Sector coupling from district heating with the waste water treatment plant



Presentation and public introduction of the concept for sector coupling of district heating with the sewage treatment plant.

Stadtwerke Gleisdorf, in cooperation with the Gleisdorf Wastewater Association, is building a district heating plant at the wastewater association’s site. Unused heat will be extracted from the treated wastewater and fed into the district heating network of Stadtwerke Gleisdorf. In the future, 4,000 MWh of climate-neutral district heating will be sustainably produced from wastewater and digester gas for the solar city of Gleisdorf. This leads to an annual CO2 saving of around 1,000 tonnes compared to the use of natural gas.

This concept was developed as part of the ThermaFLEX research project, which is led by AEE INTEC and focuses on how district heating networks can be made more flexible and efficient and operate without fossil fuels.

In the new district heating centre, unused heat is extracted from the treated wastewater, which is subsequently discharged into the river Raab, by means of heat exchangers and heat pumps. The digester gas produced in the processes of the sewage treatment plant is also completely converted into thermal energy. The digester gas will thus be used as valuable heat energy in the future and will no longer be flared off unused when there is a surplus (especially in the summer months). The energy produced in this way can then be fed into the district heating network all year round. The heat pump additionally cools the treated wastewater and, from an ecological point of view, improves the quality of the water in the Raab.

Due to the high innovative content of the concept in combination with the ThermaFLEX research project, increased investment subsidies from federal funds will also be made available for the construction of the new district heating centre at the location of the wastewater association. These funds will provide significant support for Stadtwerke Gleisdorf’s investments in climate-friendly heat supply.


Werner Höfler, Christian Fink, Erich Rybar, Peter Schiefer, Christoph Stark,  Raimund Wiesenhofer


A short video including statements (in German) can be seen here.