Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
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I used to be really interested in this, but forgot it existed over the years. Glad to see it works!
My explanation was definitely over simplified, but I'm not knowledgable enough to go into detail on the topic. I can't even point you towards something to read on the topic since everything I read about it is like 15 years old at this point.
“…the supporting structure can only withstand the forces if the interfaces between the ten individual segments of the central rings, which weighs several tonnes, are built with a level of precision of less than 100 millionths of a metre…” - and they found a small family business in the north of Italy capable of doing this!
1 meter = 100 cm = 1000mm.
So 1 millionth of a meter = 1/1000th of 1mm.
thus, 100 millionths of a meter = 0.1mm, or ~4 thou in American units. Easily achievable by hobbyists, let alone by serious, professional equipment.
Sure, that is a pretty exacting specification for what I suppose is a big machine, but I'm pretty sure very normal things like say, car engines get made to far tighter tolerances.
0.01mm is very difficult when you’re talking large custom objects with complex shapes.
> bei Toleranzen von teilweise nur 0,1 Millimeter
Keeping it all in the same units until the end here:
1 millionth of 1 meter = (1 / 1,000,000)m = (1e-6m)
1 millionth * 100 = 100 millionths => (1e-6m) * 100 = (1e-4m) = 100 millionths
(1e-4m) = .0001m | 1m = 1000mm => .0001m*1000 = .1mm
I am to used to people saying 100 millionth of a meter to mean 10 nm or 0.01 µm which would have looked insane if I had written that.
Aka 100 millionth vs 100 millionths
1 thou was achievable in routine shops in the 1940s and a tenth of a thou (2.54 micron) is a common accuracy to target these days. Obviously it depends on the context and the size of the object, at some point you move away from cutting to using grinding and lapping to achieve your results, which is ultra-timeconsuming.
Getting the same finish on a 120"/3m coil is 33 ppm. 100 ppm / 0.01% for any operation or process tends to be where things start to get really challenging. Deflection goes up by the length cubed, so increasing the size of all the tooling relative to the tolerance gets really challenging really fast.
Or the very person that someone with a show like Art Bell would have as a guest.
https://www.berryhillfh.com/obituary/ning-li?lud=4CF765EE88E...
Her claim that "You can take a bowling ball and place it and it will stay." is fascinating. I would love to see footage/video of this. Small electro marbles and globes are one thing, a bowling ball or other large non-magnetic object!? man oh man!
Nuclear fusion occurs at extremely-high temperatures. As you heat your fusion fuel to sufficiently-high temperatures to allow fusion, the matter transitions into a plasma, which is great: plasmas react to electromagnetic fields. As such, a major challenge with achieving viable nuclear fusion is making a vessel capable of holding the fusion reaction. Because we can't create on-demand gravity wells, the next best option for confinement is using electromagnetic fields to hold the plasma in the air.
So, you now have an "electromagnetic bottle" capable of suspending a fusion reaction above the reactor's walls. Now, you have another issue: how do you ensure the fuel will sufficiently mix to sustain a fusion reaction? One approach is to move the plasma in a loop. The topologically-simplest method to accomplish this loop is the torus. Such a plasma-confinement device is called a tokamak. A tokamak uses two magnetic fields, torodial and polodial, to accomplish its task. The torodial field is driven through the plasma to push it forward, while the polodial field pulls the plasma in toward the center. Proper balance of these fields will allow the plasma to circuit the vessel following a helical path, achieving confinement.
However, driving two separate magnetic fields is energy-intensive, and a successful fusion reactor will want to minimize its own power consumption to maximize the amount available for external usage. Enter the stellarator. The stellarator also drives the plasma around in a circle, it but uses a single magnetic field. How? It "tricks" the plasma into "thinking" there's only one magnetic field by using computer-optimized magnets with highly-complex geometries. This provides stellarators with a major engineering advantage over tokamaks and is a primary reason Wendelstein 7-X would have chosen it.
With the confinement vessel topology largely identified, the next main step is to figure out how to build a vessel able to contain a sustained fusion reaction. For context, fusion experiments traditionally only operate on timescales of milliseconds to maybe a second. The reason? Fusion occurs at millions of degrees, and keeping the reaction vessel cool, ensuring a continuous supply of fuel, and dealing with reaction "exhaust" (e.g., alpha particles) and stray high-energy neutrons from the common deuterium-tritium reaction (which irradiate your reactor walls because neutrons don't react with electomagnetic fields) is a major, major engineering challenge. Any operational, net-positive fusion reactor must be able to operate for days, weeks, and months on end.
What Wendelstein 7-X has been attempting to do for years is demonstrate that building such a vessel is even possible. Their overall goal is to sustain a fusion reaction for about 30 minutes. Such a timescale will show a proof-of-concept system which enables sustained fusion reactions to occur.
Currently, the preferred fuel is deuterium-tritium because the fuel is generally available and has an attainable fusion temperature. The stray neutron issue can be mitigated by lining reactor walls with lithium to breed tritium fuel. Even better is to use the helium3-helium3 reaction, which completely annihilate to produce pure energy as the output (welcome to e=mc^2, enjoy your stay). The main holdups are: (1) the reaction occurs at much higher temperatures than deuterium-tritium, and (2) he(lium)3 is quite scarce on Earth. Once Wendelstein 7-X shows how to engineer a proper confinement vessel at a "lower" temperature, you can then work on the higher temperature levels required for he3-he3. Also, he3 is plentiful on the surface of the moon, so mining the surface of the moon will be performed to obtain the required fuel, which is the fundamental premise of the movie "Moon".
