Solar module performance claims often exceed lab measurements

A analysis crew from the Fraunhofer Institute for Photo voltaic Power Techniques ISE has evaluated over 70,000 energy measurements on photovoltaic modules which have been carried out within the institute’s calibration laboratory, CalLab PV Modules, since 2012.

Within the course of, the researchers discovered that since round 2017, the unfavourable discrepancy between the efficiency knowledge of the PV module producers and the analysis institute’s measurement outcomes has been rising. Till 2016, extra energy was measured within the laboratory on common than was promised by the producer.

Since then, a unfavourable pattern has emerged, notably within the years 2020 to 2023, resulting in a mean energy discount of about 1.3%. The newest knowledge from 2024 present a slight turnaround.

The CalLab PV Modules on the Fraunhofer ISE has been testing greater than 70,000 photo voltaic modules since 2012. For a complete evaluate of efficiency conformity, analysis scientists on the institute drew on this intensive knowledge set and analyzed 1,034 of the collected efficiency measurements taken from monocrystalline silicon PV modules below standardized situations.

The evaluation of the ability measurements of PV modules confirmed that from 2012 to 2016, measurement deviations existed throughout the standard part; the distinction was at all times lower than 1% on common. Specifically, optimistic deviations have been additionally incessantly measured. In 2016, the distinction between the producer’s energy specs and the measured energy within the institute’s laboratory was 0.6% on common.

“Since then, the data has shown a negative trend,” stated Daniel Phillip, head of the Division Module Characterization and Reliability at Fraunhofer ISE. ” For the year 2023, this culminated in a negative deviation between the manufacturer’s specification and our review of about 1.3%. A positive deviation was hardly ever observed.”

Final 12 months, the analysis scientists printed statistics on the ability specified by the producers and the ability measured within the laboratory. On the fortieth PV Symposium, which is happening this week in Unhealthy Staffelstein, they’re presenting up to date knowledge on energy conformity, which now additionally contains knowledge collected in 2024.

“In 2024, we observed a slight trend reversal, but still on average strong negative deviations of 1.2%,” defined Daniel Philipp. This could possibly be a sign that the manufacturing companies have acknowledged the tendency towards “optimistic” energy scores as an issue.

“If we assume that our data is representative of the German installation market, an average underperformance of 1.2% with an additional 16.2 gigawatts in 2024 corresponds to a total output of around 195 megawatts.” This corresponds to the nominal output of one of many largest photo voltaic parks in Germany.

“The findings also make it clear how important a reliable, continuous and independent infrastructure is for the quality control of PV modules,” stated Prof. Andreas Bett, Institute Director at Fraunhofer ISE,” particularly when the German and European PV markets are over 90% depending on imports of PV elements.

The info was filtered based on appropriate standards for the analysis. First, the research scientists eliminated inconsistent knowledge, for instance, modules and not using a serial numberkind designation, faulty modules and modules and not using a nominal worth. Additional filters have been then utilized to exclude statistical distortions, for instance, because of the completely different variety of take a look at samples per measurement marketing campaign of the identical venture and kind, and to make sure that solely measurement knowledge from new modules have been included within the analysis.

To attain a consequence that’s consultant of module purchasers, solely knowledge from initiatives the place the consumer and the producer don’t match have been thought of. As well as, solely module producers that have been among the many high 10 producers within the respective 12 months below evaluate have been included within the evaluation, in order that modules from a complete of 15 producers have been included within the analysis.

Because of complete high quality assurance measures, the CalLab PV Modules at Fraunhofer ISE has been capable of show a steady calibration stage over a few years, which can be confirmed by common interlaboratory comparisons. Solely on this manner can sturdy conclusions be drawn from such statistical long-term observations.

Offered by Fraunhofer Institute for Photo voltaic Power Techniques ISE