Transforming urbanized areas quickly and efficiently to make them less polluting and more resilient to global changes (including global warming) requires an integrative and holistic planning approach. This should be based on the concept presented in this article, of Smart Renewable Energy System (SRES), from the municipality to the district and building levels. Several methodological aspects are examined here to help understand the issues involved in energy-climate planning, qualify and validate the data and models used to address them, and choose coherent structures and technologies based on informed democratic social acceptance. The comparison of urban planning methods between two major cities (Strasbourg, France; Aarhus, Denmark) and the SRES simulations applied to a dense territory (Haut-Rhin) presented here are discussed with a view to implementing comprehensive, integrated methodological tools (scalable database, multi-parameter hourly simulations of intersectoral SRES coupling) for urban energy-climate planning.