Someone asked for information on electromagnetic plasma containment folding. I recommend reading up on magnetohydrodynamics (MHD). It's the mathematical and physical foundation of your interest.
> By twisting the plasma into a shape where the curl of B (proportional to J) is parallel to B, i.e. a helix, the cross product is 0, and thus there are no net magnetohydrodynamic forces on the plasma.
Hope all that's a good answer for you.
> Mobius aspect
You might avoid using the word "Mobius" and instead use "helical." A Mobius strip is important because it has two faces which form a single surface. The surface aspect isn't relevant in this context, so a term which refers to the shape would likely dispel confusion in a reader.
As far as I'm aware, each section of a stellarator is periodic in its own right, which means the end and start points of each section are the same. Though I'm not certain, the choice of four versus five is more likely an engineering factor rather than one of physics, whereas the distinction between a tokamak and stellarator is of physics and not just engineering.
edit: changed language about the divertors.
The most precise term to describe the "twisted ribbon" flux tube in W7-X is "toroidal helix". The toroidal quality comes from the general torus shape of the stellarator, and the helix quality comes from the twisting of the magnetic field by magnets. (The torus shape is required only topologically; look up the knotatron to see what I mean.)
The "ribbon" we're talking about is properly called the flux tube. The flux tube is the volume created by the flux surface, which is where the magnetic field lines lie. A given volume of plasma contained within a flux tube should remain inside it, causing magnetic confinement of the plasma.
The optimality of the confinement of the flux tube is expressed with the term "omnigeneity". Conceptually, a flux tube has onmigeneity if ideally all of the non-colliding plasma inside the tube stays in the tube. W7-X's flux tube appears to be approaching omnigenity. (Another experiment which approaches omnigenity is HSX. Interestingly, HSX has one set of primary magnets, whereas W7-X has two. That's likely because HSX achieves omnigenity via quasisymmetry, whereas W7-X uses various stellarator optimization techniques.)
With these points, we can call the W7-X "ribbon" a near-omnigenous toroidal helix flux tube, which sounds way cooler. So, all that said, why is a helical property desired? From what I've read, the twist in the flux surface reduces plasma drift inside the flux tube.
I think it makes sense to analogize this stuff as a circular semi-permeable pipe filled with a high-pressure "magic fluid" flowing around-and-around inside. By semi-permeable, it means fluid will leak from the pipe if the internal pressure is too high (remember that this is magic fluid). Trying to understand the helical twist along this analogy, I think the effect is evening of internal pressure across the pipe surface to reduce fluid turbulence and permeation while maximizing laminar flow. At least, that's my best analogous interpretation of "why" the twist helps.
The divertors are useful for long-term reactor operation but have no direct relevance to the magnetic field geometry. I'm guessing there's two divertors for engineering reasons (performance, redundancy, etc.) and not for reasons of basic physics.
Is that what you are saying ? Or are there other constraints on the number of twists (e.g. must be odd, ...)
It doesn't completely annihilate to produce pure energy. It produces helium-4 and two protons. Or you can react helium-3 + deuterium to produce helium-4 and one proton. The point is that helium-4 and protons are easier to shield against than neutrons, don't turn your reactor radioactive, and at least in theory their energy can be extracted directly (eg through induction) instead of through heat.
Edited to add: except helium-3 + deuterium still produces neutrons, because sometimes the deuterium will react with itself to produce helium-3 and a neutron.
Here's an interesting link which lists various fusion reactions: https://en.wikipedia.org/wiki/Helium-3#Nuclear_fuel
This is repeated a lot, but the practicalities are... questionable. Here's an article I consider to be the definitive criticism of the concept:
I want to be able to think in mobius, but my brain is currently like, "No thanks."
The core concepts in mobius-land are local curvature and global cumulative field.
Then you accidentally make something truly 3D by intersecting things and realize you have no idea what you're looking at, couldn't imagine it if you closed your eyes, couldn't replicate it if you had a picture of the result and didn't know the 2D inputs that made it... and then you realize there are probably people out there who can see that entire design in their head.
To me it's like unicycling on a tightrope or skateboarding or realistic oil painting or playing piano well. I have no real concept or reference point for what that experience must be like.
I can't figure out any kind of way someone could do that with anything resembling what I understand "thought" to be like, so I assume you must be able to process entire sequences and their alternate possibilities simultaneously?
If true 3d printing* ever gets cheap, it'll be interesting to see how much form will be able follow function, rather than manufacturing cost.
* true 3d, as in overhang are allowed. Something like a cheap FDM is more 2.5d, since overhangs aren't allowed.
They're not quite unconstrained, and the layer adhesion strength makes some geometries not strong, but they're much more than 2.5D.
I think for me, the prerequisites for mastering CAD were 1) the practice I got visualizing 3D shapes so I could translate them into unambiguous mechanical drawings on paper (I swear, I'm not that old but my college was behind and we were the last class to actually do mechanical drawings with a pencil), and 2) having a procedural thought process from coding so that I could sequence the CAD operations to get where I want.
It's a block language where you program the object rather than manipulate shapes. It works well for my brain. Ymmv
I'm not a mechanical engineer, I mostly only do incidental CAD and hobby level work, so it's not really essential to have the deep understanding of space that real MEs need.
I often don't know what sequence of operations I'll need until I actually open the app. Generally it's more of an "Oh I need a mounting hole, lets look around on the screen and see where one could go" thing, a lot of the thinking is in the app rather than in the mind.
