Climate-neutral heat sources are essential for the heat transition. Unavoidable waste heat — e.g., from industry, data centers, or electrolysers — represents a resource that has often remained unused in heating networks to date. However, the use of this waste heat can be not only climate-neutral but also economical.
In the analysis “Waste heat utilization in district heating networks: Model-based analysis of the system value of exemplary waste heat profiles,” a team from the Institute of Energy Economics at the University of Cologne (EWI) examines the costs and benefits of various waste heat sources. Using the EWI’s own district heating model DINO, three exemplary waste heat profiles are analyzed: industry, data centers, and electrolysis. The analysis compares the “system value” of the waste heat—i.e., the cost-saving potential in the heating network—with the costs of tapping it. These costs depend on factors such as the temperature level, the utilization of the components, and the distance to the heating network.
The analysis shows that the system value of waste heat in existing networks is higher at 3.1 to 4.6 cents per kilowatt hour (ct/kWh) than in new networks at 1.9 to 3.3 ct/kWh. The system value of waste heat for the heating network depends on which heat generation technologies are replaced by waste heat utilization. Existing networks often have higher flow temperatures, which make the use of alternative technologies such as large heat pumps more expensive. For this reason, the system value is higher in existing networks. The profiles examined are suitable for different applications: Waste heat from data centers has low costs due to its continuous availability and is particularly economical in new networks due to the low waste heat temperature. Industrial waste heat can be particularly suitable for decarbonizing existing networks due to its high temperature level. The volatile profile of electrolysis, on the other hand, is only economical under certain conditions, such as short distances in new networks.
