Transforming the Sector: What Can Existing Building Practices Contribute to a Net-Zero Construction Sector?

Abstract

Given that the built environment is responsible for at least 37 percent of global greenhouse gas emissions, there is an urgent need to consider and devise immediate technical and policy measures to achieve a net-zero construction sector. This thesis endeavors to explore the extent to which existing building practices can contribute to reducing embodied greenhouse gas emissions and achieving a net-zero construction sector in Switzerland by 2050, while also formulating sector-specific policy options to expedite a rapid sustainable transformation process. Based on the findings in the literature review, there appears to be a lack of comprehensive analysis of the potential for reducing embodied emissions with the means of existing building practices, and proposing adequate policy measures based on such assessment.

In terms of methodology, this thesis first conducts a bottom-up view life cycle analysis for four key scenarios, each representing significant existing building practices, which enables an informed scenario assessment. This assessment, in turn, establishes the parameters for a thorough supply chain analysis and the subsequent development of policy options. To conduct the bottom-up view life cycle analysis, an archetype modelling tool is employed. This tool leverages inventoried data of emissions per building element from a pool of case studies, allowing to calculate results of embodied emissions at building scale that are comparable across all scenarios. These results are compared against emissions targets at individual building level and against remaining carbon budget at building stock level until
2050. In a subsequent step, experts representing different segments of the construction sector and policy makers are interviewed to enrich the analysis. These interviews, coupled with the life cycle analysis, are utilized to evaluate the potential disruptive impact of scaling up each scenario on the supply chain. Finally, based on a UN policy framework for a sustainable transition, a range of policy options, informed by the expert interviews and the supply chain analysis, is developed.

This research provides a comprehensive assessment of the performance of existing building practices as regards their embodied greenhouse gas emissions, and it offers an extensive overview of the available policy options designed to facilitate the adoption of building practices that can make a significant contribution to achieving a net-zero construction sector in Switzerland until 2050.