[ars]

It would consume power by fighting against incoming particles. This would end up as heat inside it.

[rlpb]

A permanent magnet also fights against incoming particles, and doesn't seem to consume any energy. Why would an electromagnet be any different?

Edit: the permanent magnet will feel a force applied against it in the opposite direction, of course. In space, that's have to be countered by rockets though, not electrically in the current running through the superconductor, right?

[ars]

> Why would an electromagnet be any different?

Because the incoming electrically charged particle induces current in the coils of the electromagnet.

A permanent magnet does not have to deal with that - even if there is current it doesn't affect the magnetism in a permanent way.

Think about an electric solenoid: A stationary electromagnet does not consume power, a moving one does as it acts on the external magnets.