The overarching objective of SMHYLES project is to design and demonstrate, at a relevant industrial scale, safe and sustainable HESS based on the smart combination of low-CRM and aqueous ESS (batteries and supercapacitors) capable of medium-to-long duration energy storage and provision of multiple services. The project will mainly deal with 1) the design of innovative storage components of the two different HESS, i.e., modular VRFB, aqueous hybrid supercapacitor module and smart ZEBRA battery, 2) their optimal integration and management into a HESS supported by digital tools and 3) the demonstration of HESS usage in three different demo sites.