Recent operational data from a rooftop demonstration PV plant at a residential complex in Qinghai, China, reveals that BC (Back Contact) modules delivered 3.16% higher power generation than TOPCon modules, further validating BC technology’s superior performance.

The fixed-tilt (10° inclination) solar test site in Xining, Qinghai Province — situated at 2,327m altitude with 2,500 annual sunshine hours in a semi-arid plateau climate — conducted a comparative study between LONGi’s HPBC 2.0 Hi-MO 9 modules (650W power, 11.7kW system capacity, 2382×1134mm) and TOPCon modules (610W power, 49.8kW system capacity, identical dimensions), revealing critical insights into high-altitude photovoltaic performance.

1. Monthly Generation Comparison

A string-level comparison normalized to per-kilowatt output showed BC modules generated 288.21 kWh/kW in April, outperforming TOPCon’s 279.95 kWh/kW by 2.95%.

2. Weather-Specific Performance

Overcast Conditions (April 14): BC modules achieved 3.16% higher per-kilowatt output than TOPCon, with data analysis (5-minute interval monitoring) demonstrating BC’s superior weak-light response. BC systems initiated power generation earlier and maintained higher output during low-irradiance morning hours.

Sunny Conditions (April 12): BC maintained a 2.82% generation advantage under full sunlight, again exhibiting earlier morning startup than TOPCon.

LONGi’s HPBC 2.0 technology integrates proprietary TaiRay silicon wafers with advanced dual-polar composite passivation technology. Its front grid line-free design enables breakthrough improvements in light absorption and power generation efficiency, delivering distinct performance advantages over TOPCon.