Technology changes fast in solar. For years, polycrystalline silicon dominated. It was cheaper than monocrystalline, but then solar got so cheap that higher efficiency of mono won out. The whole industry shifted in ~5 years. We saw a similar rate of change with PERC. And now n-type silicon is doing the same thing. Bifacial glass/glass panels harvest light from both sides and solved the problem of back sheet degradation. N-type silicon similarly improves both efficiency and longevity. Older panels typically guaranteed ~80% of initial output after 25 years. Modern n-type glass/glass modules have warranties of 85-90% after 30 years. A panel from 10 years ago would start at ~16% efficiency and work at ~13% after 25 years. A panel today starts at ~22%, and will work at ~20% after 30 years. A current generation panel will produce ~25% more power per square meter after 30 years than a brand new panel from 10 years ago. There are panels from the 1970's that are still operating today. Solar panels can be designed to last a very long time. When panels do eventually fail, they'll be replaced with better technology that costs less, produces more power, and lasts longer.
