This book highlights recent advancements in such an important topic, through contribution from experts demonstrating different applications in 'day-to-day' life, both existing and newly emerging non-biological technologies, and thought provoking approaches from different parts of the world, potential future prospects associated with some frontier development in non-conventional energy sources. It covers different types of natural energy sources such as: Ocean, Tidal and Wave energy; Nuclear energy; Solar cells; Geothermal energy; Hydrogen Fuel; Photovoltaic modules; Gas hydrates; Hydrate-based Desalination Technology; and Hydrothermal Liquefaction of Kraft Lignin/ Lignocellulosic Biomass to Fuels and Chemicals. This book is a comprehensive and informative compilation for international readers, especially undergraduate and post graduate students and researchers.