Impact of Environmental Variables on Tilt Selection for Energy Yield Maximization in Bifacial Photovoltaic Modules: Modeling Review and Parametric Analysis

Abstract

Among the different photovoltaic technologies, bifacial photovoltaic modules outperform monofacial ones by being able to harvest the rear incident irradiance. In fact, they achieve higher power output under identical operating conditions. Consequently, the transition from monofacial to bifacial photovoltaic modules is progressing in residential and utility contexts. However, it remains to be fully clarified which installation conditions allow bifacial modules to perform best under different operating conditions. After discussing the different modeling techniques presented in the literature, this paper isolates and evaluates the influence of ground reflectivity, module height, and cloudy weather conditions on the annual incident irradiance and, consequently, the optimal tilt angle of a bifacial photovoltaic module. To focus on the bifacial aspect, each factor is analyzed from the perspectives of the front surface, the back surface, and both. Therefore, different patterns are isolated. The results show that ground reflectivity is key in determining the optimal tilt angle, as it affects the back incident irradiance by up to 431% when compared to a low reflectivity scenario. In contrast, module height and weather conditions do not affect the optimal tilt angle, although they do affect the incident irradiance by up to 5% and 24%, respectively.