alt Hacker NewsBut how expensive would be to dig a, I don't know, 1000 by 6 feet hole in the ground? I have no idea of an equivalent gravity battery...
But how expensive would be to dig a, I don't know, 1000 by 6 feet hole in the ground? I have no idea of an equivalent gravity battery...
The average US household uses about 10,000 kwhr per year. That's roughly equivalent to the gravitational energy of dropping ten tons down a 200 mile hole.