Renewable energy refers to energy that is derived from sources that are replenishable, such as geothermal heat, solar, tidal and wind energy. These energy sources are environment-friendly, and can help reduce pollution on a global scale. Renewable and alternative energy are mainly used in electricity power generation, transportation and water heating at present. This book studies, analyses and upholds the pillars of renewable energy and its utmost significance in modern times. It will serve as a valuable source of reference for graduate and post graduate students.