Deceptive Headline & I believe this sub-headline should be the headline: A method to store excess renewable energy, reuse decommissioned mines, and provide jobs

We need alt power first to store energy in abandoned mines. Construct an $NRGV mineshaft and you need to “free” energy (after construction costs) from the sun, thermal, hydro (a water wheel could power smaller projects all during the day,) wave power (being tested in the Keys a new generator which works off underwater tide currents), wind, etc.

In this study/experiment conducted by the IIASA ( International Institute for Applied Systems Analysis) they are saying you could also use sand. I’m guessing like a giant hour glass, except here there is no discharge while the top of the hour glass is filled. Not an hour glass shape, just the concept. I’d like to see that. Sand would be better used in giant construction projects, like building a new 7-Mile Bridge down in the Keys.

"Theoretically, gravity batteries can be anything with a lot of weight, like water or solid objects. The IIASA study lowered and lifted sand in abandoned mine shafts, moving it back and forth between upper and lower chambers based on energy needs.

Another advantage of the process is that while batteries tend to self-discharge over time, gradually losing their stored energy, the gravity method stores the energy in the sand (or whatever else is lifted to harness gravity) which doesn’t self-discharge."

Millions of mines? Shows me what I know about mining. I would have guessed hundreds of thousands, not millions:

The IIASA proposes using abandoned mines because there are already likely millions of them across the planet that could be relatively cheaply converted for this purpose. Most contain the basic infrastructure for the job and are already connected to the power grid.