This book is an exploration of the advancements in, and challenges of, creating efficient and flexible smart energy districts. It describes the process of adaption and the challenges faced by the decision makers, and also how simulation, optimisation, ICT approaches and business models are combined in a holistic and pragmatic way. It also offers possible business models and a means to quantify them to complete the development process. This book is suitable for students on muti-disciplinary energy engineering courses, energy practitioners, ICT vendors aiming to develop new services to target the building industry, and decision makers aiming to structure an urban renovation program.