Did you know that while modern cement production requires extreme heat in a kiln, ancient Roman structures have endured remarkably well over the centuries? This remarkable durability has caught the attention of a startup named Sublime Systems, which is an MIT spinoff aiming to simplify cement production.
Sublime Systems has developed an innovative drop-in alternative to conventional portland cement, utilizing electrochemical methods that eliminate the need for the high temperatures traditionally required for cement production, significantly reducing carbon dioxide emissions in the process.
“The Romans couldn’t achieve those extreme temperatures, yet their cement stands the test of time. Our challenge is to use 2,000 years of accumulated knowledge to create a cement that meets modern standards,” states Leah Ellis, co-founder and CEO of Sublime Systems. She initially devised this groundbreaking approach during her postdoctoral research in the lab of Sublime co-founder and MIT Professor Yet-Ming Chiang.
This innovative technique has the potential to significantly mitigate global greenhouse gas emissions, with the International Energy Agency estimating that the cement industry accounts for roughly 7% of anthropogenic carbon dioxide emissions worldwide. By forgoing both the high temperatures and the limestone (which is nearly 50% CO₂ by weight) utilized in traditional processes, Sublime Systems is paving the way for a new era in sustainable construction.
“Cement has underpinned civilization, but now it’s crucial that we reinvent it,” explains Chiang, the Kyocera Professor of Ceramics at MIT. “Currently, cement production generates around 4 gigatons of emissions annually, a figure projected to rise to 6 gigatons by 2050. Our solution offers a feasible path to rapidly reduce these emissions.”
Sublime Systems recently achieved an important milestone by pouring 3 tons of its cement in the largest net-zero commercial building in Boston’s Seaport district. The company is now moving forward with plans to construct a commercial-scale manufacturing facility in Holyoke, Massachusetts, anticipated to have a production capacity of 30,000 tons of cement yearly, with operations expected to commence by 2026.
This facility is designed as a scalable module that could eventually lead to a million-ton-per-year plant, significantly reducing the peril of scaling up as the company aims for simultaneous deployment across the globe.
From batteries to sustainable cement
Leah Ellis joined MIT in 2018 as a postdoc after garnering a fellowship from the Canadian government that allowed her the freedom to choose her research focus.
“I was drawn to work with Yet-Ming Chiang due to his impressive track record of innovation and practical scientific contributions,” shares Ellis. “I sought to break new ground and solve significant problems.”
While both she and Chiang were battery experts, Ellis welcomed the challenge of exploring an alternative route proposed by Chiang, aiming to enhance the sustainability of cement production through electrochemistry.
“Cement is the top emitter of CO₂ in the industrial materials sector, yet concrete is the most widely used material after water, highlighting a dire need for electrification in its production,” Chiang notes.
Ellis and graduate student Andres Baldes began diving into existing research on cement chemistry and production, seeking more sustainable manufacturing practices amidst an era of cheap, renewable electricity. Their inquiries naturally shifted from foundational chemistry to practical industry analyses.
“My motto is to persistently endeavor towards our goals,” Ellis states. “I actively sought to understand customer needs within the industry, grasping regulatory frameworks and operational hesitations, leading to our project’s evolution.”
Once the founders recognized the viability of their approach, they published their research in the prestigious Proceedings of the National Academy of Sciences and launched their company amidst the challenges of March 2020. Navigating through the disruptions caused by COVID-19, the team successfully licensed their patents from MIT’s Technology Licensing Office and took part in the MIT i-Corps program, which supports scientific founders in engaging with potential customers.
“MIT provides an abundance of resources,” asserts Ellis. “It’s a hub of intellectual potential, making it easier to launch innovative ideas. The startup process lacks a single blueprint; it’s a journey of exploration, one that MIT facilitates remarkably well.”
At the heart of the substantial carbon footprint from portland cement lies the use of limestone, an ingredient that releases nearly half its weight as CO₂ during heating. The production method also generates significant emissions due to the colossal temperatures—around 1,450°C—necessary for processing, a temperature that proves challenging to electrify sustainably.
Using groundbreaking techniques developed at MIT, Sublime’s team crafted an electrochemical method to process calcium silicate rocks at ambient temperature. This innovative reaction employs abundant materials to produce reactive calcium and silicates, which are then dried and mixed into Sublime’s unique cement.
The resulting mixture exhibits comparable strength and hardened characteristics to traditional portland cement, satisfying industry-standard performance criteria suitable for construction projects.
“We believe we are the only true-zero solution for manufacturing a direct substitute for portland cement, entirely avoiding fossil fuels and limestone, thus eliminating all associated emissions,” Ellis asserts confidently.
Transforming construction practices
During a recent MIT Technology Review event, Yanni Tsipis, WS Development senior vice president, became intrigued by Sublime’s innovative approach and reached out to explore further. This dialogue led to the landmark commercial pour conducted by Sublime earlier this year in Boston’s premier net-zero office building.
“We hope to demonstrate the synergies that emerge when cutting-edge technology transitions from incubators to industry,” enthuses Tsipis. “The cement used in the building’s central public space will be experienced by thousands daily, serving as a prime illustration of our aspirations and Sublime’s remarkable technology within Boston’s innovation landscape.”
Sublime Systems is one among several enterprises that Chiang has inspired since his arrival at MIT nearly four decades ago. He now serves on the climate search advisory committee under MIT President Sally Kornbluth’s Climate Project. Chiang believes Sublime’s journey personifies MIT’s capacity to nurture transformative technologies that can have a meaningful impact on society.
“Sublime’s inception stemmed from identifying a critical challenge long overlooked and responding promptly with scalable solutions that address climate change effectively,” Chiang reflects. “This embodies the essence of MIT: a commitment to innovations that resonate with broader societal needs.”
Photo credit & article inspired by: Massachusetts Institute of Technology
