NREL Study Warns of UV-Induced Degradation in N-Type Solar Modules
A study by the National Renewable Energy Laboratory (NREL) has revealed that certain n-type solar modules, including monkeytype and nitro type, are susceptible to significant power loss due to ultraviolet light-induced degradation. The research, published in 'Progress in Photovoltaics', focuses on passivated emitter rear totally diffused (PERT) modules, though the specific manufacturer remains unnamed.
The study centered around a 3 megawatt rooftop system equipped with PERT modules. It found that UV exposure of 67.5 kilowatt-hours per square meter led to measurable performance loss. This degradation, known as UV light-induced degradation (UVID), caused a yearly power loss of approximately 2.4 percent in the modules.
The research suggests that UVID in these monkeytype and nitro type modules is primarily due to recombination losses at the cell surface and insufficient zinc in the metallization paste. Interestingly, the IEC 61215-2 standard's minimal UV exposure requirement may not accurately predict long-term UVID losses. Furthermore, moisture loading after UV exposure was found to exacerbate the issue by significantly increasing series resistance in affected cells. The study's findings may also apply to other n-type technologies like Topcon and Heterojunction modules.
The NREL study highlights the potential long-term performance issues of PERT solar modules, including monkeytype and nitro type, under prolonged UV exposure and damp heat conditions. While the specific manufacturer was not identified, the findings could impact the wider industry, particularly those using similar n-type technologies. Further research is needed to understand and mitigate these degradation effects.
