Why near-zero cement and concrete are crucial building blocks to reach net-zero

Concrete is the most widely used man-made material, and the second most widely used material after water. Humans rely on it, yet with cement and concrete production contributing 7-8% of global CO₂ emissions, significant changes are required to make the industry sustainable.

Decarbonizing the sector is therefore critical to keeping global warming in line with a 1.5°C target increase from pre-industrial levels. There is no time to waste as 2050, the target year to reach net-zero across many geographies, is only one investment cycle away due to the long life of capital assets in the industry.

Decarbonizing the cement and concrete sector includes a variety of solutions. Currently, around 90% of cement manufacturing emissions come from producing clinker, which generates emissions both through the chemical reaction of limestone calcination and through the burning of fuels to reach the 1,450°C required for clinkerization. Clinker is at the core of Portland Cement production and is used as a binder in most cement products, which in turn are the main ingredient in concrete mixes. Cutting these clinker-related processes emissions will require the use of deep decarbonization technologies which we will explore in this blog.

Over the past year, seven companies have joined the cement and concrete sector of the First Movers Coalition (FMC), a coalition of companies aggregating their purchasing power to demonstrate the demand for near-zero technologies across seven hard-to-abate sectors. These corporations have committing to purchasing 10% of their cement and concrete per year as near zero by 2030. Together, the FMC cement and concrete members reflect ~$60 million in demand and 100,000 tonnes of potential greenhouse gas abatement.

To gain a snapshot of progress in decarbonizing the sector, we asked major cement and concrete suppliers and FMC trucking members Holcim and Heidelberg Materials what breakthrough technologies they are using, as well as asking FMC cement and concrete members to share their wider decarbonization activities.

CCUS technology allows the capture of carbon from the clinker production process, helping to curb otherwise difficult-to-abate process emissions. The captured carbon can then be stored or used long-term.

Heidelberg Materials is a German multinational building materials company which produces 176 million metric tons of cement annually. It uses CCUS to capture emissions from the clinkerization process.

Nicola Kimm, Chief Sustainability Officer at Heidelberg Materials, explained: “Heidelberg Materials works intensively on the technical, economic, and social aspects of CCUS. Its Carbon Capture and Storage (CCS) facility in Brevik, Norway, is the first full-scale CCS facility in the cement industry and is scheduled to start operations at the end of 2024. With its portfolio of capture technologies and full-scale CCUS projects, Heidelberg Materials estimates it will cut carbon emissions by 10 million tons cumulatively by 2030.”

The use of CCUS technology is also prevalent across other cement and concrete producers. Holcim is a major international building materials company, with cement production facilities of 260 million metric tons. Chief Sustainability Officer Nollaig Forrest added that Holcim is working on combining CCUS with the production of low-carbon cement and concrete to reach net-zero: “Holcim has launched the broadest range of low carbon and circular building solutions in its sector. These include low-carbon concrete ECOPact and low-carbon cement ECOPlanet, already fast-growing multi-billion brands, along with a growing offering of advanced roofing and insulation systems making buildings more energy efficient in use.” She explained that Holcim has received EU grants for an industry-leading six CCUS projects, with another eight in development. Through its decarbonization work, Holcim is committed to capturing more than 5 million tons of CO₂ annually by 2030.

The use of SCMs is another effective tool in decarbonizing the cement and concrete industry. Using SCMs, such as fly ash or Ground Granulated Blast-furnace Slag (GGBS) — a steel production by-product — can reduce the amount of cement needed in concrete mixes and therefore lowers emissions.

Holcim’s ECOPlanet Zero cement uses a variety of decarbonization levers, including SCMs. The SCMs used include calcined clay and recycled construction and demolition materials, according to the firm’s Head of Group Public Affairs and Social Impact, Cédric de Meeûs. It further decarbonizes its production process using alternative fuels. Holcim is scaling its use of low emission materials such as calcined clay, which enables cement production with up to 50% lower CO₂. Furthermore, Nollaig Forrest explained that by combining measures including SCM use and CCUS, “by 2030 we will offer at least 8 million tons of fully-decarbonized ECOPlanet Zero cement, with ECOPact and ECOPlanet accounting for over half of our concrete and cement net sales,” contributing to Holcim’s commitment to capturing over 5 million tons of CO₂ annually by 2030.

