Variable cost evaluation of heating plants in district heating systems considering the temperature impact

District heating systems (DHSs) play an important role for urban areas as they enable efficient and cost-effective heat supply. Existing DHSs are primarily based on fossil fuel energy therefore need to be transformed in the coming years meet climate goals of Paris Agreement. Lowering system temperatures is relevant convert fossil-based generation renewable sources. However, there a lack systemic methodology that can properly promote required changes during operation. This paper contributes first part such methodology: method evaluate average variable costs plants supply DHSs. The novelty approach lies systematic way consider impact temperature momentary thermal power plant. method’s requirements, application, results, conclusions demonstrated three case studies plants: solar thermal, geothermal industrial surplus specific results these show different set-points each plant have cost production. A comparison demonstrates increases transparency general. It concluded should used operational optimization Further, more comprehensive entire DHS infrastructures including storages, network, customers.