Dr. Werner Herrmann studied physics at Technical University Aachen and received his PhD in electrical engineering from University Hannover. He joined TUV Rheinland in 1988 and was responsible for the development of test equipment for PV module product certification, which started in 1995. His general research focus is on development of measurement and testing methodologies for PV modules and on failure diagnostic techniques for PV modules. More recently he has been studying the climatic impacts on PV energy yield. He is member of working group “WG2 - PV modules” of IEC TC82 and has more than 20 years’ experience in developing test standards.