Efficiency of Vertically Installed Solar PV Panels

Abstract

Driven by the scarcity of sufficient rooftop areas for PV installation in urban locations, this work assesses the performance and economic considerations of alternative vertical PV installations. A quantitative model-based analysis was conducted to estimate the percentage decrease in output of vertically installed PV modules. The results demonstrate that although vertical installations, driven by a shortage of rooftop space, do indeed result in reduced output, this decrease is deemed acceptable in many scenarios. For installations at high and medium latitude angles above 45°, vertical PV output reaches between 80 to 90% of that at the optimum tilt angle installation, and even surpasses horizontally installed panels for these latitudes. At latitudes between 25° and 45°, the vertical output ranges from 60 to 80% of the optimum, dropping to approximately 50% at latitudes within 20° of the equators. In all cases, the output loss can be easily offset with only a few percent additional cost associated with installing additional PV panels. Additionally, vertical systems collect less dust and require less cleaning. However, the complete system installation costs associated with vertical walls compared to rooftops are subject to specific circumstances and may still impede widespread adoption in some cases. It is expected that these costs will decrease through the implementation of innovations in this area. Examples of such innovations include PV-integrated glass windows and flexible PV panels. In conclusion, vertical wall-installed PV panels can indeed offer a viable alternative to rooftop installation in buildings with limited rooftop space.