Construction workers at WS Development’s One Boston Wharf Road project pour cement made by Sublime Systems in 2024. Photo by David Denger/In Short Media | Courtesy of Sublime Systems
Sublime Systems’ prototype cement factory in Holyoke is still under construction, but already it’s landed a contract that could unlock a huge new “megaton-scale” plant.
The Somerville-based MIT spinoff has been attracting attention across the design and construction worlds for its new way of creating cement that releases far less carbon dioxide than regular manufacturing while holding out the promise of stronger buildings.
Now, that Holyoke factory’s bigger sibling looks suddenly a lot closer to reality with a huge order from Microsoft that will provide an anchor buyer for the facility Sublime hopes to build next, capable of producing 1 million or more tons of cement annually. The Holyoke plant can currently produce only 30,000 tons of cement per year.
Sublime Systems said Thursday that Microsoft has signed a deal to buy 622,500 metric tons of cement for future data center construction, roughly enough to build 31 NFL stadiums. The dollar value of the transaction was not disclosed.
“This solves a previously intractable challenge for clean cement scale-up: the lack of long-term cement transactions contrasted with the immediate need for innovators to demonstrate bankable customers to fund their manufacturing,” Sublime’s co-founder and CEO Leah Ellis said in a statement. “Microsoft is stepping up as the first customer for our future megaton-scale plant, enabling us to more rapidly build and scale Sublime Cement as a global, enduring solution for clean construction.”
For data center providers like Microsoft and its rival Amazon Web Services, and for Microsoft’s artificial intelligence ambitions, being able to promise their services are not making climate change worse has been a crucial selling point with potential customers. Google, for example, recently signed a large deal to build advanced nuclear power plants to provide electricity to its own AI data centers.
Concrete alone produces around 2 percent of the United States’ annual greenhouse gas emissions and is the most-used building material on the planet. It’s also a primary material used in building the foundations and walls of data centers, whose designs are broadly analogous to warehouses.
A big part of the new Sublime deal is a new type of contract that lets Sublime sell “environmental attribute certificates” to Microsoft separately from the cement itself.
Because cement is traditionally produced very close to a construction project, the company said, the contract allows Microsoft to commit to buying from Sublime now, without having to wait and see where its full-scale plant will be or without having to ship cement over a long distance.
“The binding purchase is important for Sublime at this stage, enabling us to demonstrate to investors who would fund the manufacturing of our future full-scale plant that there is real demand for the cement we are producing,” company spokesperson Erin Glabets said in an email to Banker & Tradesman.
While that new “megaton-scale” plant will produce much of the cement in Microsoft’s order, enough of it will come from Sublime’s under-construction Holyoke plant. That facility is now “nearly completely booked” following capacity reservations from several cement producers and construction projects.
Sublime is generating significant excitement in political and design circles for its ability to reduce a building’s so-called “embodied carbon.” A mere 5,000-square-foot hallway in a WS Development Seaport District tower, whose floor was made of Sublime’s product, drew a who’s-who from the Massachusetts political establishment last fall.
State and local policymakers in cities like Boston are controversially searching for ways to force real estate development to decarbonize in the face of climate change, from pushing all-electric building systems to materials like cross-laminated timber whose production generates significantly fewer greenhouse gasses than traditional steel and concrete.
However, with construction costs at an all-time high developers say some measures like bans on natural gas-operated water heating and HVAC systems are contributing to the state’s collapsing housing production numbers.
The announcement of Microsoft’s order comes hot on the heels of news that Suffolk Technologies, the venture capital arm of Boston-based construction giant Suffolk was also investing an undisclosed sum in Sublime Systems.
