The book addresses the topic of integrated energy systems and networks by also providing a comprehensive overview of the emerging technologies and systems, through the characterization of paradigm energy shift. It focus on the technologies and systems having a major role in integrated energy systems, by addressing topics such as: renewable energy and distributed energy resources, power conversion technologies including Power-to-Gas (PtG), Power-to-Liquid (PtL), and Power-to-Heat (PtH), the role of hydrogen in low-carbon energy future, storage technologies of different energy carriers, electric mobility, nearly zero-energy and possibly positive-energy buildings, and renewable energy communities.