Hybrid fuels are considered as alternate options to replace fossil fuels because they have low carbon emission. They are evolving as alternative energy resources with least negative consequences. In recent years, this field has undergone extensive research and emerged as a field of great interest and importance. The book emphasizes on alternative energy services, energy efficiency and power engineering. It also deals with the various aspects and applications of energy resources, renewable energy and energy storage. The book elucidates the significant concepts and techniques of various related fields. Students and academicians related to this field will find this book helpful.