Part of the show Sun Tans, Fission and Fusion
Max in Florida asked:
What's the deal with fusion as a power source? Is it ever going to be economically possible? Is cold fusion the answer, or a pipe dream?
Well let's start with cold fusion. This was reported fifteen or more years ago as an interesting product where you didn't need big magnetic fields but you had electric currents passed into liquids. Somehow they suddenly gave energy off. Whether this is really fusion or whether this is just one of those funny things about electricity, I don't think has been fully demonstrated yet. But if you want to go to the more general idea of fusion as it is on the Sun, I think you have to say that on Earth we've been able to demonstrate fusion for a few fractions a second, a few milliseconds. We've never got electricity out of it; we've always put a lot of electricity into it and I think it's a very challenging thing that we haven't cracked.