An energy storage system is provided with one or more local energy storage systems and a procedure to operate such an energy storage system. The local energy storage systems are connected to a non-local power supply grid and/or one or more local power supply grids each compromising at least one local control unit, which is intended at least for control of the respective energy storage system for localized regulating and system tasks (LRS) for the one or more respective local power supply grids. The energy storage system furthermore comprises a central control unit connected via the communication network to the respective local control units, which is intended for control (SNL) of absorbing (En) and emitting (Ep) energy of the one or more local energy storage systems to the non-local power supply grid, with the central control unit being equipped to dispose of all portions of the local storage capacities (LSKg).