7 ms·

How close is nuclear fusion power?

17 points by agd 5y ago

willis936 5y ago
I haven't had a chance to watch this video yet, but the best video I've seen on fusion plant design came out in the past few weeks. It's titled "Former fusion scientist on why we won't have fusion by 2040". https://youtu.be/JurplDfPi3U https://youtu.be/JurplDfPi3U It really nails the feel of the fusion engineering community I've been in. Little things said in passing in this video don't show up in public facing videos (such as a reactor needing to be primarily heated via ECRH) yet are regular topics with experts.
- dgellow 5y ago
  Really good video, thank you for sharing!
fguerraz 5y ago
On top of everything you're saying, all the press about how close we are to achieving usable nuclear fusion is a huge distraction from the real problems we are facing. Energy production is but a tiny problem to solve to keep our planet habitable by humans. It's not even a big part of fixing climate change as even if we found the miracle technology today, it would take the best part of the current century to deploy it on an industrial scale, which would be too late. We need to fix what we _do_ with the energy, not just how we produce it. If we keep on building car parks and shopping malls and generally destroying what keeps us alive, even with clean energy, we are still doomed. Of course, research is essential and this is good research, but it's the press enthusiasm around experimental fusion reactors that I am criticizing here.
LBJsPNS 5y ago
20 years away. It's always 20 years away.
- pestatije 5y ago
  I thought it was 30 years, not 20.
  - ncmncm 5y ago
    Now it is never. The costs of alternatives to fusion are falling so fast that fusion cannot possibly ever catch up. Fusion was always going to be an extremely expensive source of power--much more than fission, which is itself not now competitive. Spend as much as you like on development, construction, maintenance, each dollar spent takes you farther from commercial competitiveness. Meanwhile, each dollar spent instead of on building out solar and wind brings climate catastrophe nearer. FRC D-He3 fusion might be a superb space drive. We don't know because dead-end Tokamak steals all the funding.
  - dredmorbius 5y ago
    20 is the new 30. (I also recall it being 30 years, for about the past 50.)
jvanderbot 5y ago
TFV says that key metric is ratio of output energy over input, Q. Q> 1 and you have generated energy. TFV picks apart reported successes by fusion experiments that say they have Q ~= 0.7 when in fact they are reporting the ratio of energy delivered to plasma (laser cost only) over heat measured (not electricity). TFV says actual Q values are closer to 0.1 or 0.01. Yes, that's silly of them to hype. The question is who is fooled. Do policy makers know? General public? The community? Sometimes context matters when reading tech papers but at any rate honesty and clarity matters.
rini17 5y ago
tl;dw: Sabine Hossenfelder explains that public is being misleaded by fusion industry touting "efficiency" as ratio of energy that goes only directly out of/into plasma. This is not total consumption vs. usable energy output of whole plant as you might expect. That one might well be 100 times less.
- willis936 5y ago
  >That one might well be 100 times less. It might be, but it isn't. Turn to page 170 of your copy of The Future of Fusion Energy. It goes through typical efficiencies of each subsystem then concludes: >"Multiplying these conversion factors (i.e. eta h&cd = 0.4 from the heating/current drive systems, eta steam = 0.4 from the steam cycle, and f blanket = 1.3 from the blanket), we see that Qeng is roughly a factor of 5 smaller than Q of the plasma." What's more is that due to self-heating, increases in Q becomes exponential. The distance (in terms of machine performance) from Q=1 to Q=infinity is much smaller than the distance from Q=0.001 to Q=1. So why are scientists lying to the public? The answer appears that they are not, but they simply are not being asked to explain the entire history and projected designs of fusion reactors. You need more than a TED talk or an audience who at least knows anything about physical sciences in order to even start that.
  - rini17 5y ago
    If anyone gets that kind of money, is merely "they were not asked to explain" good excuse for you? Anyway, what kind of error bars do these numbers have? We still aren't even at Qplasma = 1. As Sabine says it went from 0.67 to 0.7 in 24 years. For me that's clearly too soon to talk about "typical setup".
    - willis936 5y ago
      That was a misrepresentation by her. NIF is not MCF, it's an ICF weapons program. NIF also gets healthy funding while MCF does not. Look at PPPL's FIRE 1976 report [0]. We've been on logic 0. Given that, the progress we've made with the discovery of H-mode, integration of superconductors, MHD optimization and control, and now empirical turbulence modeling is wonderful. These advances are reflected in simultion and in real machines as triple product increases. True nuclear machines are expensive. We could have made a Q = 50 machine in 1990. We didn't. Want to fund it? If she wanted to actually show the progress of MCF performance she would have plotted triple product vs. time, where gains have been made faster than Moore's Law when Moore's Law still applied, for a period that began before Moore's Law and is continuing past Moore's Law. 0. https://fire.pppl.gov/us_fusion_plan_1976.pdf https://fire.pppl.gov/us_fusion_plan_1976.pdf
willis936 5y ago
This has been a fumble of communication by the fusion science community. The window for fusion power being a saving grace from climate change passed decades ago yet it has been the claimed raison d'etre for the research. The important thing to note is that even though all climate projections end after 2050, the world does not. Better late than never. A carbon-neutral, virtually-limitless fuel, on-demand baseload energy source will still be handy even if it's "too late to reverse climate change". It will likely have a longer term of being handy than than the internal combustion engine will. The argument this video makes at the end about "needing to spend research dollars wisely" is the exact thing the fusion researchers fear when overselling the state of the art to the public. They've been continually defunded and in spite of that still make progress. If they didn't tell the politicians what they wanted to hear do you think any fusion program wouldn't be mothballed by this point? The reality of the long-term value of the research should be enough. We, as a society, can and should afford fusion energy research. We can also afford solar panel research, energy storage research, scaling up of carbon-neutral energy sources, and still have plenty left over to address aging infrastructure and wealth inequality. The issue is how the effort of society is actually being spent is not really beneficial to society. Whether we fund fusion research or not will not change that. Fund the research.
- timmytokyo 5y ago
  >The argument this video makes at the end about "needing to spend research dollars wisely" is the exact thing the fusion researchers fear when overselling the state of the art to the public. Intentionally deceiving the public about the state of your research in order to procure funding might work in the short term. But in the long term it is bad for science. Why should the public fund people who lie?
  - willis936 5y ago
    We have an entire political class devoted to lying to the public. I expect better of the scientists, but if you were given the choice between having a chance at securing humanity's industrial course or being able to not stretch the truth, which would you pick? Importantly, this is a stretch of the truth with technically no lies actually being said. If you sat down and really talked to any fusion researcher they would not say a bald-faced lie.
DangitBobby 5y ago
Wow. I am so bummed about being lied to about this.
simonblack 5y ago
20 years away. It's been '20 years away' for the last 60 years, so I don't expect that will change much.

