The inspection data is drawn from more than 80,000 inspections across more than 340 factories globally — revealing that not a single factory worldwide achieved a top-quality grade last year. Indeed, over 70 percent rated C or D.
Not a single factory out of hundreds audited achieved an A+ rating, and over 70 percent landed in the bottom two tiers. This potentially raises concerns about the state of solar manufacturing quality currently, and invites the question whether the industry is getting better or worse.
Industry-wide quality dropped on average over recent years, primarily because financial pressures forced manufacturers to reduce quality assurance and quality control (QA/QC) measurements to cut costs.
Additionally, new technologies and module designs contribute to the low performance of suppliers in Intertek CEA’s Supplier Benchmarking ranking. During the ramp-up phase for new technologies, manufacturers require time to identify and resolve quality issues incrementally.
“Manufacturers cannot fully eliminate this degradation mechanism” said Huatian Xu, Director of Technology and Quality at Clean Energy Associates (CEA). “Precise cell design and strict quality controls mitigate the risk to levels acceptable for warranty coverage, yet the degradation persists gradually during daily operation. Theoretically, the degradation stabilises after three to four years of field operation.”
Quality problems showed up in every geography inspected — China, Vietnam, Malaysia, India, and beyond.
There are several likely reasons why it seems to be so hard for manufacturers to consistently produce high quality solar modules. For one, high-quality manufacturing requires stable markets that avoid monthly policy shifts and aggressive pricing. The industry also needs effective supply-side controls to curb overinvestment in capacity. Currently, excessive capacity drives a "rat race" among manufacturers that undermines quality.
The industry has moved aggressively to Japanese manufacturing company TOPCon, but the company has a UV degradation problem, with 2025 lab testing data showing some suppliers' modules degrading significantly faster than others when exposed to UV light, thereby decreasing module efficiency.
Manufacturers cannot fully eliminate this degradation mechanism. Precise cell design and strict quality controls mitigate the risk to levels acceptable for warranty coverage, yet the degradation persists gradually during daily operation. Theoretically, the degradation stabilises after three to four years of field operation.
Soldering seems to be a double-whammy, with the number of busbars per module increasing while smaller contact areas make soldering more prone to defects.
While higher busbar and ribbon counts increase the frequency of soldering defects, the high-density design provides a higher error-tolerance rate. By incorporating more soldering points, modules can continue producing power even if individual connections fail, which limits the impact of localised errors. However, preserving this safety margin relies on meticulous equipment monitoring and maintenance to prevent systemic failures. Consequently, Intertek CEA designates soldering as the top priority for field-based quality assurance (QA) activities.
New US factories in particular show critical defects at rates that stand out against other manufacturing countries in the dataset.
Over the past nine years, Intertek CEA has conducted more than 80,000 quality inspections in over 340 PV module factories. Its 2025 data reveals rising soldering defect rates and emerging reliability risks as the industry shifts toward n-type products. This report presents the latest defect trends, key risk areas, and supplier performance insights, along with practical steps to reduce quality and long-term reliability risks across the PV supply chain.
“While higher busbar and ribbon counts increase the frequency of soldering defects, the high-density design provides a higher error-tolerance rate” added Mr Xu. “By incorporating more soldering points, modules can continue producing power even if individual connections fail, which limits the impact of localised errors. However, preserving this safety margin relies on meticulous equipment monitoring and maintenance to prevent systemic failures. Consequently, Intertek CEA designates soldering as the top priority for field-based quality assurance (QA) activities.”
Intertek CEA provides quality assurance, supply chain and technical services to the fast-growing solar energy, energy storage and green hydrogen sectors. It is headquartered in the US and has an operational base in China.
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