Concrete is ubiquitous in the modern built environment, making it the second most used material on Earth after water. But its main ingredient, cement, accounts for about 8% of global carbon emissions due to the intensive production process required.
Now, California-based startup Brimstone Energy aims to disrupt the entire cement industry with a novel production method that could eliminate these emissions entirely.
The Problem With Conventional Cement
The high carbon footprint of conventional cement production stems from its key input, limestone. Limestone is commonly used because it contains the essential calcium molecules needed to make cement.
However, limestone naturally contains about 50% CO2 by weight. Heating the limestone to over 1400°C drives off the CO2, producing clinker that is then ground into cement powder. This calcination process alone accounts for more than half of cement’s emissions.
Overall, the production of cement is responsible for 7-8% of global CO2 emissions, nearly as much as the entire transportation sector. With concrete being the most widely used man-made material, surpassed only by water, this makes cement production a prime target for emissions reductions.
Brimstone’s Breakthrough Production Method
Brimstone Energy aims to eliminate cement’s carbon footprint completely through a novel production process. Instead of using limestone as the feedstock, Brimstone uses calcium silicate rock, which is even more abundant but contains no CO2.
The company employs patented extraction technology to remove the calcium, leaving behind silica. This avoids the emissions associated with calcining limestone.
The end product is chemically identical to ordinary Portland cement and meets industry certifications. But because no CO2 is released from the feedstock, Brimstone’s cement production process is completely carbon-free.
In fact, the calcium silicate rock actually absorbs some CO2, making the cement carbon-negative.
“Our process will replace 100% of cement production facilities worldwide, leading to a fully decarbonized system,” said Brimstone co-founder and CEO Cody Finke.
Advantages Over Conventional Cement
Aside from eliminating carbon emissions, Brimstone claims its novel cement production process has several other advantages as well. For one, the cost of production is expected to be lower than conventional methods.
This is because calcium silicate rock is more abundant than limestone, and the extraction process is more efficient.
There are also no changes required on the construction side, as Brimstone’s product is chemically identical to the Portland cement builders already use.
It can be poured into concrete without any modifications to existing practices. The company has already obtained certification that its cement meets all industry standards.
According to Finke, this means the cement can be adopted immediately without concerns about performance or safety. “People already know how to build with it, so construction will not be delayed. People already know how to specify it, that way there are not safety concerns,” he said.
The potential to completely remake how cement is produced worldwide has investors excited about Brimstone’s technology. The total addressable market is enormous, with around 3000 cement plants currently operating globally.
Transitioning all these facilities to Brimstone’s process represents a multi-trillion dollar opportunity to slash cement emissions while actually reducing costs.
Major backers include Breakthrough Energy Ventures, Amazon Climate Pledge Fund, Fifth Wall, and others. To date, the company has raised $60 million.
The Path Ahead
Brimstone Energy is currently working on a pilot plant to further develop and scale up its breakthrough cement production method. If successful, this could pave the way for finally decarbonizing one of the world’s largest industrial emitters.
Cement production accounts for 7-8% of global emissions, driven by the CO2 inherently present in limestone feedstocks. By utilizing calcium silicate rock instead, Brimstone’s novel process promises carbon-free cement that can directly replace Portland cement worldwide.
With investor excitement growing, the company aims to prove the viability of its technology. If achieved, Brimstone could enable the concrete industry to finally address its massive carbon footprint. This would deliver an urgently needed solution for slashing emissions from the vital buildings and infrastructure sectors.