On Tue, 31 Aug 1999 10:36:05 -0400 CountZero <email@example.com>
> Which brings up a point I've been unhappy about for a _long_ time.
> We don't have a shortage of energy, one way or another we can
> generate/capture enough for most purposes that are currently
> relevant,> the problem is lack of a sufficiently energy dense storage
> (btw,> the jet pack of the '60s used H2O2).
> If my understanding of super conductivity is correct, a super
> conducting> coil should be able to store an arbitrarily large amount of
energy.> Is this correct?
No, not at all, at least not without making the storage coil correspondingly larger and more expensive. Superconductive coils can store energy for long periods of time without loss, but you cannot exceed a certain energy density in any known superconductive storage system. The details vary depending on which particular medium you are considering.
Superconductors appear to be limited in the current they can carry without failing to remain superconductive. The situation is particularly bad for the new high temperature superconductors.
But suppose you found a superconductive material that could carry a billion amps in a wire 1/4 inch thick. Then the magnetic forces would tear the coil apart.
Suppose you could overcome the problem of containing the magnetic forces. Then how would you pump a billion amps into the coil? If you use magnetic fields to pump energy into the storage coil, the pumping field would have to exceed the field in the coil. How would you generate the field?
This is not to say that it won't be possible someday to store energy at high density in superconductors. But not with today's technology.