Solar panel degradation refers to the natural, gradual decline in a module’s ability to generate electricity. Even without any moving parts, degradation affects all solar panels, reducing their efficiency and output as they age.
Several factors contribute to solar panel degradation:
Manufacturing quality. Higher-quality panels tend to degrade more slowly due to better materials and higher fabrication standards.
Weather. Harsh conditions that include UV radiation, hail, rain, wind and ice cause solar cells to lose 0.5% of their output for every 1°C above the STC-rated temperature of 25°C
Thermal cycling. Hot and cold cycling due to prolonged weather exposure causes expansion and contraction that may lead to microcracks in the cells and solder joints.
Care and maintenance Proper transportation, storage, installation and maintenance can help minimize efficiency loss. Conversely, faulty wiring, poor installation engineering and careless handling can cause physical damage that affects connections and performance.
Time. Electrical components that connect arrays (rows of PV panels in an installation) and connect the overall system to the grid can affect connectors, coatings, diodes and other components over time, reducing overall system performance.
Degradation is expressed as a percentage loss per year. For most modern solar panels, expect a degradation rate of 0.5-1% annually. Depending on their age and the factors listed above, a used solar panel that is five years old will be 2.5 – 5% less efficient than it was brand new.
Efficiency loss in a used solar panel is balanced out by a cost that is 5-20% of the original cost.
Sources
- “Solar Panel Degradation Rates” by the National Renewable Energy Laboratory (NREL)
- “Performance and Reliability of Photovoltaic Systems” by the International Energy Agency (IEA)
Shop used solar panels >