An electrical energy distribution system for a vessel or platform with at least a primary energy source comprising an AC generator. A first output of the AC generator is coupled to a first DC bus via a transformer and an AC to DC converter and a second output of the AC generator is separately coupled to a second DC bus via a rectifier. The second DC bus is operable at a first voltage level and is connected to one or more primary consumers. The first DC bus is operable at a second voltage level, lower than the first voltage level and is connected to secondary consumers. In the event of the output of the AC generator to the primary consumers on the first DC bus being insufficient, energy from electric energy storage elements is supplied to the primary consumers via the rectifier and the first DC bus.