Modelling of Bifacial Gain for Stand-alone and in-field Installed Bifacial PV Modules

Bifacial solar cells enable the absorption of light also by the cell's rear side, hence increasing the energy yield of a bifacial module, Yb compared to the energy yield of a monofacial module installed under the same conditions, Ym, by BG = (Yb - Ym) / Ym, the bifacial gain. This contribution presents a simulation model for the prediction of the BG of bifacial PV modules (stand-alone and integrated in a PV field). The model has been implemented as a software tool and the results obtained by applying the tool to various relevant system configurations (ground albedo, geographical locations, module height and tilt, diffuse irradiation fraction) are shown. These results allow to determine the optimum installation parameters for highest BG for a given installation site. Finally, the tool is validated by comparing the simulated results with the actual BG monitored on bifacial modules during several months on an outdoor testing site.