4 ms·

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.

• EGreg 2y ago
  The battery doesn’t have to hold the entire year’s energy — come on :-P
  • mft_ 2y 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?