This paper concerns the impacts of the meteorological data, the choice of the load profile, and the time simulation (1 to 11 years) on the energy flows and on the H 2 /O 2 /H 2 O storage sizing in a PV/FC/EL hybrid system (PEPITE project). The simulations were computed with the ORIENTE software. 4 load profiles have been investigated (3 diurnal and 1 nocturnal) with an identical daily consumption (26 kWh).According to load profiles, the gap observed between the most favorable and the most disadvantageous years induces H 2 storage variations rates between 45.5 % and 55.3 %. Furthermore, if we compare the most penalizing meteorological year with the sizing when we simulate several successive years, we also obtain variation rates ranges from 24.4 to 37.9 % for the 3 diurnal profiles. The nocturnal profile presents specific results because it is unsustainable. The main conclusion of this work is the great importance to consider several consecutive years of tilted irradiation data, 7 in our case, to size the H 2 /O 2 /H 2 O storages.