Eugene Leitl (
Wed, 1 Sep 1999 19:56:58 -0700 (PDT) writes:

> 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.

That's the bad part about them: they quench too easily. Catastrophic failure is not a particularly enticing aspect of what is supposed to be a storage medium.

> 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.

It helps to make the coil large, very large. Like some ten miles in diameter.

> 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?

My physics recollection is notoriously hazy, but I don't think you have to bring it up to full field in a single stride.

> 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.

I think it might be useful in the outskirts of the solar system. It's already damn cold out there.