Aging infrastructure allows leaky natural gas pipelines to generate explosions, and the results can be lethal. This series of events is exactly what hit three towns north of Boston last September, when state police received reports of as many as 70 fires, explosions, and suspected gas leaks over the course of 1 day.
Methane leaks from natural gas pipelines are costly hazards that unearth deadly consequences. By tracking leaks from up in the atmosphere and under the ground, researchers aim to inform policy and influence the oil and natural gas industry to manage escaping methane.
This new approach—tracking harmful methane leaks from above and below ground level—could generate economic benefits while offsetting environmental costs, according to a new study presented 12 December at AGU’s Fall Meeting 2018 in Washington, D. C. Kathleen Smits, an environmental and civil engineer from the University of Texas at Arlington who is the principal investigator on the project, admits, “our ultimate goal is to find leaks more efficiently so we can ultimately fix them.”
Methane is a powerful greenhouse gas, trapping 84 times more heat than carbon dioxide during the first 20 years after it’s released. Unchecked methane leaks from the 3 million miles (about 4.8 million kilometers) of gas pipelines in the United States have the potential to wreak havoc on people and the planet, so quickly pinpointing leakage sources is critical for public safety.
Along with their enhanced global warming potential, fugitive methane emissions are equally dangerous on local scales. Last September’s series of natural gas leaks near Boston turned deadly when ruptures in a pipeline that ran beneath the foundation of virtually all homes, schools, and businesses in the area caused multiple explosions.
“Methane doesn’t smell like anything really,” said Bridget Ulrich, who coauthored the research and is a postdoc at the Colorado School of Mines. To make methane detectable, gas companies add a smellier gas known as methyl mercaptan as a safety precaution.
“Once you can smell it with your nose, it’s definitely already too late. We need to be able to detect these much sooner,” said Ulrich.
Because detecting methane leaks is motivated by public safety and because the effects are seen so immediately, preventing leaks from turning into deadly explosions remains a priority for policy makers: “I see it as an opportunity—number one—to drive the technology to be able to do better,” said Smits.
Searching the Sky and the Soil
Traditionally, tracking methane has been done from space using satellites or by people on the ground, but Smits and her colleagues described a holistic approach that harnesses science from both techniques. Taking rain and wind into account, the researchers examined how weather affects soil conditions and potential leaks.
The researchers found they could locate leaky sources more quickly by better understanding how methane migration changes under different weather and wind conditions. They simulated a natural gas leak and found that rain prevents methane from trickling out of the ground naturally, whereas sweeping winds flush the gas away quickly.
Even when wind speeds are low, small gusts of wind wash away any sign of methane leaks and further complicate the detection process. “You’d have to be walking around with a sensor on your shoe to detect it, really,” stated Ulrich.
Technology to Tackle Leaks
Peter Murdoch, a science adviser from the U.S. Geological Survey who was not involved in the study, believes that “it’s the kind of study we need in order to be able to build towards that capacity, to be able to provide early warning for gas leaks.”
People are looking to natural gas to replace coal as an energy source because it emits much less carbon, but recent research has found that persistent methane leaks from the oil and natural gas supply chain continue to go unnoticed. Thus, this new approach for detecting leaks could solve a pervasive environmental health issue in addition to reducing the risk of explosions.
Murdoch observes that this method of methane detection is the type of “highly sophisticated monitoring to really solve the problem.”
—Katie Brown ([email protected]), Environmental Journalist, University of California, Santa Cruz