Yeah OP is really screwing himself there.

If I’m not mistaken you jumped a magnitude there somewhere… 685 Milliwatt are 0.685 Watt. If we say 12h of production that comes out to 8.2 Watt Hours. A kWh is 1000 Wh. It’s just a little fart of electricity.

And the question as always is what are the conditions that create the 750g water. I can guarantee you it’s not dry dessert air.

That’s the problem, you would throw the money away. NASA used it for something useful.

Yes not pumping up but pumping down. The described plant doesn’t use a natural reservoir but a fracked artificial one that need water injected into it. That water injection is what they want to use the excess renewable energy for and it you be equivalent to the charging of the battery.

Isn’t you storage capacity of excess electricity limited to the power requirements of the water pumps? And isn’t that only a small amount of your total energy output as your output is created by heating water to steam and not like in a pumped hydro from the work of the pumps.

So it’s not so much a battery in a sense that your output is the input minus losses, it’s a baseline power plant that is shut down intermittently to increase the output from net to gross by running your pumps with excess power at a earlier date.

If I’m not missing something here I’m very sceptical that this is a battery as much as a fast response generator with a efficiency boost by using excess renewables.

If anyone knows more please tell me, the article is not really useful.