A new report from IDTechEx explores green cement technologies for lowering scope 3 emissions. 

The company provides trusted independent research on emerging technologies and their markets. Eve Pope, technology analyst at IDTechEx, explores three of these emerging development areas. 

IDTechEx report 

Scope 3 emissions are indirect greenhouse gas emissions that occur in a company’s value chain, but are not produced by the company itself. In terms of corporate sustainability and emissions reductions targets, they are hard to quantify and even harder for businesses to reduce. 

The embodied carbon from construction can often be a significant contributor, with most of this CO₂ coming from the cement used. The IDTechEx report, “Decarbonisation of cement 2025-2035: Technologies, market forecasts and players”, explores innovative new green cement solutions that increasingly enable companies to decrease scope 3 CO₂ emissions. 

Cement alternative space covered in the IDTechEx “Decarbonisation of cement 2025-2035 report” and relation to conventional ordinary Portland cement (OPC). Source: IDTechEx

Cement from new materials 

Background 

Modern life is built upon billions of tons of new concrete each year. Concrete has reliable characteristics, and due to its excellent performance in construction applications, it is the second-most consumed material on earth (behind only water). 

Cement, concrete’s key ingredient, is made from limestone. However, the underlying calcium carbonate chemical composition of limestone means that the CaO compound crucial for cement can only be unlocked by releasing CO₂, resulting in a high carbon footprint. 

Proposed solution  

Green cement players are therefore exploring new starting materials, other than limestone, that can produce similar or identical cements with well-understood and reliable properties. 

Examples of cheap, abundant calcium sources are basaltic rocks and calcium silicates. Some of the players innovating in this space include Solidia Technologies, Brimstone, Sublime Systems and C-Crete.  

Each company has developed its preferred approach to cement-making – from lower-temperature kiln processes to using electrochemistry, or mechanochemical activation.  

Another option, with added circularity benefits, is to reactivate cement paste recovered from demolition concrete. This has been trialled by industry leader, Heidelberg Materials, via the recycling of captured CO₂. Start-up Cambridge Electric Cement is also developing its own approach, based on co-processing during steelmaking in electric arc furnaces. 

New cement chemistries 

Background 

The cement sector is no stranger to replacing cement with waste materials and preventing them from going to landfill. Repurposing waste such as coal fly-ash from the energy sector and granulated blast furnace slag (GBFS) from the steel sector, as supplementary cementitious materials, is already well established. 

Proposed solution 

Green cement innovators want to take this further, utilising even greater amounts of industrial waste streams through alternative cement chemistries. 

Alternative cements based on alkali-activation and CO₂ mineralisation for hardening and strengthening are being developed. These different routes can produce cements with desirable properties, using increasing amounts of fly-ash or steel slag. 

Replace fossil fuels with renewable power 

Background 

Taking inspiration from the transportation sector, electrifying the cement production process and using renewable energy are other pathways towards cement decarbonisation. The difficulty here is achieving the high temperatures required for cement making economically, and efficiently, that does not involve fossil fuel combustion. 

Key development areas include efficient heat transfer and thermal energy storage to account for the intermittent nature of certain renewable energy sources, such as wind and solar. 

Proposed solution 

Finland-based Coolbrook has developed rotodynamic heating technology, which enables fully electric high-temperature heat generation up to 1 700°C with a high electricity-to-heat generation efficiency.  

Synhelion’s approach, currently being developed with major cement producer CEMEX, skips the electrification stage by utilising heat directly from the sun (concentrated solar power), deploying thermal energy storage and its own solar receiver design.  

Such technologies are promising not only in the cement sector, but also for decarbonising other high-temperature, carbon-intensive industries such as steel and petrochemicals. 

Business impact 

What does this mean for businesses seeking to lower scope 3 emissions? 

While businesses may have limited involvement in selecting materials when constructing new premises, the green cement space is working to expand access to low-carbon cement to bigger pools of buyers.  

Over recent years, this may have taken the form of carbon credits or the emerging book and claim chain of custody model. Some businesses are already using this to lower aviation-related scope 3 emissions from transportation/travel, via the purchasing of sustainable aviation fuel (SAF). 

This model enables businesses to purchase the sustainability benefits of green cement when access to the physical concrete product is limited. Microsoft championed this environmental attribute certificate approach to cement decarbonisation, and it is expected to become increasingly popular as companies strive to reduce scope 3 CO₂ emissions. 

Issue: How to decrease scope 3 CO₂ emissions. 

Solution: A new report explores three innovative green cement solutions to this issue. 

Full acknowledgement and thanks go to IDTechEx for the information in this article. To find out more about this report, visit www.IDTechEx.com/Cement or email research@IDTechEx.com.