Energy which is obtained from natural resources such as sunlight, waves, tides, rain, biomass and geothermal heat is referred to as renewable energy. These resources are constantly replenished and are carbon neutral in nature. According to their source, renewable energy can be classified into wind energy, solar energy, hydropower, bioenergy and geothermal energy. It is used for various purposes such as electricity generation, transportation and heating. Research in this field involves marine energy, artificial photosynthesis and cellulosic ethanol. Renewable energy resources are considered to be an alternative to conventional fossil fuels. This book includes some of the vital pieces of work being conducted across the world, on various topics related to renewable energy. Also included herein is a detailed explanation of the various concepts and applications of renewable energy sources. As this field is emerging at a rapid pace, the contents of this book will help the readers understand the technological advancements in this field.