It's tough to say, it depends on the failure modes.
Certainly one failure mode is just "wearing out" -- Being exposed to light and heat for a long time just causes changes in the structure of the panel that prevents it from producing power anymore.
Another failure could be related to damage to the frames or wiring, another could be related to stuff like kids throwing rocks or fat birds landing on them or high winds.
The first one could be highly overestimated because they test MTBF by running in an oven basically, and so if their models of thermal acceleration of damage are off, it could be a problem.
The second on the other hand could be highly underestimated.
Yet another failure mode I just thought of is "no failure mode at all". People will replace solar panels not because there's anything wrong with them, but because there's a newer shinier model out there. It happens, believe it or not!
Big reason for a secondary market to develop. Lots of people would happily install second hand solar panels with 40 years of life left.
MagnetoMancer@slrpnk.net 1 year ago
Well, sure, its negativity was always overblown by those in bed with oil company's. But, there is a grain of caution here that nobody is talking about and that is, yes Solar power is one of the clean and infinite powers available to us...But the materials required to build PV panels do not last forever and the Earth is not producing anymore of it; so technically we cannot claim this tech is sustainable forever. So, there is a need to engineer a design, and buy it when available, that is itself recyclable at the end of its 15+year service 'life".