Reducing emissions from cement with the Carbon Xprize

Cement production is one of the less obvious climate change challenges. At 5% of global emissions, it’s easy to focus on transport or electricity. But if we succeed in reducing emissions by the 80-90% required, that 5% would begin to loom very large. Left unattended, half our carbon budget could end up going on cement before we knew it.

So when the Carbon Xprize revealed its ten finalists last week, it was good to see some competitors among them working on concrete. One example is Carbon Upcycling UCLA, who capture CO2 from power plants and lock it away in a cement alternative. They’re calling it CO2NCRETE, naturally, and it’s a carbon neutral building material.

Going one better is Canadian start-up Carbicrete, who claim that their concrete block is actually carbon negative. It’s made from steel slag, a waste product that is widely available from the steel industry. Since the block is cured with CO2 as well, it effectively sequesters more carbon in the concrete than is emitted in manufacturing it.

I’ve been keeping an eye on the Xprize since it was launched in 2015, and I’ll be interested to see if the chosen technologies can now be successfully demonstrated at a larger scale. If you haven’t checked in recently, I can recommend browsing the ten teams remaining, and the technologies they are pioneering. Only a couple of them can share the prize in 2020, but there’s room for all of these innovations and more in the industry.

• feature image by Samuel Zeller