Copyright © Yale CEA, 2023.
180 York St, New Haven, CT 06511, United States
cea@yale.edu | +1203.432.2288
Cement, steel and aluminium are the three largest sources of embodied carbon in the building sector. One of the lowest hanging fruits is to facilitate and/or mandate the adoption by industry as well as energy infrastructure planners of already developed best available technologies for decarbonisation and to maximise the use of clean energy in manufacturing processes.
Adopting decarbonisation technology in a manner that reduces emissions globally will require close coordination of national and international efforts in data collection, standards, and leadership in trade mechanism development (see chapter 6).
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Leverage advancements in low-carbon electricity, both from the grid and on-site (or district) renewable power generation sources.
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Invest in the development of neighbourhood micro-grids and peer-to-peer power sharing between different stakeholders.
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Increase funding and provide incentives for public-private partnerships to accelerate the development, demonstration and commercialisation of concrete decarbonisation technologies and techniques.
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Invest in materials science capacity in concrete technology and practice.
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Invest in the transition to biobased cementitious binding materials from agricultural and forest detritus.
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Promote the research and development of Carbon Capture, Utilisation and Storage (CCUS) technology that could reduce carbon emissions and increase material strength, thereby reducing use.
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Improve building codes to mandate the design and implementation of ‘circular’, modular concrete components that can be easily disassembled and reused.
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Encourage upgrades of existing plants to best available technology in steelmaking.
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Provide financial and structural support for phasing out coal-based primary steelmaking technologies (blast furnace/basic oxygen furnaces) with low-emission technologies (direct reduced iron coupled with electric arc furnaces).
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Incentivise material efficiency strategies across the steel life cycle to increase steel’s circularity and reduce its embodied carbon.
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Fund development and demonstrations of transformational new methods for CCUS, hydrogen steel production and electrolysis of iron ore.
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Sharply increase the availability of low-carbon electricity for aluminium production to reduce the high embodied carbon of virgin aluminium.
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Incentivise material efficiency strategies across the aluminium life cycle.
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Improve collection and grade-specific sorting at end-of-life to maximise the use of scrap in future aluminium production without the risk of downcycling to low-value applications.
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Invest in and enable the transition of digitised off-site manufacturing to greatly reduce yield losses in manufacturing.
To decarbonise, the built environment sector must learn to design with nature-based processes. This means shifting from “extracted” non-renewable materials to “grown” renewable materials. The decarbonisation of the cement sector and other major emitters can be enhanced by shifting to bio-based materials and other low-carbon replacements. However, these emerging methods are often not yet cost competitive, and widespread biases remain that protect entrenched methods. Sustainably scaling up implementation cannot be enforced without substantial investment in research and development alongside incentives and/or enforceable building codes. There are substantial dangers of an unregulated shift towards biomaterials backfiring and causing unmitigated environmental degradation.
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Adopt both “push” and “pull” market approaches to scale up sustainable bio-based building materials, by pushing to create consumer demand by supporting low-carbon building material enterprises at the local and bioregional level to develop and market new products, whilst cultivating broad public interest and education through powerful advertising and public education campaigns.
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Create local economic incentive schemes across timber, biomass and renewable building material producers who improve local and regional biodiversity conservation and enhancement practices.
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Accelerate international and local regulatory frameworks to normalise industry adoption of bio-based materials, including by standardising material performance criteria, integrating these materials into building codes and training stakeholders in the mainstream construction industry.
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Facilitate and invest in industrial enterprises promoting the use of localised, low-carbon earth masonry and replace high-carbon cementitious material and binders with secondary and bio-based binders wherever practical.
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Dramatically reduce the risk of regional forest fires and increase the carbon sequestering productivity of regional forests and agricultural lands by facilitating education and investment in enterprises focused on collection, incineration and upcycling of forest, agricultural and biomass resources.
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Promote investment and incentivise the use of by-product resources in the improvement of conventional building materials – such as fly ash from coal and agricultural industries or sewer sludge ash.
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Partner with industry associations to educate building design professionals about alternative, low-carbon construction materials and components (both virgin and secondary materials), and about the potential environmental impacts across the life cycle when selecting materials for a building.
Despite growing awareness, most material cycles continue to be more linear than circular. As a result, non-renewable, energy-intensive materials still supply the majority of demand. So far, recycled materials are not available in sufficient quantities and qualities, and the gap between supply and demand for recyclables is growing in most sectors. A new supply-and-demand model is needed, with new enterprises that allow for the careful dismantling of buildings and for the storing, preparation and maintenance of second-cycle materials for resale that will enable circular economies while providing job opportunities.
In developed economies, it is critical to improve industry methods to repurpose the massive quantities of failing concrete and steel from 20th-century infrastructure that are nearing the end of their first life, so that they can be transformed into material “banks” for new construction and slow the pace of non-renewable material extraction. Government incentives, awareness campaigns, and legal and regulatory frameworks have shown to be effective to incentivise approaches for re-use and recycling (Liu, Bangs and Müller 2013). Recycling systems for building materials tend to require similar kinds of support across countries, including promoting markets for re-usable products, providing incentives for the creation of re-use centres (Forrest 2021) and developing specialised contractors.
To facilitate this, far more investment is required for research and development and for equipment to recover and process construction, renovation and demolition waste materials.
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Incentivise building designs that last as long as possible and, where possible, incorporate design for disassembly and modular construction to facilitate end-of-life recycling .
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Adopt renovation policies that encourage the diversion of end-of-life material for recovery and recycling, promote regulation and measuring of whole building life-cycle carbon emissions, incorporate design for disassembly, and provide quality long-lasting material assemblies in retrofit solutions.
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Promote the consideration of end-of-use strategies during material specification in the design of new buildings and renovation solutions to avoid waste and associated emissions later in the building life.
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Incentivise a marketplace for material re-use and develop standards to ensure the quality and efficacy for their use, in order to provide assurance to actors in the building sector.
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Target economic incentives to increase overall recycling volumes, incentivise efficient collection and sorting to create competitive secondary markets, and put premiums on the cleanliness of recycling streams to minimise downcycling.
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Facilitate stakeholder engagement among designers and recyclers to identify chokepoints and problems with the quality of supply.
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Invest in new equipment for collecting, sorting and converting secondary materials onsite at the time of building deconstruction so that it can be efficiently repurposed into a new life cycle with its value retained.
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Put in place market incentives (recycled content) and regulatory incentives (collection targets) that ensure that polymers collected from construction, renovation and demolition waste are diverted from landfills and towards recycling.
In developed urban areas, the highest carbon saving strategy is the preservation of existing building stock. Much can be done to promote the reuse of buildings, components and materials by modernising zoning and building regulations, in particular to allow for the transition of under-utilised office and commercial spaces to be converted into housing.
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Remove regulatory barriers to the reuse of buildings and components.
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Prioritise and expedite adaptive reuse projects when processing zoning applications.
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Support the development and distribution of toolkits for adaptive reuse.
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Develop adaptive reuse funding to encourage the repurposing of buildings over demolition and construction.
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Develop a comprehensive district-level plan for the future that includes preservation strategies.
Copyright © Yale CEA, 2023.
180 York St, New Haven, CT 06511, United States
cea@yale.edu | +1203.432.2288