Renewable energy hybrid power systems have been proven through their ability to address the limitations of single renewable energy system in terms of power efficiency, stability, and reliability while operating at minimum cost. In this regards many research and practical experiences have been done. The present paper reviews the different hybrid PV–Wind renewable energy hybrid systems used for electrical power generations. Different criteria of sizing the different system components of hybrid renewable energy power plant at the most preferable logistical environmental and economical considerations have been discussed. Also, the paper discussed some of the optimization approaches which are used to compare the energy production cost and performance of different hybrid system configurations using simulation techniques. Based on the fact that, potential of the wind and solar energy is not equal in Oman, this paper will discuss the optimum sizing process of two proposed hybrid PV–Wind plants in Oman.