Of course you can't make nicely parametric things without a lot more thought so I will often wind up having to redo things that aren't one offs...
https://www.microwavejournal.com/articles/21001-printed-reso...
I have no idea if there are any advantages over a simple planar circular loop though.
2. Alternating currents will dissipate even with zero resistance, because the circuit will emit EM waves.
Those crazy electromagnets they use on these stellarator are simple superconducting loops that they 'charge' by inducing a current. That current is maintained so long as the superconductor stays below a certain temp. There is even something called a SMES (superconducting magnetic energy storage) that stores power this way, as I understand it they have a 0% self discharge rate.
If you have a hypothetical continuum of charges moving in a circle, and you use Maxwell’s equations, you’ll find that given a constant charge density, no EM radiation will be emitted.
If you have a superconductor, you should really be using quantum mechanics to understand it. If you can imagine that an electron can “orbit” a nucleus without emitting EM radiation, then you can imagine that current can flow in a loop without emitting EM radiation. The behavior cannot be explained by thinking of the behavior of a single electron, but must be explained by considering the behavior of many electrons in a quantum mechanical system.
Also note that the actual speed of electrons (the “drift velocity”) moving around a loop of wire is extremely low, so if you treat electrons as point charges and ignore quantum mechanics, and you calculate the amount of EM radiation that should be emitted by a typical loop of wire, you will get an extremely low amount EM radiation emitted, which would be very difficult to measure.
I spent a lot time staring at Escher images as a teen, so I think my brain says "yes please". I have no idea what to do with any of it, so it's not like it does me any good.
That explains why folding is important, as for the mobius, I oversimplified a bit. The Wendelstein has 5 folds, making it a mobius, but I think I read about one in Spain that had only 4 folds. That would mean the mobius isn't imperitive, but I'm sure there is a good reason for it.
Really a stellerator doesn't need 'folding' at all, they can be as simple as a twisted torroid. I didn't want to go into excruciating detail though, the more in detail I go the more likely I am to say something that is wrong lol.
Edit: I looked it up, the one in spain is called "TJ-II"
That effect works both ways too, where a single wire with a digital signal will spew out radio waves, 2 wires with opposing signal cancel each other out and emit no em waves.
The effect with the stellarator is more like stirring a pot.
With mobius strip you regularly flip between inside and outside, so the plasma particles get more even force applied.
Draw a torus and then draw rectangular "bands" across it, they will represent the containment magnets.
Due to pure geometry, the area closer to the center will have a smaller distance between bars. This means that the magnetic field will be stronger near the center.
This in turn means that particles will separate (depending on charge) and drift to the sides. It seriously interferes with the containment.
You can fix that by changing the torus into something resembling "8", so that particles move to one side when they fly through the upper part, but then they'll move back as they fly through the lower part.
Of course, you can't just do that in 2D because the part in the middle of "8" will have no magnetic field. You need something without self-intersections. You can try to move one side up and another down. But that doesn't quite work either because you will get another set of preferred directions.
So instead you go with the gentle twisting, resulting in the Möbius-looking shape.
What's even more interesting is that the fusor - the simplest possible design for a thermonuclear reactor, so simple that anyone skilled in electrical engineering and having access to proper civilan equipment can build one with ease - seems to be invented _after_ both stellarator and tokamak.
That said, I never particularly liked stellarator design. The very _complexity_ of it somehow feels subtly wrong, like doubling down in the wrong direction.
However, this is one of the cases where I would absolutely love to be proven wrong. We are far past due big breakthroughs in the field.
In the long run, it's not known stellarators will be the eventual winner in the long race for a viable fusion reactor. The attributes in a winner will be net-positive operational efficiency and superior energy harvesting abilities. Perhaps multiple approaches will be viable.
To be honest, I've been interested in the domain for quite a time and I still want to build a fusor or a polywell at some point just to see it glow. Probably won't happen though.
This made me think of modern jet fighters being designed to be aerodynamically unstable, making them all but impossible for human pilots to operate without flight computers. Apparently the maneuverability benefits make the added complexity more than worth it.
https://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting...
> The very _complexity_ of it
> somehow feels subtly wrong.
I understand that it was hard to build, but isn't that just because it's a one-off?
Any one part of the inside of it looks no more oddly shaped than the outside of any modern car, and we've managed to scale that.
I read an article a while ago which sold me on the stellarator that said something like: "The tokamak has magnets in a configuration that gives simple engineering but hard physics, whereas the stellarator has hard engineering to make a complex magnet but that results in simple physics".
The engineering is a much more understood beast. It was still fairly novel as they had to have a computer do the design of the magnets, but that is now a solved problem. But then if that allows us to simplify the (very difficult and novel) physics it feels like the "obviously" correct decision.
The other thing that makes me a stellarator fan is that the JET/ITER work is later and more expensive that predicted at every stage. The W7-X provided a plan for the runs they wanted to do and upgrades to the reactor and they have basically run entirely to schedule.
it’s a fair demand to make, given that his TV predecessor was called Scotty and DID have a Scottish accent
https://www.youtube.com/watch?v=4PG5PCd284o
Edit: But as to the why, it's fun. Just like the "input/output translation" trickery.
If you listen to this with headphones, or speakers with decent separation, paying attention to this feels interesting. It's similar to the way listening to "binaural beats" can do interesting things to your brain.
