I phrased it poorly - from an engineering standpoint, the amount of power a superconducting power line can carry is effectively limitless for practical purposes

I phrased it poorly - from an engineering standpoint, the amount of power a superconducting power line can carry is effectively limitless for practical purposes, in relation to the amount of material required. But yes, of course -- as I did say, eventually enough current flows that the magnetism induced breaks down the superconducting effect. > what are the benefits? 0% loss, vs, maybe 10%? With current lines, yes, rarely over 10% in practice. But what might be built without that barrier? There are many tens of gigawatts of undeveloped hydroelectric power in northern Canada, but that power has to be brought over some 5000 kilometres to New York or Chicago or Toronto. That can't currently be done. The losses are too high. America's primary solar power generating regions in the future, likewise, appear to be far from the major cities. > Again for energy storage, what's the energy density? How much does it cost, if it's even possible to configure for that use? It sounds like you expect to power a car from an AA-sized cell - not happening IMHO. Yes, it's already used, real-world actual applications: https://en.wikipedia.org/wiki/Superconducting_magnetic_energy_storage https://en.wikipedia.org/wiki/Superconducting_magnetic_energ... The energy density is too low for anything like domestic use. It will probably be most useful at grid scale. The economics may not work out. > Again, IMHO, not happening, except maybe for a few specialized switching applications. Switching at just under 1 THz has been demonstrated recently. Anyway, I agree. I already said as much -- "a rather unlikely prospect". C'mon. I'm just excited about superconductors. They're cool! Except hopefully not anymore! I don't believe anything I said was factually wrong. Your primary gripe seems to be that I'm not sufficiently pessimistic about the likelihood of some of the possibilities. So -- room temperature superconductors are probably not real. And everything I spoke of must be understood as conjecture and hypothetical, with large and unknown variables, regarding things like the practical cost and material workability of the room temperature superconductors, which may not even be possible. Better?