The PV plant is monitored to assess the performance of the entire system. A monitoring system is used to monitor the inverters and report performance parameters, system status and weather data to the user locally or remotely. The PV plant is equipped with monitoring equipment. Each inverter in the plant is equipped with a dedicated SMA-COM (SMA datalogger), which is a data logger that continuously collects, stores and uploads all the data from the inverters. The datalogger measures instantaneous current, voltage, frequency, real and reactive power generation and communicates over an IP-based network. The weather station (Sunny Sensorbox) includes an irradiation sensor, an anemometer, an ambient temper- ature sensor as well as a module temperature sensor. This equip- ment is connected to the overall plant monitoring system and the values are stored within the same network. The simplified block diagram of the monitoring system is shown in Fig. 3. The data collected is averaged over 5 min intervals