This research proposes a comparative analysis of a photovoltaic system interconnected to the public distribution network, using PVsyst® software, a program used by engineers for sizing photovoltaic systems. The aim is to analyze the energy generation estimated by the software with the actual project data, i.e. the energy that was actually generated. A comparison is made that highlights the main parameters of the project, such as efficiency, generation and losses. This work is divided into two stages. The first stage involves collecting data on the project site, such as geographical data, irradiance, energy production and information on the equipment used. For the second stage, a simulation is carried out using the PVsyst® program according to the input data.