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by Alan Neuhauser
WHEN A CANADIAN STARTUP announced this spring that it would soon begin building a new type of facility that could remove carbon dioxide from the air, it sparked considerable fanfare.
Headlines declared the project, which this spring won $68 million in financing, a “potential solution to global warming.” The design, the brainchild of an acclaimed Harvard physics professor and Time magazine “Hero of the Environment,” won backing from Bill Gates.
Theoretically, such a facility could work virtually anywhere, extracting harmful greenhouse gases from the air on a massive scale. But the concept was embraced early on by oil companies, which quickly saw the possibility of liberating the drilling and extraction process from complaints about the emissions it generates. In fact, the plant under construction is being built in the heart of Texas oil country, in partnership with a subsidiary of one of the largest oil firms in the U.S., Occidental Petroleum. Occidental was one of three oil conglomerates to make sizable investments in the company.
The idea behind the facility, called carbon capture, isn’t new: It’s been in use for years at a handful of coal-fired power plants, oil and gas processing facilities and fertilizer plants in the U.S. The oldest operating site began vacuuming CO2 from a natural gas plant in 1972. Trees, which suck up CO2, could also be described as engaging in natural carbon capture.
What makes the Texas project different, though, is its promise to remove carbon dioxide through “direct air capture:” Rather than drawing CO2 from a smokestack, it instead pulls the gas from the open air regardless of location or even the gas’s concentration. Carbon Engineering, the company behind the project, says that with little more than off-the-shelf industrial-scale fans, filters and common chemicals, it’s solved a challenge long seen as beyond the reach of engineers or any reasonable budget.
“The idea of pulling CO2 out of the air has been around for 40–50 years, but what’s the challenge is doing it at scale in a cost-effective manner,” says Steve Oldham, the CEO of Carbon Engineering. “Hopefully we have the answer to that.”
But beyond the glowing headlines, outside experts vigorously dispute such assertions. The amount of CO2 floating around in the ambient air is generally 300 times less concentrated than in a smokestack or pipeline, making the gas far less efficient to capture. And professors from the nation’s top engineering schools – from Stanford to MIT, Berkeley and Carnegie Mellon – insist that the company’s math simply doesn’t add up.
“In general, air capture and storage on a meaningful scale is a far tougher problem than CO2 capture at power plants and industrial facilities,” says Edward Rubin, an environmental engineering professor at Carnegie Mellon University’s Wilton E. Scott Institute for Energy Innovation. “Much harder to find the needle in a haystack that’s 300 times bigger – hence, much more costly.”
Another professor put it more bluntly. “A lot of numbers being thrown out there today are just unbelievable,” says Howard Herzog, a senior research engineer at the MIT Engineer Initiative. “From what I’ve read, I’ve seen so many red flags that I’m totally shocked.”
Carbon Engineering insists that its technology works. The carbon dioxide its Texas plant collects will be injected and stored underground, making the entire loop carbon-negative, the company says. By its calculations, the Texas plant will remove 500 kilotons of CO2 per year from the atmosphere – the equivalent of planting and nourishing some 20 million trees.
“Basically you have a carbon-neutral fossil fuel,” Oldham says. “We have extracted from the air, in advance, an amount of CO2 that is more than the CO2 produced when you burn that crude.”
The design is “deceptively straightforward,” he says. The CO2 binds with a liquid chemical, the mixture then pushed through a filter. Carbon Engineering has been testing the approach since 2015, when a pilot facility at its headquarters outside Vancouver began pulling up to a metric ton per day of CO2 from the air. The planned site in Texas will aim to capture 500,000 metric tons a year, the company says – and, with expansions, perhaps as much as 1 million.
“I actually used to work in satellites, so I can actually say it’s not rocket science,” Oldham says. “Our technology has always been designed for scalability. It’s a question of repeating the same plant many times.”
The goal, he says, is to buy time: To stave off the worst consequences of climate change as electric vehicles make inroads and solar panels, wind turbines and – more recently – battery storage expand and replace the coal, gas and oil plants that remain entrenched in the world’s electric grids.
“We are not in a position as a society today to move off fossil fuels. So from an environmental perspective, we think this is worth doing,” Oldham says.
The idea has found outside support. In a study this week in the journal Nature Communications, for example, a team of European scientists concluded that while technologies like those being developed by Carbon Engineering should “be developed and deployed alongside, rather than instead of, other mitigation options,” they’re still worth pursuing.
