amaiDec 2022Strongly recommends
Mandatory video by Sabine Hossenfelder: ▶ this video So they probably are talking again about Q_plasma, not Q_total .
in “US scientists boost clean power hopes with fusion energy breakthrough” · View on HN
How close is nuclear fusion power?
How close is nuclear fusion power? on HackerTube: recommended by 15 Hacker News commenters across 7 separate months, 2021–2022.
Sabine Hossenfelder
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Sabine Hossenfelder explains how close nuclear fusion really is to break-even, and why headlines about ITER and lab milestones are misleading. She distinguishes plasma gain (Q plasma) from whole-system gain (Q total) and shows the latter is still far below one.
Why Hacker News recommends it
HN commenters post it under nearly every fusion breakthrough story as the standard reality check on Q-factor hype.
- people recommended it
- 15
- separate months
- 7
- strong recommendations
- 5
- discussed on HN
- 2021–2022
“Mandatory video by Sabine Hossenfelder”
What HN commenters said
20 Hacker News comments link this video. Each one links back to its thread.
supergirlDec 2022Strongly recommends
everyone should watch ▶ this video to put this into perspective. for some reason, all the news articles are extremely misleading. previous output ratio for this fusion method was something like 70%, now it is 150%. it's a useful improvement, but not a major breakthrough. the whole system still consumes 100x more energy than it produces. 100MJ of energy is needed to power the laser. the laser generates only 2MJ of energy that powers fusion. fusion generates 3MJ of output energy. so all the articles are saying "they put 2MJ energy and got 3MJ energy back". no, they put 102MJ and got 3MJ.
in “US Department of Energy: Fusion Ignition Achieved” · View on HN
limaoscarjulietFeb 2022Strongly recommends
According to Sabine Hossenfelder, published numbers are frequently mis-stated on purpose. When you look at frequently reported Q Plasma (or plasma efficiency) we are not that far from it being > 1. However, we should look at Q Total (total efficiency), which is still way below < 1, even in the best plans. ▶ this video For years, I was hoping fusion is close. After watching Sabine's video, I'm not so optimistic anymore.
in “Major breakthrough on nuclear fusion energy” · View on HN
TaylorAlexanderNov 2021Strongly recommends
It’s true that ITER will not produce net power and that the administrators have misled the public about the difference in Q factors. You can have a reactor which produces more thermal power than you put in to it that is still a net power drain when you factor in the rest of the plant operations to keep it going. All clearly explained in this great video. ▶ this video There is a real risk that by focusing on the wrong Q factor you sink all your budget in to plants which can never work as a real power plant. Still I am hopeful that ITER will be sufficiently valuable as a research system that we do move closer to commercial fusion power.
in “The chase for fusion energy” · View on HN
lisperOct 2021Strongly recommends
Neither. From TFA: "While the latest experiment still required more energy in than it got out, it is the first suspected to reach the crucial stage of ‘ignition’, which allowed considerably more energy to be produced than ever before, and paves the way for ‘break even’, where the energy in is matched by the energy out." Here [1] is an excellent video by Sabine Hossenfelder about why you should not get too excited about this result. [1] ▶ this video
in “Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab” · View on HN
mbar84Dec 2022Recommends
The question is, in terms of energy input, are we talking about Q-total or Q-plasma? Based on the video by Sabine Hossenfelder, my guess would be, the announcement references Q-plasma. That would mean that the announcement is a motte-and-baily miscommunication, as it promises much more than people are lead to read into it. Motte: We got more energy out than we put in. Bailey: Oh, what we really meant is, more energy was produced, than was put into the plasma, though we didn't actually capture any energy and also, there was actually a great deal of energy also needed to run all the ancillary systems to keep the plasma confined. How close is nuclear fusion power? ▶ this video
in “U.S. to announce major breakthrough in zero-carbon nuclear fusion energy” · View on HN
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rogerallenDec 2022Recommends
▶ this video explains the difference between Qplasma and Qtotal. I hope this presentation will be as forthright.
in “DOE SEC. Granholm to Announce Major Fusion Energy Breakthrough 10:00 Am EST” · View on HN
planck01Aug 2022Recommends
I hope you win! I usually get my reality checks from Sabine Hossenfelder, who a while back explained that all these fusion claims are wildly optimistic. You can find her video here: ▶ this video I am no scientist, so it is hard for me to know if team optimistic or team pessimistic is right. But even if it is the latter, I think we should put more money and research on it!