Also if you are in the habit of putting an entire album on repeat and this is one of your favorite albums, then you've probably heard this a zillion times. If you have your music player set in "randomize by album" mode, then, well, it's the first track on this album, so every time it comes up you'll hear most of it unless you instantly decide you are not in the mood for Orbital 2, and even if you're not in that mood it may be pleasant to let everything come back into phase before going to another album.
----
The next track on the album starts up entirely in the left ear, with a tinny, distant little loop, and the words "Even a stopped clock tells the right time twice a day". Once it brings in a deep bass, this bass is also doing some weird cross-ear phasing things.
And then the third track also opens with "Even a stopped clock..."; a theme has been established at this point. Time is a loop, and a stopped clock is right twice a day. The opening of "where time becomes a loop" is also a bit of a joke; Orbital's musical craft is very much about making a bunch of short loops that work together, and bringing them in and out over each other for four to seven minutes. Occasionally as much as thirty minutes, the extended version of "The Box" is glorious. This is something that utterly dominates most electronic dance music now, but Orbital was one of the first notable acts to really go hard on this, and this is their second album; they are saying "yes it's just more loops, we think they're good loops, enjoy!".
By the time you get to the last track, you've probably forgotten about Worf's repeated mantra. Especially if it's your first time listening to the whole thing and Halcyon + On + On just blew all the cobwebs out of your head. But Orbital returns to the idea, with two different loops that are very close in sound and length, played on both channels: "Input Translation"/"Output Rotation". They begin in phase with each other, drift out, and come back together. And the album is over.
Or, if you have the CD player on repeat (remember, this album is from a time when people bought CDs and probably stuck them into a one-disc player, maybe a 3 or 5-disc player if they were lucky, and the whole album is built with an awareness of this), you're back where you began, inputs translated and outputs rotated, and ready to be reminded of the Theory of the Moebius.
Time has become a loop. Come out of the trance Orbital has put you in. Do you want to experience this loop again? Does it feel rude to jump to another album before Worf's come back into phase again? You may as well let him get you back in sync with the moment the album began before going back into normal time.
You just describe the first time I every danced with Lucy. I went back and forth with this disc and The Orb's A Huge Ever Growing Pulsating Brain That Rules from the Centre of the Ultraworld.
is this where we talk about
- the 39:59 mix of The Orb’s “Blue Room” (which, like several other Orb singles, is better than the album version thanks to Jah Wobble providing a proper bassline)
- the academically-verified lack of repetitiveness in Autechre’s “Flutter”
- and Orbital’s “Criminal Justice Bill?” on the “Are We Here” CD single, which is four minutes of silence
The Orb Live '93 CD was one of those that if a CD could wear out like a cassette, that would have been one (two technically) that would have from my collection.
Those two albums sound like a pretty good soundtrack for making a good trip more likely!
They should've gone with a catchier name like "forbidden cruller".
403s is about 7 minutes, so less than Wendelstein 7-X.
Apostrophes are already tricky for English as a first language, it must be hell for English as a second language speakers.
On the other hand it is reminiscent of a Georgian I met who used to be occupied with winding regular tire sized coils by hand, for over land transmission lines. This is chirurgical precision, literally hand-craft.
We do a lot of thinking with our hands. It stands to reason, metaphorically speaking, that Wendelstein is an experiment to gain hands on experience. Therein lies the difference to megalomanic projects that exceed initial estimates, eg. BER airport, which are a running gag by now.
Insolvency means the investment returned no profits so investors on those projects stopped paying. It likely doesn't mean that the cheques bounced on liabilities. And it obviously doesn't mean that investment in this space had to stop.
But that's exactly what it means:
All while not being able to properly simulate the outcome on a computer.
Stellarators are superior to tokamaks, so an energy-positive stellerator will be about 2 times smaller than a tokamak. But we're still talking about a building-sized vacuum chamber.
That's why for ITER it makes sense to go with a simpler design to de-risk the main objective: building a burning plasma laboratory.
[edit]
Found it: "Energy turnover is defined as the amount of heat multiplied by the duration of the discharge[1]." By "amount of heat" I assume they mean "heating power delivered to the plasma" b/c the the only way to multiply by time and get Joules is to start with power.
1: https://gigazine.net/gsc_news/en/20230227-wendelstein-7-x-en...
> The energy turnover results from the coupled heating power multiplied by the duration of the discharge
The numbers:
> The energy turnover of 1.3 gigajoule was achieved with an average heating power of 2.7 megawatts, whereby the discharge lasted 480 seconds
Also:
> Within a few years, the plan is to increase the energy turnover at Wendelstein 7-X to 18 gigajoules, with the plasma then being kept stable for half an hour
i.e. 10 megawatts for 30 minutes
Ie, would it be feasible in a power plant scenario to settle for 30-60 minutes of stability, and just restart?
I lost money on the endeavor, though.
There has never been a net-positive-energy magnetic confinement fusion experiment. Inertial confinement fusion has had 2 events that were "more energy out of the fuel than delivered to the fuel." But is still about a factor of 100 away from what is needed for "more electricity in than out"
I know for conventional fission reactors the heat of fission is basically used to run a steam turbine. Given the extreme heat of the plasma, and that it must be magnetically suspended so that it doesn't even touch the sides of the containment, how is that heat transferred to some other medium to generate electricity?
That doesn't entirely follow. 2 particles whizzing past each other at relativistic speeds have extreme temperatures but don't offer much energy. Mass is in this equation.
