Thermal energy storage (TES) systems are commonly used in combination with renewable energy sources like solar and wind. They are designed to store thermal energy in the form of heat for later use. The EU-funded HYSTORE project will advance TES technology by combining different innovative components. The project aims to achieve up to 150 % energy density and 50 % lower capital expenditures compared to the state-of-the-art TES systems. HYSTORE also plans to develop a smart aggregator and open-source multi-service platform to optimise the provision of hybrid energy and power services. The project will cover four different use cases in various climates and environments, for district heating/cooling connected and non-connected buildings.