Solar Power Panel Lifespan

[gutharius]

Is there a set length of time one should expect a solar panel to last before it no longer can convert light into electricity?

My assumption is yes. This is because i know that when light hits the semiconductor in a solar cell electrons of that semiconductor as set loose and forced to flow in a certain direction. Hence my deeper question. Will the semiconductor at a certain point "run out" of electrons and there by make the solar ccell useless?

 

[IEC]

I don't think it is so much that as the n-type and p-type silicons will eventually degrade due to exposure to heat, elements, UV radiation, etc... correct me if I'm wrong.

 

[gutharius]

Yeah I saw that a 21year old 22W solar panel was producing on average 19W today. So i guess this would show that there is some degredation but not much to be noticeable. That and the afore mentioned panel was made 21 years ago with what I would assume is now outdated technology.

 

[Gioron]

The electrons will never run out, since they're flowing in a loop out from the solar panel, into whatever its powering, and then back into the solar panel. It generates power by pushing the electrons in a loop, not by giving electrons away. All electric circuits you're likely to encounter are like this. AC circuits will push one way and then the other, but its still basicly the same thing and has to have the loop in order to work correctly. Static electricity is different, thats not exactly an electric circuit (its more like a balloon of electrons that you can pop if you get too near).

And I'm not entirely sure, but I'd guess that solar panel lifespans are roughly the same order of magnitude as LED lifespans. They're not likely to degrade enough to notice before outside factors break them or you stop using them.

 

[pm]

They usually degrade by about 3% immediately after they are put into use due to an not-entirely-understood phenomena called "light degradation". Manufacturers (should) take this into account when specifying the panel/cell output. Over time temperature cycling and weather-induced flex can also reduce the efficiency by introducing very small crystalline defects. As a general rule of thumb, panels degrade by about 10% over 20 years. Many manufactuers offer warranties on new panels of 5-25 years depending on the type of panel and the manufacturer.