In this paper the effect of considering reliability indices is investigated along with economic factors for design an optimal combination for PFWHS with minimum cost and maximum of responding to load power demand.// To obtain an optimal design using an intelligent algorithm seems more effective according to extent of variables and magnitude of objective function. In this paper PSO algorithm is used for optimization. //Also to investigating the impact of component availability rate on system under study costs and reliability due to failure and repair rate of system components and uncertainty in wind speed and solar irradiance, two scenarios are considered.// In first scenario the availability of all components is considered 1 and in second scenario isn’t considered 1 because of failure and repair rate of components and uncertainty in wind speed and solar irradiance.