Bifacial TOPCon modules cost a little more and give 6–9% more power over a lifetime. Here is when that is worth it.
Panel technology moves fast. Mono PERC was the standard for five years; TOPCon (tunnel-oxide passivated contact) cells are now replacing it across the industry.
Why TOPCon yields more
Lower degradation (about 0.4% a year against 0.55%), a better temperature coefficient for Indian summers, and bifaciality of around 80%, so the rear face collects light reflected off a white terrace.
When PERC still makes sense
On small, tightly budgeted systems where the roof is dark and the panels sit flush, the bifacial gain is small. For those homes, our Surya 3 package uses PERC to keep the cost down.
