Meta buys low-carbon cement certificates from Sublime Systems to cut data center construction emissions

Meta has agreed to buy 180,000 tonnes of low-carbon cement certificates from Sublime Systems, a startup using an electrochemical process instead of traditional limestone kilns. The deal is meant to reduce emissions from data center construction, where concrete and steel carry a large embedded carbon footprint. Sublime says its process cuts CO2 by 70 to 80 percent versus conventional cement and targets a price of $160 to $180 per tonne. The certificates are Environmental Attribute Certificates, which let Meta support production at Sublime's planned U.S. plant without taking physical delivery. Critics point to double counting and greenwashing risks. Meta and Sublime argue the mechanism is a practical way to fund commercial-scale plants before direct purchases are feasible. Cement production accounts for roughly 7 percent of global CO2 emissions. With Microsoft signing a similar deal in 2025, low-carbon cement is moving from lab to procurement, but Sublime still has to prove the process at scale and manage electricity costs.