Pigeon Presence on PV Modules ARE Largely Random Events

Abstract

The presence of pigeons on PV modules can negatively affect the output power of a solar renewable energy system. The body of the pigeon itself (and especially the tail) may cause short periods of shading of individual cells, leading to the formation of hotspots. Bird excreta left by the pigeon may cause longer periods of shading, leading to an extended reduction in output power. Some type of intervention may be required to repel pigeons from PV modules, in order to try and maintain the overall efficiency and sustainability of a system. The purpose of this paper is to evaluate the reduction in output power of a pico-solar system in order to determine if a possible pattern, or routine, exists with regard to the presence of pigeons. A 10 W pico-solar system was installed in a semi-arid region of South Africa that is home to the feral pigeon (Columba livia). A pigeon detection technique was developed and applied over a period of 13 months to determine when and for how long these pigeons rest on top of a PV module (these are referred to as events). Although these events are primarily random in nature, results do indicate that feral pigeon presence is lowest on a Wednesday during the week and in the summer periods of January to March during a calendar year. They tend to spend, on average, 118 seconds perched on top a PV module, where their tail and droppings cause the most significant impact in terms of interrupting the direct beam radiation from the sun for an individual cell. It is recommended to use these results in formulating an appropriate intervention that may be used as a scare tactic to repel feral pigeons away from PV modules.