Bifacial Solar Panels in Kerala: Does Double-Sided Generation Work on Tiled & Flat Terraces?

Conventional monofacial solar modules absorb sunlight solely from their front glass surface. The rear of the panel is covered by an opaque white or black polymer Tedlar backsheet that blocks all light.

Bifacial solar panels replace this opaque backsheet with high-transparency tempered glass. Active TOPCon n-type silicon cells inside are engineered with symmetrical front and rear grid fingers. When direct sunlight hits the front, power is produced normally. Simultaneously, ambient diffuse sunlight bouncing off the terrace floor, parapet walls, and surrounding cloud cover hits the underside of the panel, generating continuous secondary current.

This secondary energy gain is known as the "bifacial bifaciality factor", which in modern n-type TOPCon modules ranges from 80% to 85% of front-side efficiency.

Albedo refers to the reflectivity of the surface beneath the solar panels. In Kerala, typical terrace surfaces exhibit varying albedo coefficients that directly dictate the backside generation bonus.

Applying a white weather-coat reflective cooling paint or laying light-colored exterior terrace tiles drastically enhances backside generation, turning your flat roof into an active reflective optical basin.

A common mistake in domestic solar installations is mounting bifacial panels flush or too close to the floor (e.g. 30 cm). Without sufficient clearance, sunlight cannot bounce underneath, resulting in almost zero bifacial gain.

At GSR Energies, our engineering team standardizes custom hot-dip galvanized elevated structures that elevate the bottom edge of the array 1.2 to 1.5 meters above the terrace. This not only allows ample diffuse light reflection from all angles, but also keeps the terrace 100% usable as a shaded living space for washing machines, clotheslines, and rooftop leisure.

In tropical coastal states like Kerala, high relative humidity (often exceeding 85% during monsoon season) combined with airborne salinity poses a long-term threat to traditional polymer backsheets. Over 10–12 years, backsheets can yellow, crack, or suffer from moisture ingress that leads to Potential Induced Degradation (PID) and ground faults.

Bifacial panels feature dual 2.0 mm tempered glass sheets encapsulating the cells front and back. Glass is completely chemically inert, zero-permeability to moisture, and highly scratch-resistant. This dual-glass sandwich provides fire class A rating and allows manufacturers to offer 30-year linear performance warranties with degradation rates as low as 0.4% per year.