NEW YORK -- The doors of a metal box slide open, and a drone rises over a gas well in Pennsylvania. Its mission: To find leaks of methane, a potent greenhouse gas, so that energy companies can plug the leaks and reduce the emissions that pollute the air.
The drone is among an array of instruments whose purpose is to detect leaks of methane, which scientists say causes roughly 30% of human-made global warming. Along with satellites, ground sensors and planes armed with infrared cameras, drones are part of the backbone of a new federal policy to compel energy companies to record and slash their methane emissions.
The problem is, no one knows when -- or even whether -- that will be possible. Technology that might allow for precise methane measurements is still being developed. Under the Biden administration's Inflation Reduction Act, enacted into law last year, companies must start producing precise measurements of their methane emissions next year and face fines if they exceed permissible levels. Yet if no one knows how much methane an energy company has emitted, it's unclear that any fines could be justified.
"They don't measure the methane because the capability hasn't been there," Drew Shindell, a professor of earth science at Duke University, said of regulators. "It's challenging to really go measure all these methane sources."
Even energy companies that have begun developing systems to reduce their methane emissions are likely years away from being able to make comprehensive calculations. Most of them are measuring leaks for only a fraction of their operations.
Satellites, which help connect emissions to a single source, aren't widely enough available. Ground-based sensors and drones require vast amounts of money and time to widely distribute.
On top of all that, any agreement on what equipment would be acceptable to measure methane and how it should be used requires a rigorous process involving industry, government and environmental scientists.
"We need to develop these standards, and this can take years, so the process is slow," said Thomas Lauvaux, a climate scientist at University of Reims in France.
Despite the obstacles, climate scientists and environmentalists say they still welcome the administration's effort, under the Inflation Reduction Act, to slash methane emissions. Even if the timeline outlined in the law's methane reduction program is unrealistic, they say, it's likely to prod companies to accelerate their efforts to reduce leaks.
"The fact that there are these rules and now a pricing regime for methane for the first time is a huge benefit for dealing with the oil and gas sector that we just haven't had the tools to do until now," said Deborah Gordon, senior principal at the Rocky Mountain Institute, which seeks to accelerate a transition to clean energy.
Under the new law, the EPA can fine companies $900 per ton of methane starting in 2024, rising to $1,500 in 2026. For companies with significant leaks, the costs could be substantial. Kayrros, a satellite analytics firm, observed a Texas natural gas compressor station that released about 2,000 tons of methane over eight days in 2020. That leak would trigger fines of of $1.8 million if it occurred in 2024 or $3 million in 2026.
'KIND OF SCARY'
Most energy companies don't measure their actual methane emissions. Instead, they produce estimates based on how much methane they say typically escapes from their equipment.
Scientists have found that those estimates vastly understate the problem. Using data from satellites and aerial surveys, they concluded in peer-reviewed studies that nations and companies are emitting double or triple as much methane as they're reporting.
"The past three years have been the fastest-growing years on record in terms of methane emissions, which is kind of scary," said Daniel Jacob, a leading climate scientist at Harvard University. "It's absolutely critical because ultimately, from the standpoint of evading climate change, you want to stop methane from increasing and you want it to start decreasing."
And while scientists count it as progress that energy companies will eventually have to accurately measure emissions of the destructive gas, it seems doubtful that this can be achieved within a year, after which the government could fine companies for emitting too much methane.
"We need many more satellites before we can even pretend that we are tracking," Lauvaux said.
The companies that are now gathering emission measurements from planes, drones, ground sensors or infrared cameras on satellites face a significant obstacle: Those efforts are sporadic and cover only a sliver of the vast oil and gas industry.
The EPA hasn't yet released details on how companies should measure methane emissions. And the task of sorting out the details falls on an EPA staff that was depleted under the Trump administration.
Methane, the main ingredient in natural gas, has been shown to produce roughly 80 times the climate-warming power of carbon dioxide over a 20-year period. The gas is released from pipelines, storage tanks and energy facilities. It also wafts from landfills and the cattle industry. Scientists say a substantial reduction in the emissions is among the changes that could make the swiftest impact on climate change.
Though oil and gas companies have equipment to capture methane leaks, it's not widely deployed. Even the most advanced such equipment is often improperly installed or maintained and is prone to failure.
"If we can collectively get our act together over the next eight years and dramatically slash methane emissions around the planet, we still have a chance as a society to get our arms around the larger climate problem and avoid the worst impacts," said Riley Duren, CEO of Carbon Mapper, a nonprofit that analyzes emissions data from satellites and flights.
In recent years, climate scientists and companies have found and fixed methane leaks using infrared cameras on airplanes or satellites. In a series of flights over California and other states since 2016, Carbon Mapper detected 8,000 methane plumes and published its findings on a public portal. When Carbon Mapper alerted the facilities to the problem, Duren said, roughly half the leaks were fixed.
