multiTESS Plant in Jülich

The storage of high-temperature heat with subsequent conversion to electricity in steam power processes is known from solar thermal power plants. In these applications, the high-temperature heat is collected by concentrating solar collectors. The idea with thermal electricity storage is to load the storage unit using a power-to-heat concept from surplus electricity from the grid instead of solar energy. The multiTESS (multifunctionalthermalelectricity storage) storage concept is being developed by the Solar Institute Jülich for a decentralised and flexible electricityand heat supply. In contrast to the conventional power-to-heat approach, the heat in the thermal electricity storage system of multiTESS is stored as high-temperature heat at up to 1000 °C and can thus be partially converted back into electricity in a thermal power process. The multifunctionality of multiTESS is based on the flexible choice of heat source and sink (cf. Figure 1). Electric heating or waste heat can be used as heat sources. In addition to electricity, heat can also be provided at different temperature levels during storage.

In the TESS 2.0 project, the utilisation chain Power-to-Power&Heat of the multiTESS concept is mapped for the first time in the form of a pilot plant. The project, which is funded by the BMWi, benefits from the expertise of the industrial partners Dürr Systems AG, Kraftanlagen Energies & Services and Otto Junker GmbH. The focus is on the generation and process control of 1000 °C hot air, the storage of the high-temperature heat, as well as the integration of reverse power generation and heat extraction. For the generation of the high-temperature heat, the project partner Otto Junker GmbH has developed an innovative heating concept (state of the art: 750 °C). The conceptual design and the construction of the ceramic storage tank, which is also new, were carried out by Dürr System AG. In addition, Dürr Systems AG contributed a CHP-capable high-temperature ORC module, which can release condensation heat from the thermodynamic process at a level of up to 95 °C. The detailed planning of the plant concept was largely realised by Kraftanlagen Energies & Services. The Solar Institute Jülich is the idea generator and initiator of the project, acts as project coordinator, provides support in the concept planning and carries out the scientific tests after completion of the enclosure.

During the tests, the operating behaviour of the individual components is to be investigated and their process control optimised in the overall system. The aim of the project is to realise an innovative and primary energy-saving overall system from the combination of the individual components.