Investigating the Shading Impact of Rail on the Energy Output of a PV System in Hong Kong

Abstract

This paper investigates the shading impact of rail on the power performance of a PV system. In order to find out the reasons of energy loss, an on-site inspection and testing was conducted. The shading and aging problems were found in the process of visual inspection. The shading problem can be further subdivided into edge-shading, pillar-shading and nameplate shading. To further understand and quantify the impact of different types of shadings on the power output performance, the I-V curves of a PV module were tested under different solar radiation. The testing results showed that the impact of different types of shadings on the power performance varied with the Sun position, solar radiation as well as the time. In general, the edgeshading effect reduced the energy output of PV system by 11%-15%, the pillar-shading effect reduced the energy output by 15%-19%, and both effects of edge-shading and pillar-shading reduced the energy output of PV system by 18%-35%. Thus, the main reason that resulted in the energy loss of this PV system was attributed to the shading impact. If the edge-shading and pillar-shading problems are solved, the annual energy output of the PV system could increase about 20%-24%.