The industry standard for the service of solar panel lifespan is 25-30 years. However, solar panels will not fail in 25-30 years. On the contrary, their output will be much lower than the manufacturers' expectations. If you don't know how long your roof panel can generate enough energy, it is difficult to understand the upfront cost of using solar energy. Your solar panels will be able to offset decades of electricity consumption, but it is also important to understand industry forecasts and degradation rates.

How long can solar panels last?

Generally speaking, the service of solar panel lifespan is about 25-30 years. However, this does not mean that they stopped generating electricity after 25 years - it just means that energy production has dropped, which manufacturers believe is a big drop.

Solar panels will continue to work for decades because they will not be damaged by wind, debris or any other external factors. This is mainly because solar panels do not have any moving parts - they rarely break from the inside and are usually only damaged by external forces, such as poor rack settings or bad weather.

The key factor for sustainable use of solar panels is the degradation rate of solar panels

A 2012 study by the National Renewable Energy Laboratory (NREL) found that the output of solar panels decreased by 0.8% on average every year. This rate of decline is called the degradation rate of solar panels. Although this decline rate indicator will vary depending on the brand of battery panel you buy, the degradation rate provided by high-end manufacturers such as SunPower is as low as 0.3%. With the continuous progress of solar panel technology, the degradation rate of solar panels is also improving. In the whole industry, it is common to have a degradation rate of less than 1%. Since this research was carried out in 2012, more efficient technologies have been developed, and the energy output of many newer panels has decreased by only 0.5% per year (or better!)

What exactly does panel degradation rate mean? For the above example, a degradation rate of 0.8% means that in the second year, your panel will run at 99.2% of the original output; By the end of their 25 year "service life", they will still be running at 82.5%. A slightly more durable battery panel with a degradation rate of 0.5% may generate about 87.5% of the power, which is about the same as when it was first installed. To determine the expected output of a solar panel after a specific year, you can simply multiply the degradation rate by the year you are interested in, and then subtract this number from 100%.

There are also several different warranties for solar panels, which can let you know how long the service of your solar panel lifespan is. The manufacturer will provide equipment warranty to prove manufacturing defects, and performance warranty to ensure that your panel will generate a certain amount of power. The performance warranty of your solar panel usually lasts for 25 years, which can give you a better understanding of how much power your solar panel system is expected to generate over time.

You don't need to worry about the carbon footprint of solar panels. The service life of solar panels from 25 to 30 years is significantly longer than its "energy return time" (epbt). Epbt refers to the time it takes for a solar panel to generate enough clean electricity to "repay" the energy originally used to make it. An analysis by Brookhaven National Laboratory in 2010 found that the epbt cycle of solar panels is only six months - in the past six years, with the improvement of panel production efficiency, this number must have decreased.