“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.’ ”
via The Tiny Swiss Company That Thinks It Can Help Stop Climate Change – The New York Times