Multi-scale, circular economic potential of non-residential building stock

Lead Research Organisation: University of Sheffield
Department Name: Civil and Structural Engineering

Abstract

Reducing the demand for new materials and reducing embodied carbon will be one of the most significant challenges that the construction sector faces in the coming decades. The 20th century oversaw a 23-fold increase in accumulated resources extracted, including materials currently locked in buildings and infrastructure. This rate of consumption far exceeds the planet's capacity to regenerate, and has serious implications for global greenhouse gas (GHG) emissions. Addressing this interlinked material demand and emissions problem requires a step-change in practice, and implementation of circular economic (CE) reduce-reuse-recycle strategies, where materials are highly valued and remain in use for as long as possible. However, detailed knowledge of material types and quantities that are locked in the building stock is lacking, making estimation of CE potential unfeasible. This project will develop a spatially multi-scale framework to assess CE potential in individual buildings, cities and countries.

Application of this new framework to non-residential construction in the UK will enable estimation of CE potential in the existing stock - at building, city and national level. The framework will utilise bottom-up material flow analysis to assess building level material intensity, embodied carbon and CE potential. This will be combined with remote sensing and satellite data to assess city level building stocks, with demand modelling applied to explore future material demand scenarios - considering different construction mixes and optimised CE potential. The embodied carbon implications of this material demand will also be forecast so it can be considered as part of UK decarbonisation pathways. This will be essential as the proportion of embodied carbon in the whole life carbon of the built environment is only increasing, and will continue to do so as the electricity grid is decarbonised and thus operational GHG emissions are minimised. This research will build the evidence base to demonstrate the role the circular economy can have in tackling these challenges in construction, and provide the knowledge required to facilitate shifts in policy and practice.

Planned Impact

Through the development of a multi-scale framework, material demand, CE potential and embodied carbon of the UK building stock will be assessed, including the development of building level benchmarks, city level CE potential and UK material demand, with scenario modelling to explore the impact of increasing CE potential on material demand and embodied carbon. The project thus has the potential to impact upon a range of stakeholders, including the construction sector, UK Plc, and global society.

The construction sector: The benchmark metrics developed during the project could be applied by clients to their building stock to understand its CE potential, and associated embodied carbon. This will assist in decision making regarding retrofit, deconstruction and material salvage. CE potential of the stock enables the potential future value of materials held in the buildings to be estimated; this has the potential to shift the mindset from a disposable, consumption approach, to one where construction materials are valued, and kept at highest value use. The benchmark metrics could also be used by building designers and contractors to both understand how 'good' their designs are compared to the average stock, as well as to develop methods to help achieve buildings with higher CE potential, and lower embodied carbon. Members of the advisory group, which will include: Fosters+Partners, AECOM, Expedition, BAM, Cundall and Hawkins Brown, will be amongst the first to apply these metrics and benchmarks, which could also give them an initial competitive advantage when bidding for work with CE potential or carbon reduction requirements. There is also potential for this to be area of specialisation for UK consultants, leading to skills export opportunities.

UK Plc: This research will identify CE opportunities within the UK non-residential stock. This has the potential to stimulate new business models, for example to develop material reuse markets, at local, as well as, national levels. This could reduce UK unemployment and result in up-skilling of workers, for example from demolition to deconstruction techniques. Reducing the UK's demand for new materials in construction would also improve resource security, reducing reliance on imports. Exploration of the relationship between material demand for non-residential building and UK decarbonisation pathways could also lead to effective contributions towards achievement of legally binding decarbonisation targets. The identification of levers for change could further support either industry incentives, new business models, or policy mechanisms - assisting the UK in transitioning to a circular, decarbonised economy.

Society: Global society will be a beneficiary from the proposed research as one potential outcome of application of the findings is global GHG emissions reduction, which is crucial to mitigate the impacts of climate change. Realising CE opportunities could also stimulate new job markets. More broadly, the lessons learnt will be applicable to countries around the world, and the framework could be utilised to model their building stocks. Material intensity estimates for different building types, could also be utilised in world wide energy demand and decarbonisation modelling e.g. by the International Energy Agency, contributing to this important work

Publications

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