Concrete solutions for a greener cement industry

Published on: May 8, 2024

The total volume of cement production worldwide reached an estimated 4.1 billion tonnes in 2022. Back in 1995, the total global production of cement amounted to just 1.39 billion tonnes, an indication of the extent that the construction industry has grown in recent decades.

Reducing CO2 emissions while producing enough cement to meet demand will be challenging.

“Cement is the binding agent that gives concrete its strength and concrete is the manufactured material that we use the most on the entire planet. We are talking about huge amounts, and the demand will just keep on increasing,” says Aaron Maltais, researcher at Stockholm Environment Institute (SEI).

Cement CO2 emissions remain stubbornly high according to data from the International Energy Agency (IEA). So, what is the role of cement in clean-energy transitions?

Innovative strategies to combat cement’s carbon footprint

Key strategies to cut carbon emissions in cement production include improving energy efficiency, switching to lower-carbon fuels, promoting material efficiency (to reduce the clinker-to-cement ratio and total demand) and advancing innovative near-zero emission production routes. The latter two contribute the most to direct emission reductions in the net-zero scenario. Aligning with that scenario will require the development and deployment of technology that is not currently available.

Many entrepreneurs are scratching their heads trying to come up with new solutions. Mixing concrete with, for example, by-products from iron and coal production to reduce the proportion of cement is one option. Another possible solution is to inject carbon dioxide into the concrete. The concrete is then mineralised, which makes it harder which, in turn, leads to less material being used. An additional benefit is that the concrete acts as a kind of carbon sink, which is anything that absorbs more carbon from the atmosphere than it releases. Canadian Carboncure is a leader in this field.

Recycling is also crucial for reducing CO2 emissions. Founded in 2020, the Swedish startup Cemvision is making strides in this area. Their inaugural product line features two cement binders crafted from industrial by-products rather than raw limestone. Last year, the company-initiated pilot-scale production of what is touted as “the world’s first 100 percent circular, fossil-free, decarbonized cement clinker.”

Another trend is to produce concrete that contains alternative binders, such as slag from steelmaking.

Many Swedish concrete manufacturers already offer a climate-improved concrete with up to 40 per cent lower climate impact than standard concrete, according to Karin Comstedt Webb, vice president at Heidelberg Materials, Sweden. But today, the reduction of CO2 emissions from cement still relies heavily on carbon capture and storage (CCS) due to chemical reactions when heating limestone to produce clinker.

”If you were to start producing green cement in Sweden, I believe that many construction companies would find it difficult not to buy it given sustainability efforts and goals,” says Aaron Maltais.

”But green public procurement is also important for the cement sector. Given that the government has decided that we are aiming for net zero, it is reasonable to expect that the state will start buying green cement to create the first markets,” adds Björn Nykvist, researcher at SEI.

CCUS – a necessary complementary solution

CO2 has been captured, transported and stored in Europe since 1996, when the Sleipner project started in Norway. Apart from heavy industries, CCS can be supplied to gas-fired power plants, which provides flexibility to an electricity grid with a higher share of intermittent renewables.

CCS is an important part of the EU’s climate policy. Recently, a legally binding target was set to reach an annual injection capacity of at least 50 million tonnes of CO2 by 2030. Today, as the map below indicates, ongoing and planned CCS projects will amount to 35 million tonnes of CO2 per year by 2030. In March 2023, Denmark became the first country in the world to develop a cross-border CO2 storage site, shipping CO2 from Belgium and injecting it into a depleted oil field under the Danish North Sea. If the technology can be used in the future for biogenic carbon dioxide from large-scale combustion, it can also enable negative carbon dioxide emissions. The carbon dioxide that is separated can be used as a raw material in the manufacturing industry; the term CCU is used, where the U stands for utilisation.

CCS is still an emerging technology. It is noted by some that carbon capture and storage (CCS) has been promoted as a means to mitigate CO2 emissions while still using fossil fuels, which raises questions about its role in the broader strategy for moving towards renewable energy sources. Continued investment in fossil fuels creates lock-ins that effectively prevent the transition to a clean-energy system.

There are also risks associated with storing carbon in geological formations. The most significant risk from geologic carbon sequestration is leakage of CO2. Two types of CO2 leaks are possible— atmospheric and subsurface. These might be caused by slow leaks through slightly permeable cap rock or catastrophic releases due to a rupture of a pipeline, the failure of a field well or the opening of a fault.

Pioneering industrial-scale CCS in cement production

Sweco is assisting Heidelberg Materials’ Brevik Sementfabrikk in Porsgrunn, Norway to reach net-zero towards 2030 with a carbon capture facility scheduled to be in operation during 2024.
The carbon capture in Brevik is a part of the CCS project “Langskip” and the Transport and Storage part of the project will be conducted by Northern Lights with storage sites in the North Sea.

Sweco is performing several tasks during the realisation of this project:

• Client project manager for civil /client representative
• Client construction managers for all civil contracts and for mechanical contracts under FLS and Aker
• Client health and safety coordinator for the execution
• HSE Manager and site lead for Heidelberg Materials and principal undertaking
• Site area planning and construction coordination
• CSR (Corporate Social Responsibility)
• Independent control according to technical regulation for structural and geotechnical engineering
• Leads coordination meetings among contractors and company representatives

“We have summoned experienced resources and project managers for this project, people with many years of experience from industrial projects in the region. This ensures the client a good implementation and control of the project,” says Arild Hauge, Senior Industry Advisor, at Sweco Norway.

Heidelberg Materials’ Swedish CCS plant initiative

Sweco was selected by Heidelberg Materials to assist with the permit application for a CCS plant in Slite, Gotland. The initiative represents a significant step towards climate change adaptation in Sweden. Sweco’s role includes environmental impact assessments and contributing to the plant’s feasibility study.

The goal of the CCS plant is to capture and store around 1.8 million tons of CO2 per year by 2030, which could aid in reducing national emissions. This project, one of Sweden’s most comprehensive climate adaptation initiatives, is part of broader efforts within Sweden to meet climate targets in the construction sector by 2030.