Wendelstein 7-X achieves world record
ipp.mpg.de
ipp.mpg.de
The lack of the current might make it more stable vs. the tokamak.
It's perhaps important to point out that fusion is not difficult; it's very easy in fact. The hard part for power generation is plasma physics, i.e. being able to contain and control a plasma effectively. That's what 7-X is designed to research. If you can control a sustained plasma, fusion power is relatively easy.
Identifying and understanding those new behaviours sounds more like science than engineering to me. (That said, scientists frequently do engineering and engineers frequently do science; I've been on both sides of it).
https://en.wikipedia.org/wiki/Fusor
He was an inventor of a variety of television technology, and I believe the designs were very similar to his fusor. Unfortunately, the design cannot be made "exothermic" IIRC, and the research ruined him financially.
Which is the primary impediment to developing viable fusion reactors. So yes, it is absolutely about fusion. We're not trying to contain plasma because we think it'd be a neat thing to do. We're trying to contain plasma because it's necessary for fusion.
We already know that energy production is viable if we can solve the containment problem. Saying this project "isn't about fusion" is like saying "guns don't kill people, bullets do".
No. That's only a small part of the problems. What is probably a far more difficult problem is the fact that any nuclear fusion which is remotely viable in this century will use a Deuterium-Tritium reaction. And tritium is an isotope which does not occur in nature - it is unstable. Therefore tritium has to be bred, using heavy water reactors. And lots, lots, of uranium. The idea is now to breed tritium, using neutrons from nuclear fusion, and further nuclear chemistry which is supposed to happen in a breeding blanket. But this runs into an additional problem, the deuterium-tritium reaction has no neutron surplus, as uranium fission has. And in addition to the very difficult task of exfiltrating traces of Tritium, one essentially needs a breeder technology (similar to Monju in Japan), and there are huge, unsolved material sciences problems, such as constructing a large structures which withstands very strong magnetic forces, very high temperatures, and a very high neutron flux, and this of course without any elements like carbon which will become radioactively activated.
Oh, and I forgot, the whole process is also unlikely to be clean, because of the breeder technology needed.
And all these questions are so extremely difficult, that today's large projects, like ITER, do not even address them.
More on these issues for example in the article by Michael Moyer which is contained in the page below (Michael Moyer, "Fusion's false Dawn", Scientific American 302, 50 - 57 (2010) doi:10.1038/scientificamerican0310-50 )
http://energyskeptic.com/2014/why-fusion-is-still-30-years-a...
Lithium-7 plus a high energy neutron yields tritium, helium, and a lower energy neutron. I don't know what a practically engineered system can do, but a 14.1 MeV neutron from D-T fusion formally has enough energy to transmute 5 lithium-7 nuclei into tritium and helium (each transmutation is endothermic to the tune of 2.466 MeV).
I agree about the huge unsolved material science problems. I just don't think that tritium availability lies on the critical path of unsolved problems for industrial fusion power.
Well.
https://scholar.google.co.uk/scholar?hl=en&as_sdt=0%2C5&q=Sa...
http://fti.neep.wisc.edu/pdf/fdm1273.pdf
M.E. Sawan and M.A. Abdou, "Physics and Technology Conditions for Attaining Tritium Self-Sufficiency for the D-T Fuel Cycle", Presented at the Seventh International Symposium on Fusion Nuclear Technology, May 22-27, 2005, Tokyo, Japan; to be published in Fusion Engineering and Design.
Abstract + conclusions:
"There is no practical external source of tritium for fusion energy development beyond ITER and all subsequent fusion systems have to breed their own tritium. To ensure tritium self-sufficiency, the calculated achievable tritium breeding ratio (TBR) should be equal to or greater than the required TBR. The potential of achieving tritium self-sufficiency depends on many system physics and technology parameters. [...] It is clear from the above discussion that both the required and achievable TBR values depend on many system physics and technology parameters. Many of these parameters are not yet well defined. In addition, the rapidly decreasing tritium resources imply that the time window for the availability of tritium to supply fuel for the DT physics devices is closing rapidly. It is, therefore, necessary to establish without delay an extensive R&D program to determine the “phase-space” of plasma, nuclear, material, and technological conditions in which tritium self-sufficiency can be attained.
