This paper compares the performance ratio of Photovoltaic (PV) plants using central and distributed inverters. A Single Diode Model is selected to simulate the electric behavior of PV-modules, including the dependences with environmental conditions. With the aim of reducing computational costs and avoiding complex mathematical resolutions, a graphical method is developed by the authors to estimate the power generation under different solar irradiation and temperature conditions. A Spanish PV plant is used to assess the power differences generated by both central and distributed configurations. Results under a variety of situations are also included in the paper.