About Us

About INTERSTORES project

Future energy systems will integrate diverse, variable renewable energy sources to replace fossil fuels, use sector coupling and waste heat recovery, and interact symbiotically with various users. Seasonal Thermal Energy Storages (sTES) are existential for peak-shaving and load-shifting in these systems and they increase the usability of decentrally generated thermal energy. 

INTERSTORES aims to achieve successful market acceptance, technological attractiveness and competitiveness by improving performance, cost efficiency and increased reliability. By pooling engineering, (hydro-)geological, environmental, and applied disciplines as well as expertise from different sectors, 14 partners from 9 countries will ensure a high exploitability through technology transfer measures. 

For this, INTERSTORES promotes the full-scale realisation of two different sTES variants. Two demonstrators address one crucial concept of versatile sTES solutions in Europe’s future energy systems: The combination of several tuneable sTES.The overarching goal is to prove the international market potential of novel Reno-sTES and Giga-CTES by demonstrating highly favourable techno-economic and environmental performance. 

With the unique opportunity of full-scale demonstration, INTERSTORES’ innovations will close critical gaps for arriving at reliable facilities, robust operational functioning and replicable implementation. The two solutions will reveal crucial differences regarding optimal design, integration potential on different scales, operating conditions, costs, environmental impacts and benefits. 

Finally, INTERSTORES will not only demonstrate the application of planned innovation modules for sTES to the project’s demo sites but also set a major focus on maximising their replication potential. This will be achieved by complementing technological and digital developments at the demos with research on European transfer sites, regional markets and new business opportunities.

Key documents

INTERSTORES objectives

  • Former water basins will be transformed into thermally insulated water-gravel filled sTES, connected to an evolving multi-source/consumer LowEx energy system and equipped with high-resolution monitoring devices;
  • Prototype performance will be validated by resembling the installed Reno-sTES as a digital process twin with the modular representation of ambient ground, storage basins and the local energy system;
  • Robustness and reliability will be achieved by digital analysis of operational conditions, failure potential and stress tests; model-predictive control will be implemented by performance-optimised charging/discharging;
  • Technical performance and robustness will be enhanced by integrating ambient ground as a storage medium and by the installation of a lateral geothermal trench to recycle sTES ground heat loss
  • Excavated rock caverns will be turned into robust CTES by ambient rock mass characterisation, monitoring, tailored cavern rock wall lining;
  • Prototype performance will be validated by resembling the installed Giga-CTES as a digital process twin with the modular representation of ambient ground, storage caverns and regional energy system;
  • Robustness and reliability will be achieved by digital analysis of operational conditions, failure potential and stress tests; model-predictive control will be implemented by performance-optimised charging/discharging;
  • Realisation of Reno-sTES with multiple basins and Giga-CTES with multiple caverns, individually controlled for flexible integration in the energy system; 
  • Representation of different major thermal energy sources (waste incineration plant, solar, industrial waste heat, power-to-heat) on local industrial/office LowEx energy system as well as on regional energy system;
  • Digitally optimised management and control of sources, sTES and consumers by digital process twin with high predictive capability.
  • Holistic assessment of local and global environmental sTES impacts by developing an enhanced life cycle assessment (LCA) framework that accounts for underground space use and local thermal impacts;
  • Life cycle impact assessment (LCIA) that combines different priority criteria such as global warming potential, land/water use, primary energy consumption, etc.;
  • Evaluation of the environmental performance of both sTES variants by comparing (observed, simulated) entire system performance with/without sTES, recycling with non-recycling, and optimisation based on digital twin.
  • Elaboration of ideal application windows for both sTES variants, based on detailed scenario analyses, techno-economic and environmental multi-criteria optimisation, and identification of major design variables and decisive investment/operational cost factors;
  • Development of a planning and operation toolset, by transforming the site-specific digital twin into a streamlined, user-friendly software that is modular and accounts for evolutionary energy systems;
  • Detailed analysis of replication sites and diversity of site requirements to expand market potential; first-tier assessment of sTES replication at identified transfer sites identified and promoted by industrial partners

Interdisciplinarity

AIT, HLU, THI and VTT bring in their competencies in energy system and heat supply network engineering. However, THI specialises in local 5th-generation DH systems (simulation, implementation), whereas VTT is internationally leading in regional energy system simulation. AIT has a major institutional focus on digitisation and control and accordingly is the ideal partner for digital twin development and storage simulation. HLU (CH) has unique competencies in AI- and data-based energy system solutions and offers this as a key competence. WIZ complements the digital competencies of our team by their specialisation in the development of user-friendly and market-ready software in cooperation with research institutes. 

Essential tasks involve applied material research and material selection optimisation covered in the labs by VTT (concrete research and corrosion science) and AIT (thermal engineering). MLU and GTK share common competencies (field/lab/simulation) in geology, geothermal and environmental science, but with different areas that are connected in INTERSTORES: While MLU is focused on (geo)thermal processes in (unconsolidated) sediments (relevant for IN-Campus), GTK is focused on hard rocks and thus complementarily addresses processes in the crystalline rocks of the VECTES site. 

Bringing together energy engineers with geologists is elementary for the (under)ground-based sTES solution of the project. MLU additionally covers environmental assessment as an international leader in LCA involving geological facets.