Creation Covenant Alliance

A Boston Startup Develops a Low-Carbon Cement Solution

Sublime Systems secures a major Department of Energy grant to produce fossil-fuel-free cement at an industrial scale.
Close-up of a blue-gloved hand tamping concrete into molds.

And a massive grant from the Department of Energy to soon produce it at an industrial scale

This past June in downtown Boston, a building was nearing completion with an unusual lobby. A bronze-lettered plaque in the concrete floor read, “This floor is the first commercial use of Sublime Cement made with a fossil-fuel-free manufacturing process. A step on this floor is a step closer to our post-carbon future.” Cement production, typically a source of significant carbon emissions, has been reimagined by Sublime Systems. Their pilot plant in Somerville, Massachusetts, has developed a process that avoids traditional emissions.

“Concrete is so prevalent it’s invisible, like the air you breathe,” said Leah Ellis, CEO and cofounder of Sublime, during a plant tour. Since 2020, she and Yet-Ming Chiang have led efforts to make cement more sustainable, using electrochemistry to break down calcium silicate without fossil fuels.

Close-up of a blue-gloved hand tamping concrete into molds.

Decarbonized cement is tamped into molds.

Portland cement has been industry standard since the late 1800s, with lime as its core material. The process involves heating limestone in 2,500°F kilns, emitting carbon dioxide. Cement production accounts for at least 8 percent of global emissions; for comparison, aviation is at 2 percent. Decarbonizing cement could have an outsize benefit on emissions reductions.

While several companies are researching cement decarbonization, Sublime leads with a commercial client and a fully decarbonized process, matching Portland cement’s standards. “Same strength, set time, flow, durability,” Ellis noted, without relying on carbon capture.

Ellis, a battery scientist and former Tesla intern, describes the science of using electricity to transform materials as “magic.”

Cluttered concrete-floor workspace with a red mixer and green and yellow buckets stacked up

At Sublime’s pilot plant in Massachusetts, technicians manufacture and test small quantities of cement.

In Sublime’s pilot plant, technicians produce small quantities for commercial use, such as downtown slabs. As they scale, their cement could be used in more structural applications. The pilot plant resembles a typical warehouse, with rows of tools and concrete mixers. In a sectioned area, the team refines their process for mortar production.

The process involves weighing Sublime’s carbon-free cement, adding water, and mixing with sand. In May, scientists tested the flow of Sublime’s cement without affecting its strength, using a metal disc and silicone spatula to distribute and test the mixture.

“These test methods for cement are very specific,” remarked Michael Sheahan, a scientist at Sublime.

Cylinders of cement samples with various notations written on the top

At Sublime’s pilot plant in Massachusetts, technicians manufacture and test small quantities of cement.

The cement industry lacks a clear career path, notes scientist Summer Camerlo-Bass, who joined Sublime after graduate school to pursue more sustainable work. Sublime’s limited commercial reach is due to production constraints, not lack of interest. This will change in 2026 when Sublime opens a commercial-scale plant in Holyoke, funded by a Department of Energy grant of up to $87 million. This facility will produce tens of thousands of tons of cement annually.

Close-up of a blue-gloved hand holding concrete

The shape of this cement mortar shows Sublime’s material performed as expected during a strength test.

“When people think of clean tech, they think of wind turbines, solar panels, and EVs. I also want them to think about cement,” Ellis said. Sublime’s cement, lighter due to its production process, contrasts with traditional cement’s color in the lobby of the Boston building.

The Future of Cement

A Quiet Force

Sublime Systems’ pilot plant is in a residential neighborhood. Without hot kilns and harmful gases, it’s safe for locals to visit the nearby brewery.

Industrial Revolution 2.0

Sublime’s upcoming hydroelectric-powered plant in Holyoke, on a former paper mill site, will contribute to the electrification revolution in manufacturing.

Concrete Jungle

Humans produce 30 billion tons of cement annually. The total mass of concrete on Earth may surpass that of all living matter in about 15 years. Concrete is ubiquitous—once you notice it, it’s everywhere.

Original Story at www.sierraclub.org

Trending News

Mississippi River Faces Persistent Saltwater Intrusion, Region Seeks Long-Term Solutions



For the third consecutive year, the Mississippi River is experiencing significant saltwater intrusion, prompting local communities and environmental experts to search for sustainable solutions. This recurring issue arises as the river’s flow decreases, allowing saltwater to move upstream and threaten drinking water supplies. The U.S. Army Corps of Engineers is actively involved in addressing this problem, employing temporary measures like saltwater barriers to mitigate the impact on affected areas.



Saltwater infiltration poses serious risks to public health and agriculture, as freshwater sources become compromised. The situation is exacerbated by prolonged periods of drought, which have reduced freshwater flow in the Mississippi River. According to the National Weather Service, drought conditions have worsened due to climate change, increasing the frequency and severity of saltwater intrusion events.



Local authorities are collaborating with federal agencies to explore permanent solutions. Among the proposed strategies are enhanced levee systems and improved water management techniques. The U.S. Army Corps of Engineers is evaluating the feasibility of long-term infrastructure projects to prevent further saltwater encroachment. Additionally, community leaders are advocating for increased funding to support these initiatives and safeguard the region’s water resources.



The impact of saltwater intrusion extends beyond drinking water concerns, affecting local ecosystems and agricultural productivity. Farmers in the region have reported crop damage due to elevated salinity levels in irrigation water. The Natural Resources Conservation Service is working with farmers to implement adaptive practices, such as planting salt-tolerant crops and improving soil management techniques.



As the Mississippi River continues to face challenges from saltwater intrusion, stakeholders emphasize the importance of collaborative efforts and innovative solutions. The ongoing threat underscores the need for comprehensive planning and investment to protect one of America’s most vital waterways from the impacts of climate change and environmental stressors.

November 19, 2024



Environmental activists have raised concerns over the fossil fuel sector’s significant impact on COP29, the latest United Nations Climate Change Conference. Activists argue that the industry’s presence diverts focus from critical climate actions.



The conference, designed to promote global climate agreements, faces criticism for allowing fossil fuel companies to participate extensively. Environmental groups claim these companies undermine efforts to reduce carbon emissions and transition to renewable energy sources.



According to Climate Action Network, fossil fuel representatives have increased their lobbying activities, aiming to weaken climate policies. These industries allegedly influence negotiations, leading to watered-down commitments that fail to address the urgency of climate change effectively.



Experts suggest that the influence of these companies stems from financial contributions and longstanding relationships with decision-makers. Critics argue that this affects the conference’s ability to enforce meaningful climate change regulations.



During the event, several protests highlighted the need for transparency and a stronger focus on sustainable energy solutions. Activists are calling for increased participation of renewable energy stakeholders in future conferences.



The controversy surrounding fossil fuel involvement at COP29 underscores the ongoing challenge of balancing industrial interests with the global imperative to combat climate change.



November 19, 2024