How much would such a coating reduce the efficiency of the panel though? I’m seriously asking btw, I don’t know the answer or very much about PV panels.
In what sense?
>lowered maintenance costs
Not really, actually - hydrodynamic bearings already work on the "zero wear due to zero surface contact" principle. The reason this is using magnetic bearings is just because it needs super-super low friction, under super-tiny loads, in order to work.
>Probably a lot less noise
Bearings aren't generally noisy. If they were, they wouldn't be very good bearings!
I'm not sure about UV filters that will be stable for 1000 years. Regular glass blocks most UV, but lets through about 25% of the frequencies close to blue.
For museum and artwork protection time frames acrylic is popular. It blocks almost all UV and is still stable after 25 years. I don't know how that extrapolates to 1000 years.