This is a comprehensive overview of the latest advancements and strategies for achieving a sustainable energy future. It offers a multidisciplinary perspective on energy sustainability, integrating research on community-driven energy transitions, digital innovation, automation, and urban climate adaptation. The book examines the role of positive energy districts in facilitating just energy transitions, the realities of energy communities in Austria, and Romania’s ambitious urban decarbonization initiatives in Re?i?a. The book also highlights the transformative potential of digital services in enhancing energy efficiency, the development of automation systems for resource conservation, and the innovative concept of climate fitness for resilient urban environments. Featuring case studies from Europe and beyond, it offers a multidisciplinary perspective on energy sustainability, bridging technological advancements with social, economic, and policy-driven approaches. This is a seminal text for researchers, policymakers, urban planners, and professionals working toward a greener and more equitable future.