Test Result Spotlight
A bifaciality specification is missing on a surprising number of module datasheets, but when it is included, most datasheets state 75 ± 5% for PERC and 80 ± 10% for TOPCon modules. Kiwa PVEL’s measured bifaciality for PERC supports this specification; however, Kiwa PVEL has not measured any TOPCon BOMs with an average bifaciality exceeding the 80% datasheet value, and 29% of TOPCon BOMs had a measured bifaciality less than 75%. While still within the often stated -10% range, differences between the measured and specified values can be meaningful to energy yields. For example, changing from the specified bifaciality of 80% to the measured value of 74% for a recently tested TOPCon BOM resulted in the PVsyst simulated specific energy yield decreasing by 0.8% for a fixed tilt system and 0.5% for a single-axis tracker system in Las Vegas, NV.
