7 ms·

I remain skeptical that fusion will ever be a commercially viable energy source. I'd love to be wrong. The engineering challenges are so massive that even if t

• lordfrito 1y ago
  No one wants to acknowledge that the economics will likely never work out for the reasons you mentioned. Too much maintenance -- and very expensive maintenance at that. It's far cheaper cost per watt to build a traditional fission reactor and run/maintain that. Another reason is that ̶t̶r̶a̶n̶s̶m̶i̶s̶s̶i̶o̶n̶ distribution costs are half of your energy bill... so even if you could theoretically get fusion energy generation for "free" (which is impossible) you've still only cut your power bill in half. Edit: I meant to say distribution costs not transmission. Looking at last months bill I paid $66.60 to deliver $51.76 of energy (about 56% of my total bill was delivery). The raw distribution charge was $49.32 or 42% of the bill. I'm not alone in these numbers, but your mileage may vary.
  • cmrdporcupine 1y ago
    And the transmission costs argument is precisely why we'd likely be better off solving the problem of distributing power production across a more decentralized grid with a lot of wind and solar and battery all over the place
    • bell-cot 1y ago
      Problem: the capital & maintenance costs of the grid vary very little with its utilization %. So if you build loads of wind & solar & battery all over - either (1) you've got to build so much battery capacity, all over, that you'll never need the grid, or (2) you've still got to build the grid to get you through occasional "calm & dark" periods. Either way, you're looking at vastly higher capital expenses.
      • markvdb 1y ago
        Not necessarily. A slightly different approach might become lower TCO in the medium term: - moderately overbuild solar - batteries for short term storage - natural gas for seasonal storage
  • WillAdams 1y ago
    Excellent points. One wonders if this is why Lockheed-Martin dropped their effort: https://www.lockheedmartin.com/en-us/products/compact-fusion.html https://www.lockheedmartin.com/en-us/products/compact-fusion... (that page is still up, but news reporting indicates it has been dropped)
  • jmyeet 1y ago
    Transmission is a really interesting problem that creates all kinds of distortions. Say a house uses 10,000kWh per year at $0.10/kWH so $1000/year electrcitiy bill. Now say you get a solar system that produces 5,000kWh per year, focused in the summer months (where your power bill tends to be higher anyway). You may even export some of that power back to the grid. Have you cut your power bill in half? No. It's probably down ~20-25%. Why? Because regardless of how much power you use (within limits) you still need a connection to the power grid and that needs to be maintained. You'll often even see this on the electricity bill: fixed charges like "access charge" per month. We benefit from being on a connected grid. Your own power generation might be insufficient or need maintenance. It's inefficient if everyone is storing their own power. So it's unclaer what the future of the power grid is. Should there be large grids, small grids or no grid?
    • VagabundoP 1y ago
      There also resilience. Having small to medium local storage increases the stability of the grid. Renewables and something like Iron-Salt battery containers, would be pretty efficient over all. Easy to roll-out, very safe. We'll still need some sort of base load somewhere and backup to restart everything obviously. But the big giant power plants (with the huge capital costs, delays and NIMBY headaches) might become less necessary.
    • robertlagrant 1y ago
      > the summer months (where your power bill tends to be higher anyway) This depends on where you live!
  • rixed 1y ago
    > transmission costs are half of your energy bill Wait, what? Wikipedia[0] seems to disagree: > Long-distance transmission (hundreds of kilometers) is cheap and efficient, with costs of US$0.005–0.02 per kWh, compared to annual averaged large producer costs of US$0.01–0.025 per kWh Do you maybe mean that half electrical energy dissipate between production plant and consummer? But that figure seems quite large compared to what I can find online, and this would not be a problem with "free fusion". Care to explain? [0]: https://en.wikipedia.org/wiki/Electric_power_transmission https://en.wikipedia.org/wiki/Electric_power_transmission
    • entropicdrifter 1y ago
      Where I live I pay about $0.09 per kWh for generation and about that much for transmission as well. I think that's what they're referring to, the literal bill they get from their current provider.
