The intelligent heat supply of the future 

The intelligent heat supply of the future


Around 5,400 kilometers of heat pipe infrastructure are currently installed in Austria. They lead past sewage treatment plants as well as industrial and commercial enterprises, whose residual and waste heat could be used in many ways, and on their way are open spaces on which solar heating systems and heat storage could be installed. In order to open up such alternative energy sources for heating networks in future, the Climate and Energy Fund, funded by the Federal Ministry of Transport, Innovation and Technology, launched the ThermaFLEX flagship project at the beginning of the year. The goal of the four-year project is to develop strategies for the flexibilisation of heating networks in order to increase the proportion of CO2-free heat.

Innovation Minister Norbert Hofer: “With projects like this one, which is being implemented in the flagship region of the Green Energy Lab, we are taking a forward-looking path towards innovative, secure and affordable energy. Only strong economic and scientific alliances make it possible to successfully pursue this path and thus implement our national climate and energy strategy #mission2030. “

“Heating grids are excellently suited for the integration of renewable energies and waste heat and allow the coupling with other energy sectors or energy infrastructures. In this context, it is important to adjust the differences between generation and consumption through flexible storage capacities and intelligent control strategies, “explains Theresia Vogel, Managing Director of the Climate and Energy Fund.

And this is precisely where ThermaFLEX comes in, led by the Austrian research institute AEE – Institute for Sustainable Technologies (AEE INTEC). Twenty-seven project partners from the energy industry and research as well as technology providers will support the implementation of seven demonstration plants to make district heating networks more flexible over the next four years.

“When setting up the pilot projects, we needed a wide range of different technical measures and heat sources to be able to generate the best possible learning effects for the transfer of insights to other cities,” reports Christian Fink, responsible division manager at AEE INTEC.

Waste heat, sewage, solar heat or biogas as flexible heat sources

One of these projects is the coupling of biogas production in the wastewater treatment plant in Gleisdorf, Styria, with the city’s energy supply. In a first step, the project team optimizes the biogas production in the digester to use the excess biogas for urban energy supply. So it should be burned in a combined heat and power plant to generate energy for the growing heat network of the city. This new heat source, in conjunction with a large-scale heat storage, complements an already decentralized heating plant, which consists of heat generators such as biomass boilers, solar thermal systems and gas peak load boilers as well as water storage tanks. The ThermaFLEX project team will simulate this complex system as a “virtual heating plant” by developing intelligent control strategies.

Another project intends to use additional industrial waste heat in the city of Salzburg. First, the temperature in the return of the heating network Salzburg-Hallein must be lowered. This is done via a thermally driven heat pump in the MW range, which is driven by a combined heat and power plant based on biomass.

“This will provide additional power of 30 MWth based on renewables and waste heat for the Salzburg heating network,” explains Sebastian Schuller, Center Manager Asset Management Generation at Salzburg AG.

In the district of Liesing in Vienna, the residual heat contained in the sewage system is to be tapped. Temperature levels in the wastewater of around 10 to 14 ° C are raised by an electrically driven heat pump to around 70 ° C and fed into the district heating network.

The other four demonstration plants in the ThermaFLEX project all make further important contributions to CO2 freedom in district heating and affect the Styrian district cities Leibnitz and Weiz as well as the cities of Salzburg and Vienna. As an alternative large-scale heat sources industrial heat, heat from heat recovery and solar thermal systems and biomass are to support the heat networks and replace fossil fuels.

Million funding for innovative energy supply

Overall, the Climate and Energy Fund for the research project ThermaFLEX and the demonstration projects provides around 8 million euros in funding, of which about 5 million euros as investment support and almost 3 million euros for the accompanying research. The research partners specifically support the heat network operators in the detailed preparation of the demonstration plants and the systemic integration. Implementation of the first steps are expected at the end of 2019.


Translated by google


Christian Fink
AEE Intec