Our society is facing energy challenges as the demand for energy is increasing day by day. The demand for energy in the entire world has reached the level that is difficult to be met by fossil fuels. Presently, fossil fuels are providing more than 85% of the global energy demand. These fossil fuels are limited. Also, it has a significant adverse effect on the environment, for example, acid rain, high ozone concentration, particulate and aerosols that are detrimental to air quality. The limited supply of fossil fuels and its detrimental effect on the environment has led the scientists to search for renewable energy sources. This book on "Renewable energy sources-an application guide" is an effort in the same direction. This book is written by considering Indian climatic conditions and requirements for energy. India is one of the countries with the largest production of energy from renewable sources. In the electricity sector, renewable energy (excluding large hydro) accounted for 20% of the total installed power capacity (71.325 GW) as of 30 June 2018. Large hydro installed capacity was 45.29 GW as of 31 March 2018, contributing to 13% of the total power capacity.