Construction Industry News
Two of the world's largest cement producers, Holcim AG and CRH PLC, are investing in a startup that is trying to decarbonize the cement production process. Cement and concrete account for about 8% of emissions, more than any other industrial sector.
Holcim and CRH announced a $75 million investment in Sublime Systems, including a commitment to purchase green cement from the startup’s pilot facilities and to work with Sublime on additional manufacturing locations. (CRH invested through its venture capital arm.) Somerville, Massachusetts-based Sublime has developed an electrochemical method of cement production that avoids the process of heating limestone with fossil-fuel-powered kilns.
Reducing cement emissions has long been a technological and economic challenge. Cement is essential for making concrete, and for roads, buildings and other critical infrastructure. But manufacturing the material generates carbon dioxide emissions from burning fuel (often coal) to heat kilns, from breaking down limestone, and from mining, crushing and transforming the materials.
In tests at its 250-ton-per-year pilot plant, Sublime has demonstrated a 90 percent reduction in carbon emissions compared to traditional concrete, said Leah Ellis, co-founder and CEO. The company is developing a 30,000-ton-per-year commercial plant in Holyoke, Massachusetts, expected to be completed in 2026. The Department of Energy’s Office of Clean Energy Demonstrations will fund up to 50 percent of the plant’s construction.
Ellis said Sublime's goal is to supply its technology to larger cement companies with existing infrastructure and supply chains, who would either build new cement plants with the technology or refurbish old ones.
While Sublime’s process generates far fewer emissions, there are many hurdles the company and others must overcome before they can successfully commercialize. One major constraint is the significant capital costs associated with retrofitting cement plants — often large, custom-built operations — or building new ones.
Another is demand: Low-carbon cement is more expensive on average than traditional cement, making it a tough sell for a construction industry already operating on razor-thin margins. New regulations, including New York’s mandate for state agencies to buy clean concrete, could help spur demand, said Ash Lauth, a senior campaign strategist for the global cement initiative at Industrious Labs, a U.S. nonprofit focused on industrial decarbonization. But the industry has a long way to go: Last week, Industrious Labs published an analysis that gave Holcim a “D” for its sustainability efforts.
The investment from Holcim and CRH brings Sublime’s total funding to more than $200 million since its founding in 2020. It’s another vote of confidence in the startup, which was one of six projects selected for the Department of Energy’s $1.6 billion program to finance the decarbonization of cement and concrete.
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