There is this concept of "Gravity Storage" [1] which could be promising, if some testing were to be done on it. Basically you cut a large cylinder out of the e

There is this concept of "Gravity Storage" [1] which could be promising, if some testing were to be done on it. Basically you cut a large cylinder out of the earth and lift it by pumping water below it. When you then need the energy, you release the water with the help of the weight of the cylinder and use it to generate electricity. It sounds a bit crazy, but it could be worth testing that approach, since it can also be used in a flat area like a desert. In any case, the company filed for insolvency this year [2]. There is a podcast episode [3] from "omega tau podcast" dedicated to it, which is worth listening to. [1]: https://heindl-energy.com/ https://heindl-energy.com/ [2]: https://heindl-energy.com/about-us/ https://heindl-energy.com/about-us/ [3]: https://omegataupodcast.net/299-gravity-storage/ https://omegataupodcast.net/299-gravity-storage/