The book has been written for all those interested about the subject of energy and its related subtopics. Practical examples should provide the reader an easy understanding of sometimes a bit more complex subjects. However, it must be mentioned that the aim of this book is not to cover all scientific details, but it should provide evidence for the way it's done now, the way we'd suggest, and some alternative ways we might be able to do it. In some cases, we use the FERMI approach for easy approximation, and in other cases we use initial conceptual formulas that of course need to be further developed when models need to be fully designed and implemented in new or existing industrial environments. Because of its interdisciplinarity and its easily kept explanatory texts, this book should be used as a key introduction and a reference book for energy policymakers, undergraduate and graduate studies, engineers, as well as casual readers.To facilitate reading and understanding, the book has been divided into four parts: Part a: Energy Strategy ModellingPart b: Guide to Blockchain and Fuzzy logic Part c: Recovering waste energy Part d: Importance to Hydrogen.The difference between the first and second edition is mainly in a larger size of print and in some optimized graphics formatting