An electricity generating installation includes an electricity generation unit of a gas turbine, steam turbine or combined-cycle type, wherein the electricity generation unit is coupled to a generator and is connected to a distribution network, an energy storage unit configured to store kinetic energy and electrical energy, and a standby electricity generation unit. The installation further includes a controller configured to manage the operation of the energy storage unit and configured to manage the connection of the energy storage unit to the electricity generation unit and to the network. The controller receives a series of information originating from the network, the energy storage unit, the electricity generation unit and a network operator in order to control the generation of electricity to be delivered to the network and to auxiliary systems of the installation from the energy storage unit.