The system allows the generation and distribution of energy on board a motor vehicle provided with a propulsion unit, a tank for fuel at least one distribution network or line for electric energy, electrical energy generation devices connected to the at least one distribution network or line, and a plurality of selectively activatable electrical utiliser devices or apparatus connected or connectable to the at least one distribution network or line. The electrical energy generator devices includes (at least) a microcombustor electricity generator matrix or battery connected to the fuel tank, and a supervision and control unit associated with this generator matrix or battery and coupled to the distribution network or line and arranged to control the operation of the said generator matrix or battery in a predetermined manner as a function of the electrical power required or consumed by the said network or line.