GAP is a software for the analysis and planning of energy power systems for a given territory or at the level of a country. It will make it possible to optimize investments related to energy generation and the development of new power plants and to control the maintenance of networks and the risks of supplying energy on the network following environmental and / or technical hazards. At the heart of the GAP lies a simulation model of generation scenarios, calculating the technical and economic results of different hypotheses of expansion of the generation park. Various scenarios can be studied and compared in order to identify, through these sensitivity studies, the most technically and financially optimized options. The proposed reports thus allow a detailed analysis of the technical and economic results and the follow-up of indicators of strategy development for power generation expansion planning activities.