Nuclear fusion: WEST beats the world record for plasma duration
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For example, if you could make batteries at a price of $115/kWh, the cost for enough capacity to sustain the US power grid for a week would be around 24 trillion dollars, and that's just for the batteries and not any of the associated electronics or the land or the photon collectors themselves. It seems like to make your plan work you'd need a scalable storage technology with a significantly lower cost per kWh of capacity.
Optimized combinations of batteries and longer term storage typically comes out to maybe 12 hours of batteries, sometimes less.
We wouldn't need the hydrogen until the last few percent of the grid goes renewable; until then natural gas would be fine.
To use hydrogen for that you'd need close to a TW of hydrogen fuel cells, and storage tanks to hold enough hydrogen to run the whole grid for a week, and enough hydrogen production equipment to refill those tanks in a reasonable amount of time if you had to use them, none of which gets used but once every year and a half. That might still be cheaper than a week's worth of lithium batteries but it's still not cheap when it's something you have to pay for on top of the generating equipment and batteries needed to run the grid on a normal day.
And it still leaves you in a bad way if you had enough hydrogen for 7 days but the clouds persisted for 9.
A once-through steam cycle with steam generated by hydrogen-oxygen combustion heating additional water (save the oxygen from electrolysis also) might have even lower capex. The combustion would occur with water injection in a kind of rocket-like combustor, no heat exchangers needed. This is potentially cheaper because it avoids spending 50+% of the output of the turbine on the compressor.
Hydrogen, like natural gas, is extremely storable, very cheaply, in underground storage formations. Nations typically store months worth of natural gas, and the volume could be greatly extended. Europe for example has the geology to store millions of GWh of hydrogen, and that's not even touching the salt formations under the Mediterranean.
A 65%/35% renewable/natural gas grid probably doesn't need any storage at all.
I don't know why I post, somethings just to dissipate negative emotions, sometimes to share a favorite anecdote. Sometimes to joke, maybe,? Although those are more likely to be closed without posting.
A Modest Proposal is a lot less funny when you have people who really do believe we should eat babies to solve the Irish problem.
In a forum where people credulously propose orbital platforms to “sell sunlight at night” [0], I find myself erring on the side of assuming seriousness…
"All the energy we could ever use, forever and forever and forever."
"Not forever,"
In December, Chinese battery pack prices declined to 100 $/kWh according to BNEF, which was a new record low. Also battery production goes up by at least 20% per year for the last years and battery energy storage installations go up by 30%, see BYD, CATL, and Tesla annual reports.
Availability might be a problem in the West, but China is installing them on a massive scale. So being “not available” (if that’s the case) should, I think, be interpreted as a Western call to action and not as a fact of life. South Korea produces 30% of all car batteries and multiple South Korean plants are planned for the US, so I have hope that things will start moving.
As a result they filed instead for bankruptcy last fall.
I would like to see EU issue a law against building new natural gas power plants, dictating that either countries start building that cheap grid-scale battery solutions or find non-fossil fuel alternatives, which ever is currently cheapest. Im tired of seeing that even countries like Sweden are investing into new natural gas power plants in order to address days when the wind and sun are not producing enough energy.
‘Simpler’: move earth to where the energy goes: https://en.wikipedia.org/wiki/Dyson_sphere
If me move the reactor close enough to the center of the earth, eventually we can get to zero g. We then also solved the confinement problem.
Space solar is an old idea and the Soviets/Russians have worked on it since the 70's; and nowadays, like most other Russian inventions the Chinese are commercializing it. https://www.ft.com/content/2d43ed21-9f9d-4e90-a18b-ad46f0a47...
Microwave energy transfer should work. That's what I like about the Helion fusion reactor design they don't use steam to power generators it's direct power no water or steam.
I applaud this nuclear arms race. 22 minutes is really impressive for a technology that’s always been “20 years away”. I think I will do a deep dive on the technical challenges of fusion.
Cracking natural language comprehension with digital computers is an example from our field and it’s here.
Exactly, there are experts in the field less than a decade a way who said 50+ years easily. And there we are.
Not that it's not impressive, but LLMs do not "comprehend", for a start.
I don't think so. I am not setting the "goalpost" here, it was expressed as "LLMs have cracked natural language comprehension".
I just don't think they have. There are tons of statements I would agree with regarding what LLMs have achieved, but this one is not part of them :-).
How are we disentangling comprehension of natural language itself from comprehension of the subject matter being discussed via said language sample?
I think that by most reasonable metrics LLMs can reasonably be said to comprehend natural language itself. However they clearly are deficient in logic and reasoning, as well as comprehension of many of the concepts that the natural language is used to express.
No, it's not. It's just a legit illustration of somethings state of development on fundamental levels. It simply means "we have no f**ing clue how we can do this, but future..". This is different from something we have already solved, and you just need to throw money on it to scale it to whichever level you need it.
> Cracking natural language comprehension with digital computers is an example from our field and it’s here.
That's the point, everything in research is always x0 years away, until the breakthrough happens and it's finished.
We can already do fusion, and by every metric it is scaling. Triple product is increasing, etc.
Fusion does not become a viable source of energy until it scales beyond a certain point, but there is no "leap" between here and there that we know about, just better and better containment. We are descending a gradient, not looking for one.
If we had never managed to get fusion outside, say, hydrogen bombs, then I'd agree that we have no idea how to do it, but we have -- using many methods. Tokamaks seem to be the best one for scaling it so far, but there's other possibilities that I wish we would research more.
Technology usually has a range of performance, what it can do and what not. And our technology for fusion-process is not in the range for a commercial reactor, so we still need a breakthrough in our understanding.
But at some point the problem becomes not one of plasma physics, but of engineering and economics. Regardless of the plasma physics, the walls of the reactor can withstand only so much power/area and only so much cumulative neutron irradiation. Issues like this seem mundane and therefore easy, but they're perfectly capable of rendering a technology into a nonstarter.
I also didn't see anything about vessel irradiation, which also never seems to be discussed. I get it probably isn't as big a problem as solid fuel rod fission in terms of waste creation, and tritium breeding may help, but it still will be kind of the same problem with LFTRs: a reactor design will fundamentally need an ongoing reconstruction/replacement strategy due to the vessel irradiation and transmutation from high energy neutrons.
Feel free to correct me if this isn't as big a problem as I think it is.
Still people make jokes about fusion research, some things just take time.
I recommend this excellent review of the even more excellent book „The future of fusion energy“
https://www.astralcodexten.com/p/your-book-review-the-future...
Fusion research progress is underappreciated. But Moore's Law is for an existing industry. Prior to that, it took 10 ^ 6+ improvements in various technologies to make computing possible.
Developing it from scratch is a whole other matter.
Likewise advancements in fusion beget advancements in fusion by increasing understanding of the challenges faced.
Surely this is aided by ever more sophisticated computational models? Maybe not the dominant factor in Moore's law, but maybe not negligible?
Modern computers are certainly a nice quality of life improvement for researchers though.
That said, commercial production lines might be a different story. Now I'm wondering what the minimum viable computer system would be to implement the firmware for ASMLs machines, for example. Probably more than vacuum tubes but I'm guessing you could pull it off with an old 8 bit chip. That's just a guess though.
If a time traveler from the future gave everyone at ASML and TSMC computers that ran 4 times as quickly so they could run their models faster, but no one could take a look at how they worked or were made, it wouldn't have any noticeable effect.
So?
> and do you honestly think an asml duv machine could exist with 1980s computing power?
I think something comparable could be, yes. The difficulty is in the precision, not the controls. Hell, the controllers in the actual machine likely only have 90s level computer power.
I can't see anything like a linear/square relation in fusion reactor design (even accepting that ML's premise of shrinks being linear in time is not a law, just something that sometimes happened, and sometimes didn't...)
It borders on a national security issue.
That makes it less impressive; any fluorescent-light tube can maintain a stable plasma for years, after all, without even magnetic confinement.
https://www.energy.gov/science/articles/science-close-develo...
