Without having a concise estimate of anything, I will clarify that I live in a green wedge suburb, and that we have constant leaf drop from eucalyptus. Blossoms, gumnuts, leaves, and pretty much birds will absolutely cause a lot of dirt and build up.
From a website regarding what the expectation of solar panels is, and its worth keeping in mind, that Australia has a very extreme climate when it comes to UV and rainfall:
What Causes Degradation?
According to the NREL study, the crystalline silicon modules located in extreme climates showed high degradation rates. For very cold climates, panels subjected to heavy wind and snow loads suffered the most. On the other hand, panels in similar climates that were installed in a facade, eliminating the snow load, had very low rates of degradation.
At the other extreme, panels in desert climates exhibited large decreases in production over time – close to 1% per year – mainly due to high levels of UV exposure. Panels in more moderate climates such as the northern United States had degradation rates as low as 0.2% per year. Those panels could retain 96% of their production capabilities after 20 years
Do Solar Panels Expire?
Solar panels do not carry an expiration date. However, most solar panel manufacturers attach a warranty to each panel. That warranty ranges from 10- 25 years in length.
https://thosesolarguys.com/how-often-do-you-have-to-replace-solar-panels/I dont have an opinion either way. I see solar panels as making up a very real part of our energy production future, but underselling the maintenance of these things benefits nobody.
There are a few points of failure in solar systems, buyt its conceivable that over time, components will fail, thereby reducing efficiency requiring repair and maintenance. Anyone stating, that rain and wind will clean them is not atuned to the reality of the australian climate. Park your car on the street for a week, and come tell me that there is no chance of dirt and grime. Its worth noting the aforementioned website advises that they should be cleaned once a year at minimum or twice a year dependant on location and extremes of polution (i.e. sooty buildup, dirty rain, I dont know about you guys, but there is often a thin layer of grime and dirt on my car although driving contributes to this) and if you live in my area (green wedge north-east melbourne), gum leaves and gum nuts, tree sap, bird poo all are very real problems. We are under a flight path, and get those little waxy dots on our vehicles frequently, and I would wager, this would cause a few issues a long the way.
We were advised that one connection problem, could render a whole section offline, and it will only really display the impact after a period of time of decreased production, thereby also requiring some maintenance. Yes, the reporting could be able to be more instantaneous, but the resolution of these issues, are not as simple as made out either.
Overall, I live by one rule when it comes to technology. Expect the worst, and hope for the best, and I dont see the reporting based on renewables as operating as anything but a best case scenario. That to me is a considerable interest when it comes to this stuff more than the actual technology itself.
(20min delay)