Jumpjng back up the stack: photon radiation is mostly considered a loss since it transfers energy out of confinement and does not impart it on other fuel. You nominally extract your heat via neutrons: same as fission reactors. Some designs (Helion) aim for reactions with charged byproducts. The reaction produces a current that can be coupled by a surrounding coil, much like a transformer but powered by current induced by plasma rather than another copper wire.
For the German-speaking crowd here, the Alternativlos podcast guys were there twice and had lengtly conversations with the researchers there. Like, between nerds. Really cool, if you understand the language.
https://alternativlos.org/36/ (from 2016)
https://alternativlos.org/51/ (most recent, from may 2023)
https://omegataupodcast.net/312-the-wendelstein-7-x-fusion-e... (from 2019, 3Hrs, English)
But it sure is fun to dream!
This one in particular isn't setup to do that, and as far as I know, none are yet. It's a pretty simple engineering problem, and, until we can maintain fusion for months at a time, it's not really something that needs to be built.
There is, however, one fusion concept that shows some promise that doesn't require all that that helion energy is developing (helionenergy.com) they're yet to create net-power, but, their idea has some promise, and avoids the common problems with other forms of fusion power. I don't really see it as the be-all to end-all in the space, but from what I can tell they very well might be the stopgap that is needed between large scale stellerators and fission.
The energy of the reaction is mostly carried away as high-energy neutrons. So, the way to get energy back is to "capture" those neutrons. Since neutrons are not electrically charged, you can't use them to directly create electricity, so all you're left with is using them for heat.
Unfortunately, since they are electrically neutral, they're also relatively hard to catch. You need a dense material where they will have a good chance to hit some nucleus. The proposed designs are typically some kind of liquid metal blanket being circulated around the reactor and onto a place where it can boil water to produce steam to spin a turbine. Lithium is the metal most proposed for this, since it also has the advantage that it can produce tritium when bombarded with neutrons (tritium being the super rare half of the fuel that goes into the reaction).
https://www.helionenergy.com/faq/
(See "How does Helion generate electricity from fusion?" question)
To entirely skip the steam cycle portion is to intentionally make a much less efficient design.
For space-constrained, high-value, applications where economics don't matter that much, such as a submarine, that would make sense, but otherwise...
(I'm still not convinced of their explanations, but a fast proton may be easy to catch by the magnetic field and create the effect they want.)
See the diagram here: https://undsci.berkeley.edu/teach-resources/products-of-deut...
With fuel costs insignificant, your cost per kWh is mainly capital cost. Let's say it's all capital just to keep it simple. I don't know how much the input energy will be but if your choice is between, say, generating net energy of 50MW without a turbine or 54MW with a turbine, then you would skip the turbine if it adds more than 8% to the capital cost. I suspect Helion has done this calculation in detail.
Helion's other fuel is helium-3 which they'll make themselves by fusing deuterium. So the helium-3 cost will directly depend on the capital cost of the reactor producing it.
(This may be the same reactor, both generating electricity and breeding He3. Or they may use dedicated He3 breeders, and minimize the D-D reactions in the generators.)
However, D+T fusion is the only type of fusion that we have been able to sustain for any significant amount of time with reasonable energy inputs. What Helion is planning to do is completely unexplored and requires some major scientific advances.
Still, it seems very indirect. Like generating solar power by using a parabolic mirror to heat water instead of photovoltaic panels... but of course I just found an example of doing that too: https://en.wikipedia.org/wiki/Parabolic_trough
Usually the liquid is some sort of oil that csn reach higher temperature and then the oil is used to heat water
Another design uses hundreds of mirror centered around a high tower with molten salts as the heat medium
The really good part of this design is that the molted salts can produce energy for 3-4h after the sun is set.
The 90% efficiency quoted in the comments is 90% of theoretical maximum efficiency. This theoretical maximum is about 50% for the best systems.
What's the reason for that?
Leaves farmland, if you want to do this kind of thing at any sort of required scale. (Sure you can put solar cells on barn roofs, but the premise was scale magnitudes beyond that.)
In fact, most plants can only use sunlight for a few hours a day, and must then endure the heat for the rest of the day. A few crops -- wheat, corn -- offer slightly reduced yields when shaded, but many others -- particularly peppers -- yield better with partial shade. Even where yield is reduced, the extra year-round revenue and radically reduced water loss may even the score.
Or in other words: Fusion is too expensive at this point to be useful.
(+) These numbers are for the USA. I found a mention of a cheaper project in Chile https://about.bnef.com/blog/cost-of-new-renewables-temporari... but I don't know what the situation is in Europe. And wind might be even lower.
On http://generadoras.cl/tipos-energia/energia-solar scroll down to "Capacidad por región", Antofagasta and Atacama are the desert regions in the with over 90% of installed capacity.
In Germany or the Netherlands it is a bit harder to find space for large solar plants.
And to windy places. Happening already in Europe, building new industrial plant close to the huge and fast growing offshore North Sea wind power plants
The first TVs were for the very rich, and had 4" bw screens. Now they're 80", thin, and insanely cheap.
Then some countries stepped up the subsidies game and booom, prices fell dramatically since suddenly everybody wanted a piece of the cake. And competition drove this all down.
All you need is for somebody to start. Or we just keep telling ourselves that it's too expensive, shrug, and move on.
Also note how the goal posts changed. Until recently, everybody made fun of fusion by basically saying it's too hard, it's too far in the future. Now it's not too hard anymore, it's just too expensive. What's next? Too loud? Too big? Induces headaches with the esoterically minded?
https://orcutt.net/weblog/wp-content/uploads/2015/08/The-Tro...
