two scenarios are considered. As it is clear that considering complete availability of components in first scenario causes better reliability indices compared to second scenario but this is misleading to design the PFWHS, technically and economically. According to obtained results, neglecting the rate of components availability in hybrid power generation systems has unsuitable results on reliability of load supply, so to achieve the actual behavior of PFWHS, the rate of components availability must be considered in suitable insight to designer for reliable and economic designing