If my solar panel system is not going to pay for itself in a really long time, I want to know that the panels are going to work for much longer than that.
As part of my investment calculation that I am putting together I need to know how long solar panels can last.
I am borrowing a book from a friend of mine called “Photovoltaics Design and Installation Manual” by Solar Energy International published in 2004 that says:
“Durability. Most PV modules available today show no degradation after 10 years of use. It is likely that future modules will produce power for 25 years or more.”
I did some more research and found that it depends on the type of panel used. Here is a quote from BoatUS site:
“ Over time, all solar cells have a tendency to degrade slightly under the suns rays. Crystalline panels have a
much slower degradation factor than thin film and will therefore continue to produce energy for a longer period
of time. Warranties will reflect this: crystalline panels are often guaranteed from 20 years to lifetime. Thin film panels receive shorter warranties (usually from 2-5 years), but have been known to still be putting out a charge for up to double that time.”
I decided to take a look at some warranties, for the Sharp NE-165U1 solar panel it says:
“25 year limited warranty on power output”
Depending which way I go, having a 25 year warranty sounds pretty good. I am sure in 25 years solar panels will be a bit more efficient and need to be replaced.
Keep in mind what the warranty actually means… In most cases the warranty is declaring the module will maintain a minimum % of declared efficiency at the end of that warranty period. Typically 80% of rated power, if I recall. So it’s not like after 20 years the module will be ‘junk’. Just not as good as it once was…
I purchased a 45 watt solar panel kit with 3-15 watt thin film panels from Harbor Feight Tools, and over the past two years, since I purchased them, they have degraded by 75%. Each panel was originaly putting out .93 Amps now they are only giving .23 Amps each. Made in China.
Edward,
Wow, that is a big drop! I will have to write about that some time.