What is a Bifacial Module?

A bifacial solar module has active solar cells on both its front and rear surfaces. The rear side captures albedo light — sunlight reflected off the ground, rooftop, or nearby surfaces — adding to total generation.

Bifacial gain

The additional rear-side energy (Bifacial Gain, BG) depends on:

• Ground albedo: 0.15–0.25 for dark soil; 0.5–0.9 for white gravel or snow
• Mounting height: Higher clearance → more uniform rear irradiance
• Row spacing: Wider pitch reduces rear self-shading

Typical BG in India ground-mount: 8–18%. Single-axis tracker + white gravel: 15–25%.

Module construction

Bifacial modules use dual-glass (glass-glass) or glass-transparent backsheet laminate. Glass-glass modules have better durability and are preferred for utility projects.

ALMM and bifacial

MNRE's ALMM testing (aligned with IEC 61215-2:2021 bifacial addendum) requires manufacturers to declare both front Pmax and Bifaciality Factor (typically 0.70–0.85).