    • lordfrito 1y ago
      I meant to say distribution costs not transmission. Looking at last months bill I paid $66.60 to deliver $51.76 of energy (about 56% of my total bill was delivery). The raw distribution charge alone was $49.32 or 42% of the bill. I'm not alone in these numbers, but your mileage may vary. My point is that the infrastructure related to the delivery of energy to a physical location is a non trivial part of an energy bill, and that this part doesn't go away magically because "fusion".
    • bell-cot 1y ago
      Long-distance transmission, of huge quantities of electrical energy, IS very efficient. Distributing tiny fractions of all that energy to each of millions of individual residences, then maintaining all the short/complex/low-capacity wiring needed to do that - that part ain't the least bit efficient.
      • pfdietz 1y ago
        Total losses on the US grid are about 6%, last I checked. It could be slightly more efficient, but only slightly.
• bryanlarsen 1y ago
  We're at a point where even "free hot water" is not competitive with solar for power generation. It costs more to build a 1GW coal power plant than it does to build a 3GW solar power plant (the 3X is capacity factor compensation). And most of the cost of that coal power plant is the steam turbine and its infrastructure. We're not at that point yet with natural gas because a combined cycle turbine is more efficient than a steam turbine.
  • cyberax 1y ago
    > 3GW solar power plant Except that it needs to be around 30GW plant to compete with a 1GW coal. And it needs storage for several days of energy.
    • bryanlarsen 1y ago
      Sure, if it's by itself and not connected to a continental grid.
  • nothercastle 1y ago
    People really don’t understand how huge that is. There is no way to make the math on nuclear or fusion work when the power extraction portion of the plant costs more than solar even if you zero out the generation costs
    • doctorwho42 1y ago
      I see this is fallacy, there are a ton of industrial processes that use a ton of power just to produce heat. A great early use case for fusion will directly use the heat for these industrial processes. For example, aluminum requires ~14-17MWh to produce 1 ton... If you use the heat directly you reduce your processes inefficiency by removing the conversions: heat to steam to electric to heat. Yeah, next 50 years you might not see coal/nat gas being replaced by fusion. But you will see fusion displacing chunks of what those powerplants will be powering
      • 1y ago
• hovering_nox 1y ago
  Nobody is building commercial plants any time soon; it's still in the experimental phase, with new discoveries happening almost every month. I see it similarly to the difference between a car with a combustion engine and an electric one. Combustion engines are fully developed. We're reaching the maximum possible performance and utilisation. It's a dead end. However, with electric cars, for example, new battery development is far from over. E.g sodium batteries. And just off the top of my head, in fusion, the discovery of better electromagnets, as happened a while back, can quadruple energy output.It's not a dead end, and writing it off would be short-sighted.
  • CGMthrowaway 1y ago
    They are building a commercial plant right now, and it will come online in the next 10 years. https://news.mit.edu/2024/commonwealth-fusion-systems-unveils-worlds-first-fusion-power-plant-1217 https://news.mit.edu/2024/commonwealth-fusion-systems-unveil...
    • Lutzb 1y ago
      Unless I missed something they haven’t even completed their technology demonstrator (planned for 2026). No construction has taken place in 2025.
• bell-cot 1y ago
  Yep. But so long as there is a boatload of prestige and funding to be harnessed via fusion research, it'll be a Really Big Thing. Centuries ago, an ambitious and clever alchemist could harness a fair quantity of those things via transmutation research. Vs. these days, we have repeatedly demonstrated the ability to transmute lead into gold. But somehow, there's no big talk about, or prestige in, or funding for scaling that process up to commercial viability.
  • jmyeet 1y ago
    There are a couple of factors in play with any research, including fusion. If there's money to be had for funding then somebody will research it. But another more nefarious factor is the nexus of fusion energy research and nuclear weapons research [1]. To build and maintain a stockpile of nuclear weapons (specificially thermonuclear weapons) you need appropriate trained nuclear energy physicists. [1]: https://thebulletin.org/premium/2024-11/the-entanglement-of-fusion-energy-research-and-bombs/ https://thebulletin.org/premium/2024-11/the-entanglement-of-...