>> In the H-mode, a calm edge without turbulence reduces how much heat and how many charged particles the plasma loses. This leads to a sharp increase in pressure across the entire volume of the plasma, including the core where the conditions that can lead to fusion occur. The reduced energy and particle losses also minimize damage to the material surfaces surrounding the plasma.
Suppose we had one prediction market M_1 for “On January 1st 2070, resolves ‘yes’ if there has been a commercially successful nuclear fusion power plant, and otherwise resolves ‘no’”, and then another market M_2 that, maybe it resolves in 5 years as ‘yes’ if the price of M_1’s ‘yes’ is greater than 30%? Or… hm, that seems problematic because people could just buy a bunch of M_1’s “yes” right before M_2 resolves? Or maybe that’s a self-correcting problem because people could… no, still seems like a problem..
Well, what if instead of a prediction market about the future value of another prediction market, it was futures contracts for the shares in a prediction market? Like, the right to buy or sell shares in “yes” or “no” at a particular price?
So like, if you’re confident that the prediction market will assign probability p or higher on a particular day 5 years from now, then if you bought futures which, on that day each of the futures could be used to sell a share in “no” at the price (1-p), then… well, if the probability assigned to “yes” on that day is indeed p or higher, then the price of “no” would be (1-p) or lower, so one buy a share in “no” at a price less than (1-p) and then sell it at (1-p)..
Hm, issue there is one still needs to buy the “no” in order to sell it, so that doesn’t seem to really fix the “what if there is no liquidity in 5 years?” issue?
I guess one could spend 1 to create a share of “yes” and a share of “no”, and then sell the “no”, and be left with the share in “yes” which is ostensibly worth at least p, and then like, sell it a bit later when there’s more liquidity or something?
I probably don’t know what I’m talking about about this.
What more insight could gamblers provide about nuclear fusion that expert physicists and engineers can't? Why and how would their predictions be more accurate than industry leaders?
Prediction markets are known to have an optimism bias when it comes to stuff like this.
The world spends 10% of global GDP on energy, about $10 trillion per year. The world will spend something like a quadrillion dollars on energy this century, possibly more as the world gets wealthier and per capita energy use increases. A billion dollar investment is just one part in a million of that. Fusion doesn't have to be very likely to succeed to make such speculation worthwhile.
For example, Bill Gates is going to die like everyone else and give most of the money away, like Warren Buffet.
They can spend a significant amount of money in life if they see nuclear fusion is possible, even if they do not recover the costs.
The only thing that is needed for this to happen is investors being confident that the money is not going to be wasted.
I personally know rich people that are betting a significant part of their wealth in fusion(millions USD) even when they know there is a risk that they will never recover the money.
How much have you given away? If you just don't like rich people, say that, don't disguise it with false facts and moralising.
> Why are we still pretending he is a philanthropist and not one of the biggest oligarchs of our time?
My pet is both a cat and brown coated.
Yes
Has given money in the order of hundreds of billions to charity?
Yes
Both can be true.
If you’re giving away money to shush people, or gather support for your politics, or gain something else out of it then you do not receive the beneficial connotation.
Strictly going by definition, dictators can be philanthropists.
I think there was (maybe still possible?) a real missed opportunity to pitch green energy in a national security or America First way. I don’t think the average republican voter wants us to be as tied to OPEC the way we are.
We could still product as much—or more!—oil in Texas while reducing our care for anything in the Middle East.
The real missed opportunity IMO is one of not communicating how well we are doing.
It's certainly feasible to build a crude oil pipeline from Texas, but the local refineries don't necessarily want it. They prefer the flexibility that comes from getting supplies by ships and trains, even though pipelines have a much lower risk of major spills or fires.
https://www.lubbockonline.com/story/news/state/2013/05/31/ki...
National security arguments also don't work in cases like this, because "national security" isn't the real reason the government does a thing, it's the excuse given to the public when Republicans want an unconstitutional boondoggle. But fossil fuel companies are a Republican constituency so it would typically be the Democrats advocating for something like that and their excuse calendar uses different phrases.
If you want to get Republicans to support it you either need to bring it within their cultural norms to want it, e.g. American-made Cybertruck can stomp their old truck in a drag race and the Tesla guy is their friend now, or it just needs to be more profitable so they want solar on their roof to save on electricity.
You can also use different methods when appealing to people with different values. Typical plan from the left is to subsidize it with tax dollars, but you can also ask things like, what makes solar installations expensive? Are there ways to make it easier for homeowners to do it themselves to avoid costly professional installation? Is there some kind of regulatory capture causing things like inverters and transfer switches to cost two orders of magnitude more than the price of their raw materials? Try thinking like the people you're trying to convince if you want to get them on your side.
> We found that repealing the ban was associated with:
> ...
> Decreasing profit margins for petroleum refiners as they paid more for domestic crude oil relative to international prices
The US is a net exporter of oil. That doesn't mean they're not importing a ton of it and then exporting even more, e.g. because the Northeast is closer to Canada than Texas so New York uses a lot of oil from Canada and then the gulf states export to other countries.
Changing that in the long-term would raise prices (higher transportation costs, less competition) and changing it in the short-term (i.e. in immediate response to a foreign supply shock) would raise prices significantly because of short-term logistical issues. Also, to the extent that it lowered relative prices, the difference would come out of the profits of US oil companies and increase the profits of their foreign competitors as customers in the EU and other places experience even more of a shortage. "Piss off your allies and domestic industry to the benefit of foreign adversaries" is usually not a winning strategy.
Meanwhile those sorts of export bans will leak like a sieve anyway. Even without formally violating them, you'll see things like energy-intensive industries moving production to the place with cheaper energy until the cross-border price stabilizes, which means higher prices outside the US would lead to higher demand (and thus higher prices) within the US.
It's a global commodity market and you don't even want it to be otherwise.
I believe the trend in Lazards is that storage+wind or storage+solar will drop under natural gas combined cycle this year or next year on a LCOE basis.
This is true of every energy system ever.
> let alone the first that will be built as commercially viable standalone without subsidies
The entire enterprise is practically government subsidies. The recent advent of VC is a rounding error.
None of them solve this problem, though:
> Now, of course, one can hope to sell your shares in “yes” or “no” 5 years from now, but there may not be enough liquidity?
In general, if there isn't liquidity in the primary market you should expect the derivative markets to be even worse. You would use options not to find extra liquidity - and binary options on illiquid markets like you describe are indeed particularly prone to market manipulation - but to express very particular views.
> another market M_2 that, maybe it resolves in 5 years as ‘yes’ if the price of M_1’s ‘yes’ is greater than 30%?
Like this one - you should buy this contract if you really do want to make a bet the price will be over 30%, and you don't care much about getting a big payday if the price is 90 or keeping most of your money if the price is 29.
I'm not sure how this works, how are they confident enough that they can make it produce net power?
ARC which they announced siting for and is intended to be their first grid-attached net power provider only just had the location selected so I don't believe its got much construction going on yet. The goal for that plant to be producing power is "early 2030s".
They haven't even gotten to Q>1, let alone building a real power plant.
Is this something where it's on the precipice and small tweaks bridges from 22 minutes to basically indefinitely?
These are science machines to learn about plasma and increase performance of future machines. A real reactor involves a lot of engineering to handle the heat rejection problem (and turn it into a revenue stream if you're clever). In terms of the pulsed nature: not really a problem if you keep the duty cycle high enough and maintain sufficient buffers in your coolant to keep the turbines happily turning away.
I look at it as a large optimization problem at this point. Each part of the machine is workable but not yet sufficiently optimized to achieve profitable operation.
Yes, stellarators are different.
I've seen photos of what the inside of experimental tokamaks look like after many cycles. Metal is eroded away and deposited around the chamber in interesting patterns. Unfortunately a image search isn't surfacing the images I have in mind.
An easier (more fun) version of this with some context is here: https://x.com/olshansky/status/1892069988707729614
I'm not clicking that shit
* https://addons.mozilla.org/de/firefox/addon/twitter-to-nitter/
* https://addons.mozilla.org/de/firefox/addon/nitter
Nuclear fusion: New record set at Chinese reactor EAST https://news.ycombinator.com/item?id=42917662 03-feb-2025
China's artificial sun burns for 1000 secs, creates record in fusion research https://news.ycombinator.com/item?id=42854306 28-jan-2025
It should be a good time to be an engineer.
