In-Field Electroluminescence Imaging: Methods, Comparison with Indoor Imaging, and Observed Changes in Modules Over One Year

In-field electroluminescence (EL) can be a valuable tool for quantifying the condition of photovoltaic (PV) modules and systems. Recent advances in Southern Company's custom, low-cost, in-field EL system have improved image quality and image capture rates. We present an overview of our methods and equipment, provide validation by comparing with images from more conventional indoor EL methods and equipment, and summarize changes seen at a utility-scale plant over one year using our methods.