Introduction

‍The solar module landscape is evolving rapidly. The industry standard has shifted from Polycrystalline to Monocrystalline PERC (Passivated Emitter and Rear Cell), and now towards Bifacial and TOPCon technologies. For developers and investors, selecting the right technology is a trade-off between higher upfront CAPEX and higher specific yield (kWh/kWp). This white paper provides a comparative technical analysis of these technologies to aid in procurement decisions.

Technical Superiority of Bifacial Modules

‍Bifacial modules generate power from both the front and the rear side, capturing light reflected off the ground (albedo).

• Albedo Gain: Depending on the ground surface (white gravel vs. grass), bifacial modules can provide a 5% to 20% gain in generation compared to monofacial modules.
• Durability: Most bifacial modules use a "glass-glass" structure, which offers better protection against micro-cracking and moisture ingress compared to the traditional glass-backsheet structure.
• LCOE Impact: Although bifacial modules have a higher cost per watt, the increased generation density often results in a lower LCOE, making them the preferred choice for large-scale utility projects.

Emerging Technologies: TOPCon and HJT

‍The roadmap beyond PERC is already visible.

• Tunnel Oxide Passivated Contact (TOPCon): This technology builds on the existing PERC manufacturing lines but offers higher efficiency limits. It minimizes surface recombination losses, pushing cell efficiency toward 25%.
• Heterojunction (HJT): HJT combines crystalline silicon with amorphous silicon thin films. It offers the lowest temperature coefficient in the industry, meaning it performs significantly better in hot climates compared to PERC or TOPCon.
• Degradation Rates: Both TOPCon and HJT offer lower first-year degradation (<1%) compared to PERC (2%), preserving value over the long term.

‍