It is well known fact the known sources of fossil fuels in the world are depleting very fast and by turn of the century, man will have to increasingly depend upon renewable resources of energy. For developing countries like India, large scale demand of heat energy for meeting day to day domestic, institutional and industrial requirements can be met by utilizing solar thermal systems, biogas, PV Cells, wind energy, Geothermal, MHD etc. i.e. from non-conventional sources of energy. Non-conventional sources of energy is one of the areas of emerging technologies which have higher priority with reference to national needs. Energy needs of a developing country like India is going to increase significantly in foreseeable future, is a well-known fact. Keeping the above consideration in view, a number of universities, colleges and polytechnics are now offering this course for students. The treatment of the book begins with fundamental and develops in a way that allows the practical man as well as the student to expand his knowledge progressively. "This book covers several useful aspects regarding various sources of energy which is emerging as a high priority to national needs. The book is written in seventeen chapters. It deals with the different non-conventional energy systems, the book has been divided into seven units * Solar Energy * Wind Energy * Energy from biomass and biomass * Geothermal energy * Energy from oceans * Chemical energy sources * Additional alternate energy sources and improved energy utilization