The generator comprises at least one source of pressurized gas and a closed hydraulic circuit containing a solution comprising an electrically conducting vehicle liquid in which a charge of micro- or nanoparticles of a metal material is dispersed. The circuit has at least one inlet port connected to the source so that, when in operation, it receives a flow of pressurized gas capable of causing circulation of the solution within the circuit in a predetermined direction, forming a two-phase gas-liquid mixture with it, a restriction in cross section, downstream from the inlet port calibrated in such a way as to cause an increase in velocity and condensation of the two-phase mixture, and at least one outlet port, located downstream from the restriction through which the gas mixed with the solution can be released and discharged from the circuit. The generator also comprises magnetic field generating devices, associated with a length of the hydraulic circuit lying between the inlet port and the restriction in cross section in order to generate an induction flux (10) at right angles to the direction of flow of the solution in that length of circuit, and at least one pair of electrodes placed in contact with the solution in that length of the hydraulic circuit, and facing each other in a direction essentially at right angles to the lines of force of the magnetic field and the flow direction of the solution in that length of circuit. The arrangement is such that, when in operation, an electric current whose strength depends on the flow velocity of the solution in that length of the hydraulic circuit, the strength of the associated magnetic field and the electrical resistance between the electrodes flows between the electrodes.