The paper is focused on a new solar urban planning approach for building densification and preservation in existing urban areas. Dense urban environments provide a complex settlement, where solar availability and urban daylight can become a scarce commodity, especially since buildings become increasingly taller. This is mainly due to the complex and dynamic
overshadowing effects created on the building envelope. Accurately quantifying these effects could be the key to predicting reductions in solar availability which, in turn, can significantly affect daylight and the thermal performance of buildings, as well as the potential for PVs and other renewables sources. It is therefore necessary to use simulation tools in order to predict the mutual complex effects. In accordance with European building regulations, which are going toward a Net Zero Energy City, this paper presents a new design approach using generative modeling tools and dynamic simulation software in order to develop a sustainable urban planning method.