Now if you want power when the grid goes down while the sun isn't shining, you can add some backup batteries to your intertie system, a small wind generator, or an adequate sized fossil fueled generator.
The intertie systems can handle the various alternate inputs and pump the excess power back into the grid, or tap it when you need additional power yourself.
No batteries, I feed directly into the grid thru my meter, which runs backwards when I'm generating more than I use.
And how often do you clean the array and how long does it take?
In the valley the dust is ubiquitous and eternal, and the efficiency plummets unless the cells are kept clean.