Since around 2017, the module power measured in the calibration laboratory of the Fraunhofer Institute for Solar Energy Systems ISE has increasingly deviated from the manufacturer’s specifications. This is the result of an analysis by the institute of 1,034 of the more than 70,000 module power measurements taken since 2012.
The analysis shows that the measurement deviations were within the usual range until 2016 and were always below one percent on average. In particular, positive deviations were also frequently measured. In 2016, the difference between the manufacturer’s performance specifications and the performance measured in the Institute’s laboratory averaged 0.6%. “Since then, the data has shown a negative trend,” says Daniel Phillip, Head of the Module Characterization and Reliability department at Fraunhofer ISE. “For the year 2023, this culminated in a negative deviation of around 1.3 percent between the manufacturer’s specification and our verification. A positive deviation was almost never observed.”
© Fraunhofer ISE
Last year, the scientists had already published statistics on declared and laboratory-measured power. At the 40th PV Symposium this week in Bad Staffelstein, they are presenting updated data on power conformity, which now also includes the data collected in 2024. “In 2024, we observe a slight trend reversal, but still strong negative deviations of 1.2 percent on average,” explains Daniel Philipp. This could indicate that manufacturers have recognized the tendency towards “optimistic” performance data as a problem. “If we assume that our data is representative of the German installation market, an average reduction in output of 1.2 percent corresponds to a total output of around 195 megawatts with an expansion of 16.2 gigawatts in 2024.”
© PHOTON
