Paper No 311 – Towards integral assessment of heat pumps and refrigerants using LCA: A case study for the German building stock – 14th IEA Heat Pump Conference, Chicago, USA
Heat pumps are the key technology to defossilize the heat supply of buildings, which for now is predominantly based on burning fossil fuels. In Germany, 19 Million residential buildings consume about 865 TWh of fossil fuels and emit about 120 Million tons of CO2 each year, mainly for heating purposes. Reducing GHG emissions is critical to achieving climate goals, and replacing combustion-based heating technologies is crucial to GHG mitigation. To recommend appropriate alternative technologies and accelerate the corresponding deployment, there are standardized indicators for heat pumps in each sustainability dimension: For instance, economic and environmental aspects can be represented by energy labels, while social aspects (e.g., acoustics) are currently not in focus. In particular, from an environmental point of view, the focus is on labeling emissions due to the refrigerants’ Global Warming Potential (GWP) and operating-related emissions. However, the focus on GHG emissions bears the risk of unnoticed burden shifting to other environmental impacts, such as ecotoxicity or land use. To avoid burden shifting, a holistic assessment of heat pumps and refrigerants using life cycle assessment (LCA) is necessary. This work investigates the environmental assessment metrics beyond climate change and applies them to heat pumps and refrigerants in existing buildings in Germany. To evaluate essential assessment metrics simultaneously, a fundamental data basis is prepared through an extensive literature and database review. While there is scientific consensus on the fundamental understanding of heat pumps and refrigerants, some assumptions still need to be made to obtain meaningful results. Therefore, a key finding of this work is that further research is mandatory. In addition, we identify the main contributors to improving the environmental impacts of heat pumps and refrigerants using LCA: For low GWP refrigerants in heat pumps, the refrigerant choice is less important in terms of environmental aspects, here resource availability (flour range) and proper handling (avoidance of leakage) are essential. Currently, emissions from electricity generation dominate the environmental impacts of heating with heat pumps. Using renewable electricity instead will lead to some burden shifting but reduce most environmental impacts so that the production of heat pumps and refrigerants gains importance for further impact reduction. For future research, consider potential improvements in the supply chains of materials and refrigerants using dynamic LCA.