J
jeremy
6 minutes
Glass-Glass Bifacial Modules: Dropping the Backsheet for Rear Light
A glass-glass bifacial module uses a second sheet of glass in place of the plastic backsheet. Bifacial means the cells collect light on both faces. The rear glass lets light bounced off the ground, a roof or snow reach the back of the cells. Over a bright surface this can add several percent more energy. Glass also blocks water far better than a polymer film. So the encapsulant is often POE, which makes no acid, and the module can last longer. Each glass sheet is often thinner, about 2 mm, but the panel is still heavier. The factory change is simple chemistry: more soda-lime glass, no fluoropolymer film. That removes the PFAS backsheet and its HF risk if the panel burns. The cost is more glass. Glass is melted in gas-fired furnaces near 1500 C, so it adds embodied carbon per panel. A heavier panel also needs stronger mounts. At end of life, two glass sheets glued together are harder to split than glass and plastic. Recyclers must part them to get clean glass and reach the cells inside. After this Concept you can spot a glass-glass module on a data sheet, explain where rear light comes from, and weigh a fluorine-free back against extra glass and weight.