I specifically studied the German grid, and it needs about a MONTH of storage to compensate for a once-in-a-century Dunkelflaute (a period with little wind, no sun, and cold temperatures).
If you accept slightly less than 100% renewables, you could use diesel or gas backup for these once-in-a-century events.
Rooppur Nuclear Power Plant cost $6 per Watt of installed capacity over the projected 50 years of lifetime. Simple natural gas turbines (not combined cycle) cost around $2 per Watt over 50 years in just capital costs. This doesn't take into account the cost of the fuel, or the magic infrastructure to produce, store, and deliver hydrogen.
I'm taking Rooppur Nuclear Power Plant as the base for comparison because it's an example of what you can do, when you have a "mass produced" design that you can just quickly build.
I also doubt anyone is going to be buying Russian nuclear power plants in Europe anytime soon. The strategic risk and associated cost (as seen with importing natural gas from Russia) would be far too high.
Not much higher, though. Russia makes money on these contracts. South Korea has
> I also doubt anyone is going to be buying Russian nuclear power plants in Europe anytime soon. The strategic risk and associated cost (as seen with importing natural gas from Russia) would be far too high.
Of course. I'm not suggesting that Russia should be relied upon for ANYTHING at this point. It should be as isolated economically as possible.
I'm just using this as an example of what you can do with a streamlined construction pipeline for plain old PWRs. No fancy new technology, no breakthroughs, just regular old good project management.
That's a lot. Even cheap gas turbine power plants will cost around $100B to build.
And while the one-month Dunkelflaute is exceptional, the shorter versions lasting a couple of days happen basically every year. As a result, you probably need about 2-3 weeks a year of various levels of backup utilization every year.
This is how it looks in practice: https://energy-charts.info/charts/power/chart.htm?l=de&c=DE&... - look at the period from 18th Jan to 25th Jan. The renewable generation fell to around 8% of the nameplate capacity during that period.
I have not seen any real plans to fix this. My prediction is that Germany will just continue to burn gas and coal well into 2030-s.
A combined cycle power plant costs about $1/W of capacity (and for rare events, simple cycle would be even cheaper), so one could back up the entire grid with these at a small capital cost compared to powering the grid with nuclear. For Europe, these would also be useful for seasonal leveling, allowing solar to provide a larger fraction of Europe's energy demand.
Hydrogen is an example of "Power to X" (PtX), where excess power, when available, is used to make some very storable commodity. This review article talks about how important these are to reaching 100% RE.
https://ieeexplore.ieee.org/document/9837910
"With every iteration in the research and with every technological breakthrough in these areas, 100% RE systems become increasingly viable. Even former critics must admit that adding e-fuels through PtX makes 100% RE possible at costs similar to fossil fuels."
I have not seen any real plan to achieve this. Right now, it's basically a giant asterisk with a footnote saying: "Magic happens here".
One plan I've seen where authors went totally wild and actually tried to compute what's needed, required converting 80% of housing to district heating with molten salt storage, all kinds of energy storage, and 2x price electricity increase.
I've seen estimates that simply building out hydrogen backup will cost on the order of $300B in power line and pipeline upgrades (because hydrogen can't just be piped through natural gas pipes). And it will still require expanding the renewable fleet.
I'm not at all optimistic about that.
FWIW, I think power-to-natural-gas has the biggest chance, because it can re-use the natural gas infrastructure. But it's still going to be too expensive.
There is nothing preventing this from being applied to Europe. All the technologies are available. It's just a matter of integrating existing capabilities, which is the surest kind of innovation.
No pipeline upgrades are needed for hydrogen for grid storage, since there's no need to move hydrogen away from the storage caverns. It can be created and consumed there. It could be useful to build pipelines, of course, but it isn't necessary. I am NOT suggesting using hydrogen to replace natural gas in distributed applications.
Power-to-natural-gas has the problem of where does the carbon come from. CO2 capture (either from the atmosphere, or from the exhaust of the CC plants) would add to cost, and then the CO2 needs to be stored also. And, the round trip efficiency will be considerably below that of hydrogen. Power-to-liquid fuels would make more sense; it doesn't cost that much more to turn CO2 + H2 into such fuels instead of to methane. Liquid fuels (normally for air or ship transportation, for example) could also serve as a rare event backstop along with hydrogen, for once-in-a-century events, as long as the CC plants can burn both.
You're making it right now.
> If you haven't seen "any real plan" that just reflects your disinterest in seeing such a plan.
No. I did a full literature search and I read most of the articles in that area.
> There is nothing preventing this from being applied to Europe. All the technologies are available. It's just a matter of integrating existing capabilities, which is the surest kind of innovation.
What is "this"?
> No pipeline upgrades are needed for hydrogen for grid storage, since there's no need to move hydrogen away from the storage caverns. It can be created and consumed there.
The thing is, most of German storage is in the northern part (Rehden, Etzel, Epe, etc) due to geology. That's not where the consumers are, so you need to build a huge amount of power lines.
To give you a perspective, a fairly typical natural gas pipeline can transfer around 1 Bcf of gas per day, which translates to about 12GW of power. This is the same as the largest ultra-high-voltage direct current (UHVDC) line in the world (in Brazil), built at the cost of around $2.5B for 2400 km.
And you'll need many, many such lines to transfer power from the points of generation and consumption to the hydrogen hubs. This is in addition to already expensive hydrogen production and gas turbines.
