How is the future world energy demand to be met? The rates of use of the fossil fuels — coal, oil and natural gas — are increasing all over the world. The remaining stocks are finite and are not renewable. This book considers the various options of renewable energy, including water energy, wind energy and biomass, solar thermal and solar photovoltaic energy. And should the nuclear option remain open? The work also examines the environmental implications and economic viability of all fossil and renewable sources, introduces more distant future options of geothermal energy and nuclear fusion, and discusses a near-future energy strategy.