Superconductors are substances that conduct electricity without resistance at low temperatures  Their use, however, will never be economically feasible, unless there is a substance that superconducts at a temperature above minus 148 degrees Celsius  If there is such a substance, that substance must be an alloy of niobium and germanium
Unfortunately, such alloys superconduct at temperatures no higher than minus 160 degrees Celsius
The use of superconductors will never be economically feasible.