Getting the industry on the path to net zero

Mike de Silva is head of sustainability at Clancy Group

Taken together, the production of steel and concrete contribute as much as 16 per cent of global annual carbon emissions. This puts the construction industry in an optimal position to help drive the decarbonisation of both industries.

Addressing the embodied carbon of steel and concrete in ongoing and future projects is high on my agenda. That is why I’ve become an adviser to international non-profit Climate Group, to join my peers in unpicking the tricky issues facing the construction sector.

Steel and concrete are fundamental components of the built environment. The United Nations predicts that 68 per cent of the world population will live in cities by 2050, requiring significant growth in homes and infrastructure – and demand for steel and concrete will inevitably increase. It is therefore crucial that we act now to set both industries on a path to net zero.

Philosophy of circularity

As a sector, we can assess the potential reuse and repurpose of steel and concrete in existing assets at the beginning of a project. Circularity is an important philosophy for our sector to incorporate into the design, build, and demolition of buildings and infrastructure. By taking this approach, we have a fighting chance of satisfying global demand while minimising the immense strain we are placing on our planet.

“How we use concrete and steel more efficiently in the construction sector is a vital question”

Aspects of circularity do exist across the steel and concrete industry. For instance, fly ash, a waste material from electricity generation, and slag from steelmaking have long been used in the concrete mix to replace Portland cement. This is not, however, a long-term solution. As these heavily polluting industries seek to decarbonise their own emissions, these materials will be at a premium.

As we have seen from Climate Group’s SteelZero initiative, demand for low-emission and net-zero steel is rising. Steelmakers are coming under increasing pressure to eliminate the use of coke in the production process, meaning that slag is also becoming less available in specific geographies.

Supply chains under pressure

This adds to pressure on global supply chains. It will require a re-evaluation of alternatives to slag and thermal coal-derived ash in concrete applications, especially where products are needed for aggressive ground conditions or maritime structures. How we use concrete and steel more efficiently in the construction sector is a vital question as we move deeper into the resource and carbon-constrained future of the mid- 21st century.

Additionally, a reliance on carbon capture and storage (CCS) to mitigate carbon emissions from cement manufacture potentially kicks the can down the road. These technologies still need to be evaluated and rolled out at scale within a widely distributed production system. And, with the economics still largely unproven, CCS isn’t a silver bullet. We should watch that space keenly if ordinary Portland cement is to remain the material of choice.

At Clancy Group, we are increasingly bringing design and material efficiency to the heart of what we do. We are engaging with our supply chain to tell them where we are on this journey and what we expect of them. This doesn’t only apply to concrete but also to steel and all our major material purchases. We recognise that this is a collective journey and we can only reach the finishing line if we collaborate, sharing knowledge and learning.

A consistent demand signal from our customers and competitors helps to drive change across the construction sector and the materials value chain. I am delighted to be advising Climate Group on its heavy industry programme, as it has a strong track record of shifting whole systems towards a cleaner future. It does this by forming powerful networks of business and harnessing their collective action to shift different systems, such as industry, towards net zero. The steel industry has been a key focus through Climate Group’s SteelZero initiative, but it is now looking to tackle another high-polluting industry – concrete.

As a significant consumer of steel and concrete, the construction sector has a critical role to play in the decarbonisation of some of the highest-emitting sectors. It is only by working together that we can really drive change.

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