Thermal energy storage (TES) makes it possible to store energy for use days or months later. TES technology stocks thermal energy by heating or cooling a storage medium. The EU funded THUMBS UP project will develop and demonstrate daily and weekly TES for EU buildings. By innovating at different levels, from modelling to materials and enhancing heat exchanger solutions, the project will design high-performance TES solutions in line with EU sustainable economy goals. Specifically, it will create bio-based phase change materials from raw materials currently wasted in the EU food industry and thermochemical materials relying on non-hazardous materials. The project will set up three demo sites in Spain and Sweden – in different EU climates and energy market contexts.