Could excess power from CA be exported to Mexico or Central America?
Agriculture is different. They rely on much cheaper prices and besides, you'd have to transport it uphill.
What's the best way to transport a million kg of water? Build a cloud.
If you're thinking statewide, you could just evaporate seawater, and it's eventually going to rain out somewhere in the mountains.
I wonder if hydrogen generation would be more along the lines of what you're thinking. Hydrogen is an energy store not an energy source -- it takes more energy to produce hydrogen than you get out. But that just means it's a type of battery. It seems conceptually simple to produce... if a plant can be made simple enough (low enough capital costs that the idle time matters less), I wonder if hydrogen generation/burning has been studied as grid-level storage to do this kind of time-of-day energy arbitrage.
(With the amount of interest in grid-level storage and by the law of markets-are-efficient, presumably someone has run the numbers...)
What makes US desalination impractical is not the cost of desalinating, but either or both of:
- the cost of building a plant in the first place
- the availability of cheaper fresh water
it's not hard to come up with some creative solutions... How about a giant bag or huge tanks out in the ocean for holding the water, instead of building dams. Or injection wells to replenish the water tables during the rainy season, pumping it out during the rest of the year.
It just seems weird that millions of gallons of fresh water gets dumped into the ocean, and nothing is done to capture even some of that water.
"First they come and take our jobs. Now they want us to give them free power!"