This week ICR looks at the fast-changing world of construction and the attempts to make it more sustainable. This follows the recent publication of the World Economic Forum's white paper, 'Scaling Low-carbon Design and Construction with Concrete: Enabling the Path to Net-Zero for Buildings and infrastructure'.
The white paper has been produced by the World Economic Forum in collaboration with the Global Cement and Concrete Association (GCCA) and Boston Consulting Group (BCG). It aims to provide a framework for scaling low-carbon design with concrete that players across the value chain can adopt. The seven-part solution offered is aimed to support architects, engineering and construction (AEC) companies. The recommendations include:
• adopt consistent life-cycle emissions measurement
• increase collaboration across the value chain
• reduce risk through piloting, data and engagement
• evolve operating models with extensive leadership support
• signal demand and scale supply
• prioritise carbon reduction in procurement
• establish supportive public policy.
The built environment is responsible for around 40 per cent of global carbon emissions across the full project lifecycle, according to the International Energy Association (IEA). BCG analysis attributes 30 per cent of material related emissions in buildings to concrete, 25 per cent to steel, 12 per cent to aluminium, 10 per cent to chemicals and plastic and 23 per cent to other building materials. Many of cement and concrete’s properties make them indispensable for infrastructure and buildings and consequently, as the urban environment grows, cement demand is forecast to grow by 20 per cent between 2020-30, according to the GCCA.
Low-carbon practices and design
The white paper states that adopting low-carbon practices, low carbon design and construction is the critical enabler for reducing the carbon footprint of buildings and must be prioritised by AEC firms, cement and concrete producers, project buyers, investors and governments. Total concrete emissions can be reduced by 40 per cent by 2030, according to the GCCA, if the cement and concrete process is decarbonised by 16 per cent, lower-carbon cement and concrete products are specified in construction projects (six per cent) and volumes of material are optimised (18 per cent).
Other significant low-carbon design levers include the enabling of thermal efficiency in designs, increasing structural resilience and longevity, and the 'design and disassembly' approach to allow for the reuse of materials after building demolition.
One barrier to progress for low-carbon construction is the accurate measurement of the carbon footprint of materials, despite the existence of environmental product declarations (EPDs) and especially as products can vary by region and materials. Added to this are the problems of the fragmented design and the process of building with uncoordinated decision making at various project stages. Industry norms and risks can also run counter to lower-carbon choices, or may not cater for blended cements and low clinker factor cements, or products developed from demolition waste. Supply and demand imbalances and uncertainties can also prevent the use of lower-carbon materials. Furthermore, the white paper states that low-carbon cement and carbon products have to be produced at greater scale, and their availability and costs must be made more competitive. Finally, real-estate developers, governments and corporations must prioritise low-carbon design of buildings.
Innovations will help
Innovation is continually going to change what is possible and this week CemNet also highlighted that a new recipe had been designed for a concrete that absorbs more CO2 than it emits during its lifetime. Engineers at Washington State University created carbon-negative concrete by substituting limestone for volcanic rock and other materials, using biochar, a charcoal made from organic waste. Treated biochar can absorb 23 per cent of its own weight in CO2 from the air around it.
Lessons for the cement and concrete sectors
For cement and concrete producers, the lessons from the white paper are to increase the support and education of low-carbon products and materials to AEC firms. They also need to invest in EPD production and in the scaling up of low-carbon materials. Others will need to follow the example of Holcim Germany which, in January 2023, became the first European cement producer to publish EPDs for its entire cement portfolio. the company is also the first German cement producer to provide customers with product specific ready-mix concrete EPDs. Making choices easier for AEC firms with clearly-defined EPDs should encourage greater volumes of low carbon cement and concrete to be incorporated into construction projects.