17 points by agd 5y ago

I haven't had a chance to watch this video yet, but the best video I've seen on fusion plant design came out in the past few weeks. It's titled "Former fusion scientist on why we won't have fusion by 2040". https://youtu.be/JurplDfPi3U https://youtu.be/JurplDfPi3U It really nails the feel of the fusion engineering community I've been in. Little things said in passing in this video don't show up in public facing videos (such as a reactor needing to be primarily heated via ECRH) yet are regular topics with experts.

dgellow 5y ago
Really good video, thank you for sharing!

fguerraz 5y ago

On top of everything you're saying, all the press about how close we are to achieving usable nuclear fusion is a huge distraction from the real problems we are facing. Energy production is but a tiny problem to solve to keep our planet habitable by humans. It's not even a big part of fixing climate change as even if we found the miracle technology today, it would take the best part of the current century to deploy it on an industrial scale, which would be too late. We need to fix what we _do_ with the energy, not just how we produce it. If we keep on building car parks and shopping malls and generally destroying what keeps us alive, even with clean energy, we are still doomed. Of course, research is essential and this is good research, but it's the press enthusiasm around experimental fusion reactors that I am criticizing here.

LBJsPNS 5y ago

20 years away. It's always 20 years away.

pestatije 5y ago
I thought it was 30 years, not 20.
- ncmncm 5y ago
  Now it is never. The costs of alternatives to fusion are falling so fast that fusion cannot possibly ever catch up. Fusion was always going to be an extremely expensive source of power--much more than fission, which is itself not now competitive. Spend as much as you like on development, construction, maintenance, each dollar spent takes you farther from commercial competitiveness. Meanwhile, each dollar spent instead of on building out solar and wind brings climate catastrophe nearer. FRC D-He3 fusion might be a superb space drive. We don't know because dead-end Tokamak steals all the funding.
- dredmorbius 5y ago
  20 is the new 30. (I also recall it being 30 years, for about the past 50.)

jvanderbot 5y ago

TFV says that key metric is ratio of output energy over input, Q. Q> 1 and you have generated energy. TFV picks apart reported successes by fusion experiments that say they have Q ~= 0.7 when in fact they are reporting the ratio of energy delivered to plasma (laser cost only) over heat measured (not electricity). TFV says actual Q values are closer to 0.1 or 0.01. Yes, that's silly of them to hype. The question is who is fooled. Do policy makers know? General public? The community? Sometimes context matters when reading tech papers but at any rate honesty and clarity matters.

