Performance Analysis of Bifacial Photovoltaic Modules and Its Practical Implications

One of the key directions in the development of photovoltaic technologies is increasing the electrical energy yield per unit area, in which bifacial photovoltaic modules are playing an increasingly important role. These modules are characterized by their ability to utilize not only the incident radiation on the front side but also the radiation reaching the rear side, primarily originating from reflection from various surfaces. However, the actual performance gain strongly depends on the installation environment, geometric configuration, and surface reflectivity. The aim of the present study was to provide a quantitative evaluation of bifacial module performance under both real and controlled measurement conditions, with particular emphasis on the separate assessment of front- and rear-side irradiance contributions to electrical power output. The measurements were carried out in Hungary, in the town of Keszthely, under natural conditions with natural grass as ground cover, as well as in controlled configurations using full covering of the module. Based on the field measurements, bifacial operation resulted in an average power increase of 8.7% compared to the monofacial reference. Additional investigations revealed that, under controlled conditions, the electrical response of the rear side reached approximately 73% of the front-side power, which is consistent with the bifaciality factor of the investigated module. The results highlight a significant distinction between the intrinsic, module-level physical potential of bifacial technology and the performance gain that can be practically realized under real installation conditions. From a practical perspective, the applicability of bifacial technology is therefore highly site-specific, and its effective utilization can only be achieved through the combined consideration of installation environment and structural parameters, particularly module mounting height, tilt angle, and the availability of sufficient rear-side clearance.