A transition from a fossil fuel-based economy to one that uses renewable energy has become inevitable; this transition will not only be an engineering challenge, but will also be an economic and environmental one. Offering an interdisciplinary, quantitative approach, Principles of Sustainable Energy presents a comprehensive overview of the major renewable energy technologies currently available, including biomass and biofuels, solar thermal conversion, photovoltaics, and wind energy conversion. Written by renowned expert Frank Kreith, the book emphasizes economics as well as energy return on investment analyses for each technology and integrates the need for energy conservation with the overall aspects of building a sustainable energy system with renewable sources. The author covers energy storage in depth, as it is considered one of the most important, and problematic, requirements for building a sustainable renewable energy system. Treatments of the economics of nuclear power and options for transportation systems are also included. The book contains worked-out example problems illustrating engineering analyses from a systems perspective and problem sets to reinforce concepts and applications. Examples and exercises relating to solar energy systems cover latitudes in the Northern and Southern Hemispheres and use current worldwide solar radiation data. But this text is not merely academic: its clearheaded look at the energy picture from the ground up, and the environmental, economic, and sustainability benefits that renewable energy systems can provide, make it a resource for government and industry as well as a text for engineering students.