The fires that burn excess gas at oil fields, landfills and manufacturing plants pollute the atmosphere more than they are given credit for, University of Michigan scientists found in a recent study.
They hope their research highlights a simple step facilities could take to significantly mitigate climate change.
"We found that flares are releasing a lot more methane than we previously thought," said Genevieve Plant, lead author on the study and assistant research scientist in the University of Michigan's Climate and Space Sciences and Engineering department.
"If we address this flaring issue by either reducing flaring volumes or bringing flares up to perform as they're designed to, we can reduce a lot of methane from leaking into our atmosphere and affecting the climate."
Flaring is a common practice at oil and gas drilling sites, where methane is released through the process of extracting oil. Methane is a powerful greenhouse gas and contributor to climate change. It also can add dangerous pressure to oil sites. Flaring, essentially burning the methane, allows operators to control pressure and turns much of the methane into carbon dioxide, which is a less harmful greenhouse gas.
Flares also can be used to reduce methane releases from landfills and manufacturing sites.
Some global organizations including the World Bank and the International Energy Agency have taken a stand against flaring, describing it as "a monumental waste of a valuable natural resource," a "totally unproductive" waste of energy and an "extraordinary waste of economic value." The World Bank said the amount of gas that flared each year could power sub-Saharan Africa.
And it's worse than anyone thought, according to the team of scientists led by Plant and University of Michigan Associate Professor Eric Kort. They published their research paper Thursday in the journal Science.
Experts assumed those flares were lit all of the time and that they burned 98% of the methane that ran through them, Kort said. But they don't — flares eliminate about 91% of the methane and they aren't running approximately 3-5% of the time.
That means flares emit five times more methane than assumed.
"It basically means flares go from being a pretty small part of the methane problem to 'Wait a second. This is actually a big number,'" Kort said. "This matters."
If flares in the United States were to operate as efficiently as they were thought to, burning away 98% of their methane and operating all the time, then the benefit to the climate would be the same as removing roughly 3 million cars from the road, Kort said.
"(Flares have) gone from being a source that is almost negligible to a considerable source of methane," he said.
To figure out how well the flares were working, researchers hopped aboard airplanes and flew over three major oil and gas fields in Texas and North Dakota. They took machines that measure methane and carbon dioxide and flew through flares to find out how much of each pollutant was in their exhaust. They found that the flares let more methane escape than they expected.
Another group of scientists drove around the oil fields on the ground to survey whether the flares they passed were lit or not.
While the researchers focused their work on big oil and gas fields in Texas and North Dakota, their findings are relevant for flares throughout the country, Plant said.
Michigan is not a major state for oil and gas flaring, Kort said, but that doesn't mean their findings are irrelevant.
"It doesn't really matter from a climate perspective where the flares are," he said. "The oil and gas industry has a big climate footprint and we're in the midst of seeing a lot of things changing with climate and being able to better understand what are the causes of the largest emissions, especially ones that we could address, puts us in a better place to make good decisions going forward."
