Understanding and Benchmarking Ground Reflectors for Bifacial Photovoltaic Yield Enhancement

Abstract

Bifacial modules combined with optimally positioned ground reflectors (albedo) can boost photovoltaic (PV) yield. Yet, a rigorous understanding and benchmarking of the reflector performance is missing, which leads to errors in power yield and economic estimates, thus hampering PV market penetration. Here, we address this impediment by establishing an experimentally validated reverse ray tracing (RRT) approach, combined with empirically derived parameters. First, we determine the spectro-angular reflection of a wide class of ground reflectors (diffuse, glossy, and specular). These parameters were fed into our RRT software, that simulated the PV yield, which was then experimentally validated with a model PV system. The validated framework enables determining an upper limit to PV yield enhancement and current mismatch within modules exposed to different kinds of reflectors. Our approach helps assessing already-existing natural and exotic reflectors, and inspire novel reflectors for enhanced PV yield and economic benefits.

Spectro-angular analysis of roadside-integrated bifacial solar power systems with reflecting sound barriers

“…In contrast, diffuse reflectors, or Lambertian surfaces, scatter light uniformly across a range of angles, lacking a pronounced peak in their reflection lobe. More information on different types of reflectors and their influence on bifacial solar cell output can be found in [13]. This paper uses ideal specular, diffuse, and black wall reflectors.…”

“…Finally, we did not include mismatch losses that result from uneven illumination of the modules. Our software can give us information on the distribution of the illumination and in a previous study, we have seen, that the mismatch is particularly pronounced when introducing specular reflectors [13]. Here, we assumed that all photons reaching the module contribute to the yield independent of the homogeneity of the illumination.…”

“…Furthermore, recent literature is beginning to provide comprehensive and realistic evaluations of energy yield and optimization strategies for PV installations under real irradiance conditions. The work of Pal et al develops optimization and enhancement strategies for PV installations exploring the use of bifacial modules and reflectors to enhance energy capture while using spectro-angular irradiance [9][10][11][12][13]. Huyeng et al [14] conducted a comparative analysis exploring various technical aspects of road-integrated PV systems, providing insights into the effectiveness of different configurations and their yields.…”