581 Comments
Comment deleted
Expand full comment

I’m pretty sure fusion reviewer is actually Dr Bruce Banner.

https://en.m.wikipedia.org/wiki/Hulk

Expand full comment

My joke when I was in grad school was that my job was "being one of Doc Ock's arms." After all, outside of Spider-Man 2, fusion researchers don't use complicated prosthetic rigs to run their experiments; that's what grad students are for.

Expand full comment

I thought this was a no doxxing blog.

Expand full comment

This is a technical puff piece for fusion; it is not a book review.

Expand full comment

What facts are in error?

Expand full comment
deletedJun 17, 2022·edited Jun 17, 2022
Comment deleted
Expand full comment

As an article for a lay person to understand the current state of fusion, I give this a 9/10.

As a book review, it's a 1/10.

Still appreciated and glad I read it, but it should be disqualified as a book review entry and just be allowed to stand alone as a primer on fusion and how close we are.

Expand full comment

That's my thought. While often a good book review uses a response to ideas in the book as the seed for a broader essay (like the previous one on The Dawn of Everything did), this one didn't obviously rely on the book in any particular way.

Expand full comment

Exactly my feelings as well.

Expand full comment

I think the other negative for me is that the major point, which I take to be "fusion might actually be 30 years away", buttressed by the various high probability estimates, is kind of pulled out of nowhere. The only arguments I see are (1) all we ever needed was money and time, and (2) high Tc superconductors have made more experiments possible.

Those aren't bad arguments, but I would wish they could be fleshed out a little more. *Why* is so much money needed? (OK I can kind of start answering that myself, but it would be much better to have a pro read, and surely it must be covered in the book.) What are the nasty engineering or physics problems that have been overcome? That's not easy to do for an audience that may be intelligent but doesn't know all your vocabulary, but I'm told the book did it, so some of that could be laid out here, too.

Expand full comment

Why is so much money needed?

Because the experiment needed had to be big. The two big bumps on the first graph correspond to "Build ITER" and "Build DEMO". It took us a long time to pull together enough money to build ITER.

High temperature superconductors allowed the experiments to be medium again, which decreased the cost by a factor of 10. We can now build a lot more of them, including from private capital.

The third factor is that China and Korea joined the game in about 2000. They've been spending more than anyone else and so are likely to finish their DEMOs (CFETR & K-DEMO) before 2040. I don't think that they're going to be first, so I didn't emphasize them as much, but they do provide more plausible paths to fusion.

There are nasty engineering and physics problems to overcome, but they aren't as important as the scale. And they take longer to explain than a book review.

Expand full comment

I think you can do better. The experiment has to be big is just a way to rephrase we need a lot of money. You need to say *why* the experiment has to be big. Yes, I can at least start to fill it in for myself, but to make a connection to people who aren't familiar with the physics you need to tease that apart for them.

Expand full comment

The larger the experiment is, the longer it takes for particles to move from the core to the outer edge. This improves the confinement time.

Explaining all of the relevant transport mechanisms probably takes too long for a book review, and is definitely too long for the comments.

Thank you for the advice.

Expand full comment

About half of the book reviews in the New York Review of Books over the last half century would be disqualified by a requirement to be more about the book than about the reviewer's own ideas.

Expand full comment

They have an implicit requirement that the reviewer artfully mentions the book or its author often enough to mask their own ideas as "commentary".

Next year, ACX should host a legit essay competition tier.

Expand full comment

Is that a defense of this review, or a criticism of the NYRB?

Expand full comment

This "book review" was plainly written by one of the authors or a close associate and is simply a summary of the book condensed into a blog post.

It shares the same fundamental flaw as the book: presenting some basic plasma physics and a bunch of lists of machines as if it were predictive policy analysis. Some PhD students decided to publish the first few pages of their literature review.

Expand full comment

As far as I could tell, the technical content is correct. It is not necessary to fabricate facts to write a puff piece, it's a matter of picking the facts that provide a favorable spin to the story being told; figure 3 is a case in point, i.e., multiply some numbers to create exponential growth that can be compared to Moore's law.

Expand full comment

I thought that I deflated the puff around figure 3 a few sentences later by pointing out that the trendline does not continue.

Expand full comment

Pointing out that the trend line does not continue creates a sense of failure being snatched from the jaws of victory.

I was experiencing cognitive dissonance up to seeing this figure. These book reviews have been good/excellent/superb, and this was my mindset when starting to read. Figure 3 slapped me around the face and I suddenly saw the 'review' for what it was.

Expand full comment

> multiply some numbers to create exponential growth

Lawson's criterion has long been used as a measure of how well fusion is working. It wasn't made up recently to make line go up.

Expand full comment

Lawson's criterion is usually plotted with temperature on the x-axis https://en.wikipedia.org/wiki/Lawson_criterion

Nothing wrong with switching things around to show a different perspective. Adding in a line to show a comparison with Moore's law is great marketing copy.

Expand full comment

This chart is also used in this paper (University of Technology, Sydney)

https://epress.lib.uts.edu.au/student-journals/index.php/PAMR/article/download/1385/1466?inline=1

Expand full comment

Yes, I've seen things like this 30 years ago. When you are looking at something versus time, you tend to plot it as something per time.

Expand full comment

There are not facts in error per se but the review still reads like a puff piece. Even if we solve the significant fundamental plasma physics problems, there are significant engineering challenges involved in fusion that are barely mentioned or brushed under the rug. These include the difficulty of effectively injecting tritium fuel, parasitic power consumption, proliferation risk, and radiation damage to the reactor itself. More on that last point: consider that DT fusion neutrons (14 MeV) are much higher in energy than fission spectrum neutrons (peaked at ~1 MeV). In other words, each neutron produced is capable of dealing much more damage to structural materials than in the case of fission. This issue is already a problem for fission reactors and will only be worse for fusion.

Of course, expecting all of these topics to be dealt with fully in a single book review is to set a high bar. However when the author makes strong claims outside scientific consensus (eg, giving Renaissance Fusion, who do not have even a prototype, a 70% achieving fusion by 2040) the burden of proof is on them.

I’m happy to see resources spent on fusion research. However the challenge must be tackled with a clear eyed view of the difficulty at hand.

Expand full comment
Comment deleted
Expand full comment

Two estimates I've seen for the additional cost to adding intermittent sources of power put it at $40 and $50 per MWh above the base cost at 50% of production, due to transmission upgrade costs and idle backup generation. This goes up so that they didn't even make estimates above 80-90%

There is a large target for either low carbon baseload or energy storage that wind and solar can't reach as is, so that I see fusion as a good candidate. In particular it seems like there's no appetite for funding nuclear to the wider world due to proliferation concerns where there might be for fusion

Expand full comment

$40 to $50 per MWh adds to perhaps 20 for the original power in PV in the US. That still makes it competitive with coal and natgas (~60), and much cheaper than fission (~100 to 120). So that's a big bar to leap.

There is absolutely no way any of the mainstream fusion designs discussed here will be cheaper than fission. Literally every single piece of the plant is more expensive and complex. Deuterium is not cheap, and the tritium is breathtaking even if we figure out how to breed it, which is an unsolved problem.

Even CFS puts the LCOE in the 200/MWh range for post-FOAK. We'll just build more batteries.

Expand full comment

I live in California, land of wind and solar to the max, plus the highest electricity rates anywhere, increasing faster than anywhere else, and major reliability issues -- like planned blackouts because the solar power goes off just when the air conditioning and TVs go on -- so you will hopefully understand why I regard "proven" as more of an ideological than empirical statement.

Expand full comment

To he fair, California has terrible regulation. Isn't eg net metering required by law?

Expand full comment

California is a great example of why a reliable, clean, energy source is badly needed (I'm agnostic on "cheap").

But the way Fusion Reviewer sets out his stall, there's a hell of a long chain of "ifs" - IF public research gets government funding and IF private investment capital takes up the slack and IF ITER works and IF these other things work and IF we decide on what is the best design and so on and so on.

Other people in the thread are pointing out weak links in this chain. I get that he's an enthusiast (a fusioneer!) and so all his geese are swans, but criticism can't be brushed off simply by "you're a wet blanket".

Expand full comment

Fusion is not intermittent.

If fusion is a good idea in the long run, then at some point, someone needs to invest in it.

Expand full comment
deletedJun 18, 2022·edited Jun 18, 2022
Comment deleted
Expand full comment

I do think that we should invest in wind and solar as well. It is proven that they work at the scale we've deployed them, but not that they will work for 100% of our electricity. Mechanical energy storage solutions might work, but they have not been proven to work at the scale we need. Since there is uncertainty here, we should pursue multiple options.

If fusion is what we're going to end up using in the long run, we might as well get to where we can use it in the medium run too.

Expand full comment

I agree completely, but if we could only do one form of energy resource development at a time, fusion would not be my choice.

FWIW, I'm a MarcorLife proponent, so my main interest WRT fusion is powering really large space habitats beyond Saturn's orbit. Fusion is clearly the best choice. Locally, though, I'd put more efforts into improved batteries and other forms of energy storage. (Solar heated molten salt has its points. So do various other options.)

OTOH, the original presumption is false. We can and do invest in more than one option at a time. I don't think we're over-investing in fusion.

All that said, while I found it a very interesting argument, I didn't think of it as a book review at all. (And I couldn't really figure out how to combine those "estimates of success" to derive a final "these are the odds". I don't really think those estimates are independent.)

Expand full comment
Jun 24, 2022·edited Jun 24, 2022

Fusion is extremely intermittent. At present it typically happens for a microsecond, once every few weeks. This is just one of several rather intractable engineering problems with it.

Those other problems taken together make fusion unlikely to be worth investing in for any purpose other than curiosity.

Expand full comment

Hi!

Re. why invest in fusion over other sources? My leading order answer is that I don't believe it's a dichotomy, and even if it were, it's good to not put all eggs in basket.

Re. climate change timescales and energy transitions, potentially, but you need low carbon base load. If you're (politically?) brave, you go for fission. If you're smart, you solve affordable fusion. I don't see many other options for base load unless energy storage and grid management improve a lot.

Keep an eye on SPARC in particular for faster fusion.

But yes, let's build 'renewables' as fast as reasonably possible.

Expand full comment

To handle climate change you don't plan of fission or fusion power unless you're willing to handle a temperature rise of 2.5C+. They will/would take too long to come on-line.

What you do is really build out solar and wind (and other) sources of energy while at the same time really building out LOTS of separate storage facilities. I'm not a fan of Hydrogen, but if you overbuild the generation, you can use excess when you have it to generate fuel of some sort. (My preference would be a kind of gasoline derived from atmospheric CO2. That would be energy intensive, but you ARE dealing with an energy surplus.)

Expand full comment
Jun 18, 2022·edited Jun 21, 2022

The high estimate for Renaissance Fusion is partly because I know them and am impressed by some of the ideas that they have not yet made public. I think that's my statement farthest from scientific consensus. Maybe my prediction for Type One Energy too. If you do downgrade these estimates, the headline prediction does not change by much.

The problems that you describe are real, but I don't think that any are insurmountable. The 14 MeV neutrons should be almost entirely absorbed by the tritium breeding blanket. The book has an entire chapter on proliferation risk. I have not looked into the other problems in detail.

Expand full comment

Stellarators are perhaps the worst idea in fusion. Well, no, ICF is, but they're close.

Compared to a tok, they require dramatically larger numbers of individual magnets, the magnets (usually) have to be fantastically complex, the machine has to be built to a standard that is difficult to meet (to the point that NCSE was abandoned), maintenance is practically impossible, and their aspect ratio is absolutely terrible which leads to bad economics and really expensive tritium breeding.

The world's best stellarator currently posts numbers roughly equivalent to those being generated by toks in the 1980s. They have two orders of magnitude in triple product to meet current results. Crossing those two orders led to all sorts of unexpected new problems in the toks, which is why the graph flattened. There is no reason to suspect that the same will not happen in stellarators.

I'm not sure what secret sauce Renaissance claims to have, but it seems unlikely they have overcome *all* of these issues, especially the last one.

Expand full comment

I don't know nearly enough about Fusion to declare it a "puff" piece, but I agree it isn't really about a book.

In fairness, last contest's Georgism review wasn't particularly about Progress and Poverty but rather about Georgism as an ideology, and it won.

Expand full comment

The difference is that Progress and Poverty is a founding work of Georgism.

Expand full comment

And the Georgism review was well-grounded *in the book itself*!

Expand full comment

A couple of links to commentary on the state of play by others (neither paint as rosy a picture as this 'review')

https://inference-review.com/article/the-quest-for-fusion-energy

Sabine Hossenfelder 's take (her blog should be on everybodies rss feed)

http://backreaction.blogspot.com/2021/10/how-close-is-nuclear-fusion-power.html

Expand full comment

Wow. What Hossenfelder writes isn't just a "not rosy" take, she's basically claiming the entire field of fusion research is fraudulent to the core. Having read that my interest in fusion is now sub zero. Assuming that's true and I see no reason why it wouldn't be, all government research for fusion needs to be cancelled, right now.

Expand full comment

I mean, I think I'm a pretty average lay man with an superficial interest in fusion power, but I have known the difference between plasma break-even (which I think is the same as scientific break-even, Q=1) in OP and total break-even (engineering break-even, claimed to be ~Q=5 in the article, so 5 times as much) for a while now. This is explained in many articles I've encountered as well as in the OP, so it's not like this is some obscure thing that the fusion community is trying to hide from us.

Expand full comment

Plasma breakeven is the same thing as scientific breakeven.

The same plasma can have different engineering breakeven, depending on how the rest of the experiment or power plant is designed. ITER should have Q=10, but not hit engineering breakeven. If you took off a lot of its diagnostics and didn't have four different ways of heating the plasma, then it probably could get engineering breakeven. But it wouldn't be as good of an experiment. We want to get lots of data about what the plasma is doing and we want to try out multiple versions of different subsystems to see which one works best.

Expand full comment

The point here is that this "Q-plasma" take isn't something anyone cares about. Take the non-book-review, it says:

"We also measure the success of fusion using Q ... Q is entirely determined by the triple product."

That's the definition of Q-plasma to use Hossenfelder's (?) terms. For fusion to be a success in the way everyone else thinks about it means that it not only needs an "engineering breakeven" of >1 but it needs to have that with also a chance of being profitable ("financial Q") and relatively low risk to run the power plants. Note that profitability is so far from fusion researcher's minds it's apparently not even worth a mention in the article, have they even ever attempted to calculate this?

The issue here is that if fusion researchers really are defining success purely in terms of plasma energy balance, then how much effort can they be putting into researching all the rest of it? The article states clearly that "success" for fusion is as simple as improving Q-plasma. That's not a type of success meaningful in the real world.

And how can anyone defend the comments of the ITER guy?

"ITER will be the first fusion reactor to create more energy than it uses. Scientists measure this in terms of a simple factor—they call it Q. If ITER meets all the scientific objectives, it will create 10 times more energy than it is supplied with"

That is a directly misleading statement, isn't it?

Expand full comment

I do mention profitability in footnote 7:

"There is also ‘engineering breakeven', when you get more energy out of the entire power plant than you put in, and ‘economic breakeven', when you get more money out of the entire power plant than you put in. We need to get scientific breakeven first."

There have been some people who try to calculate the profitability, but a lot of the relevant questions are unknowable until we build a full scale experiment. For example, there has been some discussion elsewhere in these comments about the maintenance schedules for materials exposed to 14 MeV neutrons. We won't know this until we get a good source of 14 MeV neutrons, which means we need a fusion reactor.

Expand full comment

I would not have explained Q in that way. So no, I'm not defending those comments. They're also from an interview from 2006, which feels kind of cherrypicked. If you go to ITER's website, it says:

"ITER will be the first fusion device to produce net energy. [i] Net Energy: When the total power produced during a fusion power pulse surpasses the thermal power injected to heat the plasma." https://www.iter.org/proj/inafewlines

Bigot speaking to the US House is more concerning to me, because it seems less likely to be cherrypicked. It took quite a bit of effort to find the transcript of the conversation: https://www.govinfo.gov/content/pkg/CHRG-114hhrg20871/html/CHRG-114hhrg20871.htm

What we see in Hossenfelder's video is spliced - the question and the answer are not related. The question is from Grayson's opening statement. The response is from a discussion between Bigot and Foster about heat flux to the diverter. Bigot's quote continues: "It is materials, okay. When we will have continuous production of plasma energies, with some energy flux with neutrons which are as large as 20 megawatt per square meter". They are talking about the energy in the plasma and how it will impact the diverter, not the overall efficiency of the plant.

Expand full comment

My take was that the research had been captured by people motivated by writing papers, not by creating something that generates electricity.

I think that Fusion can be made to work in practice, provided the time/money is invested to solve the unforeseen technical and social (e.g., team incentives) problems. And yes, it is probably still many decades away.

Expand full comment

Your take seems to be compatible with a call to cancel funding for government fusion programs?

Private fusion efforts would still be worthwhile.

Expand full comment

Governments are the only bodies willing to fund projects that require waiting several decades before anything tangible appears.

Funding is a known problem, but how do you incentivize people to work on a problem for their entire career?

Planetary scientists have it tough with a 10-year cycle to plan/build/launch a planetary probe, which is just a third/quarter of their career.

Expand full comment

I think there's a lot of daylight between a certain degree of salesmanship, of which I think it's fair to say Hossenfelder accuses the fusion leadership, and an actual fraud (which she does not). Just think of the muddle between Q_plasma and Q_tot as the fusion equivalent of Tesla's "Full Self Driving."

There's still a serious issue here. ITER costs a crap-ton of money and time, and necessairly that means any *other* approach gets a little starved of oxygen. It's reasonable to be worried that this is not the right choice, although that has to be set against the possibility that there *is* no good choice that doesn't involved enormous piles of money and decades of labor. Reasonable men can easily disagree on the better way forward.

Expand full comment

Not sure Tesla FSD is a good example - that one may well end up in litigation. Wouldn't be at all surprising if it did at least; selling features you can't actually provide will eventually get the courts involved. See: Elizabeth Holmes. And there are sure a lot of people upset with Musk lately.

The issue here is more that, once again, we find scientists making flatly misleading statements to government and the public and then hiding behind "oh you just don't understand our technical language". I'm getting real tired of this. It's reminiscent of the way that the word "unvaccinated" doesn't mean to Pfizer/public health what it means to everyone else, or how "record breaking temperature" also doesn't have the definition you'd expect when coming from climatologists. The public will learn to stop trusting scientists thanks to this kind of practice. Arguably that's already happening.

There's a simple fix: fusion researchers need to stop talking about break even as a concept. Being extremely generous and assuming it's not deliberate, their own project leaders are sufficiently poor communicators that they keep misleading the public about what "break even" means. Even the definition of "engineering break even" is pretty useless: nobody would describe a machine as break-even if it generates more electricity than it uses but requires fuel only found on Jupiter.

Expand full comment
Jun 19, 2022·edited Jun 19, 2022

OK first of all, the public rarely hears from actual scientists doing actual work. What they usually get is science reporting, which works like this:

https://www.smbc-comics.com/comic/2009-08-30

Precise definitions of terms, and a carefully nuanced reporting takes a big backseat to "Fusion Real Soon Now! Rejoice!" or "Fusion: Giant Deplorable/Woke Fraud! Be Outraged!" in terms of page clicks, and those sweet sweet advertising dollars.

Secondly, people go *into* science in no small part because they don't *like* dealing with people, and aren't skilled wordsmiths, highly attuned to the implications and overtones their audience might take away. The stereotype of the scientist as a clueless one-dimensional dweeb who may fully grok quantum chromodynamics but gets tongue-tied ordering a sandwich is based in reality -- people who can *do* science are almost never very good at *explaining* it. And the people who have PhDs and end up doing a lot of talking to the public with some success are often a bit further from the front lines and drifting further away with time -- and develop their *own* concerns that are distinct from (1) understanding the science perfectly and (2) reporting on it dispassionately -- like, how's my new career as a science communicate going? How many "likes" are my Youtube videos getting? If they end up working for government then it gets even worse, because then it's also (3) is this going to play well/poorly with my politician employer?

Third, stuff like fusion (as well as a lot of other high-energy physics) is so expensive and labor-intensive these days that it's only done in teams of hundreds, massive collaborations. Under those cirx you don't have line workers talking to the media, you have a professional manager and professional PR staff, and for *them* their salaries are *all* about this particular project. You can't realistically expect the Director of CERN to give an objective evaluation of whether the LHC is worth the cost, any more than you can expect the CEO of United to speak objectively on whether it's better to Fly the Friendly Skies or take Ryanair and save a buck.

What investors learn rapidly, but which seems to strangely escape the Wikipedia generation, is that high-quality information is NOT FREE. It's not even cheap, it's very, very expensive, because it represents significant time and effort from somebody who is well-informed and skilled in the field. You want high-quality reporting on some issue that falls within my professional expertise, I'm happy to sell it to you, but my consulting rates start at $300/hour. Would you sell your professional skilled time for peanuts, or give it away? I mean, maybe randonly every now and then, as it amuses you, but on a regular basis you've got to pay your mortgage and all you've got to trade for dollars is your expertise.

So if you consume free information, be aware that the *true* customer for the reporting is not you -- it's whoever is actually footing the bill -- and adjust your expectations and skepticisms accordingly. If you want first-class accurate information, be prepared to pay beacoup for it. It's pointless to get mad at people who are enmeshed in the same economic necessities as the rest of us, and responding to the same signals and forces.

Expand full comment

How does "record breaking temperature" not have the definition I'd expect? What's the actual definition?

Expand full comment

Fusion research is plasma research. Don't expect anything more out of it.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

Nah, Hossenfelder had good points but has now gone completely on the contrarian for contrarianism sake side. I used to follow her blog since 2013, i stopped some three years ago.

She's probably right on LHC successor but as an example her piece on Ligo and gravitational waves was bad faith nitpicking.

Expand full comment

She definitely has gotten used to being a contrarian. And there is a place for contrarians in popular science.

Most of her videos are about cosmology or high energy physics. These fields have lots of people who communicate them to the public. Brian Greene and Michio Kaku come to mind. Having one contrarian among many popular scientists is often a good thing.

I don't know if she realizes how few popular plasma physicists there are. Her Youtube channel is much larger than ITER's (472K vs 63K subscribers), let alone Commonwealth's (1.7K). For a lot of her audience, this is the most they've ever thought about fusion. I don't like that the contrarian is the only voice a lot of people are hearing.

Expand full comment
Jun 19, 2022·edited Jun 19, 2022

I agree that contrarianism has a place (boy, i am contrarian myself) but even in hep she is not the best critic around (i would say Peter Woit wins on that).

She nitpick something she doesn’t like (like the definition of Q in this case, or the way the LIGO experiment checked the electromagnetic counterpart) and blows it up beyond proportions to claim that the entire field is rotten. Between other problems, this also makes it impossible to make a good and fair criticism where needed.

Even at her best in hep, it's not like her criticism are particularly great. Naturalness in particle physics is definitely a failed paradigm and dissecting why it failed is crucial to move forward the field (and this is not being done by the community). However, I don't think her explanation for why it failed is correct, i much prefer Woit's argument (https://www.math.columbia.edu/~woit/wordpress/?p=12108), but admittedly that may be saying more about my biases.

Expand full comment

Err, real science is all about nitpicking. If you're not nitpicking then you're not being rigorous, so if that's all you got for your assessment of her LIGO post, then it seems she proved her point.

Expand full comment

On DT fusion, Hossenfelder's problem is she isn't contrary enough. The big problems with DT were identified 40 years ago by Lidsky (and Pfirsch and Schmitter); DT fusion reactors inevitably have horrendous volumetric power density, at least an order of magnitude worse than fission reactors. This issue has nothing to do with plasma physics and is not solved by high-Tc superconductors.

Expand full comment

I have not yet read the first article. I have watched Hossenfelder's video.

Her main argument seems to be that she doesn't like how Q is defined and wants plasma physicists to define Q in a different way. Disliking someone's definitions is not enough to claim that an entire field is misinformation.

Expand full comment

This is a bad faith interpretation of that article.

Expand full comment

"In the technical literature, this quantity is normally not just called Q but more specifically Q-plasma. This is not the ratio of the entire energy that comes out of the fusion reactor over that which goes into the reactor, which we can call Q-total."

This is wrong. In the technical literature, Q is Q. Q-plasma and Q-total are terms that she invented in this video. I don't know of a single piece of peer review literature that uses her terminology.

Expand full comment

> This is wrong. In the technical literature, Q is Q. Q-plasma and Q-total are terms that she invented in this video.

Yes, they are terms invented in this video to clarify what fusion researchers are actually talking about. They are talking about Q-plasma where we're actually interested in Q-total. That's exactly what she meant by this paragraph, so no, it's not "wrong", it's clarifying the confusion.

Expand full comment

https://youtu.be/CnxzrX9tNoc?t=2849

From a recent video session Elon did at All In Summit. Not claiming EM knows this stuff best, but he seems clearly interested in the topic and would have had access to the people who know about this, and he would be looking at this from a practical/commercial rather than just scientific demonstration perspective.

Expand full comment

Elon Musk doesn't think fusion is economically viable:

- rare fuel

- heat to electricity will lose lots of energy

- maintenance of the fusion reactor

He thinks wind power and solar power will be the future.

Expand full comment

Elon Musk seems to have a cursory understanding of fusion, but hasn't looked into it in detail. Which is not surprising because we shouldn't expect him to be an expert about everything. He is both too optimistic and too pessimistic in different ways.

He says it's 100% technically possible because you just have to increase the scale. That's not how probabilities work: Would he take a million to one odds on that claim? Getting fusion is also not just an increase in scale. It's mostly an increase in scale, but whenever you make things bigger, there's a good chance that something will be different qualitatively too. This is why it's important to make progressively bigger experiments, instead of jumping from your first small prototype to a full scale reactor. Looking at the history of fusion, we have been surprised by both bad things (e.g. large turbulent transport) and good things (e.g. H mode) when we were just scaling things up. ITER and SPARC are designed for Q = 10 instead of Q = 5, so even if the experiment performs half as well as we think, it will still be good enough.

The rare fuel claim is interesting. Because it either means that he doesn't know about the tritium breeding blanket or it means that he thinks that it will never work. Tritium is very rare, but a fusion power plant should make all of its tritium on site out of lithium.

Transforming heat to electricity is done in most power plants today. I don't think it's a deal breaker.

Maintenance of the fusion reactor might be a serious problem. We don't know how much maintenance is needed until we have one running.

Putting these together, Musk thinks that fusion will cost an order of magnitude more than wind and solar. This is not outside the realm of possibility. But it's much too early to conclude that fusion will not be commercially viable.

Expand full comment

Jassby's claims that magnetic confinement fusion (MCF) has stagnated for the last 25 years, while inertial confinement fusion (ICF) has progressed. I do not disagree: "There has been little progress towards a larger triple product since 2000." I think that this is about to change, while Jassby does not.

There is a simple reason why MCF has not progressed. In 1997, the best MCF experiment in the world was JET. In 2022, the best MCF experiment in the world is JET.

There's only so much we can do with JET's size and magnetic field strength. They could probably get up to Q = 1.5 if they really tried, but not the Q = 5 that you need for a power plant. Instead, JET has been focusing on other important goals like getting the walls right and increasing how long they maintain the plasma. As soon as we get a better experiment, we will get better results, whether it's SPARC or ITER.

It is true that computer simulations did not predict JET very well and underestimated the turbulent transport. Computational plasma physics is a lot better than it was in the 1990s, along with everything else involving computers.

Jassby makes a big distinction between beam-thermal versus thermonuclear fusion. I don't know of anyone else who cares about that distinction. His footnotes for it all point to papers he's authored by himself.

There isn't a physical difference between beam ions and plasma ions. An ion typically has to collide a few hundred times before it undergoes a fusion reaction. So by the time fusion occurs, the ions from the beam are thermalized and are indistinguishable from the ions originally in the plasma.

He also seems to use the terms to describe how the plasma is heated. When the plasma is mostly heated by the beam, then Q must be small, and when the plasma is mostly heated by fusion, then Q must be large, ... because that's the definition of Q. The causality is backward. "For a purely beam-thermal system, the maximum theoretical Q is limited to less than 2" should be "When Q is less than 2, the system must be primarily heated by the beam."

Tritium is very expensive. You don't want your reactor to have to import it.

Each fusion reaction consumes one tritium and produces one neutron. Each breeding reaction consumes one neutron and produces one tritium. It looks like, in order to sustain this, you'd need perfect efficiency, which is impossible.

Which is why we're also planning on including a neutron multiplier: beryllium.

Be + n -> 2 He + 2 n

This increases the number of neutrons, which allows the system to sustain itself with less then perfect efficiency.

Jassby does not think that SPARC is a game changer: "improving cost-effectiveness is surely a distraction for MCF research". I disagree. Cost effectiveness is important on its own. And it means that we can build more reactors faster. It won't take us 25 years to get the money together to build the next big experiment.

I agree that inertial confinement fusion has made a lot of progress recently: "Progress has been extremely rapid. They crossed Q=1 a few months ago."

The big challenge remaining for ICF is going from 1 shot per day to 1 shot per second. NIF is not trying to do this, because fusion isn't their main goal. Maybe Marvel or someone else will figure it out. I hope that they do ! But I suspect that this will be harder than getting fusion using a tokamak.

Expand full comment

Why didn't you explain these interesting points in your 'review'?

A balanced discussion and explanation of the issues will likely have more impact than a blatant puff piece.

Expand full comment

I explained some of these points in my review.

I didn't go into the details of particular current experiments like JET or particular subsystems like the tritium breeding blanket to keep the review from getting too long.

Expand full comment

Sabine makes technically correct observations but they are generally less informative than the metrics she's criticizing due to scaling

ITER would have a Q-total of 1 with a Q-plasma of 10. But dial up the size and plasma powering so that the plasma has 80 MW of injected power instead of 50 MW and you increase power output by 5x as the reaction increasingly powers itself and you're talking about a net GW of electricity

There appears to be no commercial potential as it stands with ITER style tokamaks but last year a superconductor magnet was tested that doubles the magnetic strength. With current structural materials it should increase tokamak power by 10x for a given size, enabling commercial levels of power output that could be seen as possibly commercially relevant in price depending on developments

Basically at small experiment sizes the Q-total is overwhelmed by the facility size and at large sizes the relative information value of Q-total is overwhelmed by the rapid scaling potential. It's useful if you know things in some depth where if you don't I think Q-plasma is preferable

Expand full comment

"Dialing up the size" poses its own significant engineering challenges. It's not at all trivial or obvious that it would be feasible anytime soon. I guess we'll see.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

My model of last year's winner is:

(1) Pick a topic you know and care a lot about.

(2) Find the best book you can on that topic.

(3) Humorously but openly advocate for it.

There isn't a founding book on fusion like there is for Georgism. And I probably didn't execute this strategy as well Lars Doucet did. But I'm getting to talk to a lot of people about fusion and some people here like it a lot, so that's a success.

Expand full comment

Well I loved it. I’m guessing there are a lot more out there that did, too.

Expand full comment

I kind of like that some people use "book reviews" as a backdoor to make a guest post about something most readers will find interesting :)

Expand full comment

If the NYRB is good enough for Freeman Dyson, it's good enough for me.

Expand full comment

Right, as you go up the intellectual prestige level of book reviews, the the reviews become less and less tied directly to the book. At the daily newspaper book column bottom, reviews are about what the book has to say. At the New York Review of Books level, the reviews tend to be more about what the reviewer, who is an expert in the field, has to say about the subject.

Expand full comment

Well, Scott will surely be flattered that you think ACX is closer to the New York Review of Books than the Daily Yell.

Expand full comment

Yes, I think that's great. And there's a common genre of book review that does in fact review the book while doing this. This one was just a nice essay without really telling me much about the book other than that a plasma physicist thinks it's good and their parents think it's readable.

Expand full comment

Agreed. This reads as one person's opinion on fusion in general, not a book review.

Expand full comment

I have had a couple of looks through and I still can't figure out who the author of "The Future of Fusion" is, and now I'm stubbornly refusing to google it.

Expand full comment

Jason Parisi & Justin Ball

Expand full comment
Jun 17, 2022·edited Jun 17, 2022

“ Stellarators also have the best name, look the coolest, and are my favorite.”

It was worth my subscription just to get nuggets like that.

Expand full comment

No thoughts on General Fusion or TAE? As an interested lay person, I like General Fusion's approach (Steam pistons! Liquid metal vortex!), and it seems like they've made substantial progress, recently settling on a site in the UK for a demonstration scale plant.

Expand full comment

I'm in the Vancouver area so I hear about General Fusion all the time, but can never tell where they stand relative to others in making substantial progress.

