A wireless energy transfer system and an associated method for feeding an electric load are provided. The system includes a transmitter which includes a generator adapted to generate a radiofrequency signal at a first frequency and a first resonant circuit adapted to transmit the radiofrequency signal; and a receiver adapted to receive the radiofrequency signal and comprising a second resonant circuit. The second resonant circuit is adapted to be located in the non-radiative near field generated by the first resonant circuit, and the transmitter includes frequency sweeping functionality, which imposes on the radiofrequency signal generator a cyclic excursion of the first frequency in the neighborhood of a nominal frequency of the generator so that, when the first frequency matches the resonant frequency of the second resonant circuit, a non-radiative energy transfer occurs.