• AntiEgo 1y ago
  The steam reactor I guess you might be describing is tokamak, which i agree will be a dead end technology. There are interesting small fusion reactors that skip the steam step. They compress plasma magnetically, and when the fusion happens, the expanding plasma in turn expands the magnetic field, and the energy is harvested directly from the field. No steam and turbines. Here is the video where I learned about it: https://www.youtube.com/watch?v=_bDXXWQxK38 https://www.youtube.com/watch?v=_bDXXWQxK38 Maybe any physicists in this thread could share insight on how feasible this is? Your main point stands of course: this is a moonshot project, and solar works TODAY!
• HarHarVeryFunny 1y ago
  > With a dense high-energy plasma, you're dealing with a turbulent fluid where any imperfection in your magnetic confinement will likely dmaage the container. This is true of Tokamak type designs based around continuous confinement, but perhaps less so with something like Helion's design which is based on magnetically firing plasma blobs at each other and achieving fusion through inertial confinement (cf NIF laser-based fusion), with repeated/pulsed operation rather rather than continuous confinement. No doubt the containment vessel will still suffer damage, but I guess it's a matter of degree - is it still economically viable to operate or not, which I guess needs to be verified experimentally by scaling up and operating for a sufficiently long period of time. Presumably they at least believe the approach is viable or they'd not be pursuing it (and have an agreement in place with Microsoft to power one of their data centers with one of the early units).
  • fpoling 1y ago
    There are serious theoretical objections to Helion approach so I am very sceptical to their approach. Stellarators on other hand do not have any known theoretical obstacles and avoid the problem of plasma instabilities.
    • HarHarVeryFunny 1y ago
      What are the theoretical problems? Aren't they already achieving fusion with their test reactors, so what's the problem with scaling up and producing net energy?
      • hwillis 1y ago
        A 12 year old achieved fusion with a test reactor he built himself: https://www.npr.org/2020/10/09/922065766/tennessee-teen-becomes-youngest-person-to-achieve-nuclear-fusion https://www.npr.org/2020/10/09/922065766/tennessee-teen-beco...
        • HarHarVeryFunny 1y ago
          OK, and hobby rocketists have nailed a SpaceX style landing too, but so what? Have you seen the videos of Helion's reactor - hardly a basement project. Sam Altman (OpenAI) also has personally invested hundreds of millions of dollars into Helion, presumably after some due diligence!
• aeve890 1y ago
  >And stars solve the confinement problem with gravity and by being really, really large. Kinda. The main catalyst of stellar fusion is quantum tunneling. Temperature and gravity together are not enough to overcome the Coulomb barrier.
  • snowwrestler 1y ago
    Quantum tunneling does not work differently in the core of the Sun than it does on the surface of the Earth. So what is the difference between those two places? Temperature and pressure. In the Sun those arise from gravity. On the Earth, we need to create them mechanically.
• perrygeo 1y ago
  There are three main hurdles here First, actually getting fusion to positive energy ROI. That's step zero and we're not even close. Second, scaling the production of fusion in an safe and economical way. Given the utter economic failure of fission nuclear power (there has never been a profitable one), my priors are that the fusion advocates are vastly underestimating, if not willfully ignoring, this part. Finally, even if we do get to "too cheap to meter" energy, what then? Limitless electricity is not the same thing as limitless stored energy. Only 20% of our energy needs are supplied by electricity. To wit, the crucial industrial processes required to build the nuclear power plant in the first place can only be accomplished with combustible carbon. A power plant cannot generate the energy to build another power plant. Please let that sink in. We're already seeing countries with photovoltaic and wind hitting $0/kW on sunny windy days - the grid is nearly saturated for daytime load. There isn't enough demand! This makes the economic feasibility of fusion even less attractive. No one is going to make money from it.
  • Vanclief 1y ago
    Where did you get the data that there has never been a profitable one? Not calling you out, but curious of where you are getting this data. I would expect that there have been multiple nuclear power plants that provide a net positive return, specially on countries like France where 70% of their energy is nuclear.