[...] Tritium self-sufficiency in DT fusion systems cannot be assured unless specific plasma and technology conditions are met. [...]
The tritium bred in the CANDU reactors is the only practical source available for ITER and other DT fusion systems [3,4].
Citation 3 is "personal communication." 4 is this 2002 presentation: http://www.fusion.ucla.edu/abdou/abdou%20presentations/2002/...
Page 32 of that presentation, "Tritium Supply Calculation Assumptions", says it is assumed that the following will NOT happen:
• Restarting idle CANDU’s
• Processing moderator from non-OPG CANDU’s (Quebec, New Brunswick)
• Building more CANDU’s
• Irradiating Li targets in commercial reactors (including CANDU’s)
• Obtaining tritium from weapons programs of “nuclear superpowers”
• Premature shutdown of CANDU reactors
But assumptions 3 and 4 have already been invalidated. China has added CANDU reactors since the presentation and is building a few more abroad for other countries. The United States has started irradiating lithium targets in commercial reactors.
So in my judgment, closing the tritium cycle still isn't on the critical path to fusion industrialization. There are other crucial problems to solve before "where will we get enough tritium for these fusion reactors?" becomes a crucial issue.
Not at a cost that could support economic nuclear fusion, except to jump start fusion reactor development. And even that would be terribly expensive.
Tritium deliberately made in fission reactors would cost maybe $200M/kg.
A DT fusion reactor consumes 55kg of T per GW(th)-year. That would cost $11B/GW(th)-year if the T came from deliberate production in fission reactors, which is far too expensive.
Even producing the startup tritium for a fusion reactor using fission reactors is problematic.
There's a serious loop in the development schedule for DT reactors. They absolutely need good tritium breeding to make enough tritium, but such blankets cannot be developed without access to the large amounts of T that they themselves are needed to produce. Running around this loop is going to be laborious and painful, even after all the plasma physics issues are solved.
Carbon has very low neutron activation. Silicon carbide has been proposed as a material for fusion reactors for this reason. But otherwise your points are well taken.
Might as well call transistor fabrication experiments "not about computers".
How does "ion temperature" relate to "regular" temperature?
Is it similar to how we can cool down things to fractions above absolute zero, by using lasers to reduce the movement of atoms? i.e. is the "ion temperature" a measure of how fast are they moving, as opposed to the every-day meaning of temperature as "how hot something is"?
I realize that "how hot something is" depends on how fast the atoms of said "something" are moving, but since they specify "ion temperature" I'm guessing it has a very specific meaning.
I searched for "ion temperature" but only found about Electron temperature [0].
Could someone explain it to me in lay terms? :)
"[...] the ion temperature may be very different from (usually lower than) the electron temperature"
From that Wikipedia article:
"For this reason, the ion temperature may be very different from (usually lower than) the electron temperature."
So if the ion temperature of the plasma in the Wendelstein 7-X is about 40 million degrees...the electron temperature could be even higher?
What does it even mean to have a temperature of 40 million degrees? AFAIU, the Sun has temperatures much lower than that. That's utterly mind blowing...
The surface temperature of the sun is approximately 5,778 K (5,505 °C, 9,941 °F) [2].
I can guess what the insane pressure means ("estimated at 265 billion bar (3.84 trillion psi or 26.5 petapascals (PPa))"), but I don't know what millions Kelvin means. It should be kinetic energy. So maybe it means the ions vibrate very fast?
