COP28 marked the conclusion of the first global stocktake of the world’s effort to address climate change under the Paris Agreement. Unfortunately, little progress has been shown across all areas of climate action—from reducing greenhouse gas emissions and strengthening resilience to a changing climate to securing financial and technological support. The stocktake recognizes the scientific evidence that indicates global greenhouse gas emissions need to be cut by 43% (compared with 2019 levels) by 2030 to limit global warming to 1.5 degC.
Industries considered hard to abate have drawn significant attention and pressure to decarbonize. Among these, the cement industry—responsible for 6% to 8% of anthropogenic carbon dioxide (CO2 ) emissions—has been identified as one of the key hard-to-abate sectors joining the effort to reach net-zero emissions by 2050. It’s estimated that the cement industry needs to invest approximately 800 billion USD to achieve this milestone.
The world produces approximately four billion tons of cement annually. Cement, the binder that keeps concrete together, is a fundamental building block of industrial development. It has been used for centuries to build some of the most iconic landmarks including the Pantheon in Rome, Hoover Dam in the USA, and new sets of locks at the Panama Canal. We can see concrete almost everywhere we go—it’s the second most used material after water—making it extremely hard to replace.
About 60% of cement’s CO2 emissions come from the decarbonization of calcium carbonate to produce calcium oxide, the primary chemical component of cement. Calcium carbonate is commonly found in limestone, marble, and chalk. Naturally occurring calcium oxide is relatively rare because it tends to react with water or carbon dioxide in the environment to form more stable components. The remaining 40% of cement's CO2 emissions are generated during the combustion of fuels to obtain thermal energy.
One key intermediate product makes the cement manufacturing process particularly energy intensive, and that’s the formation of clinker. Clinker is formed at about 1,450 degC [2,642 degF], which is hotter than volcanic lava. Cement is produced by grinding and mixing clinker with gypsum and other supplementary cementitious materials (SCMs).
How do you decarbonize cement?
Cement can be decarbonized in a myriad of ways. Some pathways have been known within the industry for years but are now being modernized and implemented more rigorously.
The primary pathways include
- Clinker substitution—A process that involves replacing a portion of the clinker with additional SCMs, such as limestone, fly ash, slag, and pozzolana. Usage of these materials is limited by availability, pricing, and adverse effects to cement performance. A promising new SCM is calcined clay, a material that is abundant and has significant potential to increase the percentage of clinker substitution.
- Energy efficiency—An option that focuses on optimizing the process to enhance heat recovery and minimize waste. The cement industry has incorporated the use of artificial intelligence (AI) to optimize its operations. However, this lever doesn’t move the needle enough because cement plants tend to already operate efficiently to save costs.
- Alternative fuel substitution—This approach involves switching traditional fuels (coal, natural gas, and oil) with other fuels such as biomass (e.g., wood chips and nut shells), tires, and refuse-derived fuels. But usage of these alternative fuels is also limited due to availability and potential negative effects in the combustion process. Recently, hydrogen has been used in small quantities as an additive to enhance the burnability of alternative fuels; however, there are several studies currently testing hydrogen as a main fuel for combustion and for potential improvements in its economic viability.
- Renewable energy—This strategy involves shifting to green electricity. While the industry largely relies on power providers to supply green electricity, more cement plants are investing in renewable electricity, such as wind and solar, as well as geothermal power.
Even if the cement industry implements all the pathways above, the maximum decarbonization they can achieve is between 60% to 70%—falling short of net-zero objectives. The good news is that carbon capture, utilization, and sequestration (CCUS) enable the industry to then decarbonize the remaining 30% to 40%. While carbon capture has been used for decades, it has never been implemented commercially in the cement industry, making it considerably risky. The current cost of a carbon capture system is comparable to a new cement plant, making the business case for implementation nearly impossible due to the industry’s typical low profit margins.
According to the Global Cement and Concrete Association, the goal is to have 10 fully operational carbon capture plants by 2030. This number represents less than 1% of the total number of cement plants worldwide. It’s imperative that we increase momentum if we want to achieve net zero, and to do this, we must derisk capture technology and put in place the right motivational drivers for the industry to move forward.
What carbon capture options exist for the cement industry?
When considering carbon capture, the cement industry can choose between integrated or post-combustion tech. Integrated technologies haven’t been tested commercially yet and would require significant downtime for implementation, unless implemented on new builds or in new plants. There are also concerns related to clinker quality that can only be addressed once the tech is adopted at scale.
