Successful implementation of low temperature district heating case studies

Low temperature district heating is recognized as a key technology for the (cost-) efficient integration of renewable energy and waste heat sources in our energy systems. Several studies indicate that a deployment of local district heating schemes is a key measure for reaching the politically set climate goals. Further, implementation of low temperature district heating systems are recommended for taking maximum advantages of synergies with other sectors for decarbonization of the heating sector. Within the IEA DHC Annex TS2 project already realized low temperature community energy system concepts as well as planned or designed systems are identified and visualized. Furthermore, projects showing an innovative heat use or operation of buildings are also included in the analyses. The different projects are assessed and compared. The presentation of the demonstrators is set up in such a way that knowledge is generated about the indoor heating system, the district heating system and of the competitiveness of low temperature district heating systems, giving the evidence that these systems are feasible, efficient and reliable under various boundary conditions. The demonstrators further indicate that there are existing challenges, where further research on innovative district heating concepts for integrating decentral feed-in of renewable energy is required. The demonstrators included in the IEA DHC Annex TS2 are analysed in regard to which elements of new knowledge they can generate. For each demonstrator there are specific innovations in focus. Furthermore, the case studies show that the related business models for the utilities change when system temperatures are lowered. The paper presents and discusses the results from current research work within of the IEA DHC Annex TS2 on Implementation of Low Temperature District Heating Systems (Averfalk et al., 2021; Annex TS2, 2021 [1])