Bifacial Gain
The additional energy a bifacial module produces from light reflected onto its rear face, expressed as a percentage uplift over an equivalent monofacial array.
What decides it
Ground albedo above all — 5-8% over bare earth, 10-15% over light sand or gravel, and above 20% over snow. Mounting height, row spacing and structure shading on the rear face matter nearly as much, which is why bifacial on a close-packed low rooftop rarely delivers what the datasheet implies.
Specify the test conditions
Bifaciality factor (typically 70-80% for n-type cells) tells you how efficiently the rear face converts light. Gain figures quoted without the albedo and mounting height they assume are marketing, not engineering.
Related terms
Where this applies
Utility-Scale Solar EPC, Floating Solar EPC
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