Expand full comment

I don't know a lot about either of their designs, so I don't want to make too strong of statements. But I'm skeptical.

General Fusion:

Compressing a plasma is really hard. NIF has spent more than a decade figuring it out. That being said, General Fusion's plasma is magnetized, so it doesn't need nearly as much compression as NIF.

The liquid metal vortex is made of lithium-lead. If the lead gets into the plasma, it will radiate out too much energy.

TAE:

They're using proton-boron fuel, which means that they need to make their plasma 10 times hotter and 10 times better confined than if they used DT.

Both of these companies have interesting designs for their experiments. I wouldn't be surprised if some variation of these designs could work. I don't think that they're particularly close to success, but maybe that's just because I don't know.

Expand full comment

TAE has said they will licence their design for DT fusion if energy companies want to build them. However proton-boron seems so unlikely in a steady state configuration it feels reasonable to question their general assessments of their technology potential. I'd say the same about Marvel, we're basically counting on some radical laser developments though as far as I understand it's at least conceivable to do pulsed proton-boron with the effects of lasers that accelerate the target fuel so fast the energy transfer is non-thermal

I'd put General Fusion in the same boat as Marvel at least. They have good engineering advantages such as guaranteed excess tritium production and a fully liquid wall facing the fusion reaction

Despite Commonwealth Fusion System's top funding and reputation it appeared to me that their engineering problems were in need of a dramatic unknown advance to target a commercial electricity price so that the real medium term front runners were the Helions and General Fusions that need big luck in physics but could at least project commercially relevant prices. However it seems that has changed with a new simulation prediction that high power tokamaks will be able to double density or more, which could quadruple power. Now where you had a price per MWh of well over $100 for CFS ($260 for the original ARC proposal albeit not intended to be a commercially optimized configuration) vs Helion's $60 or lower it's now conceivable for tokamaks to be commercially relevant if there aren't major downside surprises for steady state high power plasmas

Expand full comment

I don't think that Helion and General Fusion have an advantage over Commonwealth. Getting the physics right is usually a prerequisite for being able to estimate what the commercial electricity price will be. Helion's price estimates are a lot more made up than Commonwealth's.

General Fusion might be in the same boat as Marvel. I put Marvel higher because progress at NIF has been much better than I expected over the last 2 years. Using the wrong fuel is still a major problem for Marvel - if they succeed, I expect that will change their mind and use DT instead. General Fusion doesn't have a big national lab doing something similar to learn from.

Expand full comment
Jun 20, 2022·edited Jun 20, 2022

Do you think that TAE needs to be aneutronic to make the geometry of their machine work, i.e., is it simply impossible to put an effective blanket around a colliding FRC machine, or are they merely pushing p-B11 because it's sexy?

I'd also like to hear your opinion on MagLIF. To me, it seems by far the most rational of the magnetized target experiments, and they seem to be making steady progress and have scaling that isn't obviously insane. Also, given the fact that it's a Sandia Z-Machine experiment, they get a fair amount of money for doing something that could eventually provide cheap fast neutrons for [CLASSIFIED] at a fraction the price that NIF requires.

Expand full comment

Hi!

I think that a long term play of p-B11 fusion a-la TAE might make sense if they can conjure up some fancy physics (read, non-Maxwellian) to minimize radiative losses.

Potentially interesting:

https://www.princeton.edu/news/2022/03/10/fisch-receives-funding-unlikely-fantastic-clean-energy-technology

Expand full comment

There seems to be a lot of negativity around this subject. My understudying is the science of this is accepted. It will work. The great difficulty is the engineering. This will be by far mankind’s greatest engineering challenge.

A lot of people will be upset if engineers solve this problem and the world continues on in energy abundance. How can we have Mad Max or some other dystopian future if engineers solve all the problems? Mankind must suffer!

Expand full comment
Comment deleted
Expand full comment
Jun 17, 2022·edited Jun 17, 2022

For some it’s just healthy skepticism. For others it’s something else.

Expand full comment

"De-growthers" are environmentalists who believe we need to reduce the economy and energy usage in general in order to preserve or restore the environment. They would be strongly opposed to cheap clean energy because of the "cheap" part: if it's cheap, then people will use it to make more stuff, mine more stuff, build more building, have more babies, etc. Which (they believe) will put more strain on the environment.

So some people would mind. Your average person, of course, would be very happy. But then again, the average person doesn't think life would be better if we had 1/10th the population and most people were farmers again.

Expand full comment

Tbf, the argument that economic growth will make people have more babies has been empirically falsified and we can expect fertility rates to go down as GDP goes up. While the rates of mental ilnesses in us youngsters grows.

Which is the reason why I am a de-growther despite not being an environmentalist.

Expand full comment

Energy abundance, and if you believe that, dear people, let me share with you this brown glass bottle full of amazing cure-all that will fix what ails you.

I'm old enough that I've been hearing about "this one weird trick will give us all energy abundance", be it nuclear power (electricity too cheap to meter!), solar power, and of course fusion.

Fusion is interesting science to research, and a clever trick if you can pull off the engineering. In twenty years time, it will still be interesting research on plasma, and clever engineering tricks to handle plasma. It will never be energy abundance for all. And no conspiracy theories about mysterious They who will be upset if engineers solve the problem will change my mind on that.

Expand full comment

You’re really on point for a stereotypical naysayer. At its core you don’t want it to happen because it will upset your worldview.

I was reading a comment the other day that said, “What about the ozone hole?! That was fake. You never hear anything about it anymore.”

The reality is there was an ozone hole, they banned CFCs, and now it’s repaired itself. There was a big problem and we fixed it.

Certain folks get upset about that because it’s just so anticlimactic.

Expand full comment

Less of this, please.

Expand full comment

Am I wrong and these people don’t exist? I could be.

Expand full comment

It doesn't matter whether you are right or wrong, because this isn't the correct way to respond to somebody either way; it is unkind and unnecessary, given that there are kind alternative ways of expressing the same general idea.

Expand full comment

Ok. What would you have said to express the same sentiment?

Expand full comment

I don't know, the response seems reasonable enough.

Expand full comment

Some guy is describing fusion advocates as claiming that its a "magical" technology, and this comment is what you take issue with?

Expand full comment

(1) I'm not a guy

(2) Kindly learn to distinguish rhetorical hyperbole from actual claims; why do you think I put the "magical technology" bit in inverted commas?

(3) I am not questioning the science qua science, I don't have the expertise to do so. The timeline sketched out seems very optimistic, but who knows?

(4) What I *am* questioning is the starry-eyed extrapolation to how this will change the world. We've seen plenty of promises of huge world-altering changes, and how many of them worked out the way they were intended? Fusion may well be a solved technology and we never adopt it on a large scale because by 2040 we have something else we're using. Please untwist your knickers about someone wondering if this time, this big promise is going to end up just like all the other ones.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

"We've seen plenty of promises of huge world-altering changes, and how many of them worked out the way they were intended?"

I'd guess maybe 10% ?

GPS works. Weather satellites work. Integrated circuits and optical fibers work...

Yes, _lots_ of things don't make it off the drawing board, and _lots_ of things don't make it past the prototype stage but, depending on how tightly you want to define "world-altering", there are at least dozens, and probably hundreds, of technical innovations that worked.

Expand full comment

There is a reason to be more optimistic than this, because there's a new, mature technology that changes the game substantially: high-temperature superconductors.

More specifically, rare-earth barium copper-oxide (REBCO) tape is available commercially from several vendors, and it gives you roughly double the field strength at liquid-hydrogen or -neon temperatures instead of the liquid-helium temperatures required by ITER's magnets. This makes the magnets cheaper to build and operate, and allows the machine itself to be about 25% the size of ITER, which makes it much, much cheaper.

It's a game-changer. It's not a slam-dunk game-changer, but it's enough of one that the traditional "fusion is the power of the future and always will be" joke is now way closer to glib than it is to profound.

That said, there are plenty of things that can go wrong. The most important of those things is that SPARC, the reactor that Commonwealth is building, is still an experiment. It's not designed to be a commercially viable system. Indeed, they've made an interesting choice to trade machine life for earlier operation. So if they really do get to Q=10-20, then there's still a whole bunch of engineering to do to get to ARC, the machine that could be at the heart of an economically viable power plant.

I see you're also using the "by the time fusion arrives, what we're using for capacity will be a done deal" argument. But that argument is only true if you expect renewables to replace fossil fuels and then grow at a very sedate pace from there on.

I doubt that's going to be what future demand looks like. Indeed, I suspect that the successful mitigation and remediation of climate change will require expending energy in profligate amounts. Want to do atmospheric carbon capture at high scale? It's a massive power hog. How 'bout desalinating and lifting enough water to support agriculture in the Punjab--or Nebraska? What if you need to refrigerate the bottom of a glacier to prevent teratonnes of ice from sliding into the sea?

I'd like to plan on the world needing one or two orders of magnitude more capacity than dumb extrapolation would indicate. That requires another old cliché from the early nuclear age: power too cheap to meter. Maybe renewables get you there. But I want a few hedges against that. Fusion needs to be one of them, and it needs to be funded aggressively enough that it's not a joke.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

I disagree. Deiseach's comment was sufficiently snarky and devoid of substantial arguments to invite a response like BronxZooCobra's. At least the latter actually included an example in which scientific and engineering progress, paired with political will, fixed a real, serious, global problem.

Expand full comment

Less of this please

Expand full comment
Jun 17, 2022·edited Jun 17, 2022

"At its core you don’t want it to happen because it will upset your worldview."

Come back to me when you get out of nappies, kid. I've been to this dance before, and it's never worked out like the techno-optimists have promised us it was going to work out.

Given that I am *constantly* scrabbling about looking for cheaper utility plans because the centres where I work *eat* electricity to run and we're on a tight budget, I would fucking *love* if somebody gave us cheap, clean, abundant energy.

You know what happened the last time there was a great plan to do this? Solar panels on the roofs of the buildings (including the building where one of our centres is located) in a new build project, to help cut down on heating costs because instead of oil and electricity, water would be heated by solar power.

You know how it worked out? Awful. First, this is Ireland - we don't get enough sun reliably throughout the year to generate enough solar power to boil a cup of tea. Second, when we got freak sunny conditions, it was *too* sunny and the panels exploded and had to be replaced.

So the "here's a cheap, clean, efficient energy source" green wishful thinking that was funded and built in all sincerity was a dismal mess. I have no reason to think fusion is going to be the one time there is never a problem and we all end up with our own personal jetpacks to fly us to the lunar tourist resorts.

Expand full comment
Jun 17, 2022·edited Jun 17, 2022

“ I've been to this dance before, and it's never worked out like the techno-optimists have promised us it was going to work out.”

It hasn’t? It’s 94 in Houston and for almost everyone it’s 72. For hundreds of years the biggest killer was Tuberculosis. When was the last time you heard of someone dying of TB? For hundreds of year one of the great toils of women was laundry - girls used to not go to school on Monday’s as that was laundry day. They would spend the day at grueling backbreaking labor.

I just threw a load in earlier today and it’s done.

