Degradation rate is the rate at which solar panels lose efficiency over time. For instance, if a panel has a degradation rate of 1% per year, it will be 10% less efficient after 10 years of operation.
According to the National Renewable Energy Laboratory (NREL), the average solar panel degradation rate is around 0.8 percent
. Of course, this metric largely depends on the materials and technologies used by the manufacturer and varies from 1% to 0.5%. Some premium manufacturers like Panasonic, SunPower or Q CELLS, offer degradation rates as low as 0.3%. Solar panel degradation rates are constantly improving as solar panel technology gets better over the years.