Life cycle assessment-based procurement of buildings using the systemic know-why planning process

The building sector accounts for an enormous share of global greenhouse gas (GHG) emissions and, therefore, is also responsible for the continuing decrease in the remaining budget of GHG emissions. The latest European Union (EU) directive on public procurement proposes that building contracts should be awarded according to life cycle costing (LCC), considering environmental externalities. In Austria, however, no feasible cost model, which considers the environmental quality of buildings when awarding contracts, has yet been developed for the building procurement process. The objective of the dissertation is the development of a cost model for the procurement of buildings that enables mandatory applications of life cycle assessment (LCA) in the future and considers the environmental quality of buildings in the award decision. Furthermore, the objective is the development of a systemic planning approach that supports the implementation of a future LCA-optimized planning process for a more environmentally friendly procurement of buildings. The environmental life cycle costing (eLCC) method monetizes building-related GHG emissions, i.e. embodied and operational GHG emissions, and integrates them as external costs into the bid prices of submitted bids. In addition, a GHG emissions bonus/malus is determined to calculate Paris-compatible cost (PCC) scenarios that are used as award criteria in the building procurement process. By combining the know-why method and the building certification system of the German Sustainable Building Council, a systemic planning process model is developed. With the application of the process model, interactions among planning measures, i.e. synergies and trade-offs, can be identified and impacts on project goals, such as optimized environmental building quality or other sustainability aspects, can be analysed. The dissertation fills the research gap of a missing cost model for a more environmentally friendly building procurement process in Austria. The results show that by implementing the LCA-based bonus/malus system in contrast to conventional building procurement processes, i.e. based on the awarding according to the lowest price, the procurement of planning alternatives with a higher environmental quality is promoted. In addition, it has been shown that the requirements for an LCA-optimized planning process are managed with the application of the hierarchical reference-based know-why model, thus, reducing project-specific undesirable developments in terms of quality, time and costs at an early stage. By developing the presented models, the LCA-based bonus/malus system for the building procurement process and the hierarchical reference-based know-why model for the planning process, the basis for further implementation steps of a more environmentally friendly building procurement process in Austria was laid. By applying the models to all building procurement processes, the greatest possible potential for the reduction of GHG emissions can be exploited, thus, making a significant contribution to achieving climate targets.