Expand full comment

"When was the last time you heard of someone dying of TB? "

Funny you should mention TB, or were you unaware it's coming back as a major disease?

https://www.mirror.co.uk/news/uk-news/health-warning-one-person-dies-27262263

"One person has died after contracting tuberculosis in the UK, as a leading health body issues a warning.

Three people have been diagnosed with TB after they came into close contact with a student who died with the disease in a Welsh town.

The University of Wales Trinity St David student died in October 2021."

https://cordis.europa.eu/article/id/436505-fighting-the-spread-of-tb

"Tuberculosis is preventable and curable, and yet 9 900 000 people fell ill with the disease in 2020 and 1.5 million died. This episode is looking at what the EU is doing to curb the spread and improve our understanding of the nature of the illness."

So yes, baby boy, people in this the 21st century *are* still dying of TB. Don't teach your grandmother to suck eggs.

Expand full comment
Jun 17, 2022·edited Jun 17, 2022

So no matter what great advancements are made you’ll be a naysayer. Is that fair to say?

If I mention that Ireland has gone from one of the poorest countries in Europe to one of the richest you’ll bring up every negative you can think of rather than celebrating that great triumph.

And obviously I meant dying of TB in a first world country like Ireland.

And that you’re trying to argue that tremendous medical advances haven’t been made…

Expand full comment

What's with all the ad hominem? From my outsider's perspective it looks like you're being very condescending and smug here. You can make your point without constantly calling someone a baby.

Expand full comment

I think that laundry story is a myth. Laundry was much difficult in the past therefore we did much less of it. Today we spend the same about of time on it because we wash every piece of cloth everyday. This partially confirmed by my childhood experience when I lived in frugal conditions (ex-Soviet country), sometimes even without electricity and washing machine.

Expand full comment

Indeed people would wear clothes many many more times before washing them. It absolutely was a huge chore, but people weren't spending 8 hours a week doing laundry.

Expand full comment

“ it's never worked out like the techno-optimists have promised us it was going to work out.”

He says via a system of electrical impulses that are converted to pulses of light that flash along hair thin strands of glass under the ocean to propagate his thoughts to thousands of people around the world.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

"a system of electrical impulses that are converted to pulses of light that flash along hair thin strands of glass under the ocean"

We got the first reliably working undersea cable in 1865, so try a little harder to impress me on that front, daddio 😀

https://en.wikipedia.org/wiki/Transatlantic_telegraph_cable

We have personal and business drama from over three thousand years ago, because of data storage:

https://en.wikipedia.org/wiki/Complaint_tablet_to_Ea-nasir

(The entire Ea-Nasir saga is wonderful, I'd recommend reading up on Some Real History That Really Happened:

https://www.tumblr.com/blog/view/mostlydeadlanguages/656166624810991616?source=share)

Technology is wonderful. Human nature, however, doesn't change. Impress me with your shiny space colony fusion future when the people inhabiting it aren't bitching about so-and-so has nicer quarters, better rations, or access to fifty-seven genders as social identities and I'm confined to only forty-six.

Expand full comment

"Impress me with your shiny space colony fusion future when the people..."

That, by the way, is why I don't think space colonies are feasible until they are governed by an AI, and we have a vastly improved sociology. And probably also a vastly improved virtual reality. Until then we'll need to have small groups with strong bonds holding them to the home planet. And I still think that's what we should be aiming for.

Expand full comment

OK, but you need to be aware that nobody predicted that years in advance. They predicted other things that didn't happen. Predictions in a complex area are almost always wrong, and when it's got chaotic resonances and strange attractors...well, the predictions are often WILDLY off, even if many of the details are correct. E.g. read "True Names" by Vernor Vinge. (That may have inspired the Matrix movies, but that's a guess.) Now compare it to on-line chat groups and other similar phenomena.

Expand full comment

There are no black swans because I’ve never seen one.

Expand full comment

More of this please.

Expand full comment

Is there any substance to this comment beyond "this will never happen because it would be too good"?

Besides, the examples you cite are not actually terribly supportive of your point. Nuclear energy didn't give us energy abundance essentially because we decided not to build it. Solar energy is _currently_ growing and getting cheaper at astonishing rates, such that the main obstacle now is storing and transporting it, not generating it.

Expand full comment

"Nuclear energy didn't give us energy abundance essentially because we decided not to build it. Solar energy is _currently_ growing and getting cheaper at astonishing rates, such that the main obstacle now is storing and transporting it, not generating it."

You have answered your own question. Right now, fusion is at the "it will be fantastic magic out of nothing clean cheap infinite energy!" hype stage (and has been since the 70s and possibly before, but I can't remember anything before then).

Nuclear power was going to be the same - and then, as you said, we decided not to build it.

Solar/renewables were going to be the same - and then we ran into "crap, we can generate it but can't store it for even and sufficient supply".

Why do *you* expect the development of fusion will run any smoother and without obstacles bobbling up? As to "there are a lot of people who will get upset if we get cheap clean abundant energy", does anyone else get the "we have the technology to let cars run on water but Big Oil is suppressing it" vibes?

Expand full comment

>You have answered your own question. Right now, fusion is at the "it will be fantastic magic out of nothing clean cheap infinite energy!"

Describing fusion as being based on "magic" is bad faith. You're unfairly trying to make them seem unreasonable by using BS terms to describe their claims.

>Nuclear power was going to be the same - and then, as you said, we decided not to build it.

Because it was too expensive to build it to be safe enough. Unless similar safety issues requiring very expensive engineering controls will be present for fusion reactors, then fission being too expensive to build is completely irrelevant to fusion's potential.

>Solar/renewables were going to be the same - and then we ran into "crap, we can generate it but can't store it for even and sufficient supply".

Again, unless this describes a problem that fusion will also suffer from, IT'S IRRELEVANT.

>Why do *you* expect the development of fusion will run any smoother and without obstacles bobbling up?

Because the issues with other power sources are not conceivably an issue for fusion. The burden of proof is on YOU to demonstrate that problems will likely exist. Otherwise, no new technology ever has any hope of working because something completely different in the past didn't work.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

Not sure about some of that. Fusion certainly has the potential for radioactivity problems like those that plague fission power -- anything that generates MeV neutrons is going to have *that* and fusion neutrons are even more energetic than fission neutrons. We don't know yet what those problems will be, and how easy/hard they will be to solve, because nobody has yet built a practical fusion reactor. But they aren't simply absent because of the technology.

Expand full comment

>Because it was too expensive to build it to be safe enough.

What killed it was the ALARA standard, which defines "safe enough" as "maximum safety possible at the same price as existing power stations" and therefore "enough spent on safety that it's not worth building". Sane definitions of "safe enough" (e.g. "safer than coal") weren't too expensive at all.

Expand full comment

"Sane definitions of "safe enough" (e.g. "safer than coal") weren't too expensive at all."

If a coal mine in Cumbria catches fire, that does not affect me. If Windscale/Sellafield goes ka-blooey, that does affect me (based on what way the wind is blowing) and I don't even get the benefit of the power it generates. "Nuclear power plant goes up in flames" is a hell of a lot more dangerous than "underground coal fire".

Expand full comment

I don't expect that commercial deployment of fusion will be rapid and unhindered. In fact, I'm not even a fusion partisan - I don't know whether it'll work or not. What I'm taking issue with is you staking out the position "this definitely won't work well enough to cause dramatic improvements" and basing it on some combo of "we haven't had something this good happen yet" and "there will be issues to deal with along the way".

Those claims, though true, aren't a meaningful argument about whether fusion will have a major impact because they apply equally well to any energy source you could imagine. Unless there's some iron law of nature that applies, arguments that treat the particular facts as irrelevant details are insubstantial.

Expand full comment

I am with you on this. Fusion energy might work but the social aspect will not be simple.

I compare this with covid vaccinations. We were not sure if the vaccine will work, but then it worked. Not perfectly but reducing risk of death about 10 times was great and we should have returned to pre-covid society in about March-April 2021 when the elderly population was vaccinated.

It didn't happen for some reason. It wouldn't have happened even if the vaccine was 95-99% effective and sterilizing. Politicians would still obsess with restrictions because the risk was not 100% eliminated and so on.

We are unhappy society not because we don't have abundant clean energy such as fusion. Fusion is an interesting scientific/engineering problem but the issues we deal with is only 5% about the lack of clean energy.

Expand full comment

Actually, I'd but the issues at over 50% due to a lack of abundant clean energy, but that would be soluble. It would be expensive, but we know several ways to handle it. We could even do it with giant mirrors in the desert that melt special salts that we then use as an energy store. So lack of a way to deal with it is not the basic problem. There doesn't seem to be a willingness to deal with them, because doing so would require small short-term sacrifices to ensure long-term flourishing. But people over-discount the future. (And, truthfully, often the people who benefited would not be the ones making the sacrifice.)

Expand full comment

I think the reason we are not building those giant mirrors in desert that the society (some rationalist geeks excluding) don't think it needs them.

I personally think that would be a cool thing but the problem is to sell the idea to others, especially policy makers. We need good story tellers, really good ones in fact. I think that's why I like Scott. He is a geek who can also tell stories.

Expand full comment

If[1] fusion works, I'm sure some people will object to it enough to stop it in their communities. But unless they can stop it everywhere, including China, the future is still coming.

[1] I'm not sold on the if yet

Expand full comment

It depends on specific details with the new technology – cost, environmental impact etc.

Right now I hear a lot of arguments from greens that nuclear power is bad not because of radiation but because it costs too much and is not profitable. Wind and solar is much cheaper and don't need to develop anything else. The countra-argument that we need to ensure base-load is hard to make because it is hard to wrap in a good story.

Expand full comment

Nuclear fission didn't yield energy abundance because the downsides to building it were too high. The goal was never *just* energy abundance. People assumed that there wouldn't be huge downsides. It's also quite expensive to run the (current) plants in a way approximating safety.

OTOH, I've read SF from the late 1930's and early 1940's. When they assumed that energy abundance was feasible, they didn't assume that this would lead to anything even approaching idylic lifestyles. Often they assumed to opposite, though you didn't get things like Heinlein's "Blowups happen" until after the end of the war. But if you were getting "energy abundance" and "energy too cheap to meter", you are/were believing PR puff pieces. (Most of them by companies trying to ensure continued government funding.)

Expand full comment

Heinlein's "Blowups Happen" is a short story from the 1940s about the boss of a nuclear power plant going insane from the high risk.

In general, golden age science fiction authors tended to assume that disasters would happen (e.g., in Heinlein stories there are usually unexplained references to "New Chicago" or the like, leaving it up to your imagination what horrible thing happened to old Chicago). They tended to assume the public would keep the same appetite for risk-reward tradeoffs, not realizing that people would become more safety conscious (e.g., swimming pools used to generally have diving boards but they don't anymore).

The one area where elites haven't got much more safety conscious is advocacy of bicycle riding, which is popular to encourage despite it becoming relatively more dangerous over the course of my lifetime as others things have become safer.

I'd be interested in why ITER is in France. I'm guessing it's related to why France relies so much on nuclear power: because France has an old fashioned modernist powerful centralized state without all the local checks that, say, California has that slows down construction by adding a whole bunch of levels of veto.

