David Keith is a bit fidgety. Maybe that's because venture capitalists have asked to come see his carbon dioxide machine. Maybe it's because the project is running months behind schedule, as experiments so often do. Maybe it's because his critics say it'll never work.

Or maybe it's a taste of excitement, because it seems entirely possible that the trailer-truck-size machine that he's leaning up against is actually going to work.

"It's amazing to see all this talk and paper get turned into hardware," he says. "I really love it."

Keith is on a patch of blacktop on the campus of the University of Calgary, in Alberta, Canada, where until very recently he has been a professor. Now his academic hat is Harvard, where he is both a professor of public policy and a professor of applied physics. His hard hat is a little start-up company, called Carbon Engineering, housed on the Calgary campus. And that company is building a machine that can actually suck carbon dioxide from the air.

The technology at the core of the device is not new. "People have done this for a long time," he says. "There were commercial processes that took CO₂ out of the air, in fact, in the 1950s, so there's no mystery that we can do it."

But those companies were just extracting small quantities of carbon dioxide for industrial purposes. Keith is after a much more important question, one that is universal for anyone trying to develop a technology: Can it be done affordably on a grand scale?

"So our interest is in building full-scale commercial systems that would take tens of thousands of tons — or more — of CO₂ out of the air," he says.

'Not As Hard As You Think'

Taking on climate change is in part personal for Keith. This wiry man has skied across many hundreds of miles of the rapidly melting Arctic, so he knows more than most people what's at stake.

Getting this project to work is also an intellectual challenge. "It's fun to go after problems where there's a wide public consensus in one direction that is sort of thin, where people haven't thought about it very much," he says.

"And on this topic, I'd say a lot of my colleagues who are experts in energy technology say it's a total joke to take CO₂ out of the air, and it must cost thousands of dollars a ton carbon.

"When we began looking hard at it, we became convinced that that really wasn't right. It's not that the other people are fools, but the other people hadn't done the engineering. And when you do the engineering, it turns out it's not as hard as you think."

As he looks at the machine taking shape, he points out that its components are all tried-and-true technology, just reassembled in a novel way for a novel result. If scaled-up versions of this contraption can work, capturing carbon from the air could alleviate one of the biggest challenges in climate change.

"It provides a route to manage emissions from transportation," he says. "Transportation needs high-energy fuels, like hydrocarbons. It's very hard to replace those with batteries, and in some instances, like airplanes, you just can't."

Keith's gift, as both an energy analyst and an engineer, is that he thinks about problems in unconventional ways. So on the one hand, Keith faces skepticism from his friends in academia.

But some very smart people are betting big money that he's right. Bill Gates turns to Keith for advice on matters of energy and climate. And Gates and a Canadian billionaire have given him $6 million to put his ideas to the test.

"It's only possible, by forming a company, to answer the question of what it actually costs to do this," he says.

Putting Captured Carbon To Work

The 600-volt power line is switched on and the machine shows its first sign of life. As they put power to one key component, the fans suck the air through the apparatus.

These fans will draw air through a 31-foot-long chamber filled with wavy plastic material. Water laced with sodium hydroxide will run down that plastic and react with carbon dioxide to pull it out of the air.

After that part of the machine is up and running reliably, Keith plans to test various chemical systems to complete the process — that is, to recycle the chemical that captures carbon dioxide, and to create a pure stream of CO₂ gas, which can then be buried underground.

Keith sees a few niche applications that could actually make this little company money. One idea is to take the pure carbon dioxide and pump it underground to push up oil. He says this oil would qualify as a low-carbon fuel, since producing it would actually take carbon dioxide out of the air.

"We think we could make hydrocarbon fuels that had substantially lower life-cycle carbon emissions than conventional gasoline," he says. "And I think that is both genuinely important for the environment and also potentially lucrative under the emerging standards for low-carbon fuels, like the California low-carbon-fuel standard."

More Options On The Table

The following day, two guys in business suits show up from Chrysalix, one of the biggest venture capital companies focused on clean energy.

Keith shows them around his equipment. They ask lots of questions, and in the end, Chrysalix CFO Mike Walkinshaw nods his head approvingly.

"We think there's a great business opportunity in solving the world's global warming issues," Walkinshaw says."We think the problem will become more manifest in the next few years and the world's going to be looking for answers. And they'll be willing to pay for it."

Walkinshaw finds comfort in standing among all of the bent metal and pipes of the device. "We love prototypes," he says. "This is excellent work that professor Keith has been doing here."

This is not the only small company exploring air capture of carbon dioxide. And with the costs so high at the moment, it's at best a distant dream to scale it up enough to affect the global climate. He agrees with his critics on that point. But Keith says costs will never come down and technology will never advance unless there's someone at the edge pushing forward.

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"I've spent 20 years of my life trying to figure out how to help solve the climate problem," he says. "I work on lots of different technologies. I don't believe any one is the silver bullet. But I do believe we need to have a larger set of potential solutions to deal with the climate problem, none of which will be perfect, none of which we understand very well, but we do a better job if we have more options on the table."

Several weeks later, Keith reports that the machine is up and operating. The technical problems that some critics thought could be showstoppers have not materialized, he says. Now the challenge is to squeeze in as much testing time as they can, before Calgary's winter weather moves in and shuts them down for the season.

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