The prospect of producing clean, sustainable power in substantial quantities from renewable energy sources is arousing interest world-wide. This book provides a comprehensive overview of the principal renewable energy sources; solar thermal, biomass, tidal, wave, photovoltaic, hydro, wind, geothermal. With the aid of 370 detailed illustrations and 50 tables of data, it explains the physical and technological principles underlying each source and examines its environmental impact and future prospects.