The conversion efficiency of solar panels is not 100%, as it is determined by factors such as material properties, manufacturing processes, and external environmental conditions. For example, the photoelectric conversion efficiency of monocrystalline silicon solar panels currently on the market can reach around 20%, while the efficiency of polycrystalline silicon and thin-film panels is around 18-19% and 10-15%, respectively.

Photovoltaic modules gradually degrade over time during operation, a phenomenon known as "photovoltaic module degradation." The degradation rate refers to the ratio of the output power to the nominal power of the photovoltaic module after a certain period of operation under standard test conditions (AM1.5, module temperature of 25°C/77°F, irradiance of 1000W/m²). This degradation is caused by multiple factors, such as decreased cell performance, surface contamination, and internal losses.