Carbon-sequestering concrete is having a moment.
In mid-April, two climate-tech startups focused on decarbonizing the world’s most widely used construction material, CarbonCure Technologies and UCLA CarbonBuilt, split the top prize in the $20 million NRG COSIA Carbon XPRIZE competition. Each will receive $7.5 million to further the development and commercialization of their approaches.
Both startups address CO2 at the manufacturing site. The UCLA CarbonBuilt approach captures CO2 generated during production and then infuses it into the concrete, using hydrated lime. The process uses 60 to 90 percent less ordinary portland cement (aka calcium silicate cement), and it doesn’t require as much heat, which has an energy efficiency benefit. CarbonCure also fixes CO2 into concrete. Its equipment (roughly the size of a microwave) is installed for free, but the company using it needs to purchase CO2 elsewhere. Right now, that CO2 is food-grade, but the idea is that it eventually could be collected anywhere.
Jennifer Wagner, president of CarbonCure, said her company’s technology is installed in about 300 plants — it added 50 units in the first quarter of this year. (For perspective, there are about 100,000 concrete factories globally.) CarbonCure’s technology is finding proponents among manufacturers setting carbon-reduction goals as well as with companies looking to invest in projects that sequester CO2 permanently, including Shopify and Stripe. Amazon and Microsoft are also among its backers. CarbonCure’s ambition is to help sequester 500 million metric tons of CO2 annually by 2030.
"What makes us unique is how scalable our solution is, and how it integrates with the existing supply chain," Wagner told me.