A comprehensive overview of the key renewable energy systems, this book begins with an introduction to renewable energy sources including solar, wind, biomass, hydropower, geothermal, and photovoltaics. It explains the physical concepts and the technological principles of renewable energy. The book also describes opportunities and limitations associated with different types of renewable energy. In addition, the book examines the environmental impact of renewable energy systems. The nano and biotechnology applications in renewable energy development are also described. A key feature of this book is a comprehensive coverage of the commercialization of renewable energies.