Wind has been utilized as a source of power for many years. The generation of electrical energy from wind has experienced a remarkable pace in the past decade because of depleting conventional resources and increasing environmental issues. Wind energy conversion has become a reliable and competitive means for electric power generation, thanks to extensive Research and Development efforts in last 30 years. The life span of modern wind turbines is now 20–25 years, which is comparable to many other conventional power generation technologies. The average availability of commercial wind power plants is now around 98%. This paper reviews WECS system covering Aerodynamics, Mechanical and Electrical aspects.