giga_TES – Giga-scale thermal energy storage for renewable districts

Project manager overall project: AEE INTEC

Project leader University of Innsbruck: Fabian Ochs (UIBK - Energy Efficient Building)

Project team: Abdulrahman Dahash, Alice Tosatto, Michele Bianchi Janetti

 Project partner:

  • SOLID Solar Energy Systems GmbH (Austria)
  • Ingenieurbüro ste.p ZT GmbH (Austria)
  • Institute of Polymer Materials and Testing - Johannes Kepler Universität Linz (Austria)
  • Bilfinger VAM Anlagentechnik GmbH (Austria)
  • Wien Energie GmbH (Austria)
  • GVT Verfahrenstechnik GmbH (Austria)
  • Geologie und Grundwasser GmbH (Austria)
  • Salzburg AG für Energie, Verkehr und Telekommunikation (Austria)
  • PORR Bau GmbH (Austria)
  • Gabriel-Chemie Gesellschaft m.b.H. (Austria)
  • PlanEnergi (Denmark)
  • agru Kunststofftechnik Gesellschaft m.b.H. (Austria)
  • SOLITES - Steinbeis Forschungsinstitut für solare und zukunftsfähige thermische Energiesysteme (Germany)
  • Metawell GmbH (Germany)
  • Smart Minerals GmbH (Austria)

Funding body: (FFG, Energieforschung, flagship)

Duration: 01/01/2018 – 30/06/2021

Project website:

Funding: € 4.4 mio


To reach 100% renewable energy supply in the long term large-scale thermal storages like pit storages or large tank storages are necessary for district heating systems. As the systems are going to be installed in urban areas the required surface should be minimized because of relatively high land costs in cities. Through installing the storages subsurface it is possible to use the surface for recreation or installation of solar collector fields and therefore minimizing of costs is reached. District heating systems require thermal energy storage volumes from 50 000 m³ to 1 M m3 corresponding to 1 bn. litres. Currently large thermal energy storages are run in Germany and mainly in Denmark, storage volumes installed lately reaching nearly 200 000 m³.

Because of the low number and the few years existing large-scale thermal storages have been in operation so far experiences with these storages for district heating systems are still limited. Improvements especially in respect to performance and durability are necessary. Cost efficiency and system integration require higher storage densities and therefore higher temperatures leading to even higher requirements in respect to the applied materials. Vapour tightness, serviceability and durability of innovative solutions for cover, walls and liners require novel materials and components as well as improved test methods. Additionally innovative construction methods are needed because of the targeted storage size and its subsurface construction. Therefore the project is structured according to the following R&D areas: Development of Components and Technologies, Materials Development and Testing, Computer Aided Storage Optimisation, System Integration and Storage Management.

Expected results from giga_TES:

  1. Comprehensive overview of requirements and challenges for application and installation of giga-scale heat storages and development of a scientific decision tool for representative future application scenarios internationally and for Austria.
  2. Development of innovative and optimal construction methods for giga-scale heat storages with particular regard to ground conditions. Based on five typical ground and rock profiles various ground-mechanical approaches addressing deep pit excavations are going to be assessed and the respective potentials outlined.
  3. Elaboration of economically viable solutions for critical storage components such as base plate, liner and cover.
  4. Development of novel polymeric and anorganic materials for the construction of large-scale heat storages as well as development of tests and methods for lifetime assessment to make accelerated and more realistic pre-selection of such materials.
  5. Development of simulation models considering different modelling depths, validation and application of the models for optimising the construction in respect to relevant boundary conditions. Additionally a methodology predicting the ground and ground water temperature increase depending on specific geologic and hydrogeologic conditions and the storage construction is going to be developed. Furthermore a co-simulation platform for optimising the system configuration and control strategy is going to be established.
  6. Assessment of the additional benefit and importance of large-scale storages in respect to existing and future district heating networks, analysing sensitivities and correlation of system parameters regarding relevant boundary conditions and with special focus on Austrian boundary conditions.

Research focus of the University of Innsbruck:

In order to assess and optimize large-scale underground thermal energy storage (TES) on district heating system level detailed dynamic models are required. TES component (e.g. hygrothermal model), TES stand-alone and TES models for system integration are developed and tested in WP 5 (led by UIBK) considering boundary conditions and the impact on e.g. ground water temperature.

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