Gilles Desthieux, Associate Professor at the Geneva Institute of Landscape, Engineering and Architecture and a Consultant in Urban Energy Planning with Amstein+Walthert Geneva, leads a team of researchers who have developed the Geneva Solar Cadaster, a tool for modelling solar radiation and energy production from building rooftops and facades. Recent urban studies have shown that our cities play a significant role in environmental issues and, in particular, energy transition. One of the targets of the EU 2030 Framework for climate and energy is to reach a minimum of 27% renewable energy consumption and reduce carbon emission. In order to achieve this target, cities will have to accurately evaluate their renewable energy sources.