rini17 5y ago

tl;dw: Sabine Hossenfelder explains that public is being misleaded by fusion industry touting "efficiency" as ratio of energy that goes only directly out of/into plasma. This is not total consumption vs. usable energy output of whole plant as you might expect. That one might well be 100 times less.

willis936 5y ago
>That one might well be 100 times less. It might be, but it isn't. Turn to page 170 of your copy of The Future of Fusion Energy. It goes through typical efficiencies of each subsystem then concludes: >"Multiplying these conversion factors (i.e. eta h&cd = 0.4 from the heating/current drive systems, eta steam = 0.4 from the steam cycle, and f blanket = 1.3 from the blanket), we see that Qeng is roughly a factor of 5 smaller than Q of the plasma." What's more is that due to self-heating, increases in Q becomes exponential. The distance (in terms of machine performance) from Q=1 to Q=infinity is much smaller than the distance from Q=0.001 to Q=1. So why are scientists lying to the public? The answer appears that they are not, but they simply are not being asked to explain the entire history and projected designs of fusion reactors. You need more than a TED talk or an audience who at least knows anything about physical sciences in order to even start that.
- rini17 5y ago
  If anyone gets that kind of money, is merely "they were not asked to explain" good excuse for you? Anyway, what kind of error bars do these numbers have? We still aren't even at Qplasma = 1. As Sabine says it went from 0.67 to 0.7 in 24 years. For me that's clearly too soon to talk about "typical setup".
  - willis936 5y ago
    That was a misrepresentation by her. NIF is not MCF, it's an ICF weapons program. NIF also gets healthy funding while MCF does not. Look at PPPL's FIRE 1976 report [0]. We've been on logic 0. Given that, the progress we've made with the discovery of H-mode, integration of superconductors, MHD optimization and control, and now empirical turbulence modeling is wonderful. These advances are reflected in simultion and in real machines as triple product increases. True nuclear machines are expensive. We could have made a Q = 50 machine in 1990. We didn't. Want to fund it? If she wanted to actually show the progress of MCF performance she would have plotted triple product vs. time, where gains have been made faster than Moore's Law when Moore's Law still applied, for a period that began before Moore's Law and is continuing past Moore's Law. 0. https://fire.pppl.gov/us_fusion_plan_1976.pdf https://fire.pppl.gov/us_fusion_plan_1976.pdf

willis936 5y ago

This has been a fumble of communication by the fusion science community. The window for fusion power being a saving grace from climate change passed decades ago yet it has been the claimed raison d'etre for the research. The important thing to note is that even though all climate projections end after 2050, the world does not. Better late than never. A carbon-neutral, virtually-limitless fuel, on-demand baseload energy source will still be handy even if it's "too late to reverse climate change". It will likely have a longer term of being handy than than the internal combustion engine will. The argument this video makes at the end about "needing to spend research dollars wisely" is the exact thing the fusion researchers fear when overselling the state of the art to the public. They've been continually defunded and in spite of that still make progress. If they didn't tell the politicians what they wanted to hear do you think any fusion program wouldn't be mothballed by this point? The reality of the long-term value of the research should be enough. We, as a society, can and should afford fusion energy research. We can also afford solar panel research, energy storage research, scaling up of carbon-neutral energy sources, and still have plenty left over to address aging infrastructure and wealth inequality. The issue is how the effort of society is actually being spent is not really beneficial to society. Whether we fund fusion research or not will not change that. Fund the research.

timmytokyo 5y ago
>The argument this video makes at the end about "needing to spend research dollars wisely" is the exact thing the fusion researchers fear when overselling the state of the art to the public. Intentionally deceiving the public about the state of your research in order to procure funding might work in the short term. But in the long term it is bad for science. Why should the public fund people who lie?
- willis936 5y ago
  We have an entire political class devoted to lying to the public. I expect better of the scientists, but if you were given the choice between having a chance at securing humanity's industrial course or being able to not stretch the truth, which would you pick? Importantly, this is a stretch of the truth with technically no lies actually being said. If you sat down and really talked to any fusion researcher they would not say a bald-faced lie.

DangitBobby 5y ago

Wow. I am so bummed about being lied to about this.

simonblack 5y ago

20 years away. It's been '20 years away' for the last 60 years, so I don't expect that will change much.