ImpactAlpha, January 18 — Mining, grinding and heating limestone to make cement, the main binding agent for concrete, releases an enormous amount of carbon dioxide.
Sublime Systems, a Somerville, Mass.-based spinout from MIT, claims to have a process that eliminates the use of fossil fuels and the release of CO2 from limestone. Sublime replaces kilns, the most energy- and fossil fuel-intensive part of the process, with an electrolyzer that makes cement from calcium at ambient temperature. “Sublime’s technology has cracked the code for low-carbon cement,” said Clay Dumas of Lowercarbon Capital, which invested in Sublime’s Series A round.
Low-carbon tech
Brimstone Energy, CarbonCure and Terra CO2 also are working to decarbonize cement. Tim McCaffery of Siam Cement Group, the largest cement producer in Southeast Asia, said “Sublime is the first company we’ve seen whose approach has the potential to decarbonize the entire process of creating cement.” Siam joined the round as a strategic investor; other investors include The Engine and Energy Impact Partners.
Sublime will use the capital to scale production from 100 tons today to up to 40,000 tons annually by 2025, and to secure advance offtake commitments. “We are able to produce cement with the same or better strength, slump, and durability than today’s Portland cement,” said Sublime’s Leah Ellis.
