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Greenhouse Gases

XPrize Carbon Removal narrows teams down to 20 finalists

Grand-prize winner will get $50 million, and runners-up will split $30 million

by Craig Bettenhausen
May 22, 2024 | A version of this story appeared in Volume 102, Issue 16


A woman in personal protective equipment works on pipes and valves on a barge in a river. Palm trees and warehouses bedecked with solar panels are visible in the background.
Credit: Captura
Captura’s lead pilot engineer, Fenfang Wu, aboard the firm’s floating direct-ocean-capture pilot plant at the Port of Los Angeles.

Cutting carbon dioxide emissions is both crucial and insufficient, according to the most recent report from the United Nations Intergovernmental Panel on Climate Change. Society will need to claw back a lot of the CO2 humans have already released into the atmosphere to avoid the worst consequences of climate change.

XPrize Carbon Removal is a technology contest that aims to help answer that call. The contest spreads a $100 million donation from billionaire Elon Musk across several teams commercializing technologies that remove CO2 from the atmosphere. The contest organizers have now narrowed down the initial crop of more than 1,300 entrants to 20 finalists.

The companies in this final round are split almost evenly among four carbon removal methods: direct air capture, mineralization, biochar creation, and direct ocean removal. To qualify for the grand prize, the firms must deploy and operate pilot plants that capture CO2 at a rate of 1,000 metric tons (t) per year or better. The XPrize judges will select the winner on the basis of the technology’s potential to scale up to 1 billion t of CO2 removal by 2050.

The grand-prize winner, to be selected in April 2025, will get $50 million, runners-up will split $30 million, 15 milestone winners have already been awarded $1 million apiece, and $5 million total went to student teams.

XPrize Carbon Removal finalists

The $100 million contest is backing four approaches to removing carbon dioxide from Earth’s atmosphere.

Air: Direct-air-capture systems blow ambient air through a material that binds CO2, which is then desorbed for sequestration or conversion into chemical products. The air finalists are Airhive, Heirloom, Octavia Carbon, Project Hajar, and Skyrenu.

Rocks: Mineral carbonation works by grinding up rocks that would normally react slowly with CO2 over thousands of years. The grinding quickens the pace of the process. The rocks finalists are Arca, Lithos Carbon, Mati Carbon, Silicate, Undo Carbon, and Yuanchu Technology.

Land: Biochar is a carbon-rich material made by heating plant biomass in a low- or no-oxygen environment. Because plants get their carbon from the air during photosynthesis, creating and storing biochar decreases atmospheric CO2. The land finalists are Climate Robotics, Mash Makes, NetZero, Takachar, and Vaulted Deep.

Oceans: Direct ocean capture capitalizes on the high volumetric concentration of CO2in seawater, about 150 times that of air. Any CO2 removed from the sea is quickly replaced by atmospheric CO2, driving down concentrations in the air. The oceans finalists are Captura, Ebb Carbon, Kelp Blue, and Planetary Technologies.

Captura, one of the finalists, says the contest is helping bring attention to direct ocean removal firms. Captura uses electrodialysis membranes to strip CO2 out of seawater, a process it says can scale at lower cost than direct air capture. CO2 from the air then dissolves into the water, leading to a reduction in atmospheric greenhouse gas concentrations.

“Receiving the $1 million milestone award not only provided crucial financial backing during the early stages of Captura’s development but also opened doors to a vast network of resources,” a Captura spokesperson says. “This helped us finance and grow our business, find investors and ultimately close a major $45.3M series A round, and build and demonstrate our first fully working direct ocean capture system.”

Captura has operated a 100 t per year pilot plant in California since the fall. Before the end of 2024, the firm says, it will start up a 1,000 t plant in Norway connected to an undersea CO2 storage facility called Northern Lights.



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