Heat from wastewater: Hesse's sewage treatment plants as sustainable energy suppliers!

Heat from wastewater: Hesse's sewage treatment plants as sustainable energy suppliers!

The heat supply in Hesse is facing a radical change uni-kassel.de reported. Heat is currently supplied primarily by fossil fuels such as oil and natural gas. In a recent study carried out by the University of Kassel on behalf of the LEA Hessen, the enormous wastewater heat potential of 187 Hessian sewage treatment plants was examined.

The study shows that around 4,000 GWh of heat could be generated annually from these wastewater treatment plants. This corresponds to around 5-6% of the building-related heat consumption in Hesse. The plan is to feed this heat into existing district heating networks at temperatures of 70-80 °C. The economic efficiency of using wastewater heat varies depending on the location and size of the sewage treatment plant. Wastewater heat is available all year round and usually has temperatures above 10 °C.

Complementary heat sources and the role of the heat atlas

Additional heat sources, such as river heat pumps, solar thermal energy and the recycling of waste, can support and supplement wastewater heat. In order to effectively use this potential, the Hessen Heat Atlas was developed, which not only shows the heat requirements in Hesse, but also locates waste heat sources. The heat atlas is considered an important tool for municipalities to identify suitable areas for heating networks and is viewed as an outstanding example of sustainability through digital solutions, as it received first place in the “Sustainability through digitalization and IT” category in the 2024 eGovernment competition.

Heating networks enable the integration of different energy sources, for example by connecting biomass plants and the local use of regionally generated energy. These networks reduce CO2 emissions and enable efficient central heat supply. Loud lea-hessen.de Heat networks also enable energy to be stored in less complex systems and reduce heat losses compared to decentralized systems.

Sustainable heat supply through new technologies

The heating sector plays a crucial role in the energy transition and the achievement of climate goals, such as this Fraunhofer IFAM clarified. Centralized heat generation is not only more efficient but also more cost-effective, especially in urban areas. The advantages include, for example, avoiding the need for space for boilers in the customer property and the possibility of using large heat pumps to integrate renewable heat sources.

However, there are also challenges, especially in inner-city regions, where lack of space and noise regulations often make it difficult to install new heat sources. Nevertheless, heating networks that consist of large heat generators and storage units offer the opportunity for sector coupling, which can increase the profitability of existing and new heating networks.

Through precise potential analyses, supported by GIS-supported inventory and potential analyses, municipalities can carry out heat planning more effectively and achieve their climate neutrality goals. The future of sustainable heat supply lies in the integrated use of waste heat and renewable heat sources, which could pave the way for a more climate-friendly heat supply in Hesse.