Energy is one of the most important factor for the growth and development of any nation. Actually it is the basic need for human beings i.e., without energy, one can't think about better living. Now-a-days coal, oil and gas are being used as energy sources but due to the increased demand, it is being expected that these resources will loose their existance in near future. In this context, the need for the alternative sources of energy arises so as to meet out the energy needs. These alternative sources may also be knows as "Non-Conventional or Renewable Energy Sources". The present textbook deals with all these renewable energy sources of future. The Book has been divided into nine chapters.