Two European entrepreneurs think they can remove carbon from the air at prices cheap enough to matter.
A pilot project at a Swiss university that uses Climeworks equipment to make methane out of airborne CO₂. Luca Locatelli for The New York Times
Just over a century ago in Ludwigshafen, Germany, a scientist named Carl Bosch assembled a team of engineers to exploit a new technique in chemistry. A year earlier, another German chemist, Fritz Haber, hit upon a process to pull nitrogen (N) from the air and combine it with hydrogen (H) to produce tiny amounts of ammonia (NH₃). But Haber’s process was delicate, requiring the maintenance of high temperatures and high pressure. Bosch wanted to figure out how to adapt Haber’s discovery for commercial purposes — as we would say today, to “scale it up.” Anyone looking at the state of manufacturing in Europe around 1910, Bosch observed, could see that the task was daunting: The technology simply didn’t exist.
Over the next decade, however, Bosch and his team overcame a multitude of technological and metallurgical challenges. He chronicled them in his 1932 acceptance speech for the Nobel Prize for Chemistry — an honor he won because the Haber-Bosch process, as it came to be known, changed the world. His breakthrough made possible the production of ammonia on an industrial scale, providing the world with cheap and abundant fertilizer. The scientist and historian Vaclav Smil called Haber-Bosch “the most important technical invention of the 20th century.” Bosch had effectively removed the historical bounds on crop yields, so much so that he was widely credited with making “bread from air.” By some estimates, Bosch’s work made possible the lives of more than two billion human beings over the last 100 years.
What the Haber-Bosch method had going for it, from the very start, was a ready market. Fertilizer was already in high demand, but it came primarily from limited natural reserves in far-flung locales — bird droppings scraped from remote islands near Peru, for instance, or mineral stores of nitrogen dug out of the Chilean desert. Because synthetic ammonia competed with existing products, it was able to follow a timeworn pattern of innovation. In much the same way that LEDs have supplanted fluorescent and incandescent bulbs (which in turn had displaced kerosene lamps and wax candles), a novel product or process often replaces something already in demand. If it is better or cheaper — and especially if it is better and cheaper — it usually wins in the marketplace. Haber-Bosch did exactly that.
It may now be that another gas — carbon dioxide (CO₂) — can be removed from the air for commercial purposes, and that its removal could have a profound effect on the future of humanity. But it’s almost certainly too soon to say for sure. One sunny morning last October, several engineers from a Swiss firm called Climeworks ambled onto the roof of a power-generating waste-incineration plant in Hinwil, a village about 30 minutes outside Zurich. The technicians had in front of them 12 large devices, stacked in two rows of six, that resembled oversize front-loading clothes dryers. These were “direct air capture” machines, which soon would begin collecting carbon dioxide from air drawn in through their central ducts. Once trapped, the CO₂ would then be siphoned into large tanks and trucked to a local Coca-Cola bottler, where it would become the fizz in a soft drink.
The machines themselves require a significant amount of energy. They depend on electric fans to pull air into the ducts and over a special material, known as a sorbent, laced with granules that chemically bind with CO₂; periodic blasts of heat then release the captured gas from the sorbent, with customized software managing the whole catch-and-release cycle. Climeworks had installed the machines on the roof of the power plant to tap into the plant’s low-carbon electricity and the heat from its incineration system. A few dozen yards away from the new installation sat an older stack of Climeworks machines, 18 in total, that had been whirring on the same rooftop for more than a year. So far, these machines had captured about 1,000 metric tons (or about 1,100 short tons) of carbon dioxide from the air and fed it, by pipeline, to an enormous greenhouse nearby, where it was plumping up tomatoes, eggplants and mâche. During a tour of the greenhouse, Paul Ruser, the manager, suggested I taste the results. “Here, try one,” he said, handing me a crisp, ripe cucumber he plucked from a nearby vine. It was the finest direct-air-capture cucumber I’d ever had.
Climeworks’s rooftop plant represents something new in the world: the first direct-air-capture venture in history seeking to sell CO₂ by the ton. When the company’s founders, Christoph Gebald and Jan Wurzbacher, began openly discussing their plans to build a business several years ago, they faced a deluge of skepticism. “I would say nine out of 10 people reacted critically,” Gebald told me. “The first thing they said was: ‘This will never work technically.’ And finally in 2017 we convinced them it works technically, since we built the big plant in Hinwil. But once we convinced them that it works technically, they would say, ‘Well, it will never work economically.’ ”
For the moment, skeptics of Climeworks’s business plan are correct: The company is not turning a profit. To build and install the 18 units at Hinwil, hand-assembled in a second-floor workshop in Zurich, cost between $3 million and $4 million, which is the primary reason it costs the firm between $500 and $600 to remove a metric ton of CO₂ from the air. Even as the company has attracted about $50 million in private investments and grants, it faces the same daunting task that confronted Carl Bosch a century ago: How much can it bring costs down? And how fast can it scale up?
Gebald and Wurzbacher believe the way to gain a commercial foothold is to sell their expensive CO₂ to agriculture or beverage companies. Not only do these companies require CO₂ anyway, some also seem willing to pay a premium for a vital ingredient they can use to help market their products as eco-friendly…