Estimation of shading characteristics of PV systems in urban area

摘要

Recently, rooftop and wall-on PV systems installed in the urban area have increased rapidly and these systems are often affected by shadow. It is important to consider the effect of shadowing by surroundings to estimate the energy output of such systems. However, it is difficult to survey obstacles precisely without expert knowledge and its costs are high. In this research, the authors proposed an easy photo survey method by using fisheye (hemispherical) photographs to capture the whole surroundings. Based on the results of the survey, the effect of shadowing and energy output of the systems can be estimated. For a case study of this method, the authors estimated the shading factor and energy output of systems installed soon on Whanchai Tower in Hong Kong. In conclusion, the results showed good possibility that this method can be applied for performance analysis of shading PV systems.