Fossil fuels-based human activity over time has generated unacceptable local levels of air pollution and GHG emissions. One of main implications of this activity is Climate Change, which unforeseen consequences are already impacting at local and global scales. This research is focused on defining an effective framework to shift that trend in the local level through the implementation of the Smart Zero Carbon City concept, which brings together the emerging Smart City paradigm and the 2030/2050 EU goals with the urgent need of decarbonizing our local environments. In this case, the study applies the Smart Zero Carbon City concept and implementation method into 5 EU cities, focusing on the case of Sonderborg municipality (DK) to extract the Key Factors towards Smart Urban Decarbonization, which are applicable to other cities facing this ambitious transition. Keywords: Decarbonization, Smart Zero Carbon City, Smart Cities, Energy Transition

Targets and goals 3.5 SWEDEN Targets and goals when planning for solar energy in the Swedish cities of Lund and Malmö 54 3.6 SWITZERLAND Comparative performance assessment of parametrically generated variants a master plan of the case studies in Yverdon-les Bains and Lausanne 64 4 Collaborative cross countries case studies 71 Scale and Planning process 4.1 GERMANY-AUSTRIA Challenges for solar energy integration in new urban disctrict developments: Comparative case of Aspern+ Die Seestadt Wiens, Austria and Munchen-Freiham, Germany 72 4.2 FRANCE-ITALY Dual use of land: photovoltaic and food production: Comparative case of Agrovoltaico, Italy and Agrinergie5, Réunion Island 80 4.3 DENMARK-SWEDEN Targets and goals when planning for solar energy in the Swedish cities and Danish cities 87 Legislation and technology 4.4 NORWAY-SWEDEN Solar rights and shading of solar facades: