Transformation plan for a district heating towards a climateneutral heat supply
A district heating network in western Germany, is undergoing a systematic transition from a fossil-based to a renewable and climate-neutral heat supply. The current network covers approximately 20 km, serving around 230 customers with an annual heat demand of about 18,000 MWh. The transformation became necessary following the decommissioning of a coal-fired power plant and the upcoming end of the current industrial waste heat contract with a local industrial company The transformation plan was developed by enerbasics, in collaboration with the heat supplier and the local city council. A structured evaluation of ten renewable and alternative heat sources was conducted, including surface water, sewage heat, geothermal energy, solar thermal, pyrolysis, and ambient air heat pumps. The methodology combined technical feasibility studies, hydrological assessments, thermodynamic modelling, and economic analysis. The results identified a multi-technology approach as the most promising. The selected configuration is based on a 4 MW air-source heat pump with 3,000 m2 thermal storage tank covering approximately 70% of the heat demand. For peak loads a 5 MW combined heat and power plant H2-ready (CHP), and a 5 MW power-to-heat (PtH) unit. providing additional flexibility and system stability. To reduce thermal losses, the maximum network supply temperature was successfully lowered from 120°C to 95°C. The concept foresees the integration of locally produced renewable electricity from an existing wind turbine and planned photovoltaic systems on industrial rooftops. The network expansion is planned in stages, combining targeted densification within the existing network area and strategic network extension to adjacent districts and new developments. The transformation plan foresees phased implementation between 2025 and 2045, providing a practical and replicable model for municipalities aiming to decarbonize their district heating systems.