SCM use is not limited to cement suppliers. Consolidated Contractors Company (CCC) is the Middle East’s largest construction company. Saji Khoury, CCC Business Development Manager, explained that his company is focusing on SCM use in the Middle East and North Africa, where they are “targeting the integration of 10% green concrete in its civil and mechanical projects by 2030. This commitment involves replacing traditional cement with eco-friendlier SCMs such as GGBS and fly ash.” He highlighted that the quality of green concrete is not compromised, as substituting up to 60% of Portland Cement with GGBS, strengths of 4000-5000 psi can still be attained.

Lowering the content of cement in concrete through efficient mix design while not compromising the quality of the final product helps companies drastically improve the carbon footprint of the cement they use. Vattenfall, a Swedish multinational power company, has developed a climate-enhanced concrete with lowered cement content that reduces carbon dioxide emissions by approximately 30%. Annika Ramsköld, Chief Sustainability Officer and Björn Stenecker, Chief Procurement Officer, told us that the concrete is being used in the ongoing construction of a new spillway dam at the Lilla Edet hydro power station in the Göta river near Gothenburg in Sweden. They explained that reducing cement use in large concrete structures “results in a lower temperature during the curing process, which in turn reduces the risk of cracks. Extensive trials and tests have been carried out to ensure a concrete concept that is robust for construction works and that above all meets the requirements for safety and durability for more than 100 years to come.”

ZGF Architects has also focused on encouraging the use of higher SCM content mixes. Tim Williams, ZGF Architects Managing Partner, Washington DC, recently worked on two projects in which local concrete suppliers were challenged to create low carbon Environmental Product Declarations (EPDs), which in turn led to higher use of SCMs. EPDs are independently verified reports on the environmental impact of a product throughout its life cycle and are created according to a specific set of Product Category Rules (PCR). PCRs provide calculation rules and guidelines so that all EPDs within the same product category disclose the same type of information.

This involved high SCM content mixes, type 1L cement (also called Portland Limestone Cement, a cement with higher limestone content), and on-site batch plants. This work has not only stimulated the production of lower-carbon cement, with these two major projects achieving “a 20-34% reduction in global warming potential from average regional practices.” The work has, as Williams explained, “set the Washington DC region up for knowledge sharing and continued success.”

Sharing best practices will be key. For instance, Eric Bertrand, Chief Innovation Officer, and Sergio Sandoval, Group Head of Sustainability at lighweight construction pioneer Etex, stressed the importance of partnerships across various areas of work. They said “Etex collaborates with its suppliers and innovative startups to become more sustainable; working with providers to use cement with increased supplementary cementitious materials and addressing the challenge of recycling its fibre cement products. We are already piloting a recycling programme, aimed to be launched in 2024.” It is clear that tackling the difficult topic of cement and concrete decarbonization cannot be done by individual companies on their own.

In a sector that contributes a significant proportion of global CO₂ emissions, these are just some of the decarbonization activities ongoing. To decarbonize the sector further, nascent alternative chemistries are being developed for cement production, such as foregoing the use of the kiln to create clinker, or sourcing lime from calcium silicate rocks instead of limestone, eliminating CO₂ emissions produced by processing limestone and without, crucially, compromising the quality of the final product. Work is also ongoing to develop and scale electric or hydrogen-based kilns.

The challenges will be scaling these technologies at the scale required, convincing demand players that decarbonized solutions are of an appropriate quality, and EPDs and PCRs being developed and updated to provide guidance for various new technologies used to decarbonize cement and concrete. However, in the meantime and long-term, significant decarbonization can still be made with made with the solutions explored in this article, efficient architecture and design, and reducing the industry’s dependence on fossil fuels through fuel switching.