European researchers developed a new classification system for photovoltaic (PV) devices, which can be used to reliably estimate their efficiency under real operating conditions.The findings of the EURAMET ENG55 PhotoClass Project, which involved a consortium of six European National Metrology Institutes (NMIs), the Scuola Universitaria Professionale della Svizzera Italiana (Switzerland), TÜV Rheinland Energy GmbH (Germany) and the European Commission's Joint Research Centre (JRC) have been recently published in the