Contrary to popular belief, fusion power generation is not really like the Sun

Sun
image credit

Most positive news stories about generating electricity from nuclear fusion mention fusion powers the sun. The implication being nuclear fusion is simple, clean and healthy. Unlike nuclear fission, which is what existing nuclear reactors use. Nuclear fission produces radioactive waste, and the reactors have a risk of meltdown. Not good. But fusion has its skeptics too. Negative fusion stories always quote some version of “Fusion Power is 20 years in the future – and always will be.” I first heard that line in the early 1980’s in college. I had a part time student job working for a grad student in the physics department, who was doing fusion/plasma research. My role? Hours and hours of time spent cleaning and prepping the very large cellophane/oil capacitors that powered plasma generation. Basically a dishwasher.

Before we get to that, let’s pause for some historical context by quoting a sampling of fusion stories from the New York Times archive (subscription required). Note the stories from 1982, 1991, 2003, 2005 and 2014 are remarkably similar. Namely a) the sun is powered by fusion, b) recent progress is a game changer, and yet c) naysayers claim fusion remains forever 20 years away.

  • 1982 – “Now, more than 30 years after they began, it appears that these fusion scientists will, indeed, be successful. Thanks in large measure to the research achievements of the past three years, particularly at Princeton, it seems clear that nuclear fusion could eventually solve a major world energy problem -the production of electricity – and it could do so with acceptable environmental hazard.”
  • 1982  (cont.) – “attempting to produce energy the way the sun does -through nuclear fusion. Fusion is the basic mechanism that causes the sun and the other stars to shine.”
  • 1991 – “After nearly a half-century of effort and many billions of dollars, scientists for the first time have produced a significant amount of power from controlled nuclear fusion. The achievement is a major step in harnessing for constructive human use the kind of thermonuclear fire that lights the sun and produces the awesome blast of the hydrogen bomb.”
  • 2003 – “With a blast of X-rays compressing a capsule of hydrogen to conditions approaching those at the center of the Sun, scientists from Sandia National Laboratories reported today that they had achieved thermonuclear fusion, in essence detonating a tiny hydrogen bomb.”
  • 2003 (cont.) – “But sustaining a dense hot cloud of hydrogen gas has proved trickier than scientists thought when they started fusion experiments 50 years ago. Even proponents say decades of research and expensive reactors are needed before a commercial power plant is possible.”
  • 2005 – “A standing joke among scientists is that fusion power — the holy grail of those seeking a boundless supply of energy to supplant fossil fuels — is always decades away. That has been the guesstimate for half a century, and it remained the guesstimate last week when an international consortium announced that it had finally resolved an internal struggle over where to site an experimental nuclear fusion reactor. “
  • March 2014 – “Fusion, the process that powers the sun, is the forever dream of energy scientists — safe, nonpolluting and almost boundless. Even here at Lawrence Livermore National Laboratory, where the primary focus of fusion work involves nuclear weapons, many scientists talk poetically about how it could end the world’s addiction to fossil fuels.”
  • March 2014 (cont.) – “The running joke is that ‘fusion is 30 years in the future — and always will be.’ Now, however, scientists here have given the world some hopeful progress.”

So why the continued investment? Well, fusion really is potentially far cleaner (3000x) than existing fission reactors. And real progress has been made. But consider this Joe Romm quote from Think Progress:

I have never been a big fan of earth-bound fusion, in part because I was an M.I.T. undergrad in October 1983 when Prof. Lawrence Lidsky published his famous critique, “The Trouble With Fusion,” in the MIT-edited magazine, Technology Review, with that unforgettable cover quoting his devastating conclusion. [ed. the quote was “Even if the fusion program produces a reactor, no one will want it.”]
What made the critique doubly devastating was that Lidsky was then associate director of the Plasma Fusion Center and editor of the Journal of Fusion Energy!

This was about the same time I was working for the grad student mentioned above. Needless to say, when he first told me the line about fusion forever being 20 years away, he also mentioned he was somewhat concerned about his choice of Ph.D. specialization. In retrospect with good reason.

More from that Joe Romm piece:

I was at the Department of Energy when the decision to approve the National Ignition Facility was being made. I can’t say any of the energy analysts thought it a particularly worthwhile investment. I can say non-energy considerations ended up playing a much bigger role in the decision than energy considerations.

Romm is referencing funding for the National Ignition Facility, but really the point could have been made for many other fusion projects over the decades. So is it just politics? In particular legacy interests left over from fusion hydrogen bomb research from the cold war? Clearly that’s part of it. But as someone who has followed this off and on for 30 years, there’s another aspect in play. The sun is awesome awesome marketing. So fusion proponents use it to good effect. Simple as that. It shows up all the time when people write about it. Rarely as directly as saying the sun is good so fusion is good. But often close. So let’s take a moment to see why generating electricity using nuclear fusion here on earth is different than the sun’s version of fusion.

  • The sun could fit a million earths inside it. That size makes the sun a poor model for an electrical power generation plant here on earth. Power plants are smaller.
  • The sun gushes insane amounts of radioactivity. Without the protection of the earth’s atmosphere, solar flares would kill you. Even from 93 million miles away. If you got within a million miles, you’d be vaporized. Scroll back up to the top of this post for a visual.
  • You get the idea. In reality the sun as a marketing hook should backfire. The sun is a seething hellish ball of burning gas. So yes, it’s a convenient illustration of fusion in the wild. But the sun’s mere existence doesn’t provide evidence either way for how difficult it would be to build a safe and economical fusion power plant here on earth.

Snark about the sun marketing angle aside, funding basic research on fusion is fine. After all, something can be technically impossible until suddenly one day it’s not. It happens. But after so many decades of hype, why not cut back on fusion funding a bit to go after more promising alternatives?

_______________________

Related posts on energy:

 

 

3 thoughts on “Contrary to popular belief, fusion power generation is not really like the Sun

  1. I don’t know much about fusion, but my thoughts were that the fusion in the sun was caused by gravity. I don’t understand how gravity could be used to create fusion on Earth. So what sort of ideas are these fusion people coming up with that don’t involve gravity as the cause of the fusion?

  2. I would like to know if scientists measured the rate of proton – deuteron fusion in the sun and if it actually is higher than what theory predicts. For a given fuel density and energy level, theory predicts a rate of fusion. In the cast of proton-deuteron fusion, I would like to know if the measured rate in the sun is actually higher than what theory predicted.

    Where can I find that information ?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s