ThermaFLEX - Thermal demand and supply as flexible elements of future sustainable energy systems

More flexibility for more renewables in district heating networks - the lead project "ThermaFLEX".

Starting point

In current discussions about the decarbonization of energy supply, many people are not aware that the demand for indoor climate and hot water accounted for 27% of Austria's total energy demand in e.g. 2019. A quarter of this is provided by heating networks, which means that the local and district heating sector plays a central role in Austria's energy supply.

Its development towards more sustainability will lead to increased system complexity due to:

  • the integration of large shares of renewable, sometimes volatile energy sources,
  • sector coupling with the electricity and gas grids,
  • decentralized energy conversion structures.

At the same time, however, security of supply must be guaranteed and energy costs must remain affordable for end customers. This can only be achieved through increased flexibility of the overall system and intelligent interaction of the elements.

About the ThermaFLEX project

This is exactly what the lead project "ThermaFLEX" is dealing with within the showcase region "Green Energy Lab". No fewer than 27 project partners (district heating network operators, technology providers and research institutions) are working on the identification, simulation-based planning and evaluation of flexibility measures. Concrete implementations are monitored and optimized over the long term. The focus is on seven demonstrators in district heating supply areas of small, medium and large cities.

Our role in the project

BEST - Bioenergy and Sustainable Technologies GmbH is mainly responsible for the optimized operation of the interconnection of several smaller local heating networks in the demo project "100% Renewable District Heating Leibnitz".

The aim is to make optimum use of waste heat from a rendering plant by supplying a neighboring local heating network at times when there is a surplus. If, on the other hand, there is not enough waste heat available, ecological heat from biomass should help to avoid the use of the fossil peak load boiler.

The optimal management of thermal storage in each network requires forecasting methods to estimate the expected heat demand as well as the available waste heat. Optimization algorithms based on these ensure that not too little or unnecessarily much heat is exchanged between the networks and that operation is optimized both ecologically and economically for both operators.


EUR 4,578.347,--

Start of project

2018-11-01 (ongoing)

Supported by


Programm “Vorzeigeregion Energie” als Initiative des Klima- und Energiefonds Österreich und des Bundesministerium für Verkehr, Innovation und Technologie


AEE INTEC (Koordinator)

StadtLABOR Innovationen für urbane Lebensqualität GmbH
Technische Universität Graz - Institut für Wärmetechnik
Stadtwerke Gleisdorf GmbH
S.O.L.I.D. Gesellschaft für Solarinstallation und Design m.b.H.
Technische Universität Wien - Institut für Energiesysteme und Elektrische Antriebe
JOANNEUM RESEARCH Forschungsgesellschaft mbH
AIT Austrian Institute of Technology GmbH
Salzburg AG für Energie, Verkehr und Telekommunikation
Rotreat Abwasserreinigung GmbH
SIR – Salzburger Institut für Raumordnung und Wohnen
Alois Haselbacher Gesellschaft m.b.H.
Energie Steiermark AG
Horn Consult
ENAS Energietechnik und Anlagenbau GmbH
Pink GmbH
GREENoneTEC Solarindustrie GmbH
STM Schweißtechnik Meitz eU
Green Tech Cluster Styria GmbH
FRIGOPOL Kälteanlagen GmbH
Abwasserverband Gleisdorfer Becken
Schneid Gesellschaft m.b.H.
Nahwärme Tillmitsch GmbH & Co KG