A high conversion rate does not always represent high power generation. What really matters is the module performance in “real world” conditions. In the solar industry, the standard test conditions (STC) have been commonly used to compare and rate different PV modules. For STC measurements, the solar cell temperature and the ambient temperature are defined at 25°C. However, the working module could be 20°C higher than the ambient temperature no matter in tropical countries or in high latitude zones. To identify the best performance among 2500 PV modules in real environmental conditions, the certification testing provider, RETC has adopted the PTC measurements, rating the solar cell at 45°C based on a 20°C ambient temperature and wind speed of 1 meter per second (2.2mph). In its recent report, RETC tested 46 PV module brands during the year 2018 and eventually listed Eterbright Solar Corporation as one of the HIGH-ACHIEVING MODULE BRANDS in elevated PTC testing conditions, which approves that our CIGS PV modules are able to behave better in real operation conditions!
Reference: Solar Power World article