Expand full comment

"Blowups Happen" assumed there wasn't any way to make the power plants safe. So much so that the only answer was to put them in orbit. When you say "Golden Age" I'm not sure whether you mean pre-war or post-war, but after Hiroshima the mood was very different. Heinlein started to move away from advocating nuclear power ("Life-line") and Poul Anderson wrote "Tomorrow's Children" to name just two.

Expand full comment

> Is there any substance to this comment beyond "this will never happen because it would be too good"?

It's not that fusion won't happen because it would be too good, it's that even if it does happen it won't be as good as you think. Fusion won't be the free energy panacea everyone seems to be selling.

Expand full comment

This is literally not an argument. There's no substance to it whatsoever.

Fusion is categorically different to fission. The fact that fission has not lead to energy abundance is irrelevant. The reason fission is so expensive is the engineering required to make it (excessively) safe. Fusion is not dangerous in the way the fission is, and so this cannot be the economic failure mode for fusion.

There are very clear arguments for why fusion will/could/should lead to energy abundance. If you're unwilling to engage with them, you shouldn't be making a post against them.

People have made bold claims about energy abundance before - this is irrelevant. Fusion is very different to these things, so simple minded appeals to analogy are not valid. If you have a *specific* reason for why fusion won't lead to energy abundance, fine, make it. But this comment is exactly identical in spirit to declaring that heavier than air flight can never work, because look at the thousands of failed attempts in the past.

Expand full comment

I'm seeing a lot of "wah-wah-wahing" for my refusal to accept "but *my* technology is different!"

I hope I can make you understand - all the arguments you are pooh-poohing right now ('well, fusion was *never* gonna be at the races') are *precisely the terms in which the fusion argument is being presented*.

Fusion will/could/should lead to energy abundance? Heard that before about nuclear. Now you are telling me fission is *completely* different (which I accept on a physical level, yes it is) and that is why it never fulfilled all those promises. But fusion is going to do it.

Look, I can't speak to when fusion is going to be a solved problem. It may well happen by 2040 or 2050. But Shiny New Abundance World? Merely solving the technical aspects is not going to bring that about, which is what I am trying to point out. We *have* experience of "as soon as we get the bugs worked out, this will solve all our energy needs!"

And has it happened like that? Are electric cars solving the problem of gas prices going up and people being discontented for the midterms? Are we zooming around to our lunar resorts? Yes, I'm pouring cold water on the Shiny New SF Future.

I would love to have it. I *want* the Shiny New SF Future I was promised as a kid in the 70s. So much of the far-flung era of the 21st Century was going to be way different because Science!

And now we're back to 70s stagflation, price increases at the petrol pumps, and you lot in the USA can't even feed your babies due to a shortage of baby formula. And we have Russia in another war of aggression.

Tell me how "this time it's different" and I'm a science denier. I'm not denying the science, I'm denying the social and political extrapolation from it. "If we solve fusion we will get cheap abundant energy". Maybe. And maybe not. I asked why countries didn't engage in fusion research, and got told "Oh well, maybe the Cold War?"

If we're going to be demanding specific reasons, I want a better one than "fusion scientists were too pure-minded to engage in politicking". Maybe countries didn't pour money into it because the game wasn't worth the candle.

And don't try and convince me that past bold claims about energy abundance before are irrelevant, when you are using the same pitch to persuade me that this time, there *is* a pig in that poke.

Expand full comment

Try zooming out a little bit. Capitalism and technology have, in fact, solved all the world's problems if you take a longer time frame and look at the right metrics.

Expand full comment

Sure, but if that argument is highly persuasive, then it suggests things like ITER are folly. We should just let capitalism and technology solve the problem of the most efficient energy generation scheme, and stop trying to use government to force one particular solution.

Expand full comment

Why limit our options? The public sector and the private sector should *both* be working on this. If success comes about through the free market, great. If success comes about through the state, also great. Yes, too much government spending can disrupt the market and reduce its overall efficiency, but ITER spending is just a few hundred million per year out of a $5 trillion budget - it's not going to tank the economy. The internet was developed through a mixture of public and private funding, and the same could very well end up being true for fusion.

Expand full comment

"Are electric cars solving the problem of gas prices going up...?"

Yes. For anyone who has one.

Expand full comment

Nuclear power has certainly been a disappointment—though it does produce a ton of clean energy and will for decades and decades—but if fusion fails as badly as solar power we *will* have energy abundance. Solar has gotten incredibly cheap and abundant over the last 20 years. You're also old enough that you will have heard stories about impending energy disaster for your entire life—peak oil, etc. Technological advances, not just in renewables but in energy efficiency and even the discovery and production of fossil fuels, have made that seem ridiculous over and over.

To be clear I don't think there's any "mysterious They" keeping us from fusion, though it certainly seems like we should have been spending more given the potential rewards. But the idea that we haven't solved a bunch of big problems since you were young is simply not true, so it's not a good heuristic for deciding whether some future technology is plausible.

I'm a car guy, and future-energy stuff makes me think about cars anyway, so for example (and I know you're not from the US, but those are the stats I know)—in 1969, when we landed on the moon and before standup comedians could conceive of asking where our flying cars were, 5.19 people died per 100 million vehicle miles traveled in America. In 1987, when I was born, that was 2.42. In 2021, that was 1.33. At the same time cars have become more fuel efficient, dramatically faster, etc.

Likewise, in my dad's lifetime (1948-) we've gotten "too cheap to meter" wrong, and he always kids me about it because he knows I love reading about nuclear power. But we've also basically wiped out polio (2000 US deaths the year he was born), measles (400 or so), and rubella (last epidemic in 1964-5 apparently caused 11,000 fetal deaths and 2100 neonatal deaths). Even COVID—we certainly could have done much better, I think, with better trial processes, and the death toll has been awful. But also, within a few months of the first community spread of COVID in my area I was in a trial receiving what turned out to be an extremely effective vaccine for it. That's incredible! And people who held themselves out as a realistic level-headed experts *at the time* were saying that it was going to take twice as long, or three times as long, or more.

I know none of this is news to you, obviously, but I just don't see how the last 40 years would make you think "energy too cheap to meter" is a uniquely impossible dream to achieve.

Expand full comment

I think we all believe in progress, but progress per se is not a good argument for the odds of success of any particular technological push -- not when history is absolutely littered with the corpses of technological pushes that failed.

Yes, human beings will probably continue to advance technologically for quite a while. But will that progress be represented by achieving practical fusion power generation? Maybe, maybe not. Progress isn't uniform. We tend to make breakthroughs in random areas, hard to predict[1], and advance amazingly in one direction while not much else happens in others. Maybe progress in this century will be amazing in fusion, or maybe it will be in some other area -- maybe someone will produce an effective vaccine against breast or prostate cancer, and a terrible scourge will be vanquished, and then arguments in the future will be like "we beat breast cancer, isn't that amazing? so why don't you believe we can develop a warp drive/fusion power/some other techno miracle?"

----------------

[1] A cautionary tale here is the fact, mentioned in the review, that high-Tc superconductors were a game-changer for fusion. But nobody was doing research into superconductors *as part of* fusion research, because nobody had an idea that much higher Tc could be achieved at all. It was a surprise. But that's kind of how science works. A lot of time, the key advances you need happen in fields you didn't expect, and so it's hard to plan for them and *especially* hard to put them into a budget and deliberately create them on a schedule as part of a "throw money at the problem until it's solved" approach.

Expand full comment

To be fair, though, while fusion is likely a pipe-dream and so is limitless energy in general, I don't believe that mere energy abundance is an impossible goal. It might not be achieved via fusion, but it can be reached via a combination of various technologies, such as solar, wind, tidal, geothermal, and of course nuclear. We have all of these technologies today, we just need to invest in them -- or, in case of nuclear power, stop banning them. There are also productive engineering projects to be developed, such as improved nuclear reactors and orbital solar collectors.

The major problem with all of these is that it would require a massive investment a la the Manhattan Project to significantly improve energy availability... and I do not believe that any Western country has the ability to do that anymore. China has the ability, but not the desire -- they're fine with coal.

Expand full comment
Jun 20, 2022·edited Jun 20, 2022

I suspect the issue is overloaded definitions of "energy abundance". Some hear that and imagine you are proposing "post-scarcity".

Suppose we get energy abundance, the price of electricity drops to 1/1000 th of current rates (or lower), everyone has an electric car that doubles as a portable battery.

No doubt we will find some amazingly wasteful ways to use energy, and then face bunch some other limits (battery material precursors become expensive, ditto for conductor metals for the distribution to end-users, or maybe there will problems in scaling the ability to reprocess used batteries to match the production [1], some environmentalists are bound to oppose solar and wind farms, ultimately there could be issues with dumping all the excess heat from all the appliances everyone is running). The energy abundance might happen, but it is a real possibility it won't be an experience of plenty ... any more than our current way of life is.

What we did with the abundance of compute cycles? Price of MHz has gone way down since the first microcomputers. The Allies had years of money and person-hours in compute effort to crack the German military codes. Today probably you could have a novelty screensaver to do it. But does it feel like in post-scarcity compute utopia?

Everyone has a smartphone and spends a lot of time on internet. Yet the high-end computing experiences are still very expensive. If you can get a VR headset, you are certainly above median income. If you can finance (out of your own pocket) enough TPU hours to train a custom GPT-4-sized language model to produce the best AGI memes for your personal fun, you are certainly a millionaire.

[1] Think of the 19th century fear of "peak horse manure" problem.

Expand full comment

There will never be "abundance" in the sense of "too cheap to meter" - there are just so many things you can do with large amounts of energy that the cheaper energy gets, the more we will demand, and we will always be operating at the frontier.

However, it does seem likely that there may well be "abundance" in the sense of a return to the growth rates of energy use comparable to those of the 1950s and 1960s. In the 1970s, there was a slowdown in overall energy use growth (along with a million other things) as the oil crisis hit. Since around 2000, total energy use has stagnated, as coal and oil started being phased out for gas and renewable. Even without fusion, if renewables can continue their exponential growth after coal is done phasing out, then we already get substantial energy growth until gas starts phasing out. With fusion, there's a good chance that continues even with gas phasing out.

https://en.wikipedia.org/wiki/Energy_in_the_United_States

Expand full comment

You’re exactly correct.

I don’t recall why likes aren’t allowed. It seems valuable to poll the commentariat as to the validity of a given argument. Our host is a fan of prediction markets. Maybe we can pay per like? It’s not a true prediction market but we can say “I really think this is true.” And $.05 goes to our hosts favored effective altruism.

Expand full comment

That's a fun idea, but he's using the Substack platform, and since this doesn't sound like an idea that many other Substacks would want to use, they might not want to go through the work of implementing it.

Also, I should share the link to Noah Smith's Substack post that got me thinking about energy abundance - I'm not sure if this is a re-blog of that post or something else related: https://economics.enlightenradio.org/2021/12/noah-smith-on-energy.html

Expand full comment

When I was age eight in 1967, 55 years ago, the L.A. Times began running a Sunday comic strip about science. It's first ever topic was "Fusion Energy Is Coming."

