Authors: Xiaojin Zhang
Journal: Verlag der Technischen Universität Graz
Status: published
Publication date: 2023
Abstract:
Mitigating greenhouse gas (GHG) emissions from buildings is important for combatting climate change because buildings are a major source of GHG emissions, which account for about 30% of global greenhouse gas emissions, and about 40% of energy-related GHG emissions. Different mitigation strategies and scenarios have been developed and implemented in the “energy” and “industry” (including the construction product industry) sectors. This allows us to explore different pathways for the development of future energy supplies, their greenhouse gas emissions, as well as the influences on future manufacturing of building components and construction products. Such scenarios are also of great importance when a transition from static to dynamic life cycle assessment (LCA) of buildings is made throughout their service lives. In particular, the consideration of these scenarios would impose consequences in the life cycle stages (as defined in EN 15804 Sustainability of construction works – Environmental product declarations – Core rules for the product category of construction products) including module A1 (product stage – raw material supply) and A3 (product stage – manufacturing) for future new buildings, B4 (use stage – replacement) and B6 (use stage – operational energy use) for both existing and new buildings. While in the field of energy supply, the possibilities and consequences of decarbonization strategies are being discussed and partly taken into account in the building LCAs in selected countries, corresponding discussions and implementation considering the manufacturing of building components and construction products are still in their infancy. It is necessary to make a transition by including these scenario-based dynamic considerations both on the side of operational and embodied impacts. More importantly, scenarios used to derive these considerations should have a complete global coverage, addressing consistency for both energy systems and underline assumptions between individual countries and regions. This background report takes an example of considering future electricity supplies based on global Integrated Assessment Models, and discusses the impact of this consideration in building LCAs from both operational and embodied impact perspectives in terms of life cycle greenhouse gas emissions. These considerations are incorporated into the Swiss national building LCA database KBOB. Materials and regional electricity supplies with high emission reduction potentials are identified given different scenarios. In the end, based on this experience, recommendations are made to future national database development that can better accommodate such considerations, and the needs for future research are discussed.