Microsoft has signed a deal with low-carbon cement company Sublime Cement to purchase 623,000 tons of its low-carbon cement product, in an effort to reduce its construction carbon footprint.

The cement will be delivered over a six to nine-year period, with production of the cement originating from Sublime’s first commercial factory in Holyoke, Massachusetts.

Through the agreement, Microsoft has the priority option to purchase and deploy the cement in its construction projects when ‘geographically possible’, with data centers earmarked as one of the primary targets.

The contract will also allow for the sale of the cement's environmental attributes, in the form of Environmental Attribute Certificates (EACs), separately from the physical material, in a system similar to Environmental Attributes Purchase Agreements, where companies purchase the environmental attributes of renewable projects.

“To reach net zero, the world needs innovative technology solutions like Sublime Cement. At Microsoft, our focus is growing the market for these solutions,” said Katie Ross, director, Carbon Reduction Strategy & Market Development at Microsoft. “While we prioritize deploying physical material whenever possible, this EAC approach helps both buyers and sellers overcome geographic, supply chain, cost, and other barriers that make it challenging to introduce new technologies.”

Sublime is currently developing the Holyoke factory, with $87 million of funding support Department of Energy. The project will have a production capacity of 30,000 tons per annum and is expected to reach operational status in 2026.

The company’s cement production process works by breaking down low-value rocks and industrial wastes into their constituents through an electrochemical process that entirely bypasses the need for extreme heat, typically requiring the burning of coal or other fossil fuels.

The company says that this avoids significant levels of pollution and waste that have characterized cement manufacturing for more than 200 years while improving energy efficiency.

Microsoft’s acquisition of Sublime Cement EACs will undergo independent third-party verification and is anticipated to be administered through a future book and claim system. This development builds on a memorandum of understanding signed in 2024, in which both organizations agreed to create a book and claim mechanism designed to ensure transparency, additionality, and catalytic impact.

The Holyoke plant is designed to eliminate scale-up risk, with the company stating that the Microsoft purchase will play an integral role in ensuring the company can scale to megaton levels.

“This purchase enables Microsoft to access Sublime’s low-carbon cement technology regardless of where their construction is,” said Sublime Systems CEO and co-founder Dr. Leah Ellis.

“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. 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.”