While average kinetic energy is one way to think about temperature, think about it instead in terms of the Maxwellian particle distribution [1]. In this sense, the Maxwellian is a parameter of this distribution, and as it increases, the location of the distribution changes. A high temperature corresponds to, in this hypothetical system, more particles with higher velocities in the system. (This technically only applies to certain systems in which the assumptions hold. For example, in systems in which other degrees of freedom matter, such as vibration/rotation of molecules, the interpretation is harder. At high temperatures, these degrees of freedom are destroyed, though others, like ionization, can matter significantly.) Of course, these systems are highly collisional, in the sense that each particle will probably go only a short distance before Coulomb scattering off another particle. So the particles are not really vibrating; the energy is in translational motion, but in the mean, there is no real directionality to it, so the particles won't typically stream out of the plasma.
This can be readily understood in the context of achieving controlled fusion. Nuclei are positively charged, and therefore exert forces that tend to repel them away from other nuclei. The nuclear scale, at which nuclear reactions must occur, is very small, and the 1/r* Coulomb potential is quite large at those distances. As a result, it is to be expected that an individual fusion reaction should only occur when the kinetic energy of an incoming nucleus is sufficiently strong to overcome the Coulomb barrier. (Practically, quantum mechanics effectively reduces the barrier through tunneling, but nevertheless it is quite high.) As a result, you need a sufficiently large number of nuclei with high speed to have an appreciable fusion rate, i.e. your temperature must be high enough. (Hence, "thermonuclear" fusion.) This has to be contrasted with your confinement quality, in the sense that you have to keep your fuel at that temperature and at a sufficient density (so that your collision rate is high enough) long enough for fusion burn to consume an appreciable fraction of your fuel.
In context, the temperature seems a simpler quantity to discuss rather than the pressure. It is easier to conceive of this pressure as a momentum flux, and in stars, gravitational confinement demands that the plasma pressure balance the crushing momentum flux of the weight of the star. Such static pressures are simply outside of our ability to intuit, and result in quite counterintuitive properties of matter.
[1] https://en.wikipedia.org/wiki/Maxwell-Boltzmann_distribution
*edit: inverse square is the force, the potential goes as 1/r... update for clarity.
The sun has immense gravity and mass that produce very high pressures which permit fusion at 'low' temperatures. Maintaining high plasma pressure is difficult on Earth, so higher temperatures are used.
Temperature is fairly well understood as simply the average kinetic energy of the particles of whatever you're measuring. For more nuance, start here: https://en.wikipedia.org/wiki/Temperature#Theoretical_founda...
A plasma is composed of both ions (partially ionized atoms, or if they are fully ionized, bare nuclei) and electrons. Together, they constitute two co-located but separate fluids, whose motions may be distinct; indeed, because electrons are so much lighter than ions, they respond to forces much more readily. In equilibrium, a single fluid must have sufficiently rapid interactions so that the particle distributions are driven to a Maxwellian. In that case, for a single fluid, a temperature is well defined. In the case of a two-fluid system, self-interactions (such as interactions between ions and themselves, and electrons and themselves) may be sufficient to establish two separate equilibria corresponding to each fluid; hence, the electron vs. ion temperature. Only in the case that ion-electron interactions are sufficiently rapid would those equilibria be driven together to a single-temperature fluid, in which case, Te = Ti.
This picture becomes rapidly more complicated at very high temperature (usually, around 0.1 keV or about a million K), at which point the photons being exchanged by hot charged particles become dynamically important, and a third temperature, the radiation temperature, may emerge. At this point, the plasma must be described using three temperatures - if, and only if, you are in a situation lucky enough for equilibrium to manifest. (Fortunately, equilibrium is not usually that hard to access.) In many cases, such as when the system undergoes a strong shock, the system may be driven very far from equilibrium, but only temporarily. In others, some underlying energetic process may continuously drive the system away from equilibrium, resulting in a metastable state; this is the case in stellar atmospheres, in which NLTE (non-local thermodynamic equilibrium) processes matter a great deal. Usually, physicists resort to kinetic theory to try to understand such situations.
Thanks a lot.
It's amazing how something seemingly simple as "temperature" can be so counter-intuitive.
http://omegataupodcast.net/22-nuclear-fusion-at-mpi-fur-plas...
