The air we breathe has a carbon problem. But in Hellisheidi, Iceland, a geothermally active plateau just outside of Reykjavik, a new technology is taking a small but mighty step toward fixing it.
A plant called Orca, built by Climeworks, is the first-ever facility where CO2 is being filtered directly from the air and stored permanently underground.
Orca’s carbon-capturing devices resemble giant transistor radios. They fit right into an already larger-than-life Icelandic landscape, where the wind blows fierce even on a rare day when sunlight gleams off the icy mountaintops.
Though the plant has only been operational since September, its air-straining technology, known as direct air capture, has been a point of contention among environmentalists for much longer. Vacuuming up carbon dioxide was once considered a last resort, but it’s looking like we’re headed toward a future where last resorts are a must-have.
“The combination of direct air capture and storage is very likely what the world will need at a massive scale if we want to be compliant with Paris climate targets,” said Jan Wurzbacher, the CEO and co-founder of Climeworks.
Carbon removal, by math and magic
By “Paris” targets, Wurzbacher was referring to the global goal of limiting emissions to two degrees Celsius (or ideally 1.5 degrees), established under the 2015 Paris Agreement. To meet that goal, the United Nations has estimated that 10 billion tons of carbon dioxide will need to be removed from the atmosphere annually by 2050. That number is a best-case scenario, assuming that aggressive cuts in emissions are achieved through other means. Without enough cuts, the need for carbon removal could be even higher.
“It’s relatively simple climate math,” Wurzbacher explained on a video call from Zurich, Switzerland, where Climeworks is based. “By mid-century, we need to remove 10 billion tons of CO2, if everything else goes well. We might end up needing to remove 20 billion tons, because we can’t ramp down fast enough coal power plants and other stuff.”
Direct air capture technology is one among many options for removing excess CO2. There are natural methods, like planting trees, and there are technologies that capture CO2 directly from smokestacks and other emission sources. Compared to capturing CO2 at the source, it’s more challenging and costly to pull CO2 literally out of thin air, but a benefit of direct air capture is that it doesn’t require finding and stopping every single polluter. It’s a solution that works across the globe.
“When you do direct air capture, you don’t need to go where the CO2 is, because air is everywhere,” said Wurzbacher.
The Orca plant consists of eight shipping container-sized boxes, which Climeworks calls collectors. On the front of each box, there are slats, kind of like large venetian blinds. On the back, there are 12 fans that pull air through the box. Within the collectors, the CO2 molecules hit the surface of a specially developed filter material, where molecules, called amines, selectively grab onto them.
That point of contact is a magical moment. The rest of the air continues out the other side of the collectors, but the carbon sticks tight to the amines. In that moment, the CO2 goes from the chaotic fray of the atmosphere to the ordered grip of humanity, potentially remaining under control for thousands of years to come. With the application of heat, the CO2 is released from the amines, and then it gets pumped into nearby volcanic rocks, where it forms long-lasting carbonate minerals.
Currently, removing a ton of CO2 at Orca costs between $600 and $800, which is prohibitive for most potential payers. Early customers have been companies and individuals willing to pay a premium, such as Microsoft, Stripe, Swiss Re and even the band Coldplay (which hired Climeworks to cancel out some of the emissions from its upcoming world tour).
Climeworks is aiming to get that cost down to between $100 and 200. The US Department of Energy recently set a similar goal of bringing the cost of technological carbon removal to under $100 per ton. At those lower price points, direct air capture would be on par with other ambitious measures to reduce emissions.
Why Iceland?
You’d be hard-pressed to find a field site more majestic than Orca. The plant sits on the edge of a grassy plain, just beneath craggy black peaks accentuated with crisp white snow. But the Climeworks team didn’t choose to build Orca in that spot for the scenery. The site in Hellisheidi offers two elements that are essential for direct air capture: cheap renewable energy and a place to put CO2. Both of those elements are products of Iceland’s unique volcanic geology.
Orca is located directly next to the Hellisheidi Geothermal Power Plant, which is one of Iceland’s biggest sources of geothermal energy. The plant draws hot water from over a mile below the ground, where it’s naturally warmed by a volcanic hotspot. The geothermal process produces heat and electricity, both of which are key inputs to direct air capture.
The electricity is used to move air through the collector, and the heat is used to release captured CO2 from the filter material, which happens at around 100 degrees Celsius, the temperature of boiling water.
“Geothermal is particularly good to start with, because it’s 24/7; it’s heat and electricity, so it’s really well suited to what we are doing,” said Wurzbacher.
Then there’s the CO2. The rock under Hellisheidi is porous basalt, less than 1 million years old, which means it’s pretty much brand new, geologically speaking. A company called Carbfix has figured out how to inject CO2 into this young rock so that it reacts to form carbonate minerals.
Carbfix is a subsidiary of Reykjavik Energy, the municipal-owned utility that operates the geothermal plant. For over five years, it had been using its technique to store the small amounts of CO2 released from the geothermal process, so the infrastructure to store the CO2 from Orca was already in place.
“This is a big part of why Orca is in Iceland,” said McCormick. “They have waste heat and zero-carbon power from the geothermal field. They have already-drilled injection holes and excellent geology for injecting CO2, so that location has everything you want.”
Carbon storage is an essential piece of the equation for carbon removal. There are many ways to do it, but the Carbfix method is particularly promising because the carbon dioxide turns quickly into rock. It mineralizes within two years—or more likely a few months—and it will remain in that solid state for thousands of years.
“The CO2 is not going anywhere, so basically once it’s underground, we know it’s going to stay underground,” said Kari Helgason, the head of research and innovation at Carbfix.
This time frame contrasts with other methods, like storage in abandoned oil wells, which requires indefinite monitoring to make sure that the CO2 does not escape.
Another benefit of the Carbfix method is that the cost is almost negligible, especially relative to the high cost of capturing carbon.
“If we receive pure CO2, it’s pretty cost efficient,” said Helgason. “What we’re doing with Climeworks, it’s ridiculously cheap.”
Fortunately, Iceland is comprised mostly of basalt, so the storage opportunities are almost limitless. Helgason estimates that each cubic kilometer of basalt can store one hundred million tons of CO2.
“The storage capacity is enormous,” he said.
And it’s not just Iceland where this massive storage capacity exists. Carbfix put together an online atlas that maps out regions round the world with potential for geologic carbon storage.
Wurzbacher noted that Hellisheidi and Carbfix were a perfect match for the Orca plant, but Climeworks is open to other locations for subsequent projects.
“What is not so perfect is the weather and wind in Iceland,” he said. “If you ask our commissioning team if they want to build the next plant in the same weather conditions, they might rather ask for going to Hawaii or someplace else with a lot of volcanic rocks.”
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