Decaying Urban Gas Lines Are Fueling Global Warming

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About two hours into our drive around Utrecht, a city of 358,000 near the center of the Netherlands, the display providing a real-time readout of ambient methane levels begins to freak out.

The Samsung tablet was consistently showing concentrations close to the atmosphere’s background level of around 2 parts per million. But suddenly, the chart’s scale expands in order to follow a sudden spike to 300 ppm. Behind the wheel, Hossein Maazallahi, a PhD candidate at Utrecht University, says the reason is clear: A natural gas pipeline has sprung a leak. 

Maazallahi, 30, is part of MEMO2, a seven-country, public-private research project that’s training scientists to find methane leaks in fossil fuel production and municipal infrastructure across Europe. Methane is the primary component of natural gas, which is supplanting its dirtier cousins as a source of electricity.

Researchers however are finding that the pipes delivering all that gas are a lot leakier than utility companies understand. Maazallahi’s study of methane levels in Utrecht and Hamburg, Germany, recently published in the scientific journal Atmospheric Chemistry and Physics, found 81 apparent leaks in Utrecht’s network and 145 in Hamburg. Natural gas also contributes to ground-level ozone, which exacerbates asthma—a pressing health concern in communities of color, where the condition is more prevalent. It can also explode, if allowed to build up in a closed space.

But beyond more localized safety issues, the problem has a planetary component: it’s playing a significant role in global warming. Now, as the U.S. rejoins the climate fight being waged in Europe and elsewhere, with President Joe Biden’s plan to “supercharge” his nation’s efforts, finding new ways to rein in greenhouse gases will be even more of a priority. Tackling decrepit natural gas networks is likely to be high on the list.

Decaying Urban Gas Lines Are Fueling Global Warming

Methane, also known as CH4, is the second-most abundant anthropogenic greenhouse gas after carbon dioxide. But it’s 25 times more effective at trapping heat. The higher potency combined with a shorter lifespan—maybe a dozen years rather than a century or more for CO2—has brought it to the forefront of climate mitigation strategies.

In the long run, say by 2100, we’ll need to significantly reduce CO2 emissions if we want to avoid agricultural catastrophe. But to hit goals set for 2030 by the Paris Agreement—namely emissions levels that keep warming below 2ºC—focusing on methane reduction makes better sense.

“Anything we can do to reduce methane emissions now helps buy us more time to address CO2 emissions in the future,” said Robert Jackson, professor of earth system science at Stanford University and director of the Global Carbon Project, a collaboration of hundreds of scientists worldwide seeking to make greenhouse gas data available to the public. 

But the big obstacle to tackling methane emissions is that, while we know the amount of CH4 in the atmosphere has more than doubled since around 1750, we don’t know all of its sources. Besides production of fossil fuels, methane also comes from landfills, livestock, agriculture and wetlands.

Conveniently for researchers, methane derived from fossil fuels has a chemical signature that differs from other sources. That distinction helped Benjamin Hmiel figure out how much of it we’ve been pumping into the atmosphere by burning fossil fuels. For his PhD dissertation, published in Nature, Hmiel tapped pockets of air in ancient ice in Greenland to measure the proportion of fossil methane. Then he subtracted it from what’s in the air today, and determined the fossil methane humans are responsible for.

“We didn’t realize how clear of a picture we had until after the measurements,” said Hmiel, now a researcher with the Environmental Defense Fund. It turns out that our fossil fuel-based methane emissions are 25%-40% higher than we previously thought, though the scientific community continues to debate the findings.

Decaying Urban Gas Lines Are Fueling Global Warming

So where is all this extra methane coming from? Some of it from leaks, apparently.

The oil and gas industry and the U.S. Environmental Protection Agency had previously estimated methane emissions from drilling operations by taking measurements in a few locations and then extrapolating. But recently, scientists have rigged satellites with instruments to provide a more accurate picture. The more they looked, the more they found how far off-base those estimates were.

Last year, researchers from SRON Netherlands Institute for Space Research figured out that methane from the Permian Basin, a hub of drilling activity in Texas and New Mexico, was double earlier estimates.

“The largest area of production of oil in the U.S. is emitting a lot more methane than the industry says,” Sudhanshu Pandey, the study’s lead author, said. The contribution to global warming of methane leaked and vented from the Permian is equivalent to the CO2 emissions of all U.S. households over a 20 year-period, his study found.

Some of the emissions from fossil-fuel extraction are unavoidable, like when methane trapped in coal mines must be vented to avoid hazardous conditions. But some is avoidable, and operators are unlikely to pay fines for accidental release, according to research by the Niskanen Center of Washington. Norway is a leader in taxing these emissions, and thus incentivizing leak reduction. But fossil fuel industry lobbyists in North Dakota and Wyoming—two of the largest petroleum-producing U.S. states—have shot down efforts in America to emulate the Scandinavians.

