In September, the first results of the ThermaFLEX demonstrator “100% renewable district heating Leibnitz” were presented at the Smart Energy Systems Conference 2021 in Copenhagen. The presentation focused on the interconnection of the two district heating networks of Haselbacher Nahwärme and Bioenergie Leibnitzerfeld and the associated intelligent control system for the overall district heating network (energy management system, demand side management). Both measures were implemented in cooperation between the local district heating operators, the control technology companies Schneid and Beck & Partner and the research institutes BEST and AEE INTEC in spring 2021.
The network interconnection via a bidirectional heat transfer station (4 MW) enables the mutual exchange of heat as well as an efficient and resource-saving heat supply with renewable energies, while reducing the use of fossil fuels. Deficits in waste heat supply in the south on weekends and in winter are compensated by the biomass boilers in the north; in summer, individual biomass boilers can be taken out of operation thanks to waste heat from the south.
With the energy management system developed by BEST, which is designed as a model-predictive overall control system, the ecological but also economic potentials of the bi-directional heat transfer station can be fully exploited. In the process, the use of all heat generators in the entire district heating network is optimized. Initial evaluations showed a potential saving of around 9% in operating costs and around 45% in CO2 emissions for the overall system. The first test operation phases have been completed, and now the continuous operation is to be evaluated.
The demand side management system implemented by Schneid and Beck & Partner enables the consumer substations to be operated in favor of the district heating network. In this way, heat supply is throttled during peak load periods without loss of comfort, and heat consumption is forced during off-peak periods in order to adapt demand to production capacities in the best possible way. Thus, a peak load reduction of the overall demand of about 5 to 10 % can be expected.
The presentation on “Interconnection and smart control of district heating networks for increased flexibility” is available for review via the following link: