The following submission statement was provided by /u/Alias_The_J:

Crossposting from r/climate

At a Supsi University campus in Switzerland, a large PV plant (10 kW, large at the time) was built on the roof of one of the technical college buildings. Despite heavy wear and tear, including multiple forms of corrosion, the formation of hot spots on the panels, and cracks and defects in the various connections and cells, most of the array is still capable of producing at least 80% of its rated output after 40 years. This is important because it shows that, unless the modifications to production since that time have changed the situation, then PV cells will likely remain useable and competitive with new builds decades into the future, with older panels possibly having a resale value.

Please reply to OP's comment here: https://old.reddit.com/r/Futurology/comments/100t97m/pv_cells_still_generally_produce_80_of/j2jovx9/