Cement is the glue that holds concrete together, and making it releases a huge amount of carbon dioxide. In 2024, researchers at the University of Cambridge showed a way to recycle old cement inside the electric furnaces that already recycle steel. If those furnaces run on clean electricity, the result could be cement with close to zero emissions.
Quick answer: Cambridge researchers found that crushed cement from old concrete can replace the lime used in electric steel-recycling furnaces, and the leftover slag becomes new, reusable cement. Powered by renewable electricity, the process could make near-zero carbon cement at large scale.
Why cement is a big climate problem
Concrete is the most used building material on Earth. Carbon Brief reports that in 2015 the cement industry produced about 2.8 billion tonnes of CO2, around 8% of the global total. If cement were a country, it would be the third-largest emitter after China and the U.S. (Carbon Brief).
Most of that pollution comes from two steps. First, kilns burn fuel to reach very high temperatures. Second, heating limestone releases CO2 from the rock itself. That second part is hard to fix just by switching fuels, which is why new ideas like this one get so much attention.
How “electric cement” works
The method piggybacks on steel recycling. Many steel mills melt scrap metal in an electric arc furnace. To clean out impurities, they add lime, which becomes a waste product called slag.
The University of Cambridge team found that used cement, separated from crushed concrete, works as a substitute for that lime. When the slag is cooled quickly, it turns into reactivated cement that can be used to make new concrete. The researchers said the recycled cement has more iron oxide than normal cement, but that this has little effect on how it performs.
This means one furnace run cleans steel and makes cement at the same time. Because the steel mill already needs the heat, the team said the process adds little cost. The research was published in the journal Nature in 2024 under the title “Electric recycling of Portland cement at scale.”
From lab to industry
Trials at the Materials Processing Institute in the UK showed that recycled cement could be made in an electric arc furnace at scale for the first time. The researchers named the process Cambridge Electric Cement and filed a patent to help bring it to market.
Their goal is big: about one billion tonnes a year by 2050, which the university says is roughly a quarter of today’s yearly cement production. That target is still decades away, and it depends on enough old concrete, enough electric steel furnaces and enough clean power.
Using less concrete still matters
The project lead, Professor Julian Allwood, made a key point. He said producing zero emissions cement would be “an absolute miracle,” but that we also have to reduce the amount of cement and concrete we use.
In other words, better cement is only part of the answer. Designing buildings to use less material, reusing buildings instead of tearing them down and choosing lower-carbon materials where they work all help too. Families can support this by asking about recycled or low-carbon materials on remodel projects and by keeping and repairing what already exists.
Frequently asked questions
Why does making cement release so much carbon?
Cement kilns burn fuel to reach very high heat, and heating limestone releases CO2 from the rock itself. Both steps add up, which makes cement one of the hardest industries to clean up.
Is electric cement available to buy today?
Not widely. The Cambridge team proved it can be made at industrial scale in trials and filed a patent, but it is still moving toward commercial use. Researchers hope for large-scale production by 2050.
What can I do to cut concrete emissions at home?
Use less new concrete where you can, such as gravel or permeable pavers for paths, and keep and repair existing structures. On bigger projects, ask your contractor about low-carbon or recycled concrete options.
See your carbon footprint
Building materials are one part of the climate picture, and your daily choices are another. Try our free Household Carbon Simulator to see where your household’s emissions come from and which changes make the biggest difference.
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- How to Mow Your Lawn Gas-Free with a Push Reel Mower
Sources
- University of Cambridge, Cement recycling method could help solve one of the world’s biggest climate challenges
- Carbon Brief, Q&A: Why cement emissions matter for climate change
Written and reviewed by the Accessible Sustainability Alliance editorial team. Last updated October 5, 2026.
