Negative Emissions Science Collaboration Aims to Reduce Cement’s Carbon Footprint
Barely a year after a Scialog award helped catalyze their collaboration, one Negative Emissions Science team has spawned a startup company to commercialize zero-carbon cement production powered by renewable electricity and also been awarded a new $2.5 million ARPA-E grant to further their research to integrate CO2 capture with recycling technology.
The team of Greeshma Gadikota, Civil and Environmental Engineering, Cornell University, and Venkat Viswanathan, Mechanical Engineering, Carnegie Mellon University, was awarded seed funding in the first year of the Scialog: Negative Emissions Science initiative for their project, “Envisioning a Low Carbon Built Environment through Innovative Electrochemical and Chemical Processing of Construction Materials and Enhanced Circular Reuse.” Their award, funded by the Thistledown Foundation, helped support the work of a third collaborator, Viswanathan’s former Ph.D. student Gregory Houchins.
The project’s aim is to reduce the carbon footprint of the global built environment by mineralizing the CO2 produced during cement manufacturing, and recirculating it back into the process. Their project pairs the ambient temperature electrochemical synthesis of calcium silicates, the precursors for producing concrete, and the integrated reuse of CO2 and construction wastes via carbon mineralization using environmentally benign solvents to produce high-strength construction materials.
“Cement is one of the most widely used materials, and change via decarbonization is not trivial,” said Gadikota. “The one-year seed funding from Scialog was used to de-risk the project, demonstrate its feasibility, and establish proof of concept for some of our ideas. This new funding could help us make the bridge to commercialization.”
Houchins had been working on the idea for zero-carbon cement at the time of the Scialog award.
“It gave us critical resources to continue supporting development of that technology until Greg secured a Breakthrough Energy Fellows Grant to further explore the decarbonization of cement production, one of the biggest polluters on the planet,” said Viswanathan.
In October 2021, Viswanathan and Houchins spun off a new company called CHEMent that uses electrochemical technology instead of thermal processes to increase the energy efficiency of cement production, cut fossil fuel emissions, and capture other emissions harmful to the atmosphere.
Also during the project’s first year, Viswanathan launched a new research area in his group at Carnegie Mellon, and Gadikota’s group published papers in Communications Chemistry and Energy & Fuels establishing proof of concept.
The team’s new funding is from ARPA-E, a federal agency dedicated to supporting advanced research projects in the energy sector.
“This collaboration demonstrates how seed funding at the right time can be leveraged to great effect,” said RCSA Senior Program Director Richard Wiener, who heads the Negative Emissions Science initiative. “We’re delighted that Scialog rapidly catalyzed such a productive new collaborative team to find novel solutions for an incredibly important global problem.”
The initiative is sponsored by RCSA and the Alfred P. Sloan Foundation.
Viswanathan said the team’s success is a testament to the Scialog process, which encourages “a meeting of the minds.”
“Innovation requires understanding across boundaries, and you can see a great example here,” Viswanathan said. “This project allowed the integration of my work in mechanical engineering, Greeshma’s in chemical engineering, and Greg’s in physics.”
While Gadikota’s work has been on processes to decarbonize cement production, Viswanathan’s had been on defossilizing it. The need for processes that integrate the two, and the need to make it commercially viable, made these ideas come together.
Gadikota said the new ARPA-E grant “nucleated a deep collaborative network” furthered along by the Scialog community. Gadikota and Viswanathan are co-PIs on the grant and Carnegie Mellon and CHEMent are collaborators. An additional collaborator will be NES Facilitator Alissa Park of Columbia University, whose work on recycling wood and plastic to make hydrogen and remove CO2 to produce carbonates adds another component to the project. Buz Barstow, Gadikota’s colleague at Cornell University, is also a co-PI. He will develop electromicrobial pathways for producing the reagents needed in this integrated process.
“While Venkat and I consider the calcium-based components used in building materials, it makes sense to address all the other organic and inorganic components that come with construction and demolition,” said Gadikota.
“It takes time to formulate the problem, and then think how the pieces fit together,” Gadikota said. “Being able to go to Scialog, get a feel for the energy and ideas that everybody brings to the table, talk across disciplines and then to give ourselves permission to do something that’s very, very different, and then be rewarded for it -- it’s phenomenal.”
Gadikota says the next phase of their research will tackle some crucial technological challenges. They will need to demonstrate that you can make calcium silicates at scale using electrochemistry, and that CO2 can be successfully captured and converted into carbonate materials that can be looped back into making cement. They will need to evaluate approaches to close the carbon cycle and develop sustainable ways to harvest and use various chemical reagents used in the process.
“For technologies to move to market, timing is everything,” said Viswanathan, who credits this Scialog initiative for catalyzing innovation and risk-taking at the right time, when the field is going through an inflection point. “The key is to do it before everyone else. If you started NES next year, it would not have the same impact.”
He said the Scialog funding was key to getting their work off the ground before a lot of other funding was available. Now that funding opportunities are beginning to be available to research negative-carbon building materials, this group has a running start.
He said Scialog’s unique format, forming new teams to think creatively and build on each other’s ideas, is part of “a culture of changing the topic.”
Gadikota agrees.
“Conventional funding sources provide specific guidelines and encourage you to ‘color inside the lines,’ ” Gadikota said. “What’s nice about Scialog is it’s a plain sheet of paper. You draw what you want, and the more interesting the drawing, the more colors you can bring to it, the better.”
