Brimstone Energy, an Oakland, Calif.-based startup founded by two Caltech scientists, wants to decarbonize the process for making cement.
Cement, as co-founder Cody Finke said in a 2019 talk at Stanford University, is "the most-consumed human-made thing on the planet." And it's one of the most polluting materials that humans make.
About 4.1 billion metric tons of cement are consumed every year, and it's responsible for about 8% of global greenhouse gas emissions and 4% of global carbon dioxide emissions.
Finke and his co-founder Hugo Leandri met on a trip to China funded by the Gates Foundation, Leandri recalled in an interview last year with BpiFrance's Sebastian Fiedorow. The two men, who both were working at Caltech, kept in touch about their respective projects and eventually sbegan to collaborate.
"Cody’s research was focused on process emissions. Cody was working on a hydrogen technology, and asked me to help him with the reactor design. We achieved really good results together, so we continued to work together and innovate on this technology," Leandri said. "After 9 months of work, and really promising lab results we decided to start a company together."
Hydrogen production no longer seems to be the central focus, instead the company's new method for making cement without the emissions has taken over the spotlight.
Essentially, Brimstone replaces the limestone that's used to make cement with a calcium silicate input that produces no carbon dioxide emissions when it's processed.
Typically, limestone is mined, ground up and heated at incredibly high temperatures to make the base material for cement. That process releases about fifty to sixty-five percent of all carbon dioxide emitted from cement-making.
Since calcium silicate doesn't release any CO2 when it''s processed, the Brimstone Energy technology is already off to a better start, as Canary Media reported.
Having calcium silicate as the rock of choice for Brimstone means that the company can also slash the amount of heat that's used in the process -- another potential source of emissions intensity.
Dropping the temperatures used in the process allows the company to use electric kilns for the bulk of its process, as Canary Media reported. The company doesn't need to use coal, petroleum coke or natural gas.
For the highest heats, Brimstone can even return to its roots and use hydrogen in the industrial process.
“Cement production is a major contributor to global carbon emissions, and we are focused on fixing that by investing in innovative companies like Brimstone,” said Carmichael Roberts of Breakthrough Energy Ventures, a firm that's financing Brimstone's development. “Brimstone has the vision to reduce the cost, complexity, and emissions associated with this critical material.”
Joining Breakthrough, the billionaire backed investment firm focused on funding climate mitigation technologies, are a few other big name Silicon Valley investors like the firm DCVC -- and the U.S. Government. In addition to its $5.1 million in private funding, the company received $2 million in grants from the Department of Energy's ARPA-E program and the National Science Foundation.
Finke envisions Brimstone’s process being adopted by existing cement manufacturers. “We work with cement or concrete company X, and that company owns an aggregate quarry, and we could turn the rocks that they already mine for aggregate into cement and supplementary cementitious material,” Finke said.
One challenge is that the concentration of lime in the calcium silicate rocks is lower than that of limestone. That requires processing more rock — anywhere from 30 to 250 percent more — to yield the same amount of lime. But because Brimstone’s process doesn’t include fly ash, the total tonnage of material required is comparable to that used by other cement makers, according to Finke.
Introducing new cements into the market is notoriously difficult, said Ian Riley, CEO of the World Cement Association. Manufacturers of structural concrete are limited by different construction standards and specifications as to what components and ingredients can be put into it.
“It’s not really a question of whether it works. It’s a question of whether everybody believes it is going to work,” he said. He gave the example of the company Calera, which had an alternative cement product “that worked perfectly, but they just could not make progress on the regulatory side.”
A recent report from the American Economic Liberties Institute reached the same conclusion, pointing to regulatory bodies as a key bottleneck holding back the development of innovative cement products. “Prescriptive standards, outdated or restrictive procurement criteria, and cozy industry relationships make it difficult for startups to receive significant procurement contracts or government grants,” the report states.
But there is a growing consensus that solutions to clean up cement are needed. It’s a topic of discussion everywhere from cement industry conferences to think tanks to the recently concluded COP26 climate summit.
Finke told Canary that the company intended to work with existing cement companies, like HeidelbergCement, LafargeHolcim, or others and integrate their process into the larger operation of those multinational cement manufacturers.
“This isn’t carbon capture, or a cement alternative. Brimstone’s technology doesn’t change the chemistry of Portland cement. It’s a clean process with no CO2 byproduct that also produces SCM without burning coal," Kelly Chen, Partner at DCVC, said. "Our investment in Brimstone exemplifies DCVC’s work of over a decade backing brilliant entrepreneurs solving trillion-dollar problems at the forefront of climate resiliency.”