome note of caution. EID supports reliable data, too. But we wish EDF had exercised more caution, shown more patience and waited for a trustworthy set of numbers to be posted by EPA before releasing a report that the organization itself admits is based on skewed data.

There is at least one positive outcome from this paper worth special mention, however. EDF has now joined EPA, the Department of Energy, other environmental groups, academics, former regulators and independent analysts in debunking the bizarre idea that natural gas produces more carbon emissions than coal:

“[A] fleet of new, combined-cycle natural gas power plants reduces radiative forcing on all time frames, relative to new coal plants…” (EDF paper p.2)

The high-carbon claims against natural gas were, of course, cooked up by Robert Howarth and Anthony Ingraffea at Cornell University. In fact, when all is said and done, it may be found that Ithaca, New York, is where this whole guessing game about methane emissions really got started.


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