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The Quest to Trap Carbon in Stone—and Beat Climate Change

The Quest to Trap Carbon in Stone—and Beat Climate Change

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One evening inNovember 2016, Gebald attended a Marrakesh party hosted by Laurene Pouls Jobs, a philanthropist. Gebald was feeling a bit out of place among her guests, a group of prominent climate researchers and activists as well as policymakers, who were in town to attend the COP conference. It is a major annual event for climate scientists. He was jokingly making his rounds and he came across a charming, well-coiffed man with a richly coloured white hair. It was Ólafur Ragnar Grímsson, the recently retired president of Iceland. Gebald gave him the Climeworks story. “That’s fantastic!” Gebald recalls Grímsson saying. “I can store CO2Underground in my country. But we’ve been lacking the technology to capture it.”

Grímsson was talking about Carbfix, a subsidiary of publicly owned Reykjavik Energy, which was developing a system to sequester carbon by injecting it into underground geologic formations. Reykjavik Energy also operates a few clean, efficient geothermal power stations. Grímsson made some introductions, and soon after, Gebald and Wurzbacher were hammering out a partnership with Carbfix.

Although Icelandic officials were welcoming, Iceland was not as friendly. Wurzbacher and Gebald built a small experimental plant with a single intake fan near Hellisheidi in 2017, but in short order “it literally froze,” Gebald says. One day when the temperature dropped below zero, steam from the geothermal plant hit the machine’s bare metal, covering it in ice. Another time, a massive storm nearly swept away the entire multiton structure. “We had to bolt it to the ground,” Gebald says.

Four years and many hitches later, Climeworks’ new plant, dubbed Orca (after both killer whales and the Icelandic word for “energy”), came online. It sits in the verdant volcanic plain, a short drive from the visitors’ center where the opening ceremony was held. The control center is composed of eight olive-green steel boxes, each the size of shipping containers. They are supported on concrete risers and connected by elevated pipes to a low-rise white building. The steel vessels are called CO2Collectors are surrounded by large black fans that draw in rivers of air.

The collector boxes have filters that trap the CO in the air. These filters are made of amine-based sorbents or other materials.2 molecules. The carbon eventually covers the filters like water bloating sponges. The carbon eventually saturates the filters. At this point, sliding gates seal off air intake. Hot air is piped into the control center to heat them to around 100 degrees Celsius. This releases the CO2. The vacuums then pull the free-floating molecules towards the control center where tanks, ducts and other hardware compress it. It’s then piped over to a handful of igloo-sized geodesic steel domes a couple miles away, squatting on the plain like emergency housing for Martians.

Orca’s massive fan networks draw in rivers and sand.

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Photograph: Tanya Houghton

Photograph: Tanya Houghton

Next, Carbfix technicians work with machines and machines. A powerful motor pushes water into the injection well from within the domes. The CO2The gas is pumped into the water by pipeline. “It’s an underground SodaStream!” says Sandra Snæbjörnsdóttir, a Carbfix scientist with shoulder-length brown hair and earnest green eyes framed by tortoise-shell glasses who helped design the system. A few hundred meters below the surface, the soda stream flows into soil where it reacts and becomes a solid mineral. The climate-warming carbon dioxide is transformed into stone, much like the villain in a fairytale. “It’s essentially nature’s way of storing CO2,” says Snæbjörnsdóttir. There’s plenty of room for this tactic. There are likely enough geologic formations around the world to store trillions upon trillions of tons carbon.

On the most basic level, the system does what it’s supposed to: Climeworks extracts carbon from the air, and Carbfix buries it underground. Both systems use geothermal energy, which produces minimal greenhouse emissions. The capturing process is still very energy-intensive and expensive. The fans require electricity, but most of the power is used to heat the carbon to make it dissolve in the sorbent.

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