Understanding smart sustainable buildings nexus to the new smart energy system

Decarbonization, well-being, and high quality of life for citizens are some of the targets of the 17 Sustainable Development Goals of UN Agenda 2030. In this context, smart and sustainable cities should adopt cutting-edge technologies with the least environmental impact and an energy-efficient use for constructing infrastructures. Smart and sustainable buildings that maximize performance and energy use at all stages of the building life cycle are paramount. Smart, sustainable buildings are the key elements of positive energy districts and a smart, resilient, sustainable city. In this paper, after a cross-sectional summary of the European Union documents and legislative measures about building performance, the scenario on the main and appropriate methodological steps for identifying the optimal elements of positive energy districts is underlined.