XPrize Carbon Removal selects 15 milestone winners

As Elon Musk was busy buying Twitter, the XPrize Foundation announced the 15 teams that will each take $1 million of his fortune and use it to develop their concepts to remove large quantities of carbon dioxide from Earth’s atmosphere. Musk’s personal foundation has pledged to donate a total of $100 million in prize money.

The start-up Calcite Carbon Removal, for example, won for a direct air capture (DAC) technology that cycles between calcium hydroxide, Ca(OH)₂, and calcium carbonate, CaCO₃, to pull CO₂ out of the air and isolate it for transport and sequestration.

Another DAC-based winner, Verdox, is an early mover in electrochemical carbon capture, a promising but unproven route that avoids solvents and heat, two big cost drivers in many DAC systems. Verdox’s electrodes switch between CO₂ absorbing and releasing modes with a change in applied voltage. The firm will sequester its carbon with Carbfix, a CO₂ mineralization company that is also working with another milestone winner, Heirloom, and the DAC industry leader Climeworks.

An approach that’s been gaining attention recently is DAC’s aquatic cousin, direct ocean carbon capture. The California Institute of Technology spin-off Captura got its $1 million for a system that uses membranes, silver and copper electrocatalysts, and a potassium ferrocyanide/ferricyanide electrolyte to convert CO₂ dissolved in seawater into carbon monoxide, ethylene, and small alcohols. Captura plans to build a floating prototype powered by renewable energy.

The foundation gave away $5 million across 23 student-led teams in November. The $50 million grand prize and $30 million runner-up pool are still up for grabs, and XPrize officials say any project could win, even if it wasn’t among the awardees so far.