I don't see this ever becoming cost-competitive with plain old PWRs.
In detail, I'll let someone smarter than me in nuclear physics explain: https://physics.stackexchange.com/questions/175830/nuclear-f...
What they've already demonstrated is a tremendous accomplishment. But apparently if it doesn't go from idea to an option in door dash in 6 months flat that's not good enough for people here.
I hear ya. The attention span of a TikTok or less.
It is about research. It generating usable electricity is absolutely irrelevant.
You need research projects to figure out what works and what doesn't. The goal isn't to build a practical reactor.
There should be more funding in this area, but at some point you've got to build it, and that takes a ton of time. Regulations/bureaucracy could be better but at the end of the day you're not going to cut off a ton of time safely.
Once you have a working model iteration gets much much faster, but we've simply been hitting walls for decades.
You're talking about taking a technology that's so finicky we've barely gotten it to work after almost 100 years and rocketing it into space? We're no where near good enough at this to get a test that would work after the extreme violence of an escape velocity launch.
Further fusion reactors aren't like fission. "exploding" really isn't a problem . Keeping the reaction going in an efficient manner is.
IF exploding was a problem, space is probably the worst place for it? Putting it way underground would be vastly easier and a hell of a lot safer because you won't have material possible falling back to earth/hitting satellites in orbit.
"Shooting it into space" is a reference to how SpaceX disrupted the rocket industry through a "fail fast" mentality, aggressive goals, and sheer force of will.
Assumptions:
---------------------
1. The average commenter here (me!) knows a little about nuclear fusion, and a lot about online tech news.
2. There are no new ideas.
Background:
------------------------
This big science project is overbudget, making incremental progress, and the timeline is stretching to forever.
That is incredibly similar to the state of rockets 10 years ago - publically funded, making little progress.
Leap of logic:
-------------------------
Somewhere in his subconscious, OP pattern-matched to the only big successful science project in the news recently - SpaceX.
But the subconscious no good at talky talky, and OP didn't trace the train of thought, so what came out was "Shoot them into space".
Seriously, I think I might know (a fire) but I do not.
Is there any possibility these can go ban! and spread nasty stuff around the neighbourhood?
I doubt they can go thermonuclear bang! but I am not a physicist.
What is the worst than can happen?
But that doesn't really matter. This is expensive technology you don't want to blow up. Yes, more expensive than rockets.
The is a lot of interesting work going on in stellarator design optimization now, but it will likely be many years before that research is realized in another actual reactor.
I don't think that points to a commercial reactor whenever someone spends a few billions.
When you listen to the guys from this original article then you'd know that for 10-20bn USD you could likely build a real power plant with this tech within 5 years. It's obviously not without risk, which is why nobody is doing it. But the technical feasibility is there.
They also point out that once the first-of-a-kind installation exists, subsequent models will be way cheaper and way better since you'd have learned a lot and streamlined the process.
But we choose to use public money for fossil subsidies instead, cause jobs, or something.
http://large.stanford.edu/courses/2021/ph241/margraf1/
Fusion has been "a decade away" since before the turn of the millennium.
To say we should just throw $10-20 billion at a power plant and hope something comes out is not a good idea.
We should wait until one of the many multi billion dollar research plants is able to get even 10% of a reasonable to target energy output before even thinking about that.
Otherwise we would likely just sign the death of fusion in the public eye. Could you imagine the backlash if a $40 billion dollar project couldn't even produce power after two decades? (Going off how public works costs and timelines have been going is the reason for higher values)
The Podcast Alternativlos by Felix Von Leitner and Frank Rieger were twice in Greifswald to interview some of the people behind the Wendelstein. In the first episode (http://alternativlos.org/36 from 2016) they mainly focused on the development and build process and the history. The second one is from this year and they talk about the achievements and the future of Fusion (http://alternativlos.org/51/)
https://www.neimagazine.com/news/newszap-energy-considers-re...
Also their concept is just so weird, I love it. Worst case it works in space as a nuclear fusion drive :)
My guess is that they're all going to tank without government money, unless by some miracle they have truly found some special low-cost of operation on the first try that beats the current heavily optimized solutions for power generation.
It's like saying: "We should build an airport here in the desert, because we'll be able to save on cutting the grass!"
It's not going to save a meaningful amount of money. But that doesn't mean it's a bad idea.
I'm also in general skeptical about conversions of coal power plants into nuclear even for fission. Typical nuclear plants produce much milder steam temperatures and pressures than coal power plants, so their steam turbines are optimized for different conditions.
From the overall perspective, Tokamak Energy also looks promising and I'm planning to invest.
2. As CO2 emissions come down, I think there will be some focus on thermal power plants contribution to global warming. Helion will still be adding heat to the planet that wasn’t there before, but there will be less heat for a given amount of electric energy. It’s also not going to rely on dumping all that heat in a river. I don’t know if Helion is feasible. But it feels like it’s the only technology that could be feasible.
And Helium3 is not available in useful quantity. No, not even on the moon.
It would be much more expensive to build a fusion power plant than a similar-capacity fission plant, but fission is already uncompetitive, and falls farther behind by the day. Start thinking hard about uses for stable contained plasma that doesn't fuse. Advantage is, it doesn't need to be especially hot. What they have already is more than hot enough for any plausible use.
This is of course a milestone, but note they're currently testing the heating system. It doesn't mean there was any fusion happening.
