The power generated by a solar photovoltaic panel depends strongly on atmospheric conditions. In fact, a grid connected system requests a good response for variations in the solar irradiance and temperature. Under partially shaded conditions, the PV array characteristics will be more complicated via multiple maxima in the P-V and I-V characteristics. In this paper, a maximum power point tracking algorithm (MPPT) based on genetic algorithm is proposed. The developed algorithm, permit the overcome the common drawback of the conventional MPPT methods. The energy provided by the solar panel under shade is sent to grid by means of a two-stage conversion system, composed of a DC-DC boost converter and a DC-AC inverter. A simulation methodology under Matlab/Simpowersystem, is used to highlight the effectiveness of the proposed method by comparing its performance, under dynamic climate conditions.