Achieving net-zero carbon emissions in construction supply chains - Analysis of pathways towards decarbonization of buildings and transport infrastructure

Doctoral thesis, 2024

Sweden has committed to achieving net-zero greenhouse gas emissions by 2045. The construction sector, which accounts for approximately 10-15% of CO2 emissions, plays a significant role in this commitment. The sector’s emissions arise from the manufacture, processing, and transport of construction materials along with activities on the construction site.

This thesis research thoroughly explores CO2 emission reduction potentials across building and transport infrastructure construction supply chains. Employing scenario analysis, extensive literature reviews, and involving broad stakeholder participation, these studies have identified and analyzed key abatement options throughout the construction supply chain. This culminates in a detailed roadmap, delineating reduction potentials and implementation timelines with increasing ambition over 5-year time steps towards close to zero CO2 emissions by 2045.

The results indicate that it is possible to halve CO2 emissions associated with construction already today using currently available technologies and practices. Moreover, it is possible and feasible if all value chain actors do their parts to reach around 70% reduction by 2030 and close-to-zero emissions by 2045. Achieving these levels of reductions nationally necessitates implementation of comprehensive measures across the board, requiring extensive collaboration along the whole value chain.

Key strategies include enhancing resource efficiency and circularity measures besides adopting electrified industrial processes and heavy vehicles. Deep reductions in CO2 emissions are possible through consideration of resource efficiency and circularity opportunities at all stages of the value chain. Optimization of structures and concrete mixes are emphasized alongside increased reuse and recycling, combined with substitutions to bio-based materials.

For heavy transport and the construction process, progressive electrification is supported by digital and automated processes, strategic machine setups, and transport and on-site logistic optimization.

Policy measures and procurement strategies should be tailored to support the aforementioned measures with a clear supply chain focus. This includes early involvement of contractors and suppliers in planning and design, facilitating balanced risk sharing. The studies also underscore the importance of avoiding pitfalls along the way, such as over-reliance on materials or solutions that cannot be scaled up to the levels required to reach deep emissions reductions on a national or international level.

The studies included in this thesis offer insights for stakeholders to accelerate the climate transition in building and transport infrastructure construction and renewal to advance towards global climate goals. At the core of this is collective efforts, embracing solutions across the supply chain, and prioritizing the climate transition in the development of the built environment.

By assessing supply chains with active involvement from value chain stakeholders and considering the time perspective, technical maturity, and scalability of emissions reduction measures, the research included in this thesis is laying the foundation for actionable roadmaps towards decarbonizing the embodied emissions of buildings and transport infrastructure.