It's a well-known, running joke (or criticism) in the fusion community that

Fusion is always 30 years away.

refering to the considerable difficulties that harnessing nuclear fusion as an energy source has faced since the 1940's.

Who said that first?

  • 3
    $\begingroup$ In a more comical delivery, the situation is stated as "nuclear fusion is the technology of the future ...and always will be!". $\endgroup$
    – Steve
    Commented Jun 7, 2020 at 15:42
  • 6
    $\begingroup$ Nuclear fusion is 8 light-minutes away. $\endgroup$ Commented Jun 7, 2020 at 16:43
  • $\begingroup$ @RodrigodeAzevedo :-D Yes, but that distance in space, not time. $\endgroup$
    – stafusa
    Commented Jun 7, 2020 at 20:06
  • $\begingroup$ It was always "10 years away" , at least on sci.physics (that's Usenet to you youngsters) $\endgroup$ Commented Jun 8, 2020 at 15:22
  • 1
    $\begingroup$ @CarlWitthoft Strange, I've never heard about 10, always 30 years, if not 50. $\endgroup$
    – stafusa
    Commented Jun 8, 2020 at 15:32

1 Answer 1


Although one can find claims that this joke goes back to the 1960s, the joke only really started to bite after the first 30 years of fusion research had passed and we seemed no closer to the goal. This timescale matches the first explicit mention I can find of the joke which is from a 1986 "Panel Discussion on Prospects for Fusion Power", where it was stated:

Although substantial progress is made every year in fusion research, the projected time to realize the ultimate goal of commercial fusion always seems to be 25 to 30 years away.

It is amusing to note that according to recent research on "How Many Years Away is Fusion Energy? A Review", scientists now believe (on average) that fusion is 17.8 years away:

we should now say “fusion was said to be 19.3 years away 30 years ago; it was 28.3 years away 20 years ago; 27.8 years away 10 years ago.” And now, scientists believe fusion energy is only 17.8 years away.


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