CGC Mudflat PV Test Report: LONGi BC Modules lead in power generation and temperature performance over TOPCon

A new analysis released by the China General Certification Center (CGC) has confirmed the advantages of LONGi’s Back Contact (BC) modules in one of the toughest solar testing environments in China. Conducted at the Sanmen mudflat PV test base between February and April 2025, the study compared LONGi’s Hi-MO 9, built on HPBC 2.0 technology, with mainstream TOPCon modules.

The results show that LONGi’s BC modules delivered superior outcomes in two critical dimensions: power generation performance and operating temperature.

Testing solar in harsh coastal conditions

Located in Sanmen County, Zhejiang Province, the CGC test base is China’s largest mudflat PV testing facility. It recreates the challenges of marine solar projects, including high humidity, salt mist, unstable muddy foundations, and tidal effects. With around 1,800 sunshine hours per year and temperatures ranging from 5.3°C to 27.9°C, the site provides a demanding real-world scenario for long-term performance and reliability testing.

For the comparison, both LONGi’s Hi-MO 9 (HPBC 2.0) modules and TOPCon modules from a mainstream manufacturer were tested side by side:

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Results: higher output, lower temperatures

Effective utilization hours (power generation performance)

From February 15 to April 30, 2025, LONGi’s Hi-MO 9 modules recorded a cumulative power generation gain of 1.93% per kilowatt compared with TOPCon modules.

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Module operating temperatures

During the same monitoring period, the Hi-MO 9’s average backsheet temperature was 1.26°C lower than the TOPCon reference modules, with the maximum difference reaching 4.13°C.

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Evidence of BC leadership in real-world conditions

This is the first time performance differences between BC and TOPCon technologies have been verified in a mudflat environment, providing strong empirical evidence of the resilience and efficiency of BC architecture. The findings demonstrate that LONGi’s Hi-MO 9 modules not only generate more energy per kilowatt but also operate at lower temperatures - both crucial advantages in harsh coastal and marine applications.

By combining superior energy yield with better thermal management, LONGi’s BC technology offers clear long-term value for PV power stations in challenging environments. The results strengthen the case for BC modules as a preferred solution for coastal and mudflat projects worldwide, where reliability and lifecycle performance directly determine project returns.

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