Energy storage solutions for grid applications are becoming more common among grid owners, system operators and end-users. Storage systems are enablers of several possibilities and may provide effici. ••Service stacking is a promising method to improve energy storage. BESSbattery energy storage systemCAEScompressed air energy storageDSO. Current global climate policies have initiated an energy system revolution aiming for sustainable and environmentally adapted solutions. To reach the defined targets by the Pa. Energy storage is an enabler of several possibilities within the electric power sector, and the European Commission has proposed a definition of energy storage in the electric syste. In this section, the function and properties of available services and applications will be presented. To be able to categorize and compare different applications and services, the defi.