Fluctuations are induced by the wind power variations at the common coupling point of the hybrid system. The intensity of the resulting perturbations is related to the penetration ratio of the renewable energy. In this paper, wind generator and photovoltaic are combined with the diesel generator to supply energy to the DC-bus. Interactions between these sources are studied before the inserting of the ultracapacitors and lead acid batteries, for power fluctuations mitigation.   To ensure a good life cost and good performance of the system, a method of storage sizing, integrating the devices lifetimes estimation is proposed. This method takes into account the system applications conditions. The experimental test bench is designed in a reduced scale, and some simulations and experimental results are presented and analyzed.