Climate tech startups team up to decarbonize Arizona concrete plant

Local governments in the southwestern U.S. are putting up $150,000 to back what they say is a pioneering effort to "turn air into concrete at scale." The funds will help cover the cost of the "reference project," a collaboration between two climate tech startups and a masonry firm in Flagstaff, Arizona.

The firms expect construction to kick off later this year, when the two startups install their tech within Block-Lite's existing facility. It'll work like this: Aircapture will suck carbon out of the air, and CarbonBuilt will retrofit Block-Lite's curing chamber so the firm can use the CO2 to cure a lower-carbon recipe for concrete. CarbonBuilt's recipe uses less cement and integrates industrial waste that "would otherwise be diverted to landfills," such as fly ash, the startup said.

"In essence, we’re working with Aircapture to take CO2 gas from our atmosphere and then we turn it into a rock for permanent storage," CarbonBuilt said in a statement.

The $150,000 award comes from the 4 Corners Carbon Coalition, which took its name from the Southwest region of the U.S. The group counts four municipalities as members — Salt Lake City, Utah; Santa Fe, New Mexico; Boulder, Colorado; and Flagstaff, Arizona. In a statement to TechCrunch, CarbonBuilt CEO Rahul Shendure called the funds "a great first step," but said the firms involved would also put funds and time into the project.

Efforts to reduce concrete's environmental toll are a crucial part of decarbonization. Concrete producers on the whole are responsible for roughly 7% of industrial carbon emissions, the International Energy Agency, an intergovernmental group, estimated in 2018.

Aside from installing solar arrays onto its facility, Block-Lite produces masonry products the traditional way today, emitting a ton of carbon dioxide via the curing process. Through the award, however, Block-Lite told TechCrunch that it will eventually start selling "ultra-low carbon blocks to customers in Flagstaff and surrounding areas."

The headline of this story was corrected on March 8 to reflect that Block-Lite's facility is a concrete plant, not a cement plant.