Bifacial solar panel

How it works

A bifacial panel is built like a conventional PV module, but the cells are sandwiched between two transparent layers of glass. Light that strikes the front side creates the usual electric current. Any light that reaches the rear—whether it is reflected off the ground, a roof, or a nearby surface—passes through the glass and also excites the cells, adding extra power.

Front and rear cells

• The same silicon (or other semiconductor) cells are used on both sides.
• The rear side is usually covered with a low‑iron, anti‑reflective glass to let as much light through as possible.

Role of albedo

Albedo is the reflectivity of the surface beneath the panel. Light‑colored sand, concrete, or white rooftops can reflect 30‑80 % of sunlight back to the panel’s rear, while dark soil reflects only 5‑10 %.

Why it matters

• Higher energy yield: In typical installations, bifacial modules deliver 10‑20 % more electricity than monofacial ones; in high‑albedo settings the gain can reach 30 %.
• Lower levelized cost of electricity (LCOE): More energy from the same roof area means fewer panels and less balance‑of‑system cost per kilowatt‑hour.
• Design flexibility: They can be mounted vertically on façades or on tracking systems that tilt the panel to expose both sides to the sun throughout the day.

Concrete example

A 350 W monofacial panel produces about 350 W under standard test conditions. A comparable bifacial panel on a white‑sand surface in Israel might deliver 420 W (≈20 % gain) at the same irradiance, translating to roughly 1,800 kWh extra per year for a 10 kW array.

Relevance to Israel

Israel enjoys high solar irradiance (≈5.5–6 kWh/m²/day) and many installations are on light‑colored desert sand or concrete rooftops, both of which have high albedo. Using bifacial modules on ground‑mount or elevated tracker systems can therefore capture additional reflected light, boosting overall farm output without expanding land use.

Installation considerations

• Mounting height: Raising the panel 0.5–1 m above the ground maximizes rear‑side exposure.
• Cleaning: The rear side can accumulate dust; regular cleaning maintains the gain.
• Cost: Bifacial panels are typically 5‑10 % more expensive upfront, but the higher energy yield usually pays back the difference within 5–7 years.

In summary, bifacial solar panels turn otherwise wasted reflected light into usable electricity, offering a practical way to increase solar farm efficiency—especially in bright, high‑albedo environments like Israel.