Module Reliability in Winter: Field analysis of deflection and cell cracking across multiple module architectures

Snow, which affects vast areas of the northern hemisphere, can be problematic for photovoltaic (PV) systems for three reasons; one, the shading of solar cells by snow stifles power generation[1]; two, the broad geographic sweep of most snowstorms challenges the availability of solar to meet regional energy needs; and three, the weight of snow, combined with wind and cold loading, can physically damage modules and cells. Not only are load stressors in winter poorly understood but almost nothing is known about the robustness of different module technologies exposed to those stressors. This paper will present data from a field study of multiple module types, including half-cut cells, bifacial and large-form factor architectures, installed at the Michigan Regional Test Center in Calumet, Michigan. Modules were installed on single-module racks instrumented with load cells, deflection sensors, and anemometers. Each module was subjected to electro-luminescent imaging at the beginning and end of winter to document the presence or absence of cell damage; in addition, time-series data were collected to quantify snow, wind and temperature loads and images collected to compare rates of snow-shedding across module technologies.