"It's still a patchwork quilt," he said of the nation's ability to measure methane emissions. "It's not comprehensive and continuous, but it's becoming more expansive."
Aided by philanthropic donations, Carbon Mapper hopes to launch a network of satellites that would share data publicly. It would start this year with two philanthropy-funded satellites that can detect roughly 20 methane plumes each day. (Planes can typically find 10 to 20 a day.)
"The goal is to expand to many more satellites, but that's contingent on securing the capital to do that," Duren said.
The company has suggested that government help would be needed to operate at the scale necessary to combat climate change.
A handful of orbiting satellites can detect methane plumes and pinpoint the source of the leak within about 100 feet (30 meters). Most are privately owned by companies such as GHGSat, which sells data to energy companies. Using that data, scientists at a satellite data firm or energy company can try to pinpoint leaks and, based on the image and wind speed at the time, estimate how much methane was emitted.
Yet there are limitations to the technology. Infrared cameras use the sun's rays, so they can't detect methane at night or on cloudy days. And they provide only a snapshot in time. So it can be hard to determine how much methane escaped before a leak was detected.
With GHGSat's six orbiting satellites, the company can produce images of a site once every three to five days. The company plans to have 10 of them in orbit by year's end, after which it could observe each site roughly once a day.
"The biggest challenge for us is to scale faster, to offer the service to more people in more places around the world more often," said Stephane Germaine, president of GHGSat. "How do we respond to that in a way that is commercially viable, short of a government standing up and spending billions of dollars to deploy this kind of system?"
Drones produced by American Robotics, like the one in Pennsylvania, have found unlit flares emitting methane. These drones can make several trips each day to check oil wells or storage tanks. But they're not widely deployed. American Robotics expects to have 30 drone systems deployed by year's end, said Reese Mozer, the company's CEO.
"There's more demand for our systems than we have the capacity to serve right now," Mozer said.
Exxon Mobil has been using airplanes equipped with infrared cameras to find methane leaks for several years. But data from aerial flights is imperfect. A plane may fly over an oil production site for two or three seconds, perhaps six times a year.
"The problem with quantification is, you don't know what happens when the plane's not there," said Matt Kolesar, Exxon's chief environmental scientist. "What was going on right before that airplane, and what was going on right after that airplane? And so that's where industry has always struggled to say, 'Do I assume it happens until I go look again? Do I assume it goes away?'"
Exxon is installing around-the-clock methane detectors in the Permian Basin, the nation's most productive oil and gas field, comprising large chunks of Texas and New Mexico. It's installed the sensors in 14 sites; its goal is to deploy sensors at 700 sites by 2025. But just 15% of the oil and gas Exxon produces comes from the Permian Basin. So most of Exxon's sites won't receive the sensors soon.
"It requires an awful lot of additional capacity, both continuous coverage and covering a much larger portion of the facilities," said Shindell, the Duke professor.
Thousands of sites of methane leaks, he said, might exist in areas like the Permian Basin.
"There are just tons of lines that gather from wells and then compressor stations that move the gas along and then storage tanks and just one thing after another, so getting a sense of that really is a big endeavor," Shindell said. "Even the best companies are not doing that. So it requires building this whole new system to improve understanding."
The EPA is still in the early stages of implementing the climate law. The agency plans to propose a rule this year that would change emissions reporting rules to ensure that reporting and calculation of fines are based on empirical data, said Khanya Brann, an EPA spokeswoman.
The EPA has also proposed allowing energy companies to use a broader range of technologies to detect methane leaks than what's now allowed. This could make it easier for varying types of companies to comply.
The American Petroleum Institute, which represents the oil and gas industry, wants companies to have the flexibility to use a variety of technologies. The API doesn't track how much of the industry already uses methane monitors, drones, aerial flights or satellite data to find and measure emissions, said Cole Ramsey, a vice president of the institute.
"This is a process that's going to take some time," Ramsey said.
The challenges don't end with adding satellites and sensors. Any measurement system created by scientists must withstand legal challenges. If a company is accused of emitting methane, it could dispute the accuracy of the satellite images or the way scientists calculated how much leaked.
"The minute we release a policy," Lauvaux said, "they're going to jump at it with 50 lawyers and look at any loopholes, gaps, mistakes, unclear sentences."
Even so, climate scientists and environmentalists generally say they're hopeful that even if the system is imperfect, the eventual fines for improperly emitting methane would cause the offending companies to take the steps necessary to reduce emissions.
"That's the great thing about the methane fee: There's actually a benefit to stopping it quickly because there's a financial reward for not leaking," said Gordon, of the Rocky Mountain Institute.
"I think the problems are way smaller than the opportunity to finally, finally deal directly with a greenhouse gas -- and especially a very powerful greenhouse gas that has never been on the agenda."