Performance of a 1.2 kWp stand-alone photovoltaic system in Malta

Abstract

The paper presents the results of the performance of a 1.2 kWp stand-alone photovoltaic (PV) system under local conditions, during two years of operation. The sizing and construction of the system were described elsewhere. This is the first PV system to be tested locally. Monitoring and analysis of data as well as presentation of results were performed in accordance with the guidelines set by the Joint Research Centre - Ispra Establishment. The mean daily PV energy production was 3.034 kWh/kWp/day and the mean final yield was 1.89 kWh/kWp/day, with a performance ratio of 0.37. Empirical equations relating the power produced to solar radiation are presented for future use. The accumulation of dust on the PV modules during summer did not contribute to more than 2% drop in power production while wind speeds higher than 2 m/s had a cooling effect on the PV modules. The major causes for drop in efficiency were shading and the deviation of the performance from the maximum power curve, caused by the accumulation of electric charge in the storage batteries.