Covering large parking lots with solar panels is an idea that goes back decades but in America at least it’s an idea that has never really taken off.
What is the reason for that? Is it due to the overall cost or is there something else that keeps Walmart, Target, Costco, Sams Club, Malls, etc. from covering their parking lots with these panels and selling the power?
They’re usually rated 20-25, but I think I read recently that some are still producing useful power after that.
Read an article on an early adopter that had over 30 year panels. They reported it was still producing around 70% of its original rated power.
Most panels now seem to have a warranty lasting 25 years, guaranteeing that they will still be producing x% of their original capacity at that time, such as 92% or 88%. Generally a higher guaranteed percentage will cost more than a lower guaranteed percentage with the same starting output. After that time they will continue producing electricity but their output may drop faster. Someone might decide to replace them even though they’re still producing if the output seems too low.
Most batteries seem to only come with 10 year warranties, though, and DC to AC inverters might only have a 10 year warranty.
