QUOTE : Despite its technological potential, superconducting technology has been slow to materialize in the marketplace. One obstacle has always been the frigid temperatures needed to reach the superconducting state, requiring the use of elaborate refrigeration systems available only in research laboratories. That was one reason why the discovery of high-temperature superconductivity caused such a stir: The critical temperatures could now be reached by cooling with liquid nitrogen, which is both cheap and abundant. The more serious obstacle has become the difficulty of manufacturing strong, flexible wires out of the new materials; like other ceramics, they are brittle and tend to crack easily. It’s also hard to fabricate the wires in practical lengths; they tend to lose their superconductivity because of material defects when they get too long. Moreover, the most promising form of superconducting wire is encased in silver, which makes it 20 times more costly than copper wire, although the cost will decrease as demand rises.