Oil and gas producers rely on flaring to reduce natural gas venting from their facilities, but new research led by the University of Michigan shows that in the real world, the practice is much less effective than expected — releasing five times more methane in the United States than previously thought. previously.
Methane is known to be a potent greenhouse gas, but it is believed that burning it in oil and gas wells effectively prevents it from escaping into the atmosphere.
Unfortunately, data published in Science shows that we overestimate the effectiveness of burning and, as a consequence, underestimate its contribution to methane emissions and climate change. But if we fix the combustion issues, the payoff is big: the equivalent of removing 3 million cars from the roads.
Industry and regulators operate under the assumption that flare torches are constantly lit and that they burn 98% of methane when operating. Data from aerial surveys in the three geographic basins of the United States, which comprise more than 80% of gas flaring in the United States, show that both assumptions are incorrect. Flashlights were found to be lit approximately 3%-5% of the time, and even when lit, they were found to operate at low efficiency. Combined, these factors result in an average effective ignition efficiency rate of only 91%.
“There is a lot more methane being added to the atmosphere than is currently accounted for in any inventories or estimates,” said Eric Cort, associate professor of climate and space sciences and engineering, F3UEL’s principal investigator and chief scientist on the new project. Research.
Oil production can come with methane as a by-product, and when it is not cost-effective to obtain, the gas must be disposed of safely. Burning methane by igniting as it is released turns it into carbon dioxide, another greenhouse gas but less harmful on a pound-by-pound basis.
Over the course of three years, the researchers conducted 13 flights in aircraft equipped with air monitoring equipment to assess the amount of methane emitted by the flares through oil and gas production basins. The flights were conducted at the Permian and Eagle Ford oil and gas fields in Texas, as well as the Bakken oil and gas field in North Dakota.
The planes were flying downwind from the ignition sites – crossing the direct paths of the ignition plumes. Tubes and pumps draw air into devices on board, where a laser scan at a specific frequency measures the amount of carbon dioxide and methane it carries.
Measuring both gases simultaneously allowed the researchers to estimate the destructive efficiency of the flares at an individual site.
“If the flare works as it should, there should be a large rise in carbon dioxide and a relatively small rise in methane,” Genevieve said. “Depending on the relative enhancement of these two gases, we can see how well the flares will perform.” Blunt, lead author of the study and an associate research scientist in space and aerospace science and engineering.
In November, the United States, the European Union and additional partners — 103 countries in total — launched the Global Methane Pledge to reduce methane emissions. This commitment focused on keeping global temperatures within 1.5 degrees over a limit set by the scientific community to offset the worst effects of climate change. And last year, UN officials identified methane reduction as “the most powerful way we have to slow climate change over the next 25 years.”
“This appears to be a source of methane emissions that appears to be completely remediable,” Blunt said. “With management practices and our better understanding of what’s happening to these flares, we can reduce the methane source in a significant way.”
UM’s research partners for the study include Stanford University’s Department of Energy Resources Engineering, the Environmental Defense Fund (EDF); Scientific Aviation in Boulder, Colorado; and Utrecht University Institute for Marine and Atmospheric Research.
Recent research led by the nonprofit EDF similarly found that nearly 10% of torches are not lit or broken.
“This study adds to the growing body of research that tells us the oil and gas industry has a burning problem,” said John Goldstein, EDF’s senior director of regulatory and legislative affairs. “The Environmental Protection Agency and the Bureau of Land Management should implement solutions that can help end the practice of routine burning.”
The research was funded by the Alfred P. Sloan Foundation with additional support from the Environmental Defense and Scientific Aviation Fund and the University of Michigan (College of Engineering, Department of Climate and Space Sciences and Engineering; Graham Institute for Sustainability).