Featured in Celebrating solar success story – 06-2018

The older they get…

The results of a new edition of the pv magazine PID survey show that 16% of the total system capacity surveyed was or has been affected by potential-induced degradation (PID). With newer systems, however, PID scarcely occurs at all – in any case, it is difficult to discover affected systems. Time to sound the all-clear?

By

Cornelia Lichner

19 Jun 2018

Drone thermography image from 20 meters of flight altitude (left) and drone electroluminescence image at five amperes of current (right). PID was discovered in a 58 kilowatt rooftop system from 2014. The modules have been regenerating with offset boxes since November 2017. This string has improved very little however. In the IR image, it cannot be seen where the string begins. But in the EL scan the individual string is clearly visible and it is possible to see the weakness caused by the PID effect from the negative to the positive pole. The first two modules at the negative pole are marked.

Of the PV capacity installed before 2013, 25% was or continues to be affected by PID. For plants commissioned after 2013, the figure to date is only 0.9%. This is the result of a survey conducted by pv magazine of major plant management companies in Germany. This astonishingly positive development raises questions, of course. Do modules certified as …

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