While fossil fuel production facilities are by far the biggest source of leaks, the pipelines that extend from those installations to consumers are vast, able to circle the Earth 120 times if laid end-to-end. EPA estimates are that fossil fuel distribution accounts for only 7% of methane emissions in the natural gas system—but recent studies indicate that number may be low.

A 2015 study of the city of Indianapolis found leaks there were producing the global warming equivalent of the electricity consumption of up to 42,000 households. In Boston, a 2.7% leak rate was discovered in that city’s distribution network.

[Washington D.C. “is very leaky, Baltimore is very leaky, [as is] Providence, Rhode Island,” said Nathan Phillips, acting director of the Sustainable Neighborhood Lab at Boston University, who has published research on leakage from natural gas distribution systems. And with America’s disintegrating infrastructure, the problem is only getting worse. By comparison, areas where pipelines were recently replaced have up to 95% fewer leaks per mile, Jackson said. Margaret Hendrick, one of Phillips’ students, showed in a 2016 study published in Environmental Pollution that just 7% of leaks are responsible for 50% of the gas escaping from utilities’ pipes.

Capping even a small portion of them could go a long way toward reducing greenhouse gas emissions. 

Decaying Urban Gas Lines Are Fueling Global Warming

Despite generally having better-maintained infrastructure than America, Europe isn’t immune to old pipes, either.

Back in Utrecht, Maazallahi was circling the block, returning to the street corner where his electronic display first spiked. He pulls into a parking spot across from a Domino’s Pizza. Jutting out of his Volkswagen’s front grill is a quarter-inch plastic tube no different from one you might find bubbling in a home aquarium. It winds along the fender, through a crack in the passenger door and under a floormat to the backseat—where it attaches to a device that can cost as much as $90,000.

It’s called a cavity ring-down spectrometer, and it could be a critical tool in the fight to slow global warming. The gadget, made by Silicon Valley’s Picarro Inc., contains three highly polished triangular mirrors. Inside a 1-liter container kept at 80% vacuum, a laser pulse tuned to the wavelength at which methane absorbs light bounces between the mirrors. The faster the light decays, the more methane in the cavity. Simultaneous measurement of CO2 levels reveals whether a high methane reading is just from a passing car whose catalytic converter needs adjustment, or something more insidious. 

Maazallahi exits the vehicle in search of the exact location of the leak. Wearing jeans, a blue bomber jacket and Elvis Costello glasses, he starts walking along the street with a portable version of the larger spectrometer in the van’s backseat. After holding a tube over cracks beside a few metal sidewalk plates, Maazallahi investigates a drain by a curb. Bingo.

The reading is similar to the one he first measured. “A pipeline leak could easily find its way through this outlet,” he said. Maazallahi planned to notify the utility company, which has previously fixed leaks found by MEMO2 (which stands for Methane goes Mobile – Measurements and Modeling.) 

Decaying Urban Gas Lines Are Fueling Global Warming

Maazallahi said utilities use decades-old technology to discover leaks, but often can’t quantify how big a leak is.

Else de Kwaasteniet, a spokesperson for Utrecht utility Stedin, said the leaks detected by Maazallahi were mostly below its threshold for alarm. Stedin checks its entire network at least every five years, she said. Bernd Eilitz, a spokesperson for Hamburg’s utility, city-owned Gasnetz, said it checks lines every four years, with high-pressure pipes getting more frequent scrutiny. He said Gasnetz fixed the leaks Maazallahi found there.

Phillips said his project has made U.S. inroads, having mapped the natural gas infrastructure of a Boston suburb, and that he’s in negotiations with a major U.S. East Coast city about capturing methane samples on bicycles and scooters, which can get into alleys and other places that cars can’t.  

The cavity raindown spectrometer, which is also made by Los Gatos Inc. and others, is “a very stable, very elegant, very precise way of measuring methane,” Phillips said. Eilitz seemed to agree, saying Gasnetz sees “vehicle-based sensors as an interesting addition” to their current routine checks.

Bridger Photonics Inc., a Bozeman, Montana-based company that provides methane emissions data to the oil & gas industries using airborne lidar, found approximately four significant leaks per square mile in preliminary scans of metropolitan area gas distribution networks. 

Pete Roos, Bridger’s CEO, said his company can find big leaks from the air even faster than Maazallahi’s method—and that demand for such services is growing.

“Natural gas is getting pushed from all sides,” Roos said. “There’s been an evolution of understanding that for this industry to survive, they’ve got to have responsible operations and keep that gas in the pipe.” 

©2021 Bloomberg L.P.

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