Several activities ranging from subsurface data analysis, new data acquisition, database infrastructure design and policy making are ongoing in support of the large geothermal exploration effort in the framework of the ‘GEothermie 2020' program in south-western Switzerland (Canton of Geneva). The step-wise approach strategy defined by the main project stakeholders aims at acquiring knowledge of the underground geothermal potential while ensuring continue support form public and political parties. The subsurface characterisation study carried out to date mostly by the University of Geneva is delivering encouraging results in support of future identification of drilling locations based on a detailed multidisciplinary study of the entire stratigraphic succession of the Geneva Basin underground. These will allow to meet both exploration requirements (i.e. reduce subsurface uncertainties) while responding to energy policy targets (increase use of sustainable energy source and increase energy efficiency).