The objective of this work is to establish a comparison of electric power generation with solar modules oriented to the north and south façades. The photovoltaic plant, object of this study, is installed on the roof of the Cardeal Leme building, at PUC-Rio. In order to base this work, the data of the project of each one of the elements of the plant, as well as of the geographical aspects of the place were surveyed. With this information, a simulation was performed in the PVSyst software, as well as local measurements of the inputs and outputs of the solar photovoltaic power plant, in order to draw the comparisons between the two orientations. The modules that were directed to the North obtained a generation of average energy 67.81 percent higher than to the South, while in the simulation this percentage was 56.12 percent. Therefore, it has been shown that orientate the solar modules to the North, makes the photovoltaic system much more efficient and optimized.