This year’s annual workshop (Photovoltaik-Modultechnik in the official German), which is jointly organized by TÜV Rhineland and the Energy Agency NRW in Cologne, hosted some 150 experts from the German PV industry on Monday and Tuesday this week.
The focus of the event was on topics related to increasing the lifetime of solar modules as well as the avoidance and identification of failures in photovoltaic systems.
Axel Herguht from the University of Konstanz reported on the latest results on the regeneration of highly efficient PERC solar cells, which show a significant degradation in their performance within the first year of operation under illumination if they are not specially treated.
Three presentations highlighted the advances in fault detection of solar modules using thermography and electroluminescence. Bernhard Weinreich of Hawe Engineering reported that they were now able to successfully identify more than 40 different failure mechanisms by means of specific "error signatures" in thermographic images of solar systems.
The results, which Markus Schweiger from the TUEV Rhineland presented on the temperature dependence of the performance of different module types (both crystalline and thin film), were very revealing.
TÜV Rhineland operates free-field test sites at five different locations around the world, which are located in different climatic zones. By means of time-resolved irradiation, temperature and power measurements on the modules over several years, the climatic influence on the energy harvest of solar modules could be quantified in different climatic zones on a comparable basis.
The results by Markus Schweiger are helpful with regard to the task of adapting solar modules to achieving the maximum energy yield under specific climatic operating conditions that prevail in a given climatic zone. In the hottest locations, such as the Arizona and India, the temperature-dependent yield losses vary between 5-10% compared to the reference values measured at standard test conditions (25 degrees Celsius), depending on which technology is being applied to both cells and modules.
The growing professionalism of the solar industry can be seen in the fact that the failure causes are now much better understood, and so target-oriented countermeasures can be taken. The increasing relevance of PV in the electricity grid in individual countries and their intelligent coupling with storage devices will be one of the key topics at the next TÜV-Modulworkshop scheduled for the end of 2017.