Windex?

Shortly after entering western Idaho on I-84 this summer, we saw a solar power farm, then another one some time later.  Passing by the second one, it occurred to me that the panels need periodic cleaning and I asked Trish, "How do you suppose they clean those things?"  She, of course, was as clueless as I.  I followed up with, "There's probably a guy with a BIG bottle of Windex that does the cleaning.  It's his life's work.  Probably takes a year to clean them all, and by then the first one is dirty again.  Talk about job security."

The largest solar plant in the US is Solar Star in Rosamond, CA: 3200 acres, 1.7 million panels, 20.9 SF per panel.  That adds up to 35+ million SF of panel surface!   Rosamond is in the Mohave Desert, same desert I'm sitting in right now.  The Mohave is dusty.  And there are lots of birds, birds that haven't been toilet trained.  

No, Windex, paper towels and dozens of spray-and-wipe workers aren't gonna get the job done any time soon.  Besides, Windex and paper towels do a lousy job.  Home brew* and a squeegee are the way to go.

Here are some non-Windex devices:



A drone view of another method.

https://boingboing.net/2018/05/25/drones-eye-view-of-how-solar.html

There are several types of robotic devices similar to the one above, and some of these are fully automated, like this one: https://www.youtube.com/watch?v=S8b6mE6meIM

*Home brew for cleaning windows - and residential solar panels?
1/3 cup cleaning ammonia
1 cup isopropyl (rubbing) alcohol
1squirt Dawn liquid dish soap
1 gallon water

*