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 (Bi
_S/N
), and vertically installed facing east/west (Bi
_E/W
) under no-shading and shading conditions. We considered multiple locations with different latitudes and weather types and observed that without any horizon obstructions, Bi
_S/N
outperforms Bi
_E/W
for most locations. However, certain types of obstructions cause Bi
_E/W
to have higher energy yield than Bi
_S/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 Bi
_E/W
than Bi
_S/N
. Under certain shading conditions Bi
_E/W
produces up to 75 kWh/year more energy than Bi
_S/N
.