We owe a lot to cement. Buildings, bridges, a dangerously warming planet.
No building material on Earth emits more CO2 than cement. And no building material is more ubiquitous. See where I’m going with this? For those keeping score at home, cement production makes up a full 8% of all global CO2 emissions.
In no universe is traditional cement compatible with a clean, decarbonized economy. But how do you convince builders to give up something they love for its strength, versatility, and availability? You replace it with something just as strong, versatile, and available. But without the carbon. A.K.A. the Sublime game plan.
Sublime makes industry-standard cement without the industry-standard emissions.
Sublime uses a proprietary electrochemical process that takes fossil fuels — and all that nasty carbon — completely out of the cement-making equation. If you can believe it, Sublime’s process is the first major change to cement in 200 years. Think about that. In millions of projects a year, today’s builders use a material that hasn’t substantially changed since John Quincy Adams was president. Cement makers back then weren’t so different from cement makers today. They put on their pantaloons one leg at a time, then they put crushed limestone in a furnace and blasted it with 2500 °F heat, creating a chemical reaction that separates the limestone’s calcium oxide from its abundant carbon dioxide. (Limestone is almost 50% CO2, by the way.) So where does all that carbon dioxide go, you ask? Why, you guessed it: into the atmosphere. And what does it take to heat a furnace that high? Fossil-fueled fire, and lots of it, significantly compounding those emissions.1
So, how did Sublime solve the emissions problems of heating limestone in a furnace? They got rid of the limestone. And they got rid of the furnace. Instead, they use a special electrolyzer to turn non-carbonate rocks into silicates and reactive calcium, which they blend together to make their one-of-a-kind clean cement. This proprietary process uses renewable electricity, happens at room temperature, and emits not a trace of CO2. In a testament to the climate-worthiness of this breakthrough process, Climate Earth, the concrete industry’s most trusted provider of environmental product declarations, just gave Sublime their seal of approval.
Only the climate can tell that it’s not traditional cement.
Sublime’s cement mixes like cement, pours like cement, sets like cement, and holds up like cement. Because, well, it is cement. All it’s missing is the environmental baggage. Builders using this stuff simply can’t tell the difference, because performance-wise, there is none. Turner Construction Company, the country’s largest domestic contractor, saw this firsthand. At Sublime’s first commercial pour, Turner pumped, poured, placed, and finished with Sublime, all without requiring any new infrastructure or changes whatsoever on the job site.
This is a big deal for Sublime’s adoption. No contractor is going to switch to a new material if it’s hard to use or functions differently than the one they’re used to. The switch has to be seamless, the drop-in replacement a true drop-in. Given builder demand for Sublime’s product, it’s safe to say that their zero-carbon cement is just such a drop-in. Construction companies and infrastructure owners have already booked more than half the 30,000-ton annual capacity of Sublime’s first commercial plant — and the plant hasn’t even broken ground yet. Already, large construction contractors are seeing that just getting on the Sublime waiting list is such a positive signal to customers, they’re getting more business as a result.
A model for a carbon-free, job-rich future.
Government is also sending positive signals, to the tune of an $87m Department of Energy grant. With this new cash, Sublime will accelerate construction of their commercial plant, ramp up production of the world’s only zero-carbon cement to kiloton scale, and get busy building that emissions-free future. In case you’re wondering, yes, $87m is a monster grant for a company of this size and stage. It’s the government’s way of signaling not just the critical importance of clean cement for a decarbonized future, but how Sublime’s new factory in Holyoke, Mass. fits the best-practice blueprint of how to get there.
To be sure, Sublime’s new factory will pump out thousands and thousands of tons of clean building material. But it will also help build up the Holyoke community, creating good jobs with benefits, supporting the public school system, and setting up a long-term training pipeline for the area. All without choking residents on sulfur oxide, mercury particulates, and kiln dust.
This is what the clean industry transformation looks like: decarbonizing the future while rebuilding manufacturing in this country and revitalizing hollowed-out industrial communities. Folks who once thrived on making things are starting to make things again.
Talk about a masterclass in scale-up.
Four years ago Sublime was producing cement samples the size of an almond, at about a gram apiece. Today, they have actual cement customers and a 30,000-ton-per-year facility in the works. From grams to kilotons in four years? That is textbook scale-up — for a textbook only Sublime is writing. To go from founding to commercial plant in that amount of time is unheard of in heavy industry.
Like we said earlier, the output of this commercial plant is about 50% spoken for. That means if you’ve got net-zero commitments you’re freaked out about hitting, there’s still time for Sublime to help you. But even if you miss your shot at this plant’s multi-kiloton output, they’ll be ramping up to a megaton plant shortly.
Good thing, too. Meaningfully moving the climate needle takes companies with off-the-charts ambition and a freaking relentless M.O. Sublime gets it. And the way they’ve been going makes a clean future, done right, seem pretty damn inevitable.
- This part was true until very recently. Our company Antora just built a thermal battery that effortlessly heats furnaces this high using nothing but clean renewable energy. But that’s a topic for another blog post.
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