As the solar industry ushers in the bifacial era, traditional single-sided efficiency can no longer fully evaluate a module’s real value. Investors increasingly focus on comprehensive efficiency and total generation capability, which determine long-term project performance and financial returns.
Here, “comprehensive efficiency” refers not just to front-side conversion efficiency, but to how effectively a module turns available sunlight into electricity under real-world conditions—taking into account factors such as bifaciality, low-irradiance performance, and overall energy yield.
Within this framework, n-type TOPCon stands out with higher bifaciality and superior low-irradiance performance, delivering greater energy yield and project value.
The bifacial era: from efficiency to comprehensive power generation
Since the PV industry entered the bifacial generation era in 2018, the traditional single-sided efficiency metric has become insufficient to scientifically evaluate a module's total generation capability.
By 2023, the global market share for bifacial modules surpassed 50%, fully ushering in the bifacial era. Today, the bifaciality, or rear-side ratio, of leading modules has exceeded 80%. In high albedo environments such as snowfields, the rear-side generation contribution can reach up to 16.55% of total output. Consequently, rear-side gain is no longer treated as an "incremental upside" but is formally embedded into core financial assumptions including P50 and P90 energy yield scenarios.
Regional project conditions further highlight the importance of overall generation capability:
Latin America: High ground albedo in Chile's Atacama Desert (exceeding 30-40%) boosts rear-side gain.
Asia-Pacific: Harsh climates—including high temperature, humidity, and UV exposure—place greater emphasis on stable long-term energy output.
Europe: Lower-irradiance levels make weak-light performance critical for maximizing annual yield.
Middle East: Ultra-low tariffs require projects to maximize generation potential to remain profitable.
These factors are accelerating the shift toward evaluating solar technologies based on comprehensive efficiency and total generation capability, rather than front-side efficiency alone.
Price cannibalization: why generation timing matters
The rapid expansion of solar capacity is reshaping electricity markets, with the price cannibalization effect becoming increasingly evident. Prices often fall sharply—sometimes turning negative—during midday peak generation, while rising during early morning and evening hours.
As a result, the value of solar power is no longer defined by total output alone, but by when electricity is generated. Technologies that can extend the generation window and deliver more output during higher-price periods are becoming critical, placing greater emphasis on low-irradiance performance and broader generation profiles.
Against this backdrop, technologies with superior low-irradiance performance—such as TOPCon—are increasingly critical for capturing higher-value generation.
Low-irradiance performance and high-value generation
TOPCon’s superior low-irradiance response enables a broader daily generation profile, allowing modules to produce more electricity during early morning, late afternoon, and cloudy conditions.
This expanded generation window aligns closely with high-price periods in today’s electricity markets. Compared with TBC modules, TOPCon modules can deliver 6.9–8.4% higher output during early morning and evening hours, when electricity prices are typically elevated.
As a result, TOPCon modules can generate 5–10% more electricity during high-value periods, helping project owners capture greater revenue under market-based power trading mechanisms.
TOPCon’s Bifacial Advantage
Beyond its strong low-irradiance performance, TOPCon also demonstrates clear advantages in bifacial generation, further enhancing overall energy yield.
TOPCon modules typically deliver 10–15% higher bifaciality than TBC technology, enabling them to capture more reflected light from the rear side and convert it into additional electricity output.
This advantage becomes particularly significant in high-albedo environments such as deserts and arid regions, where ground reflectivity can reach 25–30%. Under these conditions, higher bifaciality directly translates into greater total generation, strengthening project performance over the system’s lifetime.
TOPCon’s economic and financial advantages
Building on these advantages in both generation timing and total energy yield, TOPCon modules deliver a compelling economic proposition.
While TBC offers higher theoretical efficiency, its price premium is often difficult to justify under grid-parity conditions. By contrast, TOPCon’s higher power generation—driven by higher bifaciality and superior low-irradiance performance—enables greater exposure to high-value periods. This translates into higher revenue and improved IRR, reinforcing its advantage in market-driven environments.
By combining the dual advantages of higher energy yield and lower initial investment, TOPCon modules achieve an LCOE 1.59%-3.4% lower than that of TBC modules.
From both a performance and cost perspective, TOPCon remains one of the most competitive and scalable technologies for the next 5 years.
