Carbon Capture Is Emerging in the Cement Industry, Part 3

The first part of this three-blog series addresses why the decarbonization of the cement sector matters and where CO2 is generated in the process. The second part looks closer at active cement decarbonization projects around the world. This third and final part of the series explores ways to create cement and other building materials using captured CO2.

As noted in Part 1, the global cement industry is responsible for 7%-8% of anthropogenic CO2 emissions, making it the second-largest emitter in industry. Cement is primarily used as a glue to make concrete, which is the second most used substance in the world after water. As the global population continues to grow and urbanize, the demand for concrete, and consequentially cement, will only increase. 

As an energy-intensive industry, the cement sector is a prime candidate for reducing its emissions. Recent strategies to do so revolve around using renewable fuels and installing carbon capture, utilization, and sequestration (CCUS) systems. However, as the cement-making process itself produces a lot of CO2, some companies are renovating their approach to clean up the 5,000-year-old process, invented long before climate change was a concern.

Using Captured CO2 to Make Cement 

In May 2022, the Global Cement and Concrete Association (GCCA) revealed its member companies will back six startups from the US, Canada, UK, Italy, and the Netherlands that aim to advance the installation of CCUS technology at their cement plants. However, in an innovative twist, two of these startups plan to use the captured CO2 to make cement instead of sequestering it. Carbon Upcycling Technologies and Fortera both use captured CO2 to produce low carbon cement and cementitious materials. 

Several other companies are also focusing their efforts on either minimizing emissions in the cement-production process where possible or reducing the reliance on cement in the concrete-production process. CarbonCure won the 2021 $20 million Carbon XPRIZE with its patented and commercialized technology that simultaneously utilizes captured CO2, while improving the properties of concrete by injecting CO2 during the concrete-mixing stage to form calcium carbonate. 

Carbicrete, a finalist for the Carbon XPRIZE, has designed a process that entirely replaces CO2-emitting cement with steel slag in the concrete-manufacturing process. The concrete is cured in a CO2-rich absorption chamber for 24 hours (as opposed to 28 days in traditional processes). Carbicrete licenses its technology to concrete plants and oversees retrofitting procedures.

Solidia targets both the cement and concrete manufacturing processes. Its cement-manufacturing technology reduces emissions by 30%-40% while using less energy than traditional methods. The cement is then cured with CO2 instead of water to make concrete. The Solidia concrete-manufacturing process has been demonstrated in 50 facilities worldwide, and Solidia has partnered with Lafargeholcim to ramp up commercialization across Western Europe and the US.

Using CO2 to Build a Cleaner, Stronger Future

Innovations introduced by these companies can offer stronger, cheaper concrete through processes that save time and are easy to implement at existing plants. The potential impact of these technologies is immense, but cross-industrial collaboration is lagging, despite the imperative to fast-track commercialization. Continued engagement between GCCA and technology providers is crucial to bridge the gap between an exciting technology and widespread decarbonization of the cement and concrete industry.

Guidehouse Insights' Global CCUS Project Tracker, scheduled to be published in early 2023, suggests 78% of captured CO2 will be sequestered by 2031. However, such a scenario would fail to capitalize on the benefits of using captured CO2 to make cement, keeping the CO2 from reentering the atmosphere for centuries, if not millennia.