Well, Is it really possible to maintain such low temperatures required for super-conductors (taking High-temperature superconductivity into account) over large distances?
What I say is – Even if we were able to pass current through superconductors, we need to constantly cool them for maintaining the zero resistance. Hence to cool, we need power. Then, superconductors wouldn't be necessary in this manner if they don't have an advantage..? Or, are there any new approaches to overcome these disadvantages?
Best Answer
The cooling over large distances is a challenge but the engineers and physicists are working on it. The current record is several km but not enough to connect cities, etc. This basically only works if the cables are in a kind of vacuum tube to reduce the cooling power.
It is not practical to transmit electric energy if you need liquid helium temperatures. The cooling costs are prohibitive. The current state of the art are cables using thin films of BSCCO (phys.org). They can operate at 77 K without problems. The current world record for such a cable in a vacuum tube is several kilometers but after some distance you need a small building along the cable to cool the liquid nitrogen inside the cable again.
There is a tremendous research effort to find superconductors with higher critical temperatures and currents but that is not so easy. The usage for practical applications is increasing but the progress is rather slow. In more exotic applications such a CERN or ITER you absolutely need superconducting cables, if it is only for space reasons: