Chemical Energy Storage systems, including hydrogen storage and power-to-fuel strategies, enable long-term energy retention and efficient use, while thermal energy storage technologies facilitate waste heat recovery and grid stability. It aims to provide evidence-based s ientific support to the European policymaking process. The storage medium is an energy reservoir that can take the form of chemical, mechanical, or electrical potential energy, with the type of storage medium chosen. Thermal batteries are made with materials that have a high capacity to absorb and store heat, such as graphite, crushed rock, and bricks. These materials are heated to temperatures up to 1800°C using electricity.