PV modules are warranted to produce at least 80% of their rating 20 years down the line. I'd imagine they very rarely need to be replaced due to losing that much. There was a Home Power magazine article of a few people who were Back to the Land type folks who bought PV a very long time ago who said their early panels produce well many decades later. I always see this "20-30 year lifespan" crap in articles where people are talking about PV, if one module really crapped out and you had to bypass it in a string you'd only lose that panel. It's when you lose an inverter and you need to replace it that you need to put some money into it but my local PV installer has only seen issues with two Enphase microinverters and no issues with the large name brand string inverters he has installed over the years. I expect a system to have the lifespan of the house they are installed in with maybe a component or two that might need to be replaced on a very infrequent basis. It's not much different than a component on a car going out, the whole car doesn't die.
On another note, you said that your DIY install was about half of the $7.50/watt quote. Can you break down the costs, roughly for what you put into the system, I'm trying to get a rough estimate of what I'd expect to pay for my installation to know if I'll be getting a fair price.
|