This book presents a highly accessible introduction to the multi-disciplinary field of renewable energy sources-an area which is becoming increasingly important. It is intended to serve as a textbook for undergraduate electrical and mechanical engineering students, but will also be useful for courses in environmental science. It will help those new to the subject to understand the basic energy conversion processes involved in various renewable energy based equipment, such as solar photovoltaics, solar water heaters, wind turbines, and biomass plants. For each technology, several possible system configurations and their usages are considered. Step-by-step procedures are given to design and cost estimate renewable energy based systems. Numerous end of chapter problems are given to reinforce concepts, and for getting used to system design and system costing procedures. Besides students, this book will also be useful for anyone interested in learning and practising renewable energy technologies.