Next to water, concrete is the most commonly used material on earth. But the traditional way to create its prime ingredient, cement, is not kind to the planet.
The global cement production industry accounts for about 8% of carbon emissions annually. It’s usually made by heating limestone, a carbonate rock, using fossil fuel-fired kilns. That’s a double whammy of CO2 emissions.
Now, in the race to decarbonize the $410 billion global cement industry, scientists are creating new ways to produce it, and startups like Brimstone, Fortera and Massachusetts-based Sublime Systems are putting those new methods to work.
“Our process doesn’t emit CO2. It avoids all CO2 emissions, both from the fossil fuel and from the limestone,” said Leah Ellis, CEO of Sublime Systems.
Sublime uses chemicals instead of heat and other minerals instead of limestone.
“By decomposing minerals at ambient temperature using electrochemistry, it actually allows us to use minerals that contain calcium for cement that aren’t limestone, and that’s what makes us true zero as opposed to net zero,” Ellis explained.
As with other new technologies, it is more expensive, but climate-forward companies like WS Development in Boston seem willing to pay more for the cement. Its One Boston Wharf Road will be the largest net zero office building in the city, with Sublime cement in the ground floor public space.
“As people walk through this building on a day-to-day basis, they’ll be able to interact with the product and learn more about a net zero carbon future in the built environment,” said Yanni Tsipis, a senior vice president with WS Development.
Sublime recently received an $87 million award from the U.S. Department of Energy that would cover half the cost of its first commercial plant in the state.
Its venture capital backers are Lower Carbon Capital, Engine Ventures, Energy Impact Partners, Prime Impact Fund, Siam Cement Group and MCJ Collective. It has raised $45 million in funding so far.
Ellis said Sublime Systems has done extensive testing on the durability of the product and expects, at scale, to be competitive with traditional Portland cement. Once the new plant is up and running, she estimated it should produce 30,000 tons of clean cement per year. For perspective, about 90 million tons of cement are produced in the U.S. per year.
“This is a first-of-a kind process, and we’re competing with a technologies that have been scaled to a million tons per year plus for, you know, decades. And so, in the beginning, just like solar panels and wind turbines, we will have a cost premium but our goal is have swift and massive impact,” said Ellis.
— CNBC producer Lisa Rizzolo contributed to this article.