How Scientists Are Using Lasers To Hunt For Leaky Oil And Gas Equipment
Wyoming and Colorado are in the top ten natural gas producing states. But in those states – and across the country – a lot of that gas is escaping straight into the air. Scientists are now working to come up with a better way to track those leaks down.
In the spring of 2017 residents of a subdivision in Firestone, Colorado, watched as a home suddenly caught fire and exploded, killing two people and injuring another. The culprit was methane. It’s the main ingredient in natural gas, which had been seeping into the home’s basement from an old pipeline.
“It would appear an unusual and tragic set of circumstances occurred here,” said Ted Poszywak, Firestone’s fire chief, in a press conference.
The event was certainly tragic, but it wasn’t necessarily that unusual. As Inside Energy reported, other homes near old gas wells have exploded in the last few years. And in 2015, a natural gas storage facility near the residential area of Porter Ranch, California, released enough methane to be called “one of the worst environmental disasters in U.S. history.”
As researchers recently found, methane leaks are happening all the time, though usually on less catastrophic scales, and usually at oil and gas facilities rather than in people’s back yards.
That’s a problem, because even if it isn’t posing imminent danger to people, methane is a potent greenhouse gas. In some ways, it’s considered worse than carbon dioxide. It also contributes to smog. But it’s hard to find.
“Methane itself is odorless and colorless,” says Sean Coburn, a chemist in the mechanical engineering department at the University of Colorado, Boulder.
The sulfurous smell we associate with natural gas is due to a chemical added in further down the supply chain, specifically to alert our noses to leaks. Before that, it’s hard to spot so-called “fugitive emissions.” You can’t see the leaks. And, Coburn says, you usually can’t hear them either.
Coburn is part of a team of Colorado researchers that received funding from ARPA-E, a research and development branch of the Department of Energy, as part of a challenge to develop cheaper, better ways to locate methane leaks.
They’re competing with half a dozen other teams to see which method work best. The competition ground is an open field in Fort Collins, Colorado, that looks like a steampunk playground, with decommissioned wellheads, tanks and pipes. It’s a testing ground for scientists made of decommissioned equipment, designed to purposefully leak small amounts of methane.
For Coburn and his colleagues, this is a sort of treasure hunt.
“Yes, the treasure being methane emissions,” says Coburn.
Somewhere out there, methane is leaking. The leaks could be escaping from any number of sources and they might be turning on and off. It’s a blind test. Coburn are his colleagues don’t know where the leaks are, but they’ve set up a very special laser, part of something called a dual frequency comb spectrometer, to find them.
About half a mile away, a laser shoots thousands of wavelengths of light out across this field of equipment, interacting with methane along its path before bouncing back on a mirror. Methane absorbs some of that light, so the team is able to tell when the laser light returns whether it’s encountered methane, other gases, or just regular, leak-free air. Based on that information, they can figure out where the leaks are to within about 15 feet and how much methane is escaping.
Coburn says earlier, simpler field tests have shown the method is very sensitive.
“If you were exhaling methane, we could detect your breath from more than a kilometer away – easily,” he says.
The group has been able to detect leaks that are exiting equipment eight times more gently than a human breath. Estimates by other researchers have shown that even if you only identified much bigger leaks -- those exiting equipment at about five times the rate of a human breath -- it could lead to as much as a 90 percent reduction in overall methane emissions.
The group is still working on publishing the results of its blind tests, but Arvind Ravikumar, a post-doctoral researcher at Stanford University studying methane detection, says it seems promising.
“Yes, it is promising,” he says. “It looks very good in the sense that it can monitor continuously, and it can detect very small leaks from far away.”
Right now, the typical method for detecting leaks is to have someone walk around a site with a handheld infrared camera. Other methods involve driving around sites or flying over them with planes or drones. The problem is, no matter what detection equipment they’re using, such methods are prone to miss leaks – even big ones – because they scan the site for such a short period of time.
On the other hand, Ravikumar says, this laser setup could sit around for a while, monitoring constantly.
But, he says, “There's always a ‘but.’ The deciding factor will always be cost.”
He estimates that the standard, handheld method costs around $500 per survey per site. Any new technology would have to be at least that cheap in order for oil and gas companies to pay attention.
“Can the cost come down so much that it is economical to deploy these technologies across the entire oil and gas infrastructure? That's the ultimate question,” says Ravikumar.
It’s hard to say if this new laser method is cost-competitive with less thorough leak detection methods. In this case, the cost depends on factors like how densely clustered equipment is within a site, and how frequently the company is required to check for leaks. But it’s in the ballpark.
“The Department of Energy gave us a target of $3,000 per site per year for continuous monitoring. We can meet that target and exceed it, sometimes by a lot,” says Greg Rieker, who leads the University of Colorado research group and launched a startup that oil and gas companies can hire to monitor methane leaks.
Rieker says they’re currently running demonstrations at actual natural gas facilities -- a well pad in Platteville, Colorado, and a methane storage facility in California. He says the cost drops precipitously the more pieces of equipment there are to monitor within an area because it just takes one laser setup to scan hundreds of points continuously within a 3-mile radius.
Ravikumar sees this technology as one piece of a bigger trend.
“With all these new technologies that are being developed, the costs for detection are rapidly coming down and so going forward there's really not that much of an excuse to not do this more rigorously and try to reduce emissions as much as possible,” says Ravikumar.
Methane leakage is one problem that’s actually solvable, he says, and the solution appears to be on the horizon.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, Yellowstone Public Radio in Montana, KUER in Salt Lake City and KRCC and KUNC in Colorado.