    • shitpostbot 1y ago
      [dead]
    • Retric 1y ago
      France lost an incredible amount of money on nuclear through capacity factor issues. The numbers are so bad they don’t want to admit what they are. However a reasonable argument can be made the public benefited from externalities like lower pollution and subsidized electricity prices even if it was a money pit and much of the benefit was exported to other countries via cheap off peak prices while France was forced to import at peak rates.
• deleted 1y ago
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• jMyles 1y ago
  Agreed. The problem(s) of scale are not only those of scaling up, but also scaling down. One of the best and most unsung benefits of solar is that it is profoundly easy and intuitive to build a very small (ie, vehicle- or house-sized) grid. In an increasingly decentralized and stateless world, it makes sense to look for these qualities in an energy source.
• onlyrealcuzzo 1y ago
  You realize this is what people said about solar energy and nuclear energy at one point, right And before someone chimes in and says Nuclear doesn't make sense - it made sense at plenty of times and in different places. It doesn't make sense in Western countries that are hell bent on making it as expensive as possible, strictly to ensure it doesn't get built, so we stick on fossil fuels as long as possible.
  • jmyeet 1y ago
    This is a meaningless argument people trot out all the time for things they just don't understand. Sometimes it applies but often it doesn't. For example, people will dismiss arguments saying FTL is likely impossible because people once said that about going to the Moon. To be fair, there was some logic to the anti-Moon argument based on physics. The big change came with multi-stage rockets that solved the weight and thrust problems. And even then it's close [1]. There are good, physical reasons why FTL is highly likely impossible. You know, based on phnysics. Likewise, the challenges to commercial fusion are also based on physics. Fusion reactions produce neutrons. Neutrons can't be magnetically contained. Neutrons destroy the container and, more importantly, lose energy from the system. But saying "people once said the Earth was flat" or "people once said we couldn't get to the Moon" and so on are just meaningless platitudes. [1]: https://www.realclearscience.com/blog/2017/07/06/if_earth_was_50_larger_we_might_be_stuck_here.html https://www.realclearscience.com/blog/2017/07/06/if_earth_wa...
• Projectiboga 1y ago
  There are multiple potential fusion reactions, duterium and tritium like in our home star The Sun is the most researched. There is also research into ones with Lithium and other left side elements. Finally the one I think has the best future is aneutronic fusion with Boron11 plus hydrogen, it gives off three alpha particles which can be converted directly to electricity. the leading model is Field Reversed Fusion. https://spectrum.ieee.org/aneutronic-fusion https://spectrum.ieee.org/aneutronic-fusion
  • pfdietz 1y ago
    > duterium and tritium like in our home star The Sun That is not what is being fused in the Sun.
    • Projectiboga 1y ago
      True, I didn't state that clearly. What I meant was our sun fuses Hydrogen, whereas I feel Aneutronic fusion using Boron-11 will be better here on earth. From, https://energyeducation.ca/encyclopedia/Nuclear_fusion_in_the_Sun#:~:text=The%20specific%20type%20of%20fusion,and%20are%20turned%20into%20helium. https://energyeducation.ca/encyclopedia/Nuclear_fusion_in_th... The overall process of proton-proton fusion within the Sun can be broken down into several simple steps. A visual representation of this process is shown in Figure 1. The steps are:[4] Two protons within the Sun fuse. Most of the time the pair breaks apart again, but sometimes one of the protons transforms into a neutron via the weak nuclear force. Along with the transformation into a neutron, a positron and neutrino are formed. This resulting proton-neutron pair that forms sometimes is known as deuterium. A third proton collides with the formed deuterium. This collision results in the formation of a helium-3 nucleus and a gamma ray. These gamma rays work their way out from the core of the Sun and are released as sunlight. Two helium-3 nuclei collide, creating a helium-4 nucleus plus two extra protons that escape as two hydrogen. Technically, a beryllium-6 nuclei forms first but is unstable and thus disintegrates into the helium-4 nucleus. The final helium-4 atom has less mass than the original 4 protons that came together (see E=mc2). Because of this, their combination results in an excess of energy being released in the form of heat and light that exits the Sun, given by the mass-energy equivalence. To exit the Sun, this energy must travel through many layers to the photosphere before it can actually emerge into space as sunlight. Since this proton-proton chain happens frequently - 9.2 x 1037 times per second - there is a significant release of energy.[3] Of all of the mass that undergoes this fusion process, only about 0.7% of it is turned into energy. Although this seems like a small amount of mass, this is equal to 4.26 million metric tonnes of matter being converted to energy per second.[3] Using the mass-energy equivalence, we find that this 4.26 million metric tonnes of matter is equal to about 3.8 x 1026 joules of energy released per second!
