3 ms·
I'm really sick of hearing about this idea. At least this one doesn't make the same mistake of suggesting it should be human powered, but the energy density of
by mrgriscom 13y ago
I'm really sick of hearing about this idea. At least this one doesn't make the same mistake of suggesting it should be human powered, but the energy density of gravity is ridiculously low compared to practically any other technology we have. It works for hydroelectric plants because they have HUGE reservoirs to supply them.
Assume one of these gravity batteries uses a 100m deep shaft with a counterweight the mass of a Cadillac Escalade. The energy stored is 100m * 2700kg * 9.8m/s^2 = 2.6 MJ.
The first deep-cycle battery I found through google (retail price $260) is 90Ah * 12V * (assume 80% discharge cycle) = 3.1 MJ. It just doesn't add up!