Concrete is an essential building material, one which is versatile, long-lasting, requires little maintenance and is 100 per cent recyclable, contributing to the circular economy. It is made up of three key constituent parts – cement, aggregates and water – and can include admixtures and colour as required.
Most of the carbon emissions associated with concrete (around 90 per cent) come from the cement content. This is because its production is energy-intensive and difficult to decarbonise with almost three-quarters of its CO2 emissions resulting from the chemical reactions that take place to produce clinker (the calcination process). As a result, the only way to decarbonise the cement industry is through carbon capture and storage (CCS), which removes these process emissions entirely.
To this end, Heidelberg Materials is proposing to build an industry-leading carbon capture facility at its Padeswood cement works, near Mold in north Wales. It would capture the CO2 produced during cement manufacture before it enters the atmosphere, transporting it via the HyNet North West underground pipeline and storing it safely under the seabed. It is a safe and proven technology that has been around for many years and has already been implemented by our parent company Heidelberg Materials in Belgium, Germany and Norway.
Padeswood CCS has been shortlisted for funding as part of the Department for Business, Energy and Industrial Strategy’s (BEIS) Phase 2 Carbon Capture and Storage Cluster Sequencing process. If selected for funding, it could mean we are able to produce net zero carbon cement in the UK as early as 2027 and would be a huge step forward in our commitment to producing net zero concrete by 2050.
We are also involved in an additional BEIS-funded carbon capture project at our Ketton cement works in Rutland. Part of the Government’s Net Zero Innovation Portfolio, the multi-industry project will see C-Capture’s carbon capture technology implemented at several sites across the country. The process uses a solvent to selectively capture the CO2 produced and requires less energy than other carbon capture technologies, significantly reducing its cost.
The remaining emissions associated with cement production originate from the fuels used to power the kilns and we are also working on projects to switch from traditional fossil fuels to carbon neutral sources.
For example, as part of a world first demonstration, we have successfully operated a cement kiln at our Ribblesdale works in Clitheroe, Lancashire, using a mix of 100 per cent net zero fuels including hydrogen.
The trial was made possible by BEIS funding, provided through the Mineral Products Association (MPA), and demonstrated the pathway to moving away from using fossil fuels in cement and concrete production. It is envisaged that combining the use of net zero fuels with CCS technology will enable the production of cement to capture more CO2 than it emits.
In addition, we are also increasing the use of lower carbon cement substitutes, such as evoBuild low carbon GGBS, in our concrete mixtures. GGBS (ground granulated blastfurnace slag) is a by-product of the iron making industry and its manufacture requires less than one third of the energy and produces less than 10 per cent of the CO2 emissions of CEM I Portland cement (PC).
More than a third of all ready-mixed concrete deliveries in the UK already contain GGBS, which can replace a substantial part of the normal PC content – generally about 50 per cent, but sometimes up to 95 per cent in special applications – and can be used anywhere concrete is needed. As a result, since 2000, using GGBS in concrete has saved more than 18 million tonnes of CO2 emissions.
Heidelberg Materials also invests to improve the efficiency and sustainability of its concrete plants. For example, early in 2022 it opened a new, rail-connected concrete plant in Landor Street, Birmingham. The rail connection allows raw materials to be transported to the plant by rail, reducing vehicle movements and associated CO2 emissions, and increased storage on site reduces the frequency with which raw materials need to be brought in.
