Comment by dwaltrip
5 years ago
When I briefly looked into this, my takeaway was that the energy density (and thus price) is much, much lower than needed to compete with other storage mechanisms.
As another poster said, gravity is relatively weak compared to the other forces.
Yes, when a magnet holds up a nail, what you're seeing is that the force of the tiny magnet on the nail is much much higher than the gravitational force of the entire earth on the nail.