Solar in desert has a lot of issues including wind and sand coverage. Although the deserts of the region may seem like unchanging environments, the ecosystem and weather is hostile to solar installations (amongst other things). Moreover, solar panels become less efficient at higher sustained temperatures, which increases land and infrastructure maintenance costs.

https://eepower.com/industry-articles/is-desert-based-solar-...

What does "self-sufficient" even mean here? Can you power air conditioning if you build enough solar plants? Yes, but that's true everywhere. That doesn't mean it's financially viable.

> Couldn't that element be self-sufficient on solar?

Night happens even in the desert. Plus what others said about wind. Here's video about a recent sandstorm: https://www.thenationalnews.com/uae/dust-storm-sweeps-across...

My first thought was that it would be like a perpetuum mobile, but since heat pumps have like 400 % efficiency, it should, yes.