Reliability of photovoltaic concentrator modules

The cost goals and calculations in the Five-Year Plan for the National Photovoltaics Program assume that photovoltaic (PV) concentrator modules will have a reliable output and an operational life expectancy of 30 years. Although the modules in the few PV concentrator systems fielded to date have so far been reliable, they have not been in the field long enough to establish performance levels for 30 years and are not necessarily representative of newer concentrator designs. Thus, extensive testing and analysis are required to evaluate and establish the reliability of current concentrator module designs. Considerable research has been done to establish appropriate qualification tests, to understand component failure mechanisms, and to obtain reliable materials and designs. Surveys of fielded systems have been conducted and test and analysis techniques have been developed in the process. Recent research on PV concentrator reliability is described, and the issues that are currently of concern in this area are discussed. Included are discussions of proposed changes to the existing qualification specifications for PV concentrators, results from a solder fatigue experiment, a description of a test technique for evaluating cell assemblies, and a discussion of the importance of quality assurance