It's not just that it's based on oil that's the problem, it's also that in general, Saudis don't even know what "work" is. Most of their revenue-generating businesses are planned and run by Westerners. They grow up with maids and servants.

In fact, I'm not sure they can do anything besides eat, pray, and watch soccer. It's a really, really strange place.

Going there on business was a very weird experience for me - the country somehow functions, but none of the locals actually do anything, as far as I could tell.

One of the 'solutions' to solar energy storage is to collect power from the east / west of you. Considering most grid scale storage is expensive and not that efficient ~5-10% transportation losses are viable which makes China, India and the EU well within range of Saudi solar electric power.

Another option is manufacturing, cheap power means cheap aluminum. And there is significant research into synthetic fuels, even if significantly more expensive than Oil right now they are likely in demand for aircraft in the long term.

The curse of oil, they have been talking about weaning themselves of it for a long time but have failed to achieve anything significant. It's more about their economy than their own consumption.