But concern remains that such technology could actually enable the continued use of fossil fuels rather than serve as a bridge to phasing them out. Occidental also plans to harness the gas captured by its new plant for what’s known as “enhanced oil recovery,” where CO2 is injected into deposits to make the company’s drilling operations even more productive. The company is the biggest employer of enhanced oil recovery in the U.S.
There is also the issue of scale: Humans last year generated a record 36.2 gigatons of carbon dioxide – each gigaton 1,000 times the size of just one of the 500 kilotons that the Carbon Engineering plant aims to remove. Removing the CO2 from just 2018 alone would require planting close to a trillion trees. The Carbon Engineering plant, by comparison, would need to be replicated some 40,000 times – and even then, only if carbon emissions leveled off, which is far from certain.
“CO2 negative – yeah, right. It’s a big sham … There’s no proof that there’s actually anything captured by anything.”
“Am I saying we should build 40,000 of our plants? God, I hope not, because that will mean we’ve failed in a lot of other measures,” Oldham says. But, he continues, “it’s less than there are water treatment plants, it’s less than there are power stations – it’s not totally ridiculous thinking about building that many. I hope that we don’t have to, but if we do, our company wants to have that technology ready.”
Other experts insist that no matter how many plants Carbon Engineering licenses or builds, the company will never accomplish what it claims – and, in fact, may simply generate more emissions. Carbon removal, at least as proposed by Carbon Engineering, as well as by two competitors in Alabama and Switzerland, remains firmly in the realm of alchemy, they argue, with one professor comparing the company’s claims and resulting fanfare to Theranos, the startup that attracted billions of dollars in investment and press attention by claiming to remake blood-testing, but whose founders were later indicted on federal fraud charges.
“CO2 negative – yeah, right. It’s a big sham,” says Mark Jacobson, an engineering professor at Stanford University and director of its Atmosphere and Engineering Program. “I’ve looked at their published data and their own numbers.”
Carbon Engineering’s planned project, he contends, simply will not accomplish what the company has claimed: It requires so much energy – generated by burning natural gas – that anywhere from a third to three quarters of the CO2 the plant captures will effectively end up back into the atmosphere, Jacobson says. The claim that CO2 injected underground will remain there, meanwhile, has yet to be proven at scale, he argues.
“There’s no proof that there’s actually anything captured by anything,” Jacobson says. “It’s a gimmick that actually does not work.”
Carbon Engineering maintains that its plans call for capturing any emissions from the natural gas plant. But while other academics have taken issue with Jacobson’s math, but they agree that his conclusions are correct.
“On this point we agree: The numbers as far as how much Carbon Engineering and the Swiss company can capture – they are wrong,” says Dan Kammen, a physicist and professor of energy at the University of California-Berkeley.
“Their assumptions about how much energy they’re going to need are way underestimated. I don’t even think they understand they have a problem. I don’t think they’ll ever get the commercial plant to work.”
Carbon Engineering’s planned Texas site wouldn’t be the first ambitious, large-scale carbon capture facility in the U.S. In 2010, Southern Company, one of the country’s largest electric utilities, broke ground for a new coal-fired power plant in Mississippi, one that would integrate carbon capture to prove the viability of so-called “clean coal.” Seven years later, the Kemper project was $5 billion over budget, the subject of a Securities and Exchange Commission investigation and multiple lawsuits, and Southern Company pulled the plug. The plant now burns natural gas.
“They spent $7 billion to prove themselves – and this is not a startup company, this is one of the two biggest utilities in the U.S. They have their own engineering force. But they so overestimated this, they lost billions of dollars,” Herzog says. “It’s easy to fool yourself if you want to believe and you don’t want to take a hard engineering look at it.”
The Kemper project, he points out, was designed to be about 220 times larger than a pilot version of the planned carbon-capture facility. The Carbon Engineering site, by contrast, is a 2,500-fold leap.
“These are giant jumps,” Herzog says. “So, as an engineer – this is crazy, alright?”
Carbon Engineering hasn’t put a price tag on its Texas project; a spokeswoman says that “financing for the project will likely be in the hundreds of millions.” The company meanwhile says that it’s aware that such a large leap in scale from its pilot plant to the one planned for Texas presents significant challenges. The study in Nature Communications concluded that scale – not cost – probably presents the biggest hurdle to the technology’s success.
“Everybody acknowledges that risk, including Carbon Engineering. We don’t hide from that risk at all,” Oldham says. He vigorously disputed the professors’ other critiques. “We’ve refined and updated and optimized our process significantly. To my knowledge, none of these people have come and actually talked to the company. Come and invite them, they’re all invited to our facility, they can come and see our systems working, we have produced financial models … the due diligence that we’ve done – come and look at it all. There’s nothing to hide here.”