[ccvannorman]

Fusion may be difficult but math and physics say we should be able to do it. Just because it's difficult and with a long time horizon doesn't mean you should throw it in the bin with "perpetual motion". (Cold Fusion however, you may throw in the bin)

Just saw a talk [0] where they talk about using lasers to create fusion. The current puck used to kick start the process costs $1M, (paraphrased) "it needs to cost 20 cents before Fusion is viable. But hey, we're in the research phase!"

[0] https://www.youtube.com/watch?v=hcGgaa2mFc4

[pfdietz]

From the point of view of an end user, it doesn't matter if a technology is not possible because it's physically impossible, or if it's so uncompetitive it's economically impossible. The net effect is the same: the technology is dead to them.