TOPCon modules provide an average power generation gain of 3.15% per-watt over XBC modules, with relative gain of up to 3.4% on a monthly basis, according to a field test conducted in Changzhou, Jiangsu province. The result is compelling evidence of TOPCon modules’ superior power generation capability and of customer value.
The field test was conducted from July 16 to September 10 using Vertex N 600W bifacial dual-glass modules based on TOPCon technology and 620W bifacial dual-glass TBC modules. To ensure accuracy, the test site closely simulated regular installation conditions. It featured a cement ground with about 30% reflectivity, with modules mounted on fixed racking systems with a 23° tilt angle (the optimal tilt for the region) and installed 0.5 meters above the ground. There was no shading on either the front or rear rows, and power generation data was collected using an IV-tracker.
TOPCon modules were proven significantly superior in low-irradiance conditions such as early morning and late evening, after an analysis of power generation data at different times of the day. From 7 am to 8 am TOPCon's power generation per watt was 6.9% higher than that of TBC, and from 5 pm to 7 pm the relative gain was 8.3%-8.4%. This result is in line with earlier field tests showing that TOPCon modules outperform XBC by about 5% in low-irradiance conditions.
TOPCon's higher bifaciality is another key reason for its superior power generation. TOPCon modules demonstrate a 2.6% power generation advantage over TBC modules, even at midday, when sunlight is strongest, which can be attributed to their bifaciality.
The high bifaciality and excellent low-irradiance performance allows TOPCon modules to deliver a 2-3% power generation gain per watt over XBC modules in actual operating conditions. These findings are consistent with results from both the National Photovoltaic and Energy Storage Experimental Platform and National Centre of Inspection on Solar Photovoltaic Products Quality.
According to a field test for 2023 by the National PV and Energy Storage Experimental Platform (Daqing Base) in March, when modules with similar wafer sizes were compared, TOPCon modules outperformed IBC modules by 2.72% in energy yield.
The front-side power generation of half-cut bifacial TOPCon modules was 1.76% higher than that of XBC modules after excluding backside generation data, based on STC front-side power, according to a CPVT field test conducted in Yinchuan, Ningxia Hui autonomous region, from January to July.
TOPCon will continue to predominate over the next five years, being able to further improve efficiency and reduce costs. Efficiency of TOPCon cells can further increase by 1% and power output of TOPCon modules can increase by 30W+. After five years, the n-type TOPCon-based perovskite-silicon tandem solar cell will lead the PV industry towards high-quality development.