Simulation of Energy Production by Bifacial Modules with Revision of Ground Reflection

Bifacial solar modules are becoming increasingly more attractive stimulated by the development of new solar cell structures enabling to capture solar insolation on both front and rear surfaces. The possibilities to be installed in the conventional south facing orientation or even vertically are further advantages. Although the potential of bifacial modules have been already shown in specific time intervals and for various ground albedos there is a lack in simulation studies up to now. In this study, we simulated the annual energy yield (AEY) of south facing bifacial modules using a rigorous calculation method of the ground reflected radiation reaching the rear module surface. The necessary tilt angle optimization is done incorporating the influence of module elevation and considering the inherent albedo coefficient. These simulations are able to reproduce measurement observations and show that at optimum tilt angles produced annual energy can be increased by 30% compared to a standard module simply by positioning modules two meters above ground instead of a close to ground installation. Furthermore, a linear relationship between albedo coefficient and AEY is demonstrated.