SOCRATCES (Solar Calcium-looping integration for Thermo-Chemical Energy Storage) was a European research project aimed at developing and demonstrating a novel thermochemical energy storage system based on the Calcium-Looping (CaL) cycle, using solar energy as the primary heat source. The project proposed an innovative solution to store renewable energy in the form of chemical potential, by cycling CaO and CaCO₃ through high-temperature calcination and carbonation reactions. This approach offers high energy density, long-term storage capability, and the potential to support dispatchable solar power generation. SOCRATCES combined concentrated solar power technology with CO₂ management, paving the way for sustainable and flexible integration of renewable energy into the grid. The project included the design, construction, and testing of a pilot plant to validate the concept under real conditions.