Amorphous solar cells are generally said to last about 20 to 25 years. Crystalline cells carry on for longer, with lifetimes expected to reach up to 30 years. Organic PV cells deliver higher efficiencies but reach the end of their operating life far sooner than other types, which is why they are so rarely used.
Solar cells lose power over the course of their lives. Once they’ve been in operation for about 20 years, electricity yields are likely to drop by 10 percent compared to the cell’s initial performance under identical levels of irradiation. One way of working out how much efficiency a solar cell is likely to lose over its lifetime is to look at the manufacturer’s warranty, which might guarantee, say, 90 percent performance after ten years and 80 percent after 20 years.
Knowing about solar cell lifetimes is not just important from an economic perspective – it also provides valuable information on the technology’s environmental impact. The figures can help us work out how much energy the system will produce in total. We can then compare this with the amount of energy that was used in manufacturing the cell in the first place. The time it takes the system to “repay” the energy that went into making it is known as the energy payback time.
This question was answered by Robert John Doelling of energie-experten.org, an online energy magazine.