Comment by EGreg

Comment by EGreg 2 days ago

Why not just dig a hole in the ground and make a gravity battery? Would be much more reusable without all the lithium garbage ... and also probably more efficient...

https://en.wikipedia.org/wiki/Gravity_battery

And the most efficient way would probably be to just have credits with the rest of the city grid. Sell electricity to them when you have a surplus (from solar) and then pay for electricity when you need it. These credits are a lot more efficient than storing the actual electricity in a battery hehe

tecleandor 2 days ago

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...

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thfuran 2 days ago

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.

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- EGreg 2 days ago
  
  The battery doesn’t have to hold the entire year’s energy — come on :-P
  
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  mft_ 2 days ago
  
  Indeed, but to store (let's say) half a day's energy, then (based on the previous calculation) it would presumably need ten tons dropping down a hole 0.274 miles, or 441 metres, deep?
  
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numpad0 2 days ago

holes in the ground are just wells, and gravity batteries are just dams. don't reinvent the square wheels, please...

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