The quest to sequester carbon in stone and beat climate change

one evening in In November 2016, Gibbald was at a luxury party in Marrakech hosted by philanthropist Lauren Powell Jobs. He was feeling slightly out of place among her guests, a group of prominent climate researchers, activists, and policy makers who were in town for the COP, a major annual event in climate circles. He faithfully made his rounds, met a sociable man with rich white hair and styled. Olafur Ragnar Grimsson was the recently retired President of Iceland. Gebald gave him the talk on Climeworks. “that’s cool!” Gibald remembers Grimson saying. “I can store carbon monoxide₂ Underground in my country. But we lack the technology to capture it.”

Grimson was talking about Carbfix, a subsidiary of publicly owned Reykjavik Energy, which was developing a system to sequester carbon by injecting it into geological formations. Reykjavik Energy happens to operate two nice, clean geothermal power plants. Grímsson made some introductions, and soon after, Gebald and Wurzbacher partnered with Carbfix.

Icelandic officials may have been welcoming, but Iceland itself was less welcoming. Wurzbacher and Gebald built a small pilot plant with a single draft fan near Hellisheidi in 2017, but in no time it “literally froze,” Gebald says. One day, when the temperature dropped below zero, steam from the geothermal plant hit the bare metal of the machine, covering it with ice. Once again, a giant storm nearly carried the multi-part structure almost apart. “We had to stick it to the ground,” Gibald says.

After four years and many hurdles, a new Climeworks plant was launched, named Orca (after both killer whales and the Icelandic word for “energy”). It is located on the green volcanic plain, just a short drive from the visitor center where the opening ceremony was held. Eight olive green steel boxes the size of shipping containers stand on concrete cranes, connected by high tubes to a low white building that represents the control center. Steel ships are called CO₂ Collectors, in front of large black fans pulling rivers of air.

Inside the collection boxes, air passes over filters coated with amine-based absorbents and other carbon dioxide-trapping materials.₂ molecules. The carbon eventually saturates the filters, like water that swells a sponge. At this point, the sliding gates close the air inlet, and hot air is pumped from the control center to heat the filters to about 100°C, releasing carbon dioxide.₂. Vacuums then draw free-floating particles to the control center, where luminescent tanks, ducts, and other devices compress the gas. It is then piped to a handful of igloo-sized geodesic steel domes a few miles away, squatting on the plain like emergency housing for Martians.

Carbfix technicians and machines deal with the following steps. Inside the domes, a powerful motor drives an incoming stream of water down into the injection well. CO₂ The pipeline dumps the gas into the water. “It’s an underground soda stream!” She helped design the system, says Sandra Snæbjörnsdóttir, a Carbfix scientist with shoulder-length brown hair and serious green eyes surrounded by tortoiseshell glasses. A few hundred meters away, a soda stream flows into the ground, where it interacts with basalt deposits, turning it into a hard mineral. In other words, the carbon gas that causes climate warming turns to stone, like the villain in a fairy tale. “It’s basically nature’s way of storing carbon dioxide₂There is plenty of room for this tactic. Worldwide, there are likely enough suitable geological formations to store trillions of tons of carbon,” says Snæbjörnsdóttir.

On a basic level, the system does what it’s supposed to: Climeworks extracts carbon from the air, and Carbfix buries it underground. And both use geothermal energy, which produces only minor emissions of greenhouse gases. But the pickup part is still very energy-intensive, and therefore expensive. Fans need electricity, of course, but the bulk of the energy goes into heating the carbon to free it from the absorbent materials.