Post-combustion technologies offer a better approach to carbon capture because they don’t interfere with the existing manufacturing process. As stated earlier, cement plays a vital role in industrialization, so accepting changes in its production can take time. Society is apprehensive of adopting new construction materials due to their high liabilities.
Fortunately, one mature post-combustion technology will soon have its first operational commercial project at a cement manufacturer.
Introducing the world’s first carbon capture facility in the cement industry
Today, absorption with amines is the most common carbon capture tech that’s used industrially. Initially, the process required substantial thermal energy to regenerate the solvent. Thanks to advancements in solvent development, the energy required has been reduced significantly, while advanced heat integration solutions are being incorporated to further minimize energy consumption.
The Brevik CCS project, currently under development, will be the world's first carbon capture facility in the cement industry. It’s set to be operational in 2025 with a capturing capacity of 400,000 tons of CO2 per year, for permanent storage as part of Northern Lights (an open-source infrastructure for CO2 transport and storage).
This first-of-its-kind project is teaching us valuable lessons on how to accelerate implementation.
Customization is not ideal
First, we’ve learned that project execution needs a complete overhaul. While engineer-to-order plants provide the perfect customization for the emitter, the cost and time spent developing the solution hinder widespread adoption and rollout. The industry must be more agile, meaning that carbon capture plants must be modularized and standardized. This approach offers several benefits:
- Time efficiency—Site preparation and module fabrication can be done simultaneously, thereby reducing a project’s timeline. Final installation time is also reduced significantly.
- Cost savings—Bulk purchasing helps achieve economies of scale and reduce labor costs.
- Quality control—Factory fabrication allows tighter quality control measures compared with building in place and helps improve safety.
- Scalability—The project can be divided into phases, with each phase waiting individually for the right drivers to make its business case positive.
- Flexibility—Standard modules ensure interchangeability between projects in case of delays or cancellations, thereby avoiding hefty penalties for both the supplier and buyer.
- Replicability—Standardized processes provide for repeatable and consistent outcomes.
The closer, the better
The second lesson we’re learning is that carbon storage needs to be cost effective and in proximity to the cement plant, as is the case with the Brevik CCS project. Cement manufacturers are increasingly aware that the quality specifications for CO2 can increase capture costs significantly, worsening an already challenged business case. There’s currently no standard CO2 specification for storage; instead, it’s left to the transportation and storage developer to determine the specifications.
Cement plants located near carbon storage or piping are more likely to reach a final investment decision given that the full value chain is in place. Unfortunately, due to the regional nature of the cement business, not all cement plants will be geographically collocated with transport or storage facilities. In these cases, the cement plant needs to take charge and start screening for potential storage sites themselves to attract a storage developer.
Value and validate the investment
Lastly, the industry must create value from their CO2 waste. Unlike the other decarbonization methods I mentioned before (each asking that we switch one cost with another), capture and storage represent an entirely additional expense.
That said, achieving net-zero cement manufacturing without CCUS is impossible. Current policies, incentives, and grants are not enough to justify the investment. The cement industry will need to put in place a market mechanism that creates additional value.
With Brevik CCS operational, the cement plant will produce the world’s first net-zero emissions cement and test the willingness of customers to pay for a green premium by using a book and claim system. Groups like the First Movers Coalition have already publicly stated their commitment to procure at least 10% of their annual cement and concrete at near-zero emissions. Others, such as the Concrete Zero initiative, are coordinating a business commitment to use 100% net-zero concrete by 2050, with two ambitious interim targets of 30% low-emission concrete by 2025 and 50% by 2030. These efforts will move faster than waiting for the implementation of any kind of green construction procurement policies.
The proverbial fork in the road for cement manufacturers
The cement industry stands at a pivotal crossroad in the fight against climate change. The sector is facing its most significant transformation in over a century, and the road ahead requires more than just technological advancements. It demands a paradigm shift in operational practices, substantial financial investments, and robust market mechanisms to incentivize the adoption of green cement.
Achieving net-zero cement will ultimately require the collaboration of industry stakeholders, policymakers, and consumers. In the short term, the industry will rely on easier pathways to decarbonize (those exchanging one cost for another), but implementing CCUS at cement plants will soon become the license to operate. Modular, standardized carbon capture units promise to accelerate the transition by ensuring time efficiency, cost savings, and scalability.
The cement industry needs to continue embracing this journey with agility and resilience. A successful transition will not only contribute to mitigating climate change but also reinforce the foundational role of cement manufacturers in industrial development—all while cementing a greener and more resilient world for future generations.
