[grw_]

I've wondered about the 'used panel' market for a while. Do you know why your seller didn't just increase the price of the property or move the panels? Does the second-hand price of panels decrease linearly with the amount of lifetime left, and how can you verify?

[workerIbe]

I got mine from a recycler, he said they failed inspection after installation for scuffs and scratches. Mine produce very close to spec. I have read that most panels degrade at about 1% per year, the ones I got were 3 years old. I checked them all to see that the open voltage was close to the specs when I got them, worked out great.

[bainsfather]

In the uk most solar installations get a generous subsidy for power produced. The fixed subsidy was set 5 or more years ago at e.g. 44p/kWh for a specific installed capacity.

The high price per kWh means it is economic for these places to upgrade their panels to newer ones that get closer to their rated output (e.g. in low light conditions etc). Hence the market for used panels.

Source: looking at the explanations on used panel shop's website - I think it is reliable.