The “measurement uncertainty” value of a photovoltaic system is a decisive factor for quality assurance for solar module manufacturers and buyers alike. The announcement in May that the Fraunhofer Institute for Solar Energy Systems (ISE) calibration laboratory ‘CalLab PV Modules’ achieved a world record by reducing measurement uncertainty from 1.3 to 1.1 percent was therefore not insignificant.
"With a global module production of around 100 GW, one percent measurement uncertainty corresponds to one gigawatt of output uncertainty. At today's prices this amounts to around EUR 300 million. High precision pays off for both suppliers and customers," explains Dr Harry Wirth, division director for Photovoltaic Modules and Power Plants, in a .
The CalLab PV Modules has recently been re-accredited as an independent calibration laboratory according to stricter new standards from the German Institute of Standardization (DIN), making it one of the first accredited calibration and testing laboratories in the world.
“A great advantage of our calibration laboratory is the combination of highly precise measurements with the capacities for processing large quantities. We are able to measure 5,000 modules per year while keeping processing times short," , head of CalLab. A test stand has also been developed for the calibration of bifacial (two-sided) solar modules – the measurement uncertainty for this technology has now been reduced from 2.5 to 1.8 percent.
As well as calibration, performance tests can be carried out for example under low radiation, different temperatures and light angles to generate yield simulations for each module. “As a result, we have significantly reduced the uncertainty in PV yield simulations," .