Expand full comment

Do you think the idea of the cost of electricity going down by a factor of, say, 20 is more implausible than the transition from not having electricity at all to having it in the first place? If so, why?

Expand full comment

What exactly do you mean by "the cost of electricity going down by a factor of 20"? Do you mean "cost of generation" or "total cost of your electricity bill at the end of the month/bimonthly billing period"?

Because I could see costs of generation going down, which of course is going to have an effect on the total of the bill. But costs of generation alone are not all that comprises a bill. I don't know how American bills are calculated, but here's a sample of an Irish bill - and please note, there is a temporary reduction of VAT from 13.5% to 9%:

https://www.youtube.com/watch?v=QtRqq1atQ-8

Under the old VAT rate of 13.5%, the total cost of this bill would be €149.43

Cost of electricity at €0.258 unit price (and that's not a standard price, it depends on your tariff) less discount = €78.61

Cost of add-ons (Standing Charge, PSO levy, and 13.5% VAT) = €70.82

Total bill: €149.43

Suppose cost of electricity plummeted to €0.052 unit price, the new bill would be:

Cost of electricity = €17.32

Cost of add-ons = €55.39

Total bill: €72.71

That is a great reduction, but as you can see, the greater part of the bill is still not the electricity cost as such. And depending on the running costs of the fusion plant and costs of getting the generated electric into the grid, etc., the add-ons might even be increased to cover the cost.

So "cost of generating power via fusion drops", sure. But maybe "cost of building, paying off debt on building, return of profits to investors and shareholders of fusion plant + other extras rises", as well.

Expand full comment

IMO mankind's biggest problem right now (aside from our own human nature) can't be solved by energy abundance. The issue is that we're fouling our own nest, and making the planet unlivable. Sure, it'll help if we stop burning so much fossil fuel, but that's not the only thing changing the climate and killing off the biosphere.

Expand full comment

With infinite energy we don’t have to live here.

Expand full comment

Imagine how much cleaner our "nest" will be when we can afford to put all our heavy industry in space!

Expand full comment

There's a hell of a lot we could do with abundant energy to make things better. You also haven't described 'the biggest problem', you've described hundreds of smaller problems and lumped them all together. There's nothing that can solve all of these problems simulteaneously, so the fact that fusion powered energy abundance can't solve them is irrelevant.

Expand full comment

"Sure, it'll help if we stop burning so much fossil fuel, but that's not the only thing changing the climate and killing off the biosphere."

It's not the only thing, but an abundance of cheap energy could easily help to mitigate a lot of the other problems too. Energy can be used to get rid of waste, after all. Energy can also be used to make all sorts of processes (not just energy generation) more efficient so that they generate far less waste to begin with.

Expand full comment
Jun 19, 2022·edited Jun 19, 2022

"Things that could theoretically be done with electricity instead of fossil fuels" covers probably 80-90% of greenhouse gas emissions - that's not a small change. And the industries that can't directly be replaced by electricity (e.g., livestock emissions) can still be handled in principle by throwing energy at carbon capture projects.

Expand full comment

Lab-grown meat is energy intensive. I think they'll get there if they're willing to use real animal meat as necessary to complete the jump over the uncanny valley, but the animal footprint could be reduced by an order of magnitude.

Expand full comment

Mankind's biggest problem right now is CO2 emission. This is a problem that can be solved by non-fossil energy abundance.

Expand full comment

I don't actually think that people will be upset if many of our problems are solved by technology. I think that a lot of people just see problems that stem from political/societal issues (e.g. global warming would be eminently solvable if governments cared and would coordinate, but because they don't/won't, it's a huge mess) and feel intuitively that they have to be solved through political/societal battles. It's actually kind of tough to have the intuition that instead of winning or losing a fight about those issues, we may just stop needing to fight due to quantitative improvements!

Expand full comment
Jun 17, 2022·edited Jun 17, 2022

That’s what I’ve been trying to say…far less eloquently. Thank you!

Expand full comment

While it's about fission, not fusion, I think this New Atlantis piece explains fairly well why laypeople are disinclined to trust "the science" when they distrust the mediators implementing the science:

https://www.thenewatlantis.com/publications/democracy-and-the-nuclear-stalemate

In the abstract, I'm irritatingly techno-optimistic! But I've also accumulated enough bad encounters with the gatekeepers of all this wonderful, life-enhancing technology to find myself, rather against my will, growing increasingly distrustful that it will benefit "people like me" when "we" need it.

Take, for example, the humble X-ray. X-rays are amazing! Sometimes they've benefited me. But they've also been used to justify denying me timely care, needlessly harming assorted body parts. I know the X-rays themselves weren't to blame. The problems were with human judgment: X-ray being the wrong tool to rule out a likely problem; wishful thinking in interpreting X-rays to avoid the liability of treating someone pregnant... I didn't have unmediated access to X-rays' diagnostic power, but access mediated by someone whose job it was to know better than I how to use this wonderful technology, and who, for whatever reason, didn't do the job promised.

Reassurance that fission *can* be made safe doesn't necessarily inspire trust that it *will* be made safe if a fission plant is built in your neighborhood. Technical reasons for fusion plants to be more feasible still wouldn't address various social and political aspects of feasibility.

Supposing we did build a fusion-fired power plant, would people worry about it exploding like a giant boiler if something got clogged, "taking out the neighborhood"? I don't know that it would "take out the neighborhood", but steam explosions still kill people, and steam driven by what could be summarized as an artificial sun does sound extra-feisty. Even if laypeople were persuaded that fusion isn't the same radioactive danger fission is, would they trust the whole apparatus, steam and all, to be sited and maintained properly so that they're not the ones "punished" by a fusion plant going "boom"?

Can laypeople trust whoever's in charge to use technology appropriately around them?

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

“ Reassurance that fission *can* be made safe ”

It is safe. It’s incredibly safe. It’s only not safe if (among other things) you discount the lives of every coal miner who died of black lung. And that’s just for starters.

Expand full comment

I don't discount those lives. Or the other stuff you allude to. I'm pro-nuclear-power. Grateful to live in a world where it's possible.

I'm also pro-X-ray. I've nonetheless accumulated experience suggesting I can't trust X-ray diagnostics to be used correctly on me. I still chalk that up to "random bad luck" or "maybe I *am* that poor of a patient advocate for myself." But it gives me more sympathy for someone in a LULU (locally unwanted land use) neighborhood who hears, guess what?! Our LULUhood's the lucky winner of the new fission plant! We're reassured that, all around the world, fission plants chug along safely and cleanly (which, yes, they overwhelmingly do), so *of course* the one planned for neighborhood will... even if previous LULUs didn't turn out so well for us.

As I understand it, a lot must go right to ensure the fission plant design that's currently dominant runs safely. We have the technology to ensure it does go right! And usually the conscientiousness, too.

Usually.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

Yeh. But then I hear there are anti-wind turbine protests in Europe. Ok, you don’t want wind, you don’t want solar, you don’t want coal, you don’t want nuclear and you don’t want Russian gas, fine. You’ll just have to freeze to death in the dark come winter.

We don’t want that most of all!

Expand full comment

If by "you" you mean the impersonal "you", rather than me, specifically, I get what you're saying. If you mean me specifically, I moved to a LULU to get a better deal on housing.

Perception snaps into schemata based on experience. One schema is "modern technology has had phenomenal success saving and improving lives, including poor and powerless lives" (which is true!). Another is "LULUs are LULUs for a reason" — and in neighborhoods with a history of suffering due to LULUs, "others benefit from modernity by dumping its dangers here". I doubt which schema wins is entirely under people's conscious control.

"If it's so safe, why won't the ritzy neighborhoods take it?" invites the logical rejoinder, "Why waste money building it on such expensive property?" but it wouldn't surprise me if the example of wealthier, more powerful neighborhoods volunteering for these projects were more persuasive to holdouts than the fact of general gains through technology. YIMBY!

Expand full comment

A miner dying of black lung is terrible, but that death does not kill me off hundreds of miles away.

"Ooops, our beautifully safe steam turbine had a one-in-a-million accident" may, if I'm living close enough to it.

You may not remember, but I do, the effects of the Icelandic volcanic eruption.

https://en.wikipedia.org/wiki/2010_eruptions_of_Eyjafjallaj%C3%B6kull

Expand full comment

Actually the coal plant likely has significant health impacts on you because its emissions are incredibly harmful. Everywhere more coal plants open infant mortality rises, as does asthma, cardiovascular disease and a bunch of other things.

"We see massive differences in the death rates of nuclear and modern renewables compared to fossil fuels.

Nuclear energy, for example, results in 99.8% fewer deaths than brown coal; 99.7% fewer than coal; 99.6% fewer than oil; and 97.5% fewer than gas. Wind, solar and hydropower are more safe yet."

https://ourworldindata.org/safest-sources-of-energy#:~:text=We%20see%20massive%20differences%20in,hydropower%20are%20more%20safe%20yet.

There's some more specific info in there and it's sources, especially Burke et al and Lockwood et al:

https://www.sciencedirect.com/science/article/pii/S2666759220300706

Like, it's scary something might blow up unexpectedly and kill you, but if we replaced all coal with nuclear total life expectancy would go up, disasters included. It's similar to comparing flying to driving. I'm not sure if you have any particular hangups there, but the argument is really similar. Flying is saver than road tripping to your destination. But people are afraid of flying because the rare air crashes are really bad and kill lots of people. But risk is likelihood multiplied by impact.

Expand full comment

I dunno. If I take a look at my latest electricity bill, only 25% of the cost is listed as due to the cost of generation. 75% is distribution and taxes and bond payments and whatnot. So if fusion reduced the cost to generate electricity by a factor of 10 -- which seems darn optimistic -- then my electricity bill would be reduced by about 20%. That's not nothing, but it doesn't fall into the category of "enegy too cheap to meter" or some such.

I thought the main argument for why fusion power is nifty is that, like fission, we don't produce pollutant gases or have to pay for expensive scrubbing tech, don't produce a crapton of CO2, and don't have to stripmine Wyoming to get the fuel, but unlike fission we don't have as much high-level radioactive waste and don't worry so much about people building nuclear weapons with the same tech. These are all defensible goals, but they're not really related to the economics of power generation.

Expand full comment

That’s a good point. The thought is that if energy is cheaper then concrete is cheaper, copper is cheaper, steel is cheaper, etc. If those things are cheaper, if the fundamental quanta of energy in our civilization is cheaper*, then vastly more things are possible.

A world with abundant energy would not have the same transmission costs as indicated by your current bill. A fusion civilization would not be on the same Kardashev scale as our current civilization .

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

Yes, I'm aware of economics. I'm just pointing out thatin tthe economic component (my electricity bill) that has the *highest* proportion of its cost going to generation, the amount isn't actually that high. The impact on the price of concrete or copper is necessarily going to be even less.

Anyway, I don't disagree that cheaper energy is better. Economic efficiency is always a win, except maybe cheaper high-quality cocaine, not sure that was a good thing when it happened a few decades ago.

