Warning! PV module power has not met standards for years, and TOPCon degradation is obvious

New research from German research institute Fraunhofer ISE finds that in 2024, the measured power of monocrystalline silicon PV panels was 1.2% lower than their rated capacity.

While this is a slight improvement from the 1.3% difference reported in 2023, it marks the eighth consecutive year that the average power of panels has been lower than the manufacturer's nominal capacity.

Since 2012, Fraunhofer has tested 70,000 panels from 15 top manufacturers in its labs, but the testing organization notes that its dataset does not include solar panels where the lab power matches the product's nameplate capacity.

Since 2012, average output power has largely fluctuated between 1% higher and 1% lower than nameplate capacity, as shown in the figure below. Although the 1.3% deviation reported in 2023 is the lowest value ever recorded for actual power output, the Fraunhofer Institute notes that the slight improvement in 2024 suggests that manufacturers may be aware of the problem.

Daniel Phillip, head of Fraunhofer's module characterization and reliability department, said: "Assuming the data is representative of the German installation market, a 1.2% drop in module performance for 16.2GW of new capacity in 2024 would equate to a total reduction of about 195MW of power generation." He added that the gap is equivalent to the rated power generation of "one of the largest solar parks in Germany." While the researchers did not propose a reason for the actual power drop, the study follows a series of investigations into solar module efficiency and reliability as solar projects make up a growing share of the global energy mix. A study published by the Fraunhofer institute last year pointed to "significant degradation" problems with TOPCon modules, while Kiwa PI Berlin said earlier this year that modules produced in the United States, India and Laos were most likely to be defective, suggesting that poor module performance is both technically and regionally influenced.