in “Three papers highlight results of record yield nuclear fusion shot” · View on HN
chiiMar 2022Recommends
This video details some of the ways that nuclear fusion energy reporting gets done (both media, but also the industry) : ▶ this video We are not near a viable fusion reactor yet. Not close.
in “HB11's hydrogen-boron laser fusion test yields groundbreaking results” · View on HN
jetruFeb 2022Recommends
Skeptical. This video by Sabine clearly explains why a lot of these fusion research claims are dubious with a focus on ITER and JET: ▶ this video
in “Nuclear-fusion reactor doubles record for energy made from fusing atoms” · View on HN
nuccyJan 2022Recommends
There is quite some misleading terminology being used in the field of nuclear fusion (see excellent overview here [1]). So I was genuinely curious what kind of Q is used in this paper, so here it is: > In this regime, self-heating from α-particle deposition exceeds the external heating input into the DT8; this ratio is denoted Qα, where the self-heating is taken relative to the heating power to the plasma—for inertial fusion this is the PdV compressional work on the fuel and not the total laser energy (P, pressure, dV, volume change). Qα > 1 is a burning plasma. So as far as I understand such Qα > 1 can be reached without sustaining neither pressure or volume, so one can think about it as an explosion rather that intuitive burning (somewhat continuous process). To summarize: Q_total = total_energy_out / total_energy_in is what matters, not any Q related to plasma energy. Since to build a power plant we just care what it consumes in comparison with what it produces. For this particular case even though Qα > 1 you likely can extract just a tiny fraction of that energy stored in plasma, while spending huge amounts of energy to heat it in the first place. 1. ▶ this video or as an article [link] Edit: I'm a big proponent of nuclear fission and fusion since both are the best (current and future) way of getting carbon neutral energy, which can cover the spikes in the grid and sun/wind-less days. It is just important to be careful with the terminology, which can be used to make research r
in “Burning plasma achieved in inertial fusion” · View on HN
jahnuNov 2021Recommends
Can anyone tell me if this is a net + like the lay person would understand it or something like the net + qplasma thing often misleadingly used when talking about tokamaks? Sabine Hossenfelders explains here: ▶ this video
in “Helion” · View on HN
AareyBabaNov 2021Recommends
This video by Sabine Hossenfelder has tempered my expectations. How close is nuclear fusion power? ▶ this video
in “Helion” · View on HN
tylermautheOct 2021Recommends
The claims on nuclear fission being just around the corner are wildly exaggerated. Sabine Hossenfelder has a great video [1] on this topic. I want fusion to be real too, but focussing on small scale fission and solar is probably a better idea. [1] - ▶ this video
in “Can Nuclear Fusion Put the Brakes on Climate Change?” · View on HN
vfclistsOct 2021Recommends
Funny how this story gets posted after soon after Dr Sabine Hossenfelder's debunking and deflate the fusion power hype - ▶ this video with a genuine Hans Gruber accent :)
in “Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab” · View on HN
belterJan 2022Cites it
Read the references you provided, but do you mind commenting briefly on the issue raised here: (At correct time) ▶ this video Edit: More specifically, would you argue the approximate calculation here is incorrect? (At correct time) ▶ this video
in “Burning plasma achieved in inertial fusion” · View on HN
david_dracoDec 2021Cites it
Sabine Hossenfelder essentially called the nuclear fusion PR a fraud, because they do not report true (full-system) efficiencies. ▶ this video
in “After years of doubts, hopes grow that nuclear fusion is near” · View on HN
gabrielblackNov 2021Cites it
I read then link to the other article explaining the new technologies developed by Helion that should permit commercially viable fusion reactors, there are no words about Q plasma or Q total: ▶ this video so the affirmation that "Nuclear Fusion Is Close Enough to Start Dreaming" could be other speculation of the press not supported by facts. Obviously I hope to be wrong.
in “Nuclear fusion is close enough to start dreaming” · View on HN
david-gpuOct 2021Cites it
Sabine Hossenfelder recently explained why breakeven fission is much further away than the public generally believes [0]. Without spoiling her explanation, it boils down to how you measure "breakeven". [0] ▶ this video
in “Ask HN: What excites you today (technologically speaking)?” · View on HN
tuatoruOct 2021Cites it
The mininum viable Qplasma would be in the neighborhood of 100.[1] Fusion may get competitive for electricity generation with a Qtotal > 500.[2] 1. Sabine Hossenfelder, How Close Is Nuclear Fusion? , ▶ this video 2. Nicholas Hawker, A simplified economic model for inertial fusion , [link]
in “Major nuclear fusion milestone reached as ‘ignition’ triggered in a lab” · View on HN