So according to the industry leaders, we will have the first 400MW plant within 10 years.
This news is either based on misleading the public, or I am about to be updated with where Fusion is?
If they get ignitions, all the other problems will be solved very fast, because there will be an enormous rush from investors wanting to invest billions.
"Necessarily" being your Zeno's Arrow. Necessary to what threshold? I can literally argue against anything to an arbitrary level of necessity. (Breathing doesn't necessarily ensure living.)
https://m.youtube.com/watch?v=KkpqA8yG9T4&pp=ygUrYnJlYWt0aHJ...
Watch this clip with Prof. Whyte from 8 years ago. It’s the team behind CFS(then still at MIT). Highly interesting. He will explain exactly what they will do(now doing), how they will do it, and why they will do it they way they are doing it.
Please note that they are pretty much on target since. I have been following CFS closely.
Essentially the breakthrough has been the ability to manufacture more powerful magnets. CFS makes the most powerful magnets in the world.
That was always the main issue, how to contain the plasma.
https://m.youtube.com/watch?v=KkpqA8yG9T4&pp=ygUrYnJlYWt0aHJ...
In a Nov. 17, 2021, news story, Ball wrote that scientists working with the MIT/CFS collaboration are planning to deliver the “first fusion machine expected to generate more energy than it uses” in 2025.
Actually, the MIT/CFS SPARC reactor is designed only to produce a fusion plasma that produces power at a higher rate than it consumes power. That measurement does not account for the input power required to operate the reactor. It’s the same trick that fusion promoters used to sell the idea of ITER, the International Thermonuclear Experimental Reactor."
I don’t know exactly what went on in that interview. I have not read it.
It’s a complex topic and easy to misunderstand.
> Please note that they are pretty much on target since. I have been following CFS closely.
And their credibility.
The predecessor, the ARC reactor in the 2014 paper, had a power density of 0.5 MW/m^3.
In comparison, a commercial PWR, which you can buy today, has a power density of 20 MW/m^3.
So, even with all the HTSC hype, their machine is still a factor of 40 worse than existing proven fission technology.
How is such a bloated, much more complex machine even going to compete with fission, never mind the alternatives that have sidelined new fission construction? The capex will be completely out of bounds.
If they don't have a prototype, and are going straight to plans for a 400MW "commercial" plant, why should we believe this is possible? What evidence is there that these plans for a massive breakthrough ten years from now will work out?
This looks, walks, and talks like a ploy to get in on AI energy demand hype. It may not be, but it has all those features, and not many other features.
They have a plausible relatively well understood path to fusion, have credibility with their background (coming out of fusion research at MIT), and have raised something like 2 billion dollars in funding.
> Can they get Q>1, much less >5 or similar for what will be needed to break even on all the rest of the inefficiencies
They think so
> and are going straight to plans for a 400MW "commercial" plant
They aren't. They're currently developing "SPARC", a Q>1 demonstration plant targeting 2027. The 400 MW commercial plant, ARC, is a follow on design targeting 2030s.
> This looks, walks, and talks like a ploy to get in on AI energy demand hype
They predate the AI boom by a lot. The project started in 2018. They had a $1.8 billion dollar funding round in 2021.
The basic concept is "hey look, someone figured out how to build better superconductors. What if we took what ITER is trying to do, but used modern super conductors to make it smaller and actually achievable". I'm not saying I think they're certain to succeed, but I don't think they're a scam and I think it's very reasonable to include them amongst the group of "industry leaders"
"The company plans to produce its first plasma in 2026 and net fusion energy shortly after."
Looks like your argument is build on just promises, not backed by any tech developments.
As for the comments about votes, they aren't a measure of terseness either. The point is to bubble comments likely to result in curious and thoughtful conversation to the top while comments which will distract from that kind of conversation (combative, vague, distractly offtopic, or whatever else the reason may be) tend to get hidden away. Whether a comment is totally on the money or absolutely incorrect, how you present the conversation starter has a far bigger drive on what types follow-on conversation will appear. Here, that also strongly implies what types of votes will appear too.
I think everyone would agree we should find ways of investing that aren't scams. The hard part is who agrees on what is a scam. I don't mind more purely private investment myself though, which has seemed to be a trend in recent years.
When a prediction is at a timescale where the person making the prediction will be retired by the time the prediction applies, you can safely ignore the prediction. That person has no reputational skin in the game.
1,337-second burn.
Also, to be bright enough that we would see it from here as a star, I imagine it would require enough material that one might as well just let gravity do the job rather that use a Tokamak?
Maybe there are efficiency gains that are large enough that it wouldn’t actually require as much material as a star? I wouldn’t guess so though.
That's all before getting into how a containment failure doesn't imply "and then everything nearby just started a self sustaining fusion reaction". The confinement itself is a key part of what enables the conditions for the fusion to continue.
Also stops immediately if no fuel is given.
Gp is just saying that if you cracked it open like an egg (or just had a minor leak even) all that would happen is it would stop fusing. The room this happened in would be a bad place to be, but it's just going to start a fire or something, not destroy the world.
Different fusion systems. Stars fuse, in general, by statistically overloading the weak force. (The Sun is volumetrically about an order of magnitude less powerful than a human being. Like 200 to 1,110 W/m^3.)
In smaller volumes, e.g. on Earth, we have to break the strong force. This releases more energy, I think. But it also requires temperatures and energy densities far higher than that which stars produce.
Not sure if that strengthens or weakens your hypothesis...
You're wrong and right. Electrostatic repulsion is the barrier, and at its limit, defines electron degeneracy pressure. But the strong force is the ultimate source of energy of the reaction, and the weak force is important in stellar reactions.
The weak force initiates proton-proton fusion [1]. (We still struggle to empirically measure its cross section because it's so low. Weak force be weak.) DT fusion, on other hand, has to crack open the energy in those delicious gluons with raw temperature. This is why PP fusion occurs around 4 MK while DT fusion needs over 1,000 MK.
[1] Anthony Phillips' The Physics of Stars
Fusion is initiated by bringing nuclei very close one of another, overcoming the electrostatic repulsion.
When fusion is successful, the output energy is a consequence of the strong forces, i.e. it is the difference between the binding energies caused by strong forces in the output and input reactants.
The role of the weak force is that it can determine the probability of success of the fusion.
When the input nuclei have enough neutrons, the nuclei that have collided may remain fused. Otherwise, even after being fused for an extremely short time, the compound nucleus will break again, regenerating the input nuclei which are repulsed, so fusion fails.
In cases when fusion would fail due to a bad proton/neutron ratio in the fused nucleus, e.g. for the case of proton-proton fusion, during the very short time when the input nuclei are fused, weak forces may transform a proton into a neutron, preventing the separation of the fused nuclei and allowing fusion to succeed.
So overcoming the electromagnetic forces initiates fusion, strong forces determine the amount of energy obtained per fusion event and weak forces can determine the probability for fusion to succeed when nuclei collide.
Protons overcoming their electrostatic repulsion doesn't mean fusion--formation of a deuteron does [1]. Protons overcoming their repulsion creates the initial conditions for fusion, but in most cases no fusion occurs. The weak force "chooses" whether fusion occurs or two protons come unusually close and fly apart.
This is a bit of a pedantic line. But nuclear physisist say the weak force initiates fusion because if we take something with as low a cross section as proton-proton interaction to be the starting point of fusion, we might as well extend it to protons being in a star at all. (A greater fraction of protons in a star will fuse than proton-proton interactions graduate to fusion.)
Without the weak force, we have no stellar fusion. Without the weak force, artificial fusion is still possible. That's both a blessing and a curse, since the weak force permits lower-temperature fusion.
> When the input nuclei have enough neutrons
Irrelevant for proton-proton fusion.
[1] https://physics.stackexchange.com/questions/526471/why-is-th...
That is, it would seem likely that fusion power would be costly to build. It would also seem apparent that if it were to fulfil its promise then the power it generates is sold at or less than the current amount. That would then seem to imply a lengthily time to make a return on the initial investment. Or am I missing something else with this equation?
