U.S. inventory of methane emissions may be based on bad measurements

REUTERS/Jim Urquhart
A key question without a clear answer: How much methane is leaking into the atmosphere?

Geez, what’s that smell?

Maybe it’s some of the methane leaking in untold volumes from the nation’s natural gas infrastructure.

Could be there’s something rotten in the research that aims to quantify those big emissions of a potent greenhouse gas.

Or it could have something to do with Wednesday’s venting of resentments and rivalries over that research, rooted in a long-stewing dispute over whether our best available measurements of methane leaks are really much good at all.

On one side of the rift is the Environmental Defense Fund and some prominent scientists who have undertaken an ambitious research initiative – in sometimes controversial partnership with oil and gas companies – to find out how much methane is leaking into the atmosphere, and where, and what might be done about it.

On the other is a guy who invented a key component of the equipment used to measure the leaks, but who has been known more widely until recently as that firefighter who raced to the top of the Empire State Building, wearing his full 55 pounds of battle gear, to raise money for charity.

His name is Touché Howard and he has published two peer-reviewed scientific papers of his own, putting en garde the EDF, the U.S. Environmental Protection Agency and Bacharach Inc.

Bacharach manufactures the $20,000, backpack-sized air sampler that carries EPA approval for measuring the methane content of ambient air. Moreover, the EPA relies on measurements made with the device for its national greenhouse-gas emissions inventories and policy decisions based upon them.

Howard says the instruments work OK with small leaks but  systematically under-record high concentrations, with error rates that can’t readily be determined and can’t reliably be prevented — although frequent, careful recalibration seems to help.

His first paper, published in March in the Journal of the Air & Waste Management Association,  got little attention in the mainstream press. But his second, published Wednesday in Energy Science & Engineering, set off quite the stir when it made The New York Times.

Errors of unknown size

The new paper lists Howard as being affiliated with Indaco Air Quality Services Inc. of Durham, North Carolina. We can assume it was in that work that he earned the patent he holds on a key component of the Bacharach Hi-Flow Sampler.

As his new paper explains, the unit has one sensor to detect low methane concentrations and another to detect high concentrations. It’s the second type that Howard invented, though he had no role in producing the Bacharach device itself.

When detected methane levels rise, the device is supposed to switch from the low-flow to the high-flow sensor, but according to Howard it very often does not. That’s based on equipment tests and also on his analysis of a rather important data set: 

Emissions measurements taken in 2013 by University of Texas researchers at wells, pumps, tanks and other equipment at 150 natural gas production sites around the country. The Bacharach Hi-Flow Sampler was used for 98 percent of those measurements, and the measurements in turn became the basis for 41 percent of EPA’s national inventory of methane leakage at such facilities.

A potent greenhouse gas

EPA is naturally concerned about methane as a greenhouse gas because it’s at least 80 times better at trapping atmospheric heat than carbon dioxide, although it doesn’t persist as long.

Howard says, however, that there’s no way to know how much methane a faulty unit is missing unless measurements are taken simultaneously by a unit known to be accurate; he told The Times that readings could be off by “tenfold to a hundredfold for a particularly large leak.”

Apart from atmospheric loading, he noted, undetected methane at high levels could also present a workplace safety issue.

I emailed Bacharach to ask for its position on the Howard study but didn’t get a reply. According to The Times, the company has issued a statement disputing some of Howard’s conclusions, suggesting that other factors could cause the data anomalies, and pledging to update its operator manuals with recommendations for more frequent recalibration.

EPA told The Times that it “would assess information ‘from a number of channels,’ including the research community and industry and the new Howard paper, ‘as a part of our routine review of new information’ for its annual inventory of greenhouse gases.”

I think it would be hard to overstate the significance of Howard’s challenge to the Bacharach device. It’s not just one study at stake but about a dozen already issuing from the EDF project, including one discussed here last December on the amount of methane leaking from nearly a half-million pressure-operated valve controllers at oil and gas wells nationwide.

Tension between researchers

The key researcher in that work is David T. Allen of the University of Texas, and clearly there is little love lost between Howard and Allen, who told The Times that:

…“Our research team made efforts to cooperate with Mr. Howard,” adding that he was reluctant to discuss “issues like nondisclosure agreements, email communications, and other university legal matters.” A spokesman for the university, Geoffrey Leavenworth, said that communications with Mr. Howard ceased after disagreements over a standard nondisclosure form.

An official of the Environmental Defense Fund said the organization welcomed the new paper. “We’re happy when people read these papers, critique them, raise questions about the instruments used, the methodology used,” said Mark Brownstein, who leads the group’s work on methane emissions.

Other scientists are taking Howard’s challenges seriously, to say the least.

Some of the best (and earliest) reporting on the situation has appeared in InsideClimate News under Lisa Song’s byline, and her piece on Wednesday included comment from Rob Jackson, known for his work on methane leaks associated with fracking as well as municipal gas systems.

After examining Howard’s study, Jackson, the Stanford professor, said it’s “too early to say whether some of the Allen values are wrong. Howard’s analysis suggests that they may be, however.” If Allen’s team has “systematically underestimated methane emissions, we need to know right away,” Jackson said. Several other scientists approached by InsideClimate News declined to comment on Howard’s paper due to the sensitive topic.

Song suggests that Howard wasn’t the first expert to notice some problems with the Bacharach equipment, and that at least some of the hostility between Howard and Allen has come from Allen’s side. After reviewing the 2013 data and seeing the anomalies, she writes, Howard

…[A]pproached Allen, hoping to investigate the problem together and perhaps issue a joint statement or correction about the 2013 study. But Howard said he was “stonewalled” by Allen’s research team.

 In July 2014, for instance, Howard and [collaborator Tom] Ferrara completed a nondisclosure agreement (NDA) that would have allowed them to view unpublished raw data from Allen’s team. The two consultants said the University of Texas had asked for the NDA as a prerequisite for viewing the data, which would have provided greater insight into Allen’s 2013 paper—but UT didn’t sign its half of the agreement, so Howard never saw the data.

Howard provided InsideClimate News with a copy of the incomplete NDA. When InsideClimate News showed the document to Allen, he said he “disagree[s] with the suggestion that the University of Texas was unwilling to enter into an NDA.” 

When asked to elaborate, a UT media representative said InsideClimate News could file an open records request.

For its part, EDF in its public comments is treating Howard’s challenge as a useful contribution, helping the science of methane measurement to evolve in customary style.

But there’s bound to be some concern about how this may affect the organization’s standing with environmentalists who see it as collaborating too closely, too often, with industrial interests they feel it should be opposing.

“What EDF is trying to do is put filters on cigarettes,” said biologist Sandra Steingraber, a scholar-in-residence at New York’s Ithaca College. “There’s no way we can frack our way to climate stability. There’s no scientific evidence for that.”

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Comments (1)

  1. Submitted by Rachel Kahler on 08/06/2015 - 12:34 pm.

    Interesting

    The topic here is interesting. I hope more investigation occurs to determine whether the methane emission estimations are accurate or wrong. And, if wrong, how wrong.

    I want to note, however, there were a few particularly vexing typos in this piece that are uncharacteristic of Mr. Meador. They actually made it hard to read in a couple of spots, and I’m still not sure what was intended.

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