Solar panels have been field tested on many installations. Practice has shown that the service life of solar panels exceeds 30 years. Photovoltaic plants operating in Europe and the USA for about 25 years have shown module capacity reduction of about 10%. Thus, we can talk about the real service life of solar monocrystalline modules of 30 years or more. Polycrystalline modules usually last 20 years or more. Amorphous silicon (thin-film, or flexible) modules have lifetimes of 7 (first generation thin-film technology) to 20 (second generation thin-film technology) years.
Solar modules usually degrade faster in the first 2 years of operation. Thin-film modules lose 10 to 30% capacity in the first 2 years of operation, so new modules usually have a capacity reserve of about 15-20%. Crystalline silicon modules currently make up about 90% of the PV market, as their degradation is much less and service life is longer than that of other types of solar modules (see table below).