Evolution of measured module characteristics versus labelled module characteristics of crystalline silicon based PV modules

•Comparison of electrical parameters measured of Si PV modules with nameplate values.•Mean divergence from Pmax rated of −3.15% for 992 modules for a period of 32 years.•Number of modules that do not meet the tolerance ranges decreased over the years.•Average Pmax results showed improvement over time due to factory solar simulators fitting.•Economic assessment of the differences between measured and labelled is performed.