I do think to be taken seriously one would need to make a good case for *why* fusion energy would be so very much cheaper than any other type. Where's the giant savings coming from? Not from simpler and cheaper to build power plants, clearly. Low fuel costs? I mean, maybe, water is cheap, but deuterium is not, although fortunately you need very little of it.

But the story of nuclear fission is cautionary: *that* turned out not to be cheap, despite the fuel costs being minimal. So one would have to make an argument why the entire generation cost, soup to nuts, fuel plus capital and operating costs of the physical plant, regulatory and cleanup costs, environmental costs, et cetera, all work out to be way way cheaper. Haven't seen that argument yet.

I don't really see why transmission costs would disappear. If anything, I would expect them to be higher. A fusion plant is *such* a complex and expensive piece of machinery that economies of scale would suggest you just build one or two for the entire United States, have them generate TW of power, and distribute it everywhere. That's how nukes worked out, after all: it turned out to be better to build a great big one, which could generate massive watts at a minimal $/watt ratio, and then pipe it around.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

“ I do think to be taken seriously one would need to make a good case for *why* fusion energy would be so very much cheaper than any other type. ”

Scale - solar will never make getting you to orbit cheap. Fusion can. You can’t think in terms of your energy needs now, with current technology, you need to think of “your” energy needs 50 or 500 years from now.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

Yes, scale is not a bad argument, but again we get back to the point that 3/4 of my energy bill *right now* is distribution, because we already kind of use scale in electricity generation -- that's why we have all these enormous towers and transmission lines going thousands of miles. So we need to understand why scale, which is already being used pretty heavily, hasn't at all reached the limits of its potential.

I'm not seeing how fusion helps me get to orbit cheap. The problem with getting to orbit is that I need to generate a lot of kinetic energy *but* I also need to generate it quickly (high thrust) *and* I need to generate it on board a flying vehicle (so the tragedy of the rocket equation). How does having gigawatts of electricity available for cheap on the ground help me out? Are you thinking some kind of railgun approach? I put all my kinetic energy into my orbital vehicle on the ground, then let it blaze (literally ha ha given friction in the lower atmosphere) to orbit?

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

Liquid hydrogen and oxygen are very effective and very expensive as a method to get you to orbit. If there was a technology where we could cheaply crack water and then condense the resulting components, that would be a big deal.

This is just a random example off the top of my head.

Expand full comment

If you're going to claim fusion will get you to orbit cheap, you need to be more explicit. Perhaps you're thinking about a laser-powered first stage? I've seen speculative designs that don't look implausible, but also aren't really convincing. Or perhaps you're thinking about something else, but it sure isn't clear what. It won't give you a cable good enough for a space elevator.

Expand full comment
founding

Right. The obvious wrong answer, per many generations of science fiction, is that we're going to fly to orbit using fusion rockets or "drives" that are vastly more efficient than chemical rockets. And maybe in the 23rd century, we'll be doing that - but none of the fusion technologies discussed here are remotely practical for earth-to-orbit propulsion. The power-to-weight ratio is going to be far too low, and the power comes in the form of relatively low-grade heat in the neutron-absorbing blanket that is difficult to turn efficiently into rocket thrust.

Fusion-based systems may have some utility in deep space transportation, where very low but continuous thrust will suffice. That's actually part of Helion's backstory, among other things. But it won't get you off the ground.

And while you can envision using "too-cheap-to-meter" fusion power to run beamed-power propulsion systems, or electromagnetic launchers, or to turn water into liquid oxygen and hydrogen, that's solving the wrong problem. As others have noted, the *energy* costs of space launch are a tiny fraction of the total. It's hardware and operations costs that make space travel ridiculously expensive. If you come up with a system that works, you can get the power from the current grid just fine.

Expand full comment
Jun 19, 2022·edited Jun 19, 2022

I don't think it's going to just be "10% off your electric bill"[1] but "there are a whole bunch of new ways we can use electricity that we didn't think of before." People who hauled water up from wells by hand would never consider daily showers or water parks.

Matt Yglesias has a bunch of articles at Slow Boring about energy abundance.

[1] I don't know off-hand what proportion of my electric bill goes to just the labor for maintaining the grid but it more than doubles during the summer months so I know it's not just 25%.

Expand full comment
Jun 20, 2022·edited Jun 20, 2022

Well, we'll see. I'm still missing the part where electricity becomes fantastically cheaper because it's produced by fusion instead of fission, or burning nat gas, or even rooftop solar. The capital costs are admittedly enormous, the operating costs (skilled labor, upkeep and repair) look to be pretty darn expensive, at least as much as operating a fission plant, and we're looking at if anything higher distribution costs because it's inherently a lot more centralized than something like a nat gas plant -- we're going to need still more transmission lines and all the associate switching and load balancing hardware, which all needs its own upkeep. Nobody is going to be dotting the countryside with 150 million K operating temperature tokomaks which require the kind of precision and care in assembly that goes into a chip fab or fission reactor.

I get that water is very cheap, but tritium isn't, and it's a bad time to be competing on the world market for lithium (plus natural lithium is only about 5% Li-6 if memory serves, so you might need expensive isotope enrichment), so while you need very little of the fuel stuffs it doesn't feel any more economical than fission fuel.

As a technological achievement is seems extremely cool, and it would be good to have some more options for power generation, but I'm just not seeing how this is going to make electricity -- from start to finish, from funding the capital construction costs to delivering it to the end user -- just amazingly cheap. It feels a little uncomfortably like an Underpants Gnome theory of energy abundance:

1. Fusion breakeven achieved!

2. ????

3. Energy too cheap to meter, changes world.

I totally agree with (3) but it's (2) that has me a little skeptical. I hope the problems are solved, I'd love to live in a world like that, but...it would take more than I've heard to persuade me it's definitely on its way.

Expand full comment

No, the great difficulty is the materials.

Engineering challenges go away if you throw enough money at them. The Manhattan Project was, primarily, an engineering challenge.

Materials challenges are potentially intractable because the material doesn't exist. You can throw all the money in the world at high critical temperature, high critical field superconductors, and still not wind up with any. Because they don't exist.

Expand full comment

Hello everyone !

I just made this account so I can engage in the conversation, while still being an anonymous reviewer. I will try to answer all the questions I find in the comments.

I have invited Jason Parisi, one of the authors of the book, to come as well.

Expand full comment
Comment deleted
Expand full comment

Thank you !

Expand full comment

Hey, my biggest issue with this is defining "getting fusion" at achieving Q>5 in steady state. I am fairly confident that SPARC will get Q>5, and I think they'll get there by 2025 as planned (with maybe a year or two of slippage), but this is a long ways off from getting us to economically or climate relevant fusion energy. I'm wondering why you chose this metric for your predictions?

Basically, I think it would make more sense to forecast ARC than SPARC, and I think the odds of ARC working conditional on SPARC are maybe around 30-50%.

Expand full comment

Once we get to Q > 5, we've effectively solved the scientific problem of fusion. Ignition (Q = infinity) only requires about twice the triple product as Q = 5 and we would probably want to operate a power plant below ignition (maybe Q = 20) to have more control. At this point, fusion becomes an engineering / economic / regulatory problem instead of a scientific problem.

That's not to say that the other parts of the problem aren't challenges. But I think that they are solvable challenges. I would probably say 80% chance that it there's less than 5 years between SPARC hitting Q = 5 and ARC. ARC here being the first fusion reactor that sells electricity to the grid.

Most of the engineering problems have to be solved to get Q = 5. Between SPARC and ARC, Commonwealth will still be economically functioning like a startup. Startups live on hype rather than profit, and I expect that hype will not be in short supply. Getting from ARC to mass produced fusion reactors that can compete with other energy sources will be harder. I don't know what the regulatory environment will be, but hopefully not terrible in at least one country.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

"At this point, fusion becomes an engineering / economic / regulatory problem instead of a scientific problem.

That's not to say that the other parts of the problem aren't challenges. But I think that they are solvable challenges."

I'm less sanguine about them being _affordably_ solvable challenges. The 14 MeV neutron material damage problem looks hard. The tritium breeding problem looks hard. I've heard magnetic confinement fusion designs described as looking more like an LHC particle detection experiment than like a power plant. Thay have expensive, delicate, parts, and it isn't clear how often which parts will need to be replaced.

Getting to Q=5 will be an extremely impressive achievement. I will be the first to congratulate the team that succeeds in reaching it. I agree that the scientific problem will have been solved at that point. Given the amount of deuterium and lithium available to us, we will basically know at that point that we have fuel for a million years.

But we will _not_ know, at that point, whether we have _affordable_ fuel for a million years. It might still be the case, after reaching Q=5, that a better choice might be any of thorium/U233 fission, or solar plus storage, or solar plus (possibly global) transmission.

Expand full comment

Then there's the personnel problem. If Igor Kurchatov and Andrei Sakhorov had been operating Reactor Number 4 at Chernobyl the night of 26 April 1986 the world would never have heard of the place. But it was being run by schmos, because you can't afford to have briliant PhDs running a power plant.

A fusion power plant needs to be able to be safely and economically run by trained apes. That's not a trivial challenge.

Expand full comment

True! But a fusion power plant doesn't have the ability to have a runaway reaction like Chernobyl did. It _does_ produce neutrons, as you've noted elsewhere, but there is no equivalent to positive-temperature-coefficient-of-reactivity that blew the 1000 ton cap off the top of the Chernobyl reactor. We could have a plasma-instability-wrecks-inner-wall-of-vacuum-chamber, but that is more at the billion-dollar-property-damage level of tragedy, not nearby-city-plus-exclusion-zone-abandoned-plus-fatalities level.

Expand full comment
Jun 18, 2022·edited Jun 18, 2022

Sure, but we can't dismiss the property damage aspect of this. People are certainly more valuable than dollars, but dollars are still valuable. Let's say you build a $50 billion fusion plant that can supply the entire Eastern Seaboard with electricity, and it starts doing so, and some asshole operating the plant closes Switch B under operating conditions X, which maybe his training didn't quite cover as emphatically as it should, and would have been obviously wrong to someone with a PhD in plasma physics -- and our beautiful fusion plant is wrecked, shazam, nobody killed thank God but will cost $15 billion and 10 years to repair.

For sure potential *investors* would be thinking about that scenario. And it's worth thinking about. Look what happened to Boeing when they figure they could do something inherently less safe in the 737 Max and rely on pilot training to compensate. (And it *did* compensate, at least in First World major airlines with comprehensive training, cream o' the crop pilots, et cetera.)

Expand full comment

You can afford to have ordinary PhDs running them,since physics PhDs are being overproduced.

Expand full comment

Conveniently, the 14 MeV neutron problem and the tritium breeding problem are the same thing. But it's still a problem that is potentially too difficult to solve affordably. The best way to figure out how often things need to be replaced is build one and see.

It's possible that fusion won't be the most affordable option for a while. But I do think that we should try to get it there.

Expand full comment

Fair enough. That seems reasonable.

Expand full comment

I'm fairly worried about the engineering challenges. Tokamaks are just very complicated, there are many parts that can break, many non-trivial challenges we ha