Industrial waste heat makes the most sense for existing grids

10.10.2025

Source: E & M powernews

Industrial plants, data centers and electrolysers generate waste heat that often remains unused. A new analysis shows where it is particularly worthwhile and which grids benefit from it.

A new study by the Institute of Energy Economics at the University of Cologne (EWI) shows just how great the untapped potential of industrial and technical waste heat is. It shows the conditions under which its use is economically viable. Continuous sources such as data centers are particularly attractive, as the so-called system value of the waste heat can be higher than the development costs.

The system value describes the potential savings in the overall costs of the heating network if waste heat is used. According to the EWI, this is between 1.9 and 3.3 cents/kWh in new networks and between 3.1 and 4.6 cents/kWh in existing networks. According to the authors, the difference is due to the higher flow temperatures in existing grids, which make the use of large heat pumps more expensive. This increases the value of the waste heat fed into the grid.

The EWI study is based on three typical waste heat profiles: Industry, data center and electrolyzer. The results show: Depending on temperature, distance to the grid and capacity utilization, the economic opportunities differ significantly. The higher the capacity utilization and the shorter the transport routes, the lower the costs per kilowatt hour of waste heat provided.

Data centers with stable temperatures

According to the Cologne analysts, data centers provide a consistent and permanently available heat source. Even if the temperature has to be raised for existing networks, its use often remains economical. Industrial waste heat, on the other hand, is characterized by a high temperature level, but in many cases is irregularly available. This leads to higher costs when using it. Electrolysers, on the other hand, have low temperatures and a fluctuating profile, but can be economically integrated over short distances and in new grids.

Ann-Kathrin Klaas, who worked on the analysis together with Maximilian Walde and Tobias Leibfritz, emphasizes: "The specific system value of waste heat decreases as the share of heat demand increases, as the most expensive generation plants are replaced first." This is why a targeted combination of heat sources is important.

Significance for municipal heat planning

The EWI considers its findings to be particularly relevant for local authorities. The use of waste heat can play an important role in municipal heat planning if the respective characteristics of the sources are systematically analyzed. Industrial waste heat is particularly suitable for decarbonizing existing networks with high flow temperatures. Data centers and electrolysers, on the other hand, could contribute to the supply of new, low-temperature networks.

The study "Waste heat utilization in district heating networks - model-based analysis of the system value of exemplary waste heat profiles" was produced as part of the "Heat transition funding initiative" of the Gesellschaft zur Förderung des Energiewirtschaftlichen Instituts at the University of Cologne.

The study "Waste heat utilization in district heating networks - model-based analysis of the system value of exemplary waste heat profiles" can be downloaded from the EWI website.

Author: Davina Spohn