There is a bare possibility of eventual usefulness for spacecraft propulsion. And, some spinoff might come out of a newfound ability to handle lots of hot plasma. Maybe for sewage treatment?
> In individual areas, temperatures of up to 600 degrees Celsius are reached (red areas). The divertor tiles can withstand temperatures of up to 1200 degrees Celsius.
How many 0's are missing there?
The picture does NOT show the plasma itself, but the temperature distribution at the water-cooled divertor baffles.
It's about the temperature of parts of the vessel that get heated by leakage from the contained plasma.
Can a physicist/thermal engineer explain what this means?
Helion, a fusion startup, claims to have solved this problem via capturing an induced current from colliding two hot plasmas together. I'd be curious if there is any way the Wendelstein can produce electricity.
Then you trap the neutrons with, for example, a lithium blanket, use them to breed more tritium, and produce energy with a turbine from the heating of the blanket.
A) the energy that is produced immediately (about 24MJ)
B) the excess energy absorbed from the Sun over many subsequent years, caused by CO2 emitted burning that coal.
The B is much larger than A. The fusion only produces A, but not B.
The dangers of climate change is not that the earth heats up by some small amount, the earth can easily cope with that. It is that continued greenhouse gas emissons are causing a ever increasing heatup due to trapped solar energy.
(It is also extremely strage that he argues for geothermal in his comments. Does he not realize what that is? Literally heating up the surface of the earth with energy from below.)
and fusion never had any advantage over fission anyways, other than that people aren't scared of it yet.
Also, if energy use does increase by 10x, the solution is simple, build giant refrigerators powered by fusion energy to cool the atmosphere. (joke)
According to the article, we currently emit 2.1w/sqm in greenhouse gasses.
If we had 10x energy and it was all fusion - it would be 0.4w/sqm.
This sounds like a massive improvement.
Additionally, I'm highly skeptical we'll be using 10x the energy in 100 years - when there's likely to be significantly less people, and everything is getting more efficient.
Sounds like the same argument that China is going to continue growing 10% per year for the next hundred years, because it did for the last 30 years. No. China's workforce is going to decline massively. It will be so much harder for them to grow at the same rate, it would take a real miracle to keep growing at that rate.
The hard part is building a machine that can burn plasma and breed tritium at appreciable rates.
Why even bother with these machines that can never be built economically?
If you can not build a research reactor which functions well, then "building a machine that can burn plasma and breed tritium at appreciable rates." is more than impossible.
Oh, is it because the technology didn't exist and first had to be developed, in incremental refinements? Initial airplanes didn't even fly and half the people trying them died? Oh...
The basic physics of DT fusion reactors led Lidsky to conclude that any DT reactor would have poor power density. And so it has proved.
Sometimes knowledge lets one rule out whole branches of the technology search tree.
For fusion, we have to ask why it's going to be an exception. The prior is that it won't be. If there's evidence it will be blocked, that's two (or more) strikes against it. Something very unusual is needed to come back from that far behind.
The continuing success of renewables, and their continuing progression down their experience curves, is bad news for fusion.
What "renewables" (with which I suppose you mean solar, hydro and wind) have going against them is their environmental impact. Sure it's not as bad as fossil fuels, far from it, don't get me wrong. But the area and materials needed for solar, the animals getting disturbed by wind turbines (birds killed, wales confused, ...) and the ecosystems that get flodded by dams are not nothing. Especially in the light that the energy demands of 8bn+ people are continuing to grow, and those 8bn will soon be 9bn and 10bn.
The promise of fusion tech is that you get much more bang for the buck, and with "buck" I mean resource use. That's not going to happen soon though, so until they we'll be stuck with solar+wind+hydro, but those are not really sustainable solutions in the long run (i.e. 100s/1000s of years ahead).
Of course, if you see fusion just as some crazy idea and know nothing else about it, then I can see how your "prior" makes sense. But once you know the details, it's quite different, since fusion is also continuing to progress down its experience curve. Tokamaks and stellerators in particular.
So, if we stipulate your environmental argument rules out renewables, it also (to a much stronger degree) rules out agriculture. This is obviously absurd, so your argument cannot succeed.
As for recent "goings on"... I do follow them rather closely. You are likely misled by a common cognitive failing. That is: if we have a set of steps needed to reach some goal, then if one of these N steps is achieved, it's natural to think that we're 1/Nth of the way there. But this is only true if the steps are equally difficult. This cognitive blind spot is exploited in those collectable coupon games you sometimes see at grocery stores or fast food outlets. The # of winners is controlled by the number of a particular rare coupon; all the others are just noise.
For fusion, the immediate steps have been plasma confinement, stronger magnets, and so on. But none of these matter if there's a later showstopper. And for DT fusion, there is. That showstopper is the inability of DT fusion reactors to achieve adequately high volumetric power density. None of the recent DT reactors are promising in that respect, and there's good reason to think this obstacle is generic. Lawrence Lidsky (and Pfirsch and Schmitter in Germany) in the 1980s pointed this out. The implication of poor volumetric power density is that DT fusion will be more expensive than fission -- and fission itself cannot compete with renewables.
(I view current work on DT fusion as "making good progress toward a dead end.")
(If Pfirsch's name is familiar, it's because he, with Schlüter, discovered Pfirsch-Schlüter currents, which are important in stellarators.)
The only effort I see that has any chance is Helion's, which does not use DT, because they can evade this showstopper (by not producing their output as heat, allowing them to potentially save on the cost of the non-nuclear part of the plant.)