A vehicle is supplied by a first electrical energy storage unit on board the vehicle, and a ground electrical network providing an energy supply by application of a supply voltage through electrical distribution. The first energy storage unit is controllable under a generator regime or a receiver regime. The supply voltage is adjusted, in the generator regime, by applying an algebraically additive supply voltage originating from the first electrical storage unit to the distribution, to maintain a supply voltage above a minimum threshold. In the receiver regime, if a surplus of supply voltage originating at least partially from a second storage unit in the generator regime is detected above the minimum threshold, this surplus is channeled energetically to the first energy storage unit of the vehicle if it is required for operating the vehicle and enables maintaining the supply voltage below a maximum threshold and above the minimum threshold.