Efficiency analysis of grid-connected photovoltaic power plants

Analysis of photovoltaic power plant (PVPP) operations is important to both investors and users and to producers of equipment, researchers and designers as well. This paper presents the analysis of the year-long operations of the group PVPPs in Serbia connected to the distribution network which was carried out through specific indicators such as electric power generation, power, capacity factors, specific yield, losses, period of cost effectiveness of the investment, etc. Special attention has been paid to the influence of the azimuth and tilt of the photovoltaic modules on the performances of PVPPs. Results obtained through the year-long extensive measurements were compared to expected yields of PVPPs on the basis of the Climate SAF PVGIS application. The results of the analysis indicate that available software applications cannot always provide a good enough forecast of expected electric power production since they cannot always assess well enough the effects of the surrounding facilities on operations of a PVPP. In addition, it has been found that the correlation between losses of annual achieved specific yield of a PVPP and the azimuth is represented by a polynomial of the second degree, whereas the correlation between losses of the annual achieved specific yield of a PVPP and the tilt is represented by an exponential function.