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How close is nuclear fusion power?

Sabine Hossenfelder · 763.6K views · 2021-10-02 · 12:50

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Overview

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.

On Hacker News

HN commenters post it under nearly every fusion breakthrough story as the standard reality check on Q-factor hype.

Recommended by 15 HN people across 7 months · HN mentions 2021–2022

Topics

Nuclear power & fusion
Search by tags
fusionITERq-factorbreak-evenenergy hype

What people said

amai · 2022-12 · Strong recommendation

Mandatory video by Sabine Hossenfelder: [VIDEO] So they probably are talking again about Q_plasma, not Q_total .

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supergirl · 2022-12 · Strong recommendation

everyone should watch [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.

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limaoscarjuliet · 2022-02 · Strong recommendation

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. [VIDEO] For years, I was hoping fusion is close. After watching Sabine's video, I'm not so optimistic anymore.

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Sources

Video by Sabine Hossenfelder, played through YouTube.

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