While plasma containment seems like an essential step towards fusion-based energy, is fusion-based energy a desirable goal?
Right now, fission-based nuclear energy is only used as a heat source for steam-driven turbines. It's a fantastically complex and expensive way to make heat.
Is fusion energy on Earth going to do something similar? And if so, is this source of heat actually going to be cheaper than using the sun as a distant fusion reactor? (Which is what drives both solar and wind energy on Earth.) It seems quite doubtful that fusion could ever be cheaper than solar or wind energy, the tech-to-energy ratio just seems massive in comparison.
So if it's not Earth where fusion energy will be useful, how about in space? Here on Earth, the Carnot cycle is used to convert heat into useful mechanical energy, then finally electrical energy, which is usually the true goal. But the Carnot cycle requires dissipating massive amounts of heat; just as much energy is dissipated as heat as gets turned into electricity. And heat dissipation isn't such an easy thing in space, is it?
I feel like I'm missing some rather large puzzle pieces here. Without them, fusion does not really seem like an engineering goal towards a good energy source, just engineering research into better containment of difficult materials. Could somebody help enlighten me?
If one connects wind turbines to an electrical grid in a larger area, the variability averages out.
Battery storage is being discussed. But what is probably more economical is that a significant proportion of energy usage is somewhat flexible in time. Take hot water generation. It is expensive to store the amount of electricity to bring 100 liters of water to boil, but it is very easy to store 100 liters of hot water for a few days. Heating and cooling make a very big proportion in modern energy use.
And this isn't a new idea at all - all of human history, our energy management was around making use of a surplus of energy, like food, for times when less was available, and using storage.
In particular, the gamma radiation energy capture in that Wikipedia article addresses another somewhat undesirable aspect of fusion in a really great way.
1. The fuel is much more common and easier to handle - uranium and plutonium are a pain to extract/transmute, handle, and package.
2. The radioactive contamination is limited to induced radioactivity in the structural materials of the reactor core; there aren't the safety concerns of radioactive neutron moderators and the like that you see in a fission reactor. Preventing the release of those materials in the case of accident is one of the big drivers of fission plant costs.
3. The core itself is fail-off, again reducing the cost and complexity of safety measures.
4. They are not dual-use (civilian/military) to the extent of the fission supply chain.
5. By comparison to the rather indirect method of using solar panels and wind turbines to extract energy from solar radiation, steam turbines are a simple and efficient way of extracting energy from a fusion reaction. The Sun is enormous, but a fusion reactor would be right here and we can extract energy from one with well-understood, efficient technology.
ad 1) Nuclear fusion as we know it does not rely only on deuterium, it needs tritium. Tritium needs to be produced by uranium fission, and after having a hypothetical fusion power plant running, by a breeding process. The technology of that breeding process is today completely unsolved.
2) Fusion reactors, if they aver will exist. will be large and will have a very large neutron flux. The will have breeding blankets which need to be several meters in size. Anything within these structures will be activated by neutrons. That means common materials such as carbon steel can't be used, because the carbon would become highly radioactive. Also, the neutron radiation weakens all known materials so that the structures will probably need to be periodically replaced. This alone will probably lead to a higher amount of nuclear waste than uranium fission plants.
3) It is correct that the fusion reaction will stop to operate when the core is damaged. But this does not mean that the plant is safe then. It will contain substantial amounts of tritium and other radionuclides. By the way, you may have seen nice photos of scientists in white coats which stand in the vacuum vessel of a a fusion power plant. Except that, if there were actually fusion to happen in these devices, nobody could enter them before they have been decontaminated in a time-consuming and expensive process. Consequently, in experiments such as ITER, no fusion happens at all.
In addition, a fusion plant will be very complex, and especially it will work with extremely large magnetic fields which have by themselves a tremendous energy content. If there is any electrical or structural failure, it is likely that the whole structure just blows apart. And it will not safe to be standing nearby.