• snowwrestler 1y ago
  > I remain skeptical that fusion will ever be a commercially viable energy source. I'd love to be wrong. I’m also skeptical, but I think the emphasis of my skepticism is on “commercially viable” as opposed to an available energy source. That is, I think fusion development will (and should) proceed anyway. There’s a good argument that nuclear fission is not really commercially viable in its current form. Yet it provides quite a lot of commercially available electricity. And it also powers aircraft carriers and submarines. And similar technology produces plutonium for weapons. In other words, I don’t think fission’s continued availability as a power source is a strictly commercial decision. I think there’s a quite a lot of technology that is not directly commercially viable, like high energy physics, or the space program. But they remain popular and funded. And they throw off a lot of commercial side benefits. The growth of solar for domestic consumer power will certainly continue and that is a good thing. But I bet we’ll have fusion too in the long run. There’s no lack of ideas for interesting things to do with extreme amounts of heat and power. For example I’m hopeful that humanity eventually figures out space propulsion powered by fusion.
• o1inventor 1y ago
  I wonder how much research has gone into neutron-deficient materials for shielding? Depleted uranium is one example but that has terrible implications due to radioactive pollution that would result, disposal costs and risks, etc. Surprised theres not more research into meta-materials and alloys that are neutron-resistant, neutron-slowing, or neutron-absorbing.
• emtel 1y ago
  I have no idea why you are being downvoted. The chances of a power source that _doesn't even work yet_ will out-compete one that is currently on both an exponential price decline curve and exponential capacity growth curve are pretty close to 0.
• ryao 1y ago
  Nuclear fusion as an energy source has major unsolved problems. Off the top of my head: * The super conducting metals required for confinement randomly stop superconducting. * The fuels produce absurd amounts of radiation and the Helium-3 solution for that might as well be fairy dust, since even if we convert the energy global economy to helium-3 production, we will not have enough by orders of magnitude to power hypothetical fusion reactors that would handle our needs. Strip mining the moon for it is supposedly a way to get it, but defacing the surface of the moon for minuscule amounts of Helium-3 per acre is unlikely to ever be profitable. * The amount of radioactive materials produced from the experiments are many times those produced in fission reactors. This is just off the top of my head. Until recently, I would have included the inability to produce more energy than we put into it on this list, but LLNL’s breakthrough a few years ago seems to have solved that. I suspect that someone with time to look into the practical issues involved in building a fusion reactor would find other issues (such as the design not being practical to use in a production power plant and thus further research being needed to make one that is). I wonder if the only reason countries fund nuclear fusion research is to keep nuclear scientists from finding employment in the production of nuclear weapons.
  • physix 1y ago
    I'd love to see some references on those three claims. None of them make sense to me.
