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.