4) As said, tritium is a key ingredient in the fusion technology that is aimed for, and it also happens to be a key ingredient of thermonuclear weapons. In addition, the required breeding technology is also highly relevant for military uses, because if you can breed tritium from lithium, you can also breed weapons-grade uranium and plutonium.
5. Steam turbines are not physically simpler than wind turbines. Apart from that wind power converters, as well as photovoltaic energy converters, can come pretty close to the physically possible optimum, there is another problem: Large steam turbines need cooling for thermodynamical reasons. Lots of cooling. The amount of cooling required for today's uranium fission plants is already a problem. For one, they cannot be built in arbitrary places - they need to be at rivers or at the coast. As the fukushiuma plant has shown, having a nuclear plant at the seaside can be a bit risky. But cooling by rivers also has costs, heating up a river to much messes up its ecology. Also, France often has energy problems in the summer, and the reason is that the rivers are too hot to cool its numerous nuclear plants.
Here another article on further problems of nuclear fusion - see the article of Michael Moyer.
http://energyskeptic.com/2014/why-fusion-is-still-30-years-a...
As a closing remark, I am not saying that fusion power plants are impossible. Sometimes, technological break-troughs happen, similar to the advances which made airplanes and aviation possible. But today, we don't even know what is required to make it possible. We are in a similar position like people from 1800 were in respect to aviation. And also, we have more urgent problems to solve - we need clean energy within the next decade, not in the next century. And fortunately, we do have the technology for that, we just need to put it in march.
2. No, although the kinds of reactors being dreamed of in the “short” long term do fit this bill. Again, the much more difficult to manage (not to mention fuel) D-3He reaction is aneutronic, and doesn’t require a breeding blanket. Another difficult reaction would be p-7Li, although the fuel would be easier to come by. I’m not claiming that we’re remotely capable of harnessing these reactions, but it’s important to point out that they exist. A high neutron flux, and the need for Trtium are not inherent to fusion in general.
3. A bigger issue would be sputtering from the neutrons and He infiltration of the vessel. Othereise, assuming d-t fusion... this is accurate.
4. We can already breed tritium, and plutonium... this is a reality we have to live with. Fusion won’t change that either way. We can also engineer plagues, and a lot of other nasty things, and every year it all becomes easier to do “out of the garage” so to speak. If we’re going to survive, we need a better solution than unspilling the milk. Maybe embracing fission energy and greatly raising quality of life around the globe would be a good first step?
5. Agreed, although it is worth mentioning that there are ways to harness energy without a turbine, they are also complex. Fusion won’t save us, it won’t save our kids or grandkids. We need fission, solar, and wind, and peobsbly a century or more of research into aneutronic fusion if we want to survive well.
But my argument is not that D-T (Deuterium-Tritium) fusion is theoretically impossible. It is practically impossible. While it is possible to generate very small amounts of Tritium in commercial reactors, a fusion power plant would need much much larger quantities before it could even be started. And while the D-D reaction is also theoretically possible, it is even more difficult to achieve practically.
This is similar to aviation in 1800: While it was theoretically possible to build a flying machine, there was, for example, no known engine which would have been able to power an airplane. And for somebody to say "we just go ahead and will solve the technical problem of having a low-weight power source within 20 years" would have been delusional. You can't summon technological break-throughs like a mythical ghost in a bottle.
So to sum up, your argument against that todays nuclear fusion research, which is dominantly based on the D-T reaction, will not lead to any energy reaction in foreseeable time, is that there are more exotic, more difficult, end less well understood reactions which are also theoretically possible but not even close to being practically usable in any way.
Looks like theoretically the Stellerator is superior in practice, while in practice only the Tokamak is being worked on practically.
Other than the very experiment the OP is about.
But thanksfully both teams are working together. We will see if something better will come out of it. Even if I'm extremely sceptical on both.
The power density of a PWR fission reactor core is 100 MW/m^3.
The power density of ITER (gross fusion power/volume inside the cryostat) is maybe 0.05 MW/m^3.
