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 and will also be useful for courses in environmental science. The book helps beginners 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. Under each technology, several possi-ble system configurations and their usages are considered. Step-by-step procedures are given to design and cost estimate several renewable energy based systems, designed for the given requirements. Numerous chapter-end problems are given to reinforce concepts, and for getting used to system design and system costing procedures. Besides students, this book will be immensely useful for individuals interested in learning and practising renewable energy technologies