Easy to find research showing the detrimental effects of masks on communication, etc: https://pmc.ncbi.nlm.nih.gov/articles/PMC10321351/
Helion's reactor, if it works, could become a source of the cheapest neutrons on the planet. It would greatly enable nuclear proliferation by providing neutrons for breeding of fissionable material for bombs.
A 50 MW DD reactor would produce enough neutrons to make half a ton of plutonium per year. Remember, none of these neutrons have to be turned around to make tritium, as they would have to be in a DT reactor.
Every schemer I have ever seen is quite a bit more complex than a fission reactor. Often, designs will depend on materials that do not yet exist.
That said there is a tremendous variety of techniques that fit under the umbrella term of "fusion," so I'm hoping to learn something more.
I've looked a lot into this in terms of how to get a project like Georgia's Vogtle to have cost less, or Olkioluoto in Finland, or Flamanville 3 in France. Big complex construction projects are expensive, and it's not clear at all to me that fusion would be simpler or smaller, or escape the rest of Baumol's cost disease that has been plaguing fission in highly developed economies.
Though I guess some of that infrastructure could be overbuilt due to excessive regulation.
Also much of the concrete and steel is needed for the containment domes. Fusion power likely wouldn’t require nearly as much protection. Perhaps just a fairly standard industrial building.
(and other than that I echo elcritch's comments)
I still think its worth researching and we'll get there at some point, but I'm not holding my breath-- the whole industry has overpromised in the past, continues to overpromise now and will be probably be irrelevant for de-carbonizing the grid by the time the technology is actually ready at an industrial scale.
Mass media reporting on the whole sector is admittedly even worse; especially for uninformed readers without an engineering background.
I believe the current timetable is no longer contingent upon funding (since they've got the funding they think they need). It's no doubt still an optimistic startup timeline, a target, that they might well fail to achieve (even without the startup failing, just being late).
It's a cool concept, but probably not gonna be viable anytime soon (if ever!).
Does the physics change as they scale up the field strength? No one is really going to know until they try (unless we get a lot better at simulating plasma real fast). If not, they lost a bet, but they lost it honestly and as far as I can tell (not a physicist) it was a reasonably good bet to make.
Can they physically build the bigger magnets they need fast enough to meet their timelines (and everything else. I understand they are currently bottlenecked on capacitors)? Apart from normal "startups are overly optimistic" issues I don't see any reason to think that they shouldn't be able to reliably predict how fast they can scale magnet size, or be limited to a linear rate. While they are big magnets, it's not exactly new physics.
I'm not sure I'd say they are "probably going to be viable" anytime soon either. I think they have a good chance, but "probably" as in ">50%" is probably pushing it. (Also depends on where you put the goalposts of course)
FWIW I believe that 2018 report was for a high gain low pulse rate plan that Helion rejected, and they are aiming for substantially lower strength magnets as a result. I can't find anything more than rumors to confirm that though.
It's just that from everything I know about the project, they still have a long way to go, and there are a lot of milestones to hit that are just pipe dreams for now (actually fusing He3, breeding it, net-gain energy extraction, ...).
I would expect progress to slow down significantly as the scale of prototypes and their complexity increases (like what happens for basically every engineering project ever)-- but progress is already slow/behind schedule to begin with...
To move that "plausibly" into "actually" you have to have very careful design review by regulators. Very careful review of construction to make sure what is constructed is what was designed. And so on and so forth. It's a lot of friction that skyrockets costs. Legitimately. People inevitably attempt to cut corners, and there's no way to make sure they aren't on the safety parts without checking. Actual currently regulatory costs seem to bear out the difference between these, with SMR people spending large amounts of money to convince regulators they didn't screw up, vs Helion fusion being "regulated like a hospital".
I'm not saying fusion has no proliferation concerns. But it's the difference between "low grade nuclear waste, or a very high tech very advanced program to weaponize a working reactor" and "even a broken reactor can be strapped to some explosives to make a dirty bomb". I can't say I'm very aware of how much proliferation concerns drive costs.
Public sentiment also helps.
I was thinking more of large scale D-T fusion, e.g. the tokamak design, which requires breeding tritium & is expected to create a lot of neutron activated waste. The tritium is especially concerning, as it's roughly as deadly as polonium-210 & highly bioavailable in the form of super heavy water.
You're probably right for smaller aneutronic designs like Helion's. If they can actually be made to work, they'll be much safer.
And the first generation will be expensive. That's how all new technology is.
It's not only initial investment. Half of the fusion fuel is tritium, which is one of the most expensive substances on Earth (a google search finds that the price of tritium is about $30k per gram [1]). For comparison, fission reactors need enriched uranium, and that costs only about $4000 per kilogram [2]. People have the idea that fusion produces many times more energy than fission, probably because fusion bombs have a higher yield than fission bombs. This is not true. The most typical fusion reaction involves one deuterium and one tritium and yields 17.5 MeV from a total or 5 nucleons. A fission reaction involves one neutron and one atom of U-235 and yields 190 MeV from 236 nucleons. So fusion yields about 4.3 times more energy per nucleon. That's respectable, but in the popular imagination fusion yields 100 or 1000 times more energy than fission, so the fuel cost can be neglected. Nothing could be further from the truth.
Perhaps one day we'll get there, but I worry that the current advancements using the rarer isotopes will end up proving to be a dead end on that road, much like so many attempts at GAI. In the short term I suspect we'd have better odds with getting thorium reactors to be economical.
https://dothemath.ucsd.edu/2012/01/nuclear-fusion/
Tritium is rare but lithium isn't, and we can make tritium from lithium using the neutrons from fusion. (We also get tritium from fission plants, which is how we'd build the first fusion reactors.)
Each fusion reaction consumes one tritium atom and produces one neutron. If that neutron hits a lithium atom, it can split that and produce a tritium atom. If everything goes perfectly and there are no losses, then you get a 100% replacement of all the tritium that you consume. If you have a 90% replacement ratio (highly optimistic), you essentially lower the cost of your tritium fuel by a factor of 10, so from $30000 per gram to $3000 per gram, or $3 MM per kilogram.
> We also get tritium from fission plants
Yes we do. Mainly from Candu reactors. There are 49 Candu and Candu-like reactors in the world, and each produces less than 1kg of tritium per year. According to [1] a 1 GW fusion power plant would consume about 55 kg of tritium per year. So you'd need to run more than 50 fission power plants to operate one fusion power plant. Most people who dream of fusion think that fission will become irrelevant, not that you'll need 50 fission power plants for each fusion power plant.
[1] https://www.sciencedirect.com/science/article/abs/pii/S09203...
Initial tritium load for a small, high-field reactor like CFS is much smaller than for ITER. And I'll note that the paper you linked has this conclusion:
> The preliminary results suggest that initial operation in D–D with continual feedback into the plasma of the tritium produced enables a fusion reactor designed solely for D–T operation to start-up in an acceptably short time-scale without the need for any external tritium source.
Ok, let's talk about that. For those who are not familiar, CFS stands for Commonwealth Fusion Systems, as startup with links to MIT. CFS aims to build a fusion reactor similar to ITER, but many times smaller, the secret sauce being that they use superconductors to achieve high magnetic fields. Back in 2022 some of the MIT guys got an ARPA-E grant to investigate the use of FLiBe to achieve atritium breeding ratio higher than 1 [1]. The results are in [2], they were published in January 2025. Here are some quotes:
> The long-term goal of LIBRA is to demonstrate a TBR ⩾ 1 in a large volume (1000 kg ∼ 500 l) of FLiBe molten salt using D–T neutron generators. Note that a full-scale LIB in an ARC-class FPP will require ∼250 000 l of FLiBe, hence the importance of understanding tritium behavior in large salt volumes.
Anyway, what breeding ratio was achieved? 3.57 x 10^(-4), or 0.0357%. It's a long way to go from here to 1.
I'm not saying it's impossible, but too many things related to fusion are just "engineering details".
[1] https://arpa-e.energy.gov/programs-and-initiatives/search-al...
[2] https://iopscience.iop.org/article/10.1088/1741-4326/ada2ab/...