    • ryao 1y ago
      There is a very well researched youtube video that explains a couple of these things: https://www.youtube.com/watch?v=FrUWoywZRt8 https://www.youtube.com/watch?v=FrUWoywZRt8 I do not recall where I heard about the helium-3 situation, but I recall hearing some figures and the prospect of having enough to run fusion reactors was not good. Doing a search suggests that I had been only slightly mislead about the scarcity of helium-3. It is still extremely rare, but the US reportedly has used up to 70,000 liters of it per year: https://en.wikipedia.org/wiki/Helium-3#Human_production https://en.wikipedia.org/wiki/Helium-3#Human_production The density of Helium-3 at STP is presumably 0.1338 g/L, based on Helium-4's 0.1784 g/L. That suggests that the total annual US industrial demand is ~9 kg. This is definitely not as bad as I had thought, but it is still fairly dire. As per wikipedia, a single 1GW nuclear fusion reactor that is 100% efficient at converting helium-3 into electricity would need 52.5 kilograms per year. 6.7 metric tons per year would be needed to power the entire US. https://en.wikipedia.org/wiki/Helium-3 https://en.wikipedia.org/wiki/Helium-3 That assumes 100% efficiency, and if the conversion efficiency is anything like a nuclear fission plant, we would be lucky to see 3% efficiency, but we could be optimistic and assume something higher. Either way, it does not change the conclusion. With an annual supply of ~9 kg, practical helium-3 fueled nuclear fusion reactors are not happening. Maybe the supply would be higher if you include other countries, and maybe we could get it somewhat higher if we try, but the reality is that helium-3 is an extremely rare isotope and the idea of using it as a practical fuel for a nuclear fusion reactor is a pipe dream unless the supply problem is solved and people figure out how to actually build a reactor that generates power using it, without encountering any of the other known problems that make this unlikely. The difficulty in scaling supply is why are people discussing wild ideas like mining the moon, or even mining Jupiter. The supply situation is so constrained that the US government is reportedly buying 3 liters of it from a company that promises that it will strip-mine the surface of the moon for it with delivery by April 2029: https://www.morningstar.com/news/pr-newswire/20250507sf81778/us-department-of-energy-buys-helium-3-from-us-space-resources-company-interlune-in-historic-agreement https://www.morningstar.com/news/pr-newswire/20250507sf81778... I fully expect them to fail to deliver. That said, the fairy dust remark was probably inaccurate, but the idea that our supply is short by orders of magnitude is correct according to mathematics.
• reubenswartz 1y ago
  I'm thinking perhaps the best place for a fusion reactor is 93 million miles away. It's already up and running, and we're making huge strides in energy collection and storage...
• credit_guy 1y ago
  > I remain skeptical that fusion will ever be a commercially viable energy source. I'd love to be wrong. It can be for deep space propulsion. The Orion project [1] demonstrated that you can power a spaceship so that it has both huge thrust and huge specific impulse with hydrogen bombs. The main issue with this project is the proliferation concerns. However, if you replace the bombs with pellets that are imploded by lasers, like the NIF experiment did [2], then you could get to the point where you can drive a rocket with non-weaponizable fusion explosions. [1] https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... [2] https://en.wikipedia.org/wiki/Fusion_ignition#2021_and_2022_ignition_reports https://en.wikipedia.org/wiki/Fusion_ignition#2021_and_2022_...
• sesm 1y ago
  It's not even about engineering challenges. - Lawson criterion is derived with the assumption of equilibrium plasma, which doesn't hold true in any real tokomak/stellarator - at required temperatures most of the energy would be in photons of thermal radiation, that don't get confined by magnetic field, so when plasma relaxes from high energy beams to thermal equilibrium, it loses all the pumped energy through radiation - with high energy beams tokomak is essentially a particle accelerator, where electrons get in the way of collision
• cubefox 1y ago
  Yeah. It will be basically impossible for fusion to come anywhere near the cost of fission. However, calling solar energy cheap ignores the necessary battery storage cost, which is substantial.
• ipdashc 1y ago
  I'm in the same boat. I'd also love to be wrong. It feels like we forget quickly that we already have nuclear power around. And yet fission constantly suffers due to economics issues, stemming from needing to build massive plants full of steel and concrete, each facility being effectively bespoke, requiring fancy equipment and electronics, needing constant monitoring, having to plan to decommission an irradiated plant and dispose of radioactive waste, and... needing to mine and refine uranium. Fusion would (maybe, unless we need helium-3) solve that last one, and only sorta solve the radioactive waste one. Everything else remains, perhaps even gets worse. Still good to see people working on it, maybe it'd be useful for far-future spaceships or areas where solar/wind aren't feasible. But I don't see how it wins economically at large.