Energy storage has increasingly come into focus as a key transformational technology in the energy system. This is driven by several factors, including: (1) the increased electrification of the energy system and the associated changes in demand patterns, driven by new loads such as electric vehicles and heat pumps; (2) the decarbonization of the power system and the associated increases in the penetration of variable renewable electricity production, and related security of supply concerns. In this chapter we explore the evolving role of storage in the EU energy system-both at present and in the future. This includes proposed changes in current legislative frameworks to support the diffusion of storage technologies-a key enabler in the EU's transition to a reliable, flexible, and affordable energy system.