There are fundamental engineering limits to fusion that guarantee the power density will suck compared to fission. So my default take on any fusion design is that it will never be competitive with fission, never mind the things that are cheaper than fission.
I'm really well past the phase of being excited about milestones like "record for a stellarator". Put it in context, show where we are on the plan. Perhaps it's behind, but still moving forward - that's fine. Confirming things work as predicted is awesome and tells me they should be moving forward at a good pace right? So where are they on that gantt chart?
There are a lot of issues outstanding for fusion to be a viable power source, and this reactor is simply exploring the dynamics of one of those issues. Putting aside hype and desperation, there is no chart yet. For a fusion plant to work and compete with any other plant, you need it to have good uptime, relatively low maintenance burdens in terms of downtime and costs, good output, a viable source of fuel, a fusion cycle that is safe and sustainable, and more.
As of today the d-t cycle isn’t sustainable because it requires tritium, produces a lot of energetic neutrons that along with helium will undermine the reactor. The problem is that more viable fusion cycles occur at significantly higher temperatures and it’s a struggle to control plasma at d-t temps. The lack of control both quenches the reaction, and exposes parts of the reactor to plasma which erodes the material. Neutron bombardment causes the metal to become brittle, and helium infiltrates and undermines it too. So a reactor would be down for maintenance a lot, which would make it difficult to work as an economically viable source of power.
As of today the tritium for the reaction has to be bred in fission reactors. There are theoretical plans to use a “blanket” impregnated with an isotope of Lithium to breed tritium within the fusion reactor, but so far no one has gotten it to sustainably work near necessary levels. As a result a fusion reactor today would require fission reactors, and it might make sense to ask why we don’t just stick to the far more mature and efficient fission technology.
There are lots of other issues that aren’t as big or obvious as what I’ve described, but ITER and desperation hype aside, there are more unsolved problems than solved. So where this reactor is concerned, be excited for what it is away from the context of “fusion any day now!” hype. Appreciate the slow, but steady progress in the context of incremental research.
If you want clean power in your lifetime, support fission plants.
Not anti nuclear or anything, but you really want a large share of wind+solar. Less hard to handle waste and cheaper. Once we are approaching 80% wind+solar we can discuss how to best deal with the difficult remaining 20% (load shifting, expanded transmission grids, storage, CCX and Carbon2Gas gas plants and nuclear are all options that are possibly going to play a role).
Now look at some of the figures in this slide deck: https://www.svensktnaringsliv.se/Bilder_och_dokument/mattias... (in particular, slide 3, showing rate of added generation/year for various countries, comparing nuclear to wind+solar+geo+bio energy, compared to the needed rate of addition of carbon-neutral energy to hit 2 deg C warming goals.) These data are also sourced from the BP statistical review and the World Bank.
If you trust that information, evaluate for yourself whether or not we can reach 80% penetration of wind and solar in time to avoid anything short of catastrophic warming.
If your response is to extrapolate current trends in cost reductions for wind and particularly solar, please bear in mind that there are no indefinite exponential growth processes in the real world where transfers of matter and energy are concerned, only processes that show logistic growth. And we can't necessarily predict when we'll reach the plateau phase of logistic growth.
What I conclude from that, personally, is that we shouldn't gamble on continued trends in solar and wind adoption to get us to decarbonization.
Bet on fusion?
I would bet on nuclear, but in the long term indeed switch to solar + wind, starting now. Which is happening... at least the last.
China is ramping up investments in renewables (including crucial grid strengthening measures) and hasn't approved a nuclear power station in two years (as of beginning of this year, I haven't heard if it has resumed building them now).
Again, I'm not ruling out that nuclear has a role to play. But most of the lobbying for nuclear seems to be based in an instinctive dislike of wind+solar rather than in facts. Nuclear is terribly expensive and there really is a waste problem (even if CO2 is clearly the more severe problem).
That said, we are in the middle of the experiment you are talking about. Renewables are cheaper now than new