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 a variety of 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 realization of two different sTES variants. Two demonstrators address one crucial concept of versatile sTES solutions in European’s future energy systems: The combination of several tuneable sTES.Overarching goal is proving the international market potential of novel Reno-sTES and Giga-CTES by demonstration of 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 facilites, 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 application of planned innovation modules for sTES to project’s demo sites, but set a major focus on maximizing 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.

BalticSeaH2 will establish the first, largescale interregional hydrogen valley in Europe. BalticSeaH2 will build a main cross-border Hydrogen Valley between Finland and Estonia and connects it with local valleys in different countries surrounding the Baltic Sea. The ultimate goal is to develop an international hydrogen economy and markets that work optimally both from the technical, economic and environmental perspectives across country borders in the Northern Europe, more specifically around the Baltic Sea. The project will develop, scale and demonstrate hydrogen use in production, storage and distribution, and in Use Cases in different sectors from industry, mobility and energy. The learnings from the cross-border build-up of a hydrogen economy will be shared with specifically identified Connected Valleys and replicated across borders between them, but furthermore, shared to boost replication and initiate new hydrogen valleys across Europe. The cross border Main Valley is to be located in the region of Southern Finland – Estonia. These regions are already connected with a natural gas pipeline, transmission cable and maritime operations and the Transmission System Operators (TSO) in both countries collaborate actively in the further development of the cross border infrastructures. The cross border nature of the Main Valley makes is possible to develop cross border markets and businesses for green hydrogen production, transport and use from the start, including also development of cross border neighbouring pricing zones for renewable electricity to reach optimized system, market and business designs for an efficient hydrogen economy.