The search for the optimal configuration of HRES is vital to avoid over costing or under-sizing of the system components. The sizing HRES is a challenging task as the system needs to cater to ever-changing load demand. This is, in addition, to continuously varying solar radiation and wind speed. This is further complicated by the fact that power production from renewable conversion devices is not necessarily linearly proportional to the input parameters. For E.g. double wind speed does not result in double power output of wind turbines. These aspects in addition to the need to look into multiple assessment criteria make HRES sizing problem task worthy to deal with.