Study: Methane emissions may be five times higher than previously thought

Global emissions of methane from existing gas infrastructure may be up to five times higher than had been believed, a new study has found.

Existing measures to burn off the powerful greenhouse gas — which is dozens of times more potent than carbon dioxide — allow far more to slip by than had been believed, according to the paper published on Thursday in Science.

A bipartisan bill put forth on Wednesday by Reps. Peter Meijer (R-Mich.) and Sean Casten (D-Ill.) seeks to tackle the problem. The Methane Emissions Mitigation Research and Development Act “focuses our best and brightest at the Department of Energy on methane emissions, one of the most potent greenhouse gasses,” Meijer said in a statement. 

“It also provides our local governments and private industries with the necessary tools to mitigate methane emissions and leaks,” he added.

Among these tools are the suite of leak detection and repair (LDAR) technologies, which include the satellite tools that the Science team used to quantify the imperfect nature of venting and flaring, common features of natural gas drilling.

At times or in areas where there isn’t sufficient pipeline or storage for the quantities of natural gas being produced — sometimes as a byproduct of more lucrative oil — drilling operators “flare,” or burn off, the methane.

It had long been believed that flaring converts all the methane into water vapor and relatively inert carbon dioxide, a greenhouse gas that, while it still heats the climate, is far less potent.

But this is an “overly optimistic view” of flaring, which leaves far more methane behind than had been believed, according to a companion essay in Science.

In fact, studies of three major natural gas basins — the Eagle Ford and Permian in Texas, and the Bakken of North Dakota — found that only 91 percent of the methane is consumed. That’s in part because flares are often malfunctioning or simply unlit — allowing raw methane to vent into the atmosphere.

If these flares operated properly at even 98 percent efficiency, they would cut emissions enough to be the equivalent of removing nearly 3 million cars from the road, the Science team found.

Enough gas was flared in 2021 to make up about two-thirds of current EU demand — but most oil and gas producers don’t directly check or report how efficiently that gas was burned off.

Complete combustion of natural gas at flare sites would also spare nearby communities from potentially toxic impacts. About half a million people live within three miles of flare sites in these three basins — which puts them at direct risk from the potentially toxic organic compounds released if those flares malfunction.

Such failures to properly combust waste gas could “expose front-line communities to a cocktail of co-pollutants that present risks of acute and/or chronic health impacts,” the team wrote in a statement.

These leaks are a major problem for both U.S. emission goals and for the attempt of gas producers to brand themselves as a low-carbon bridge fuel — or a feedstock for new-model fuels like blue hydrogen, a still largely frontier product fabricated from gas from which the carbon has been captured and stored.

The Science study builds on a 2021 paper in Environmental Research Letters that found that about 60 percent of total methane emissions from the Permian Basin — a region that produces about 18 percent of U.S. natural gas — came from 1,000 “super emitter” wells.

And the International Energy Agency in 2020 estimated global flaring efficiency at about 92 percent — approximately what the Science team just confirmed for the United States.

The solution, according to the Science team, is similar to the one Casten and Meijer are asking for: better technology. “Together, satellites, surface sensors, and models can provide more-accurate assessments of the role that improved flaring efficiency plays in overall O&G emissions and future mitigation efforts,” the researchers wrote in the companion essay.

But they cautioned that fixing the problem would require more than simply new technology, but would also require “further improvements in monitoring, regulations, and industry practices.”

The time for taking action on this is now, Casten wrote in a statement.

“2021 saw the highest annual growth rate for methane emissions to date,” he said. “This problem is not slowing down and will only increase without action.