With growing populations across the world consuming Earth's limited oil and natural gas reserves, the environmental and economic toll of energy dependence becomes an increasingly global concern. The development of renewable forms of energy—solar, wind, water, and geothermal, to name a few—offers alternatives to fossil fuels. Consumers are embracing these new modes of energy delivery and use. This extensive volume examines the possibility of a cleaner and more energy efficient future by detailing the historic and emerging technologies behind some the most promising alternative resources.