The sizing and techno-economical optimization of a stand-alone hybrid photovoltaic/wind system (HPWS) with battery storage is presented in this paper. The main objective of the present study is to find the optimum size of system, able to fulfill the energy requirements of a given load distribution, for three sites located at Corsica island and to analyze the impact of different parameters on the system size. The methodology used provides a useful and simple approach for sizing and analyzing an HPWS. In the proposed stand-alone system, a new concept Such as the supply of wind power via a uninterruptible power supply (UPS) is introduced and therefore the energy produced by the wind generator can be sent directly to the load. In this context, an optimization sizing model is developed. It consists of three submodels; system components submodels, technical submodel based on the loss of power supply probability (LPSP) and the economical submodel based on the levelized cost of energy (LCE). Applying the developed model, a set of configurations meeting the desired LPSP are obtained. The configuration with the lowest LCE gives the optimal one. Analyzing the optimal system configurations used to satisfy the requirements of typical residential home (3 kWh/day), a significant reduction in system size is observed as the available renewable potential increases leading to a considerable decrease in LCE (case of Cape corse site). The 2 days storage capacity is found to be the best for the optimal configuration with the lowest LCE. On the other hand, for low energy requirements, the LCE is found relatively high and decreases sharply with the increase in load. However, for low LPSP values, the LCE is found to rise sharply for a little increase in LPSP. (C) 2007 Elsevier Ltd. All rights reserved.