LowExTra - Feasibility of a Multi-Conductor District Heating System

District heating (DH) systems can be a promising technology for a low-carbon heat supply if the share of renewable heat and waste heat will be increased. However, the level of integration from low temperature (renewable) heat sources is currently limited by the system temperatures of the heating grid.

To develop a solution for this challenge, this paper examines the feasibility of a multi-conductor DH-grid concept which was investigated from technical and economic perspectives. The analysis of the dynamic grid and plant simulations show that a share of over 40 percent renewable and waste heat can be reached in the test area of a built-in district in Berlin. Different designs of the heat supply units lead to similar overall costs and can be competitive compared to decentralized heating concepts with comparably high level of renewable and waste heat.

However, in Germany, due to the currently low natural gas price, gas boilers are often still the option with the lowest heat production costs for the existing building stock. Therefore, political action is needed to increase the feasibility for a successful low-carbon transition and to overcome obstacles for innovative low-temperature (LowEx) DH-systems.