Low temperature district heating as a key technology for a succesful integration of renewable heat sources in our energy systems

Low temperature district heating is a heat supply technology for efficient, environmental friendly and cost effective community supply. Moreover, it is recognized as a key technology for transforming and decarbonating heat energy systems by efficient integration of renewable energy sources as solar thermal, geothermal and other waste heat sources. The results from the international cooperation activity IEA DHC Annex TS2 on "Implementation of Low-Temperature District Heating Systems" provide advice and recipes for obtaining lower network temperatures as well as information on other features to include in existing and new district heating systems (Averfalk et al. 2021). Accomplished by summarizing the economic benefits of low-temperature district heating and gained experiences from early adopters in various urban areas throughout Europe. Lessons learned can be applied in new and expanding district heating systems and are presented in this paper. We discuss economic benefits, temperature levels in buildings, temperature levels in district heating systems, an applied case, competitiveness of low temperature district heating and transition strategies for cities with existing district heating systems.