[tedsanders]

Not to be a cynic, but even if we got a room-temperature superconductor it might not be useful for power lines. The material may end up being too brittle or too expensive (most of these superconductors are complex ceramics, which are very brittle and hard to form into wires). Alos, superconductors carry electricity with no resistance, but only up to a point. If you try to stuff too much current into a superconducting wire, its superconductivity will turn off.