Many of the bifacial modules now offered by PV manufacturers employing bifacial passivated emitter and rear cell (PERC+) technology, making them vulnerable to rear-side potential-induced degradation, in addition to the conventional front-side shunting type (PID-s). Kai Sporleder, Volker Naumann, Stephan Großer, Marko Turek and Christian Hagendorf of the Fraunhofer Centre for Silicon Photovoltaics report on new testing methods designed to quantify the expected power losses of bifacial PERC+ modules in the field