Solar module warranties are typically 25 years or longer, a striking reliability requirement that allows only a slow performance degradation with time. There are very few products built today that are required to exhibit this type of longevity. In the past decade, to improve the quality of their products, high-performance cell manufacturers developed and implemented various inline process control machines that could detect poorly performing or defective cells. Low cost module manufacturers are still less likely to use the full suite of inspection steps, and even with full implementation of inline inspection it has not been possible to eliminate long-term field failures. This suggests that outdoor inspection techniques must be developed and deployed, and these must be capable of scanning a significant fraction of the installed modules to detect the most common failure modes in a statistically significant manner. With this outdoor reliability information in hand, financiers and bankers can reward high-reliability manufacturers with lower cost of capital, directly lowering the Levelized Cost of Energy, a direct benefit to U.S. consumers. This project proposes to develop a ruggedized outdoor scanner that will be used during nighttime hours to detect and quantify various defect types in installed solar modules. It will operate in a non-contact mode: the modules do not need to be unplugged or otherwise disturbed during the process, and high resolution electroluminescence images of the module defects will be collected and automatically analyzed. In Phase I, we will design, build and debug a prototype scanner that will be manually placed on top of a module, and a prototype will be delivered to a US customer for initial testing and feedback. In Phase II, we will design and implement an automated scanning platform [e.g.- buggy or drone], as well as the data analysis algorithms and infrastructure so that the machine can autonomously collect information and generate detailed statistical reports. Demand for these outdoor techniques is expected to be robust, and finance companies such as Deutsche Bank have called for this type of outdoor metrology: the installation rate of solar modules has continued to rise over the past decade, and while conservative models such as World Energy Outlook 2015 predicted a relative slowdown in 2017-2020 (with worldwide installations hovering near 40GWp/year), recent announcements by China suggest that they alone will consume more than the previous forecast. It is possible that the worldwide installation rate will approach 100GWp/year during this timeframe, and a significant fraction of these installations should be inspected for both initial quality and for year-over-year degradation.
