Hear me out:
There's a way the desert states can export and store their solar energy production cheaply, easily, at scale, without needing any rare earths (nothing that is hard to obtain / limited supply / is dirty to extract). And as part of the process, they get clean water as a side effect. Unlike e.g. export via electrolysing water and shipping the hydrogen gas which requires clean water and thus requires spending more energy on desalinization which is a dead end, literally: desalinisation is ecologically speaking terrible, and e.g. the persian gulf is already becoming saltier due to the many desal plants dumping their brine.
How?
Re-invent the Castner Process: An endlessly repeatable process.
Step 1: Combine energy + Caustic Soda (NaOH); out comes Na2 (sodium metal, ready to export), H2O, and O2. The water is clean, the oxygen you gas off (not exactly an environmental disaster, gassing off waste oxygen), the process is essentially perfect - nothing is lost, and the anode and cathode use cheap materials (iron, mostly). Ship the sodium bars in a big boat (wrap em in some oiled up paper first. Yes, if the boat sinks, it'll explode; if an H2 carrying boat springs a leak you also get fireworks. Energy storage mechanics have nasty failure modes, it's pretty much inherent in the concept).
Step 2: Once the sodium bars have arrived at some industrial port that wants energy, all they have to do is chuck a proverbial bucket of water at it; doesn't have to be particularly pure. The Na reacts, turning back into NaOH + H2 gas (useful feedstock gas! Don't ship it - ship the sodium, use the sodium to make H2 gas out of water at the site of the plant that needs hydrogen! If you don't need the hydrogen, burn it for energy) - and this reaction is highly exotermic on its own (let alone if you also burn the H2). Ship the NaOH back to the desert-based solar panels.
A boat loaded soup to nuts with sodium metal is about as energy dense as half of the energy in a boat loaded to the gills with hypercooled, hypercompressed H2. Except you can ship this stuff on any old creaky vessel vs the extremely expensive H2 carriers.
You can store the energy in any old warehouse, requiring pennies at best for safety - no need to store under pressure, nothing is particularly toxic, stuff lasts for years and doesn't lose appreciable amounts of energy during storage. Yes, if some catastrophe causes a flood to go through a warehouse full of sodium that's gonna be a nasty surprise, so preferably you don't build this stuff in the middle of town square, but it's orders of magnitude less scary than MIC, nuclear waste, a tank full of pressurized H2, and so on. This stuff is no more scary than an oil depot, really.
So.. why in the blazes isn't this a thing? Shouldn't the middle east be spending their money on a modern take on the Castner Cell instead of The Line or a pet war in Yemen?
Win win win. It can't even be patented. The only thing that needs to be done is to update/reinvent the castner cell: We haven't electrolysed caustic soda in about a century, because chlorine gas is a valuable feedstock for industry, and the Downs Cell (electrolysing salt into sodium + chlorine) is therefore the way it is done today. The sodium is a lucky byproduct (the process is run to fulfill the need for chlorine gas as feedstock). Due to this there's plenty of sodium to fulfil industrial needs and therefore no need to run Castner Cells. That's the only reason nobody's run one in many decades.
I'm sure I'm missing some key chemistry but I can't figure this one out.