One of the most popular questions related to rooftop solar power plants is related to its life expectancy. Most manufacturers quote a 25 year warranty on their solar panels. Moreover most financial agreements like PPAs are signed for around 25 years, indicating that the industry believes that the lifetime of rooftop solar PV systems is around that many years.
It’s interesting that this longevity of rooftop solar PV systems against a short payback period of around 6-8 years has brought in investment and also interest in the industry.
When manufacturers quote a warranty of 20-25 years, it doesn’t mean that the system completely fails after that period. Usually the solar panels degrade by less than one percentage each year. So typically at the end of 25 years, the panels are still at more than 80 % efficiency of its initial rated output.
Interestingly, some of the very first solar panels made in the 70’s are still delivering power to North Carolina, U.S.A and are at 80 percentage efficiency levels even after 40 years!
Now, does every component in the rooftop solar PV system last 25 years?
While panels last 25 years or more, some other parts of the solar PV power plants have life times of much less than 25 years.
- Solar panels as such have a lifespan of about 25 years as discussed above
- Mounting structures are also expected to last 25 years.
- Inverters, which act as the brains of a solar system have lifetimes of around ten years since they are complex mechanical devices. Replacement costs for the inverters need to be considered while estimating the cost of a rooftop solar power plant.
- Batteries, if used with the rooftop solar plants, need to be replaced multiple times during the lifetime of solar panels. Deep cycle batteries, which are mostly preferred over the rest, usually need to be replaced in three to five years depending on how well they are maintained.
What are the simple measures that can be taken to extend the lifespan of PV systems?
- As we all know, PV panels are not very high maintenance. Occasional cleaning of the dust and other debris off the panels should quite do the job.
- The proper working of the inverter usually indicates the health of the whole system. Contact the installers in case the warning lights on the inverters are on. Inverters are the components that require regular maintenance. Ensure that the instructions given by the installers are strictly adhered to.
- A visual inspection of the plant would always come useful. Check for any broken panels, loose wires or any other physical damage to the system and get it fixed in case it happens.