In the Solar System, the abundance of beryllium is similar to that of gold and of the platinum-group metals. On Earth, the scarcity of beryllium is less obvious only because it is concentrated in the continental crust, where it is relatively easily accessible, even if its amount in the entire Earth is much smaller.
Lead neutron multipliers would be preferable, because they only inter-convert isotopes of lead, so it is not destroyed, like beryllium.
However lead used for this purpose becomes radioactive, with a very long lifetime, unless expensive isotope separation would be used for it.
[1] https://en.m.wikipedia.org/wiki/Deuterium%E2%80%93tritium_fu...
That would still be more expensive than Solar and Wind (by 100% or more) - but I am skeptical in the same time frame those sources will be able to take over baseload generation.
It's really comparing apples to oranges.
Plus, it's a very hypothetical future. Anything could happen between now and then.
Because IMO the only approach that is even capable of delivering here is the Helion one (=> direct conversion). And that design is incredibly far from ready, the whole approach is completely unproven and their roadmap is mainly wishful self-delusion (from what we can tell by evaluating past milestones, like "first 50MW reactor finished by 2021"-- there is no 50MW reactor even now).
From my PoV, ITER-style tokamaks are the most conservative/certain design, and also the furthest along by far. That would imply:
=> Cryogenics for the magnets
=> big hightemperature vacuumchamber for plasma
=> all the thermal/turbogenerator infrastructure needed in conventional plants
=> super high neutron radiation flux (this is a problem)
I just don't see where you save anything. This is basically just a fission reactor, only a magnitude more complicated and demanding. I absolutely don't see how it could ever get significantly cheaper than conventional nuclear powerplants.
Fusion has none of this. Assuming Q >> 1 will be demonstrated in a design that can be commercialized the next biggest problem is dealing with high-energy neurons on a scale never experienced before with potential much faster degradation of materials than anticipated leading to prohibiting operational costs.
Does money even matter once fusion is attainable?
Make all energy free. What does that change? It lowers operating costs for many things, but up front capital costs are still there. Land still matters. Food still matters.
Money will still matter. Allocation of time, of resources, all that still matters a lot. Energy is big for the economy, but if its free we shift our focus to other matters of logistics.
I'm generally pro-publicly funded research. There is not any direct ROI on say the LHC, but it does fund advanced manufacturing and engineering work that might enable other more practical industrial applications. The ROI might be a century away.
It'll still make a difference in large scale energy intensive stuff, like desalination, aluminium refining, etc. but the average punter is going to save a lot more by installing solar panels.
Don't mistake skepticism for hate. I will be the first one to applaud a commercial fusion reactor. But fusion proponents often use it's pending development as an argument against fission - a technology we already have and desperately need to adopt now.
> But fusion often use it's pending development as an argument against fission - a technology we already have and desperately need to adopt now.
If it helps, CEA is also doing a ton of R&D on fission (and batteries, among others). But there, the real issues are mostly political.
Unless you can do a science fiction thing of turning off the sun, and harvesting the hydrogen in it to power local reactors in earth orbit to provide the energy (light) we need without letting the vast majority escape our solar system unused. Otherwise that big fusion reactor in the sky provides all the energy we need.
Energy storage is far from a solved problem. Tesla produces ~40 gigawatts of storage capacity an entire year. California alone consumes ~800 gigawatts of power in a day. Even if Tesla dedicated every bit of lithium it had to building storage capacity for just one state, and demand didn't increase, it would realistically still take over a decade to keeping the lights on purely with renewables for a 24 hour period. At which point the first battery packs would be nearing the end of their service life.
One of those hopefully-you-don't-need-it concerns but it is starting to become a more pressing with the uptick in wars and unrest that seems to be going on.
On a 1:500 year time horizon we know there are threats that dim the sun (possibly quite a bit shorter now that nuclear weapons are on the table and we seem to be incapable of dealing with that threat productively - the number of actors with nukes is growing). Planning for that isn't anti-renewable, it is just cautious.
And nobody was talking about K-Pg events. You'll notice the years quoted were all after the Roman Empire was founded.
Aggressive predictions have us generating ~6-10TWh of batteries by 2030 meaning we’re going to still need about another 3-6 years to actually satisfy demand (ignoring complexity of hooking up the batteries). On top of that, the batteries require rare earth metals that companies are gearing up to satisfy by strip mining the ocean floor for those polymetallic nodules, operations which have a very real risk of completely destroying deep ocean life. It seems to me like it’s slow and ecologically potentially more destructive than even global warming. Is it really wise to be betting on batteries at this scale vs tried and true nuclear fission which doesn’t carry any of these risks?
What people forget is batteries are a manufactured good, which follows Wright's Law. Manufactured goods (like energy storage, TVs, lightbulbs) obey different economic principles to scarce goods (like land, services, or goods with scarce inputs), and they have effectively unlimited supply. The supply is strictly set by demand.
Aggressive predictions of ~6-10TWh/year of batteries in 2030 are more predictions of demand, not so much predictions of supply. If market demand in 2030 is 30TWh/year, then that's what the market will produce. But don't blame manufacturers for the fact that demand in 2030 will only be 6-10TWh/year! And don't confuse this for a sector's inability to increase supply!
The response when seeing a "6-10TWh/year" prediction should be "how can we incentivize demand so that this number is 30TWh/year instead".
Lithium ion is preferred for vehicles because it's lighter, but again we are talking about stationary storage, so the extra weight of sodium ion isn't a problem.
The technology is solved, and the materials needed to make it abundant. It's all about demand. If the demand is there, the industrial capacity will follow. But right now, the market is only demanding about 3TWh/year of storage, and so that's how much industry is producing.
It takes a lot of time for new battery technologies to scale and disrupt existing ones and entrenched players have an incentive to continue competing. Sodium ion, iron air etc might replace lithium ion on the 30 year time scale but lithium ion will continue to drive down costs and up its capacity to try to compete and it has significantly more revenue to fund this by being the only player in the market. So it’s not clear when alternative batteries will start to replace lithium ion, but at scale it’s unlikely to be a quick process. And please don’t pretend like it’s all a demand side problem. It takes time to build out new factories from manufacturing all the equipment needed to acquiring and training employees. There’s plenty of demand for cheap batteries and the ability to manufacture simply isn’t there either and it’s being brought online. Oh and that capacity being added? It’s all lithium ion and requires a long pay off for that investment. Lithium ion is going to be potential a significant ecological debt worse than fossil fuels if the ocean floor strip mining gets going.
And it is all a demand side problem. If the world wanted to buy 10 or 20 TWh a year at current market prices, that's how much would be produced. But the world doesn't want to do that and hence that much isn't produced. This is Econ 101 for goods with non scarce inputs. It doesn't take ten years to scale up production for commodity goods.
As for scarcity, inputs to lithium ion ARE scarce which negates your entire model. Pretending they aren't is where you're making a mistake. Lithium, cobalt & nickle are relatively scarce and the mines for that have to scale up to meet demand as well. You've also got a workforce to train to do the work which takes time & is also input-constrained. That's why there's massive NEW lithium mines being opened in the US & elsewhere to extract existing reserves to meet the growth in lithium ion batteries. If the world thought that sodium ion or ion air was an immediate future, you wouldn't see these massive large-scale investments into lithium. Lilthium-ion batteries is going to be a large and growing market for decades which brings me back to the strip mining of the ocean floor that's coming to support that.
Whright's law by the way isn't also an inevitable effect that goes on forever. At some point your exponential plateau's and you no longer see such exponential decrease in pricing. That's why processors aren't getting cheaper and compute isn't scaling up quite in the same way as in the early days. There's only so efficient you can make something.
Most states currently only care about installing solar and wind -- not storage -- because they are still majority fossil fuels, and at the current moment it makes no sense to install storage if you still have fossil fuel to dislodge. The only exception is really California, who are installing storage, but their bottleneck is not the market's ability to deliver enough supply.
There are also many storage options beyond lithium ion if you only spent a moment to look.
Maybe fusion will be an alternative someday but for now it's just a fantasy. We need to act based on what's proven to work today.
Fission as a solution is something that is popular on social media, for reasons that are utterly mystifying to me. The arguments are invariably a few words that reach sweeping conclusions with no actual data backing it up, and lots of data contradicting it that the individual appears oblivious to.
Current supply of storage matches current demand. Supply is low only because demand is low. However, as demand increases, supply will continue to match demand, and moreover the price will actually decrease because of the fact that the learning curve is a function of production volume.
This has been a steady empirical phenomenon for 30+ years, and it's predicted by basic economics principles. It's not going to change now!
This is true for all battery types, but especially for sodium ion and iron air, which are constituted of abundant materials. Sodium ion in particular has very similar behavior and cost to lithium ion.
This confusion you're having is you seem to be conflating manufactured goods (like batteries) with scarce goods like land or services, whereby there's a fixed supply that can't be increased and where Wright's Law doesn't apply. This is not correct.
Storage is more like televisions or light bulbs, where you can basically make as much of it as you want, and the price will keep declining as more is made. And supply will always be there for demand, whatever the level of demand happens to be (in this case, a lot).
Converting every passenger car and light truck in the US to a BEV would involve enough batteries to store something like two days of the average grid output, which is more than would be needed for a cost optimal wind/solar/battery/hydrogen system for a 100% renewable grid.
Assuming the power stored in these vehicles can be reclaimed by the grid anytime they want?
It's an argument I like to use. When someone claims "we can't use X because of reason Y, we have to do Z instead" I look to see if Z also is hit by objection Y.
Another example of this is "renewables require too much material that we can't recycle", at which point I observe that the quantity of materials produced by society as a whole greatly exceeds what renewables would involve, even if the society is powered by nuclear. The US produces 600 megatons of construction and demolition waste a year, for example. Renewable waste would just be a minor blip on this existing waste stream. So, either recycling this waste isn't actually needed, or a putative sustainable nuclear-powered society has discovered how to recycle it, so just toss the renewable waste (which is almost entirely things like steel, aluminum, and glass) into that same recycling infrastructure.
Steel mills run when power is cheap. They historically have run at night (and only minimum power during the day) because cheap power is available at night. Of course there are lots of different steel mills, older ones can't shut down - but modern ones don't run 24x7, they run when power is cheap. Even the old 24x7 ones did their yearly maintenance in December - when power demand is highest (Christmas lights).
Wind and solar are easially predicted a few days in advance with high accuracy, and thus the mills change their shifts/output to follow the cheap power. If it is cloudy/no wind they will send their employees home (with pay) or do maintenance for that week while waiting on more cheaper energy. It takes a tremendous amount of energy to melt iron and so they manage this carefully because it makes them money. They can't deal with months of no production, but they can manage a week here and there.
If this isn't about ceasing carbon emissions then none of this is necessary. Fire up the coal plants!
(1) the emissions of a 98% renewable + 2% natural gas grid that comes online in 6 years, assuming fossil fuels for t between [t, t+6 years].
(2) the emissions of a 100% fission grid that comes online in 16 years, assuming fossil fuels for t between [t, t+16 years].
If you insist on ignoring the temporal nature of cumulative emissions, then sure, you can arrive at a convenient but false conclusion. But any honest analysis will consider the emissions in that [t+6 year, t+16 year] interval.
(... it would also consider things like social licensing risks leading to early plant closures like what's happening in Germany, or the fact that nuclear will likely be paired with natural gas too because demand itself is variable, and overbuilding nuclear is expensive.)
Start both with the same (current) % for renewables and (1) have some realistic ramp-up of renewables to reach 98%, and (2) keep the renewables more modestly rising in the fission version, while fading-out fossils in favor of fission
You should also account the carbon foodprint of grid-level energy storage (yes, it will be needed, even with the natural gas plans), vs the foodprint for fission plants (undoubtedly quite bad).
Renewables are by their nature much more distributed in space, which makes them much harder to enclose and control in the way required to reproduce the current structure, especially as they are mainly being built by challengers who aren't really interested of forming monopolies with the fossil industry.
Which is why we aren't building record-setting amounts of natural gas infrastructure, oh wait...
https://headwaterseconomics.org/wp-content/uploads/HE_electr...
It's not. If it was the world wouldn't be using 140k TWh of fossil-fuel-produced energy[1], and would be using a lot more than 9k TWh of renewable energy[2]
[1] https://ourworldindata.org/grapher/global-fossil-fuel-consum... [2] https://ourworldindata.org/grapher/modern-renewable-energy-c...
Even if nuclear fussion had the advantage of free combustible, the costs of building and manteinance alone could make it not practical. As of today it's not enough to have positive net return, but to have a LCOE of maybe $60/MWh (and going down). Current estimates put fussion at $120/MWh.
If it can't keep up with solar and eolic rade of fallig prices, it might be only suitable to replace fission power (which is not falling), about 10% of the grid. And there have been literally billions spent in research.
The elephant in the room is natural gas which is the true competitor to fission and is still dirt cheap in the US.
There's a reason China is installing two orders of magnitude more solar than nuclear these days (nameplate capacity basis).
On the margin I don't argue that renewables are cheaper, but you still need a way to generate base load power on demand.
If you don't count externalities (see cost of firming intermitency [1]).
> (and going down).
Not the last two years according to LCOE+ 2024. the main culprit is inflation, but the curve was nearing flat anyway.
[1]: https://www.lazard.com/media/gjyffoqd/lazards-lcoeplus-june-...
We should give the folks at model.energy the next peace prize for their effort.
Your answer gives a model unrelated to the figures I was discussing, with extremely agressive prices [1] set as hypotheses and zero network costs factored in. Sure, I can accept it as a minimum limit for the cost of a system, but that's not a very useful information, and you're not quoting this price as a lower limit either.
I don't see an honesty issue here, just someone believing that spherical cows are going to produce milk tomorrow.
[1]: e.g. the Lazard report quotes utility PV at $29-92/MWh, while your tool quotes it at 21.7€/MWh.
Neither solar or wind are free. There are costs associated e.g. with building, shipping, maintaining, decommissioning these things (and hopefully at some point recycling, but that’s not solved). Looking at the whole picture, these costs are not that different. These technologies are complementary, they have very different characteristics.
> Current estimates put fussion at $120/MWh.
Current estimates are completely unreliable, because no industrial-scale demonstrator was built. They are a useful tool for planning and modeling, but not solid enough to build an industrial strategy on them. (And it’s “fusion”)
But if there is not a clear and speedy path to get fusion to $30/MWh it's not going to make it. Batteries, solar wind, and geothermal are all busy deploying and getting cheaper every month, year, and decade. The grid system possible with 2035's solar and battery tech is going to be completely unimaginable to today's grid ops.
As of today, we are closer to mass batteries as renewable companion than fusion, at least in terms of ROI. If both end up competing for lithium, it would go to batteries unless fusion becomes dirty cheap.
Current estimations are useful because they mark the starting point for fusion: they are at around 120. They need to reach 80 to replace fission. They need to reach 60 to replace batteries. Assuming batteries don't get better ROI.
Same numbers were useful 30 years ago for solar: it was fully functional, but not yet economically sound. It was not much than a toy and a promise (as it is fusion today). Only when prices made sense it turned to a serious energy source.
I recall a story of some lab that was trying to make a lithium-based neutron detector. It wouldn't work, and when they investigated they discovered the lithium they had bought was almost pure Li-7. It was surplus sold back into the chemicals market from the US hydrogen bomb program (which needed Li-6).
Some of the other designs also look relatively cheap. Tokamaks are just the one we understand the best, so we have the highest confidence that they'll work.
Paperwork, standards, logistics, non-destructive tests, monitoring, certification, other "boring" stuff.
Tech people LOVED bitching about how complicated the USB-C standard is, how it does too much, etc.
Guess what? As a consumer, I can plug pretty much anything into anything else, use literally any brick to charge nearly any device, deliver outstanding amounts of wattage over cables the size of headphone wires, for pretty cheap, and USB-C docks that you just plug into whatever and things just hook up and function.
It does that because of the millions spent on human beings spending time to work out bugs, work around edge cases, discover what people tolerate and care about with the standard, etc.
Consumers ignored all the complaints about it being complicated and just fucking used it and it's ubiquitous and works for pretty much everyone and the only people who have bad experiences are the ones buying exclusively fraudulent cables off amazon and only some of those people are hitting those problems!
I can just plug a cable into the power port and get HDMI out of my steam deck. Holy shit.
THAT'S the future.
There's also many paths to improved fission. Fast neutron reactors, thorium, small fast neutron reactors for industrial heat, thorium reactors, accelerator-driven subcritical reactors ... Millions of years of fuel available and new ways to use the output beyond boiling water for electricity.
Note that I'm not mentioning slow neutron SMR, they're mostly pointless and just an excuse not to build current and perfectly fine PWR/BWR/heavy water reactors.
Fission still has this huge stigma about "nuclear=dangerous and bad" which clearly isn't true with the growing number of passively-safe designs... but nobody wants to fund development of those into proper commercial reactors.
Meanwhile, fusion is still different and futuristic enough to have support from governments and the general public.
Seems ironic that in a thread about fusion with loads of difficult technical challenges that will still require decades of research after 60 years of investment and research have already been poured into it, a minor issue of slight corrosion in LFTR requiring maybe a few years of research is seen as an insurmountable obstacle with "no real solution in sight".
Fusion has better security properties than fission, so perhaps it will find some use case in the far future.
For pure return on investment, I agree with your take.
Provided of course that any future threats to humanity as a single planet civilization don’t materialize. There’s a low and uncertain tail risk ignored in our calculation.
Rather, the main benefit would lie in the technological advances made in order to enable such a Mars mission in the first place (similar to advances during Apollo).
I agree with this view, but the comment I was replying to only mentioned as a benefit that Mars could be a second home (which I find rather ridiculous).
The first and second sentences of that comment literally say
> A Mars mission would benefit humanity, but less directly. The past lunar missions and space program benefited humanity in many ways.
And then it goes on to acknowledge the "second home" element, but only as a small consideration.
Dude, the relentless decrease in cost of manufactured items, this decrease that makes your current way of life possible, is driven by exactly that. Manufacturers are in life-or-death competition and we consumers reap the benefit as prices are driven ever downward.
The benefit to humanity is the technological advancement.
I bet I can guess the name of the god too!
A 'gift of God'?: The public health controversy over leaded gasoline during the 1920s: https://pmc.ncbi.nlm.nih.gov/articles/PMC1646253/
Why do you think a result like this would make anyone less skeptical of fusion? Ability to run a device for this long is not the obstacle to success for nuclear fusion. This is just another vastly overhyped "breakthrough", which we seem to have every week.
I've followed fusion for probably longer than you've been alive, and there are fundamental showstoppers for the common approaches, particularly tokamaks and stellarators. Fusion may have a chance with unconventional approaches, like Helion's, but the consensus approach looks like an exercise in groupthink that won't lead anywhere.
Just 9 days ago: https://news.ycombinator.com/item?id=43000301
>>Ability to run a device for this long is not the obstacle to success for nuclear fusion.
What an odd take. Do you also consider the list of flight endurance records to be immaterial to aircraft evolution?
This achievement is relatively unimportant. It's not the major issue that would block a DT fusion reactor. As such, achieving it doesn't move the needle much on the plausibility of DT fusion in tokamaks.
Plasma runtime in not a showstopper then?
I blame journalists not being able to proprely report on this subject.
https://physicsworld.com/a/chinas-experimental-advanced-supe...
If you're a programmer, that is. Could mean something else in physics, right?
* They pumped in "2 MW of heating power".
* This expirement wasn't about energy in-out, it was about plasma control. Specifically stopping at 1337 seconds is a way of announcing "and we could have gone longer, but we liked this number"
Fission has potential for far cheaper fuel cost and can be done with less capital cost.
We are spending a crazy amount of money researching fusion while we have only explored like 1% of the potential of fission. If only part of this money was invested in fission we could have a competition for multiple advanced fission reactors.
I don’t care about sex jokes. 42 (or 72) OTOH are cool because both are surrounded by twin primes!!! how cool is that? (semiprime coolness is significantly smaller than twin prime coolness)
how about the NORTH versus SOUTH team contests? ugh
This entire site is nothing more than a sales and marketing tool and otherwise exists to waste peoples' time.
Some of us do both :)
For me I worry it's like the search for the northwest passage. (https://en.wikipedia.org/wiki/Northwest_Passage). Explorers spent about 400 years searching for something that they knew just had to be there, but when they finally did it (1957), it really wasn't important anymore.
It’s very easy if you’re even a tiny bit interested in the scientific aspects. Since we started we’ve had several generations of superconductors, huge advances in our understanding of materials and plasma physics (a bit niche but still very cool).
ITER itself is fascinating if you’re into large-scale engineering and planning. If you are into this and not interested in ITER, I would recommend having another look.
> Explorers spent about 400 years searching for something that they knew just had to be there, but when they finally did it (1957), it really wasn't important anymore.
Yes, it’s a risk and it might well end up that way. Still, many discoveries have already been made along the way, and it is impossible to predict its success or failure without actually trying to do it.
Helion is an exception, since they have a different fuel which gives them a way to extract electricity directly.
2. Yeah, material science is also a big one. When you are working with the magnetic forces typical in a modern fusion reactor, your materials undergo a lot of mechanical stress. The "first wall" that has to bear the brunt of the nuclear reactions becomes radioactive. Some plasma ions invariably go off trajectory and we have a "diverter" to prevent them from hurting the reactor but that reduces the temperature.
3. Our reactors aren't efficient enough. Everyone taking about "q" value means the energy they put into creating the reaction to get the plasma to fuse. It's called q-plasma which is a misleading metric. The true breakthrough will be sustained q-total, which will be the ratio of the total energy you get out over the total energy you put in. Nobody in the industry likes to talk about it, because we are decades away from reaching this.
4. Modern designs are becoming extremely expensive. The most serious design right now is being funded not by a state of a country but by the biggest countries in the planet.
5. Someone help me here I've ran out of points
We already have a fusion source and a way to harvest it from afar in solar panels.
I guess they haven't been allowed on freeways yet?
And, FWIW, I think it's far from clear at this point that progress towards AGI has been overhyped. It's true that we're not there yet, but how many serious people were actually predicting we'd get there in early 2025? If anything, that one seems like it could be coming up on us faster that many had expected. But, of course, nobody really knows — certainly not me.
Actually...same with FSD, now that I'm thinking about your comment a bit more critically. There are a few people out there who keep selling a snake-oil version of the technology. But, if you tune them out, my sense is that we've actually made pretty substantial progress on that problem too. After all, there are cities in the U.S. today where you can get picked up in a driverless taxi!
It's very cool, but the article itself paints a long time line. Indefinite containment is just one part of the puzzle.
actually...
All that depends on how much burn heat we can get from those ~30mins burns... :)
They also need a lot of ignition energy which requires a powerful separate power source, which limits where the fusion reactor can be built.
Moreover, there is the issue of the reactor core being degraded by the heavy neutron radiation which is produced by the fusion reaction. So the chamber has to be replaced regularly. Which may also be quite expensive.
There are some reactor designs that use aneutronic fusion, which eliminate this particular issue.
Barring some kind of engineering failures and delays they seem on track to have things ready in the early 2030s.
In comparison with ITER, the have the advantage of newer magnet technology (which certainly helps!), but thats the only actually proven thing, and every other aspect of ARC is basically complete vaporware.
It would be a very pleasant surprise to have them extract electrical energy from the thing in early 2030, but I'm not even holding my breath for first plasma by then. But we'll see.
AFAIU, no existing tokamaks can handle sustained plasma for any significant period of time because they'll burn down.
Did this destroy the facility?
What duration of sustained fusion plasma can tokamaks like EAST, WEST, and ITER withstand? What will need to change for continuous fusion energy to be net gained from a tokamak or a stellerator fusion reactor?
Don't those materials melt if exposed to temperatures hotter than the sun for sufficient or excessive periods of time?
For what sustained plasma duration will EAST, WEST, and ITER need to be redesigned? 1 hour, 24 hours?
But IDK if they've seen recent thing about water 100X'ing proton laser plasma beams from SLAC published this year/month;
From https://news.ycombinator.com/item?id=43088886 :
> "Innovative target design leads to surprising discovery in laser-plasma acceleration" (2025-02) https://phys.org/news/2025-02-discovery-laser-plasma.html
>> Compared to similar experiments with solid targets, the water sheet reduced the proton beam's divergence by an order of magnitude and increased the beam's efficiency by a factor of 100
"Stable laser-acceleration of high-flux proton beams with plasma collimation" (2025) https://www.nature.com/articles/s41467-025-56248-4
Timeline of nuclear fusion: https://en.wikipedia.org/wiki/Timeline_of_nuclear_fusion
The extremely low efficiency of the lasers used there for converting electrical energy into light energy (perhaps of the order of 1%) has not been considered in the computation of that "energy gain".
Many other hidden energy sinks have also not been considered, like the energy required to produce deuterium and tritium, or the efficiencies of capturing the thermal energy released by the reaction and of converting it into electrical energy.
It is likely that the energy gain in the plasma must be at least in the range 100 to 1000, in order to achieve an overall energy gain greater than 1.
> A fusion energy gain factor, usually expressed with the symbol Q, is the ratio of fusion power produced in a nuclear fusion reactor to the power required to maintain the plasma in steady state
PV (photovoltaic), TPV (thermopohotovoltaic), and thin film and other solid-state thermoelectric (TE) approaches do not rely upon corrosive water turning a turbine.
Turbine blades can be made of materials that are more resistant to corrosion.
On turbine efficiency:
"How the gas turbine conquered the electric power industry" https://news.ycombinator.com/context?id=38314774
It looks like the GE 7HA gas/hydrogen turbine is still the most efficient turbine? https://gasturbineworld.com/ge-7ha-03-gas-turbine/ :
> Higher efficiency: 43.3% in simple cycle and up to 64% in combined cycle,
Steam turbines aren't as efficient as gas turbines FWIU.
/? which nuclear reactors do not have a steam turbine:
"How can nuclear reactors work without steam?" [in space] https://www.reddit.com/r/askscience/comments/7ojhr8/how_can_... :
> 5% efficient; you usually get less than 5% of the thermal energy converted into electricity
(International space law prohibits putting nuclear reactors in space without specific international approval, which is considered for e.g. deep space probes like Voyager; though the sun is exempt.)
Rankine cycle (steam) https://en.wikipedia.org/wiki/Rankine_cycle
Thermoelectric effect: https://en.wikipedia.org/wiki/Thermoelectric_effect :
> The term "thermoelectric effect" encompasses three separately identified effects: the Seebeck effect (temperature differences cause electromotive forces), the Peltier effect (thermocouples create temperature differences), and the Thomson effect (the Seebeck coefficient varies with temperature).
"Thermophotovoltaic efficiency of 40%" https://www.nature.com/articles/s41586-022-04473-y
Multi-junction PV cells are not limited by the Shockley–Queisser limit, but are limited by current production methods.
Multi-junction solar cells: https://en.wikipedia.org/wiki/Multi-junction_solar_cell#Mult...
Which existing thermoelectric or thermopohotovoltaic approaches work with nuclear fusion levels of heat (infrared)?
Such as multilayer nanolithography, which nanoimprint lithography 10Xs; https://arstechnica.com/reviews/2024/01/canon-plans-to-disru...
Perhaps multilayer junction PV and TPV cells could be cost-effectively manufactured with nanoimprint lithography.
Maybe solar energy storage makes sense for storing the energy from fusion reactor stars, too.
There's also MOST: Molecular Solar Thermal Energy Storage, which stores solar energy as chemical energy for up to 18 years with a "specially designed molecule of carbon, hydrogen and nitrogen that changes shape when it comes into contact with sunlight."
"Chip-scale solar thermal electrical power generation" (2022) https://doi.org/10.1016/j.xcrp.2022.100789
However the exhaust gas of a gas turbine will still contain a great part of the input energy.
Therefore in order to reach maximum efficiency in a power plant, you must start with a gas turbine, which must be followed by a cascade of 2 or 3 steam turbines that run at lower and lower temperatures (this combination of a gas turbine with some steam turbines is what "combined cycle" means), until you obtain exhaust steam that is not much hotter than ambient temperature, and which can be used for heating, to recover even more of the input energy than what has been converted into electric energy.
Instead of gases or steam, turbines may also use supercritical fluids, e.g. carbon dioxide, which may lead to using less turbine stages and with much smaller turbines (that must work at much higher fluid pressures).
A gas turbine that is used alone, without steam turbines that recover the heat from its exhaust gas, has normally a too low efficiency. Its use can be acceptable only for mobile generators or emergency generators, where the size and complexity are more important than the efficiency.
The duration is because plasma is heated by rising current, and that hits limit after some period of time. With self-sustaining fusion, heating shouldn't be needed after the initial pulse.
I have also read that achieving productive fusion will require temperatures above 100 million degrees.
Most of my sources are pop-sci, so correct me if I'm wrong.
I hope this international race ends up bearing fruit in a few decades, we need it
I have always wondered - assuming that the confinement problem is solved, how does the cost of the fuel compare to fission (or other generation methods?
The fuel cost is small compared to fission, but note that even with fission fuel is a small fraction of the total cost, so this doesn't save much.
Nuclear fusion breeds its own tritium from lithium.
Running a 1 GW thermal fusion reactor for a year would consume $483,000 of deuterium and $1300 of lithium. At 40% conversion efficiency and 5 cents per kwh, the fusion reactor would produce $175 million of electricity in that same year.
For comparison, fuel is about 5% of the cost of electricity from fission, and about 50% the cost from coal.
Gravity is so much less powerful than the other forces.
Inertial confinement fusion, such as the National ignition facility, does generate comparable pressures and temperatures to the core of the sun within the fuel pellet for an extremely small moment during an implosion. This is done by focusing a lot of energy on small target.
Plasma confinement techniques don’t utilize high pressure to create fusion; they rely on extreme temperatures which are significantly hotter than the core of the sun, which can produce fusion events in a plasma which is only pressurized to around 1 atmosphere (they also rely on different fuel types than the sun which fuse much more readily). The key is once again focus, a large amount of energy is put into a small amount of gas. The obvious issue with this is that the extreme temperatures would destroy any physical container rapidly - but given the electromagnetic nature of plasma, it can be contained using a strong magnetic field without reaching the surface of its physical container.
https://en.wikipedia.org/wiki/Experimental_Advanced_Supercon...
* Fusion's potential is enormous.
* Health software, like fusion, needs breakthroughs.
* Are we ready for the data deluge?
* Can we build it fast enough?
Which is understandable, since this is the easy part (not very different than the setup in a fission or coal plant), and there's absolutely no reason to do so until we have seen ignition.
With the millions of degrees being involved, seems a little more than "not very different" than a fission reactor. But would like to hear how this is supposed to work.
But one end product of the fusion process is neutrons. Neutrons are unaffected by the magnetic confinement, they pass right through and hit the jacket of the reactor, where they are absorbed. This heats up the material, which is why you can run cooling water through the jacket which turns into steam. This steam spins a turbine.
There's some engineering challenges (neutron bombardment turns steel and concrete brittle, and later radioactive), but in the end its very similar to a normal fission reactor.
Is this a joke and reference to internet culture or a coincidence? Probably the latter, but i found it entertaining.
Trust me, we are all massive geeks, including my colleagues from CEA. There is a non-small chance that the result is deliberate.
As soon as AI investors start demanding dividends, then the ROI of investing in AI will be compared to the ROI of investing in electricity production "for production sake".
Even if we shut down chatgpt, people who still switch light on.
If we only keep enough fusion reactors to run LLM inferences, but no one can afford lights, well...
https://www.theregister.com/2022/12/23/doe_fusion_ai/
https://openai.com/index/strengthening-americas-ai-leadershi...
Also: https://www.energy.gov/science/fes/articles/ai-tackles-disru...
Why is the entire planet incapable of walking and chewing gum at the same time?