A Comparison Study of the Performance of South/North Facing vs East/West-Facing Bifacial Modules under Shading Condition

Horizon obstructions can decrease the diffuse and direct light received by photovoltaic (PV) modules. In this paper, we compare the performances of the two bifacial PV system orientations: Optimally tilted facing south/north (BiS/N), and vertically installed facing east/west (BiE/W) under no-shading and shading conditions. We considered multiple locations with different latitudes and weather types and observed that without any horizon obstructions, BiS/N outperforms BiE/W for most locations. However, certain types of obstructions cause BiE/W to have higher energy yield than BiS/N. For sunnier and lower latitude locations such as Albuquerque, NM, a very large obstruction at south causes this result. On the other hand, for higher latitude locations (e.g. Anchorage, AK), much smaller obstructions at south is enough to have higher energy yield for BiE/W than BiS/N. Under certain shading conditions BiE/W produces up to 75 kWh/year more energy than BiS/N.