If this can be proven to work it could be a real difference maker to smooth out energy swings. I don't know about other areas but here in Michigan we have a number of abandoned salt gypsum and ore mines that would all be candidates for this technology.
Which is about 10 times the power and more than 10 times the storage of the proposed battery.
It's currently used to shift baseload generation from nighttime to daytime, but it could be used to store solar for evening and nighttime use.
The only real blocker to siting more is that people freak out about local environmental disturbances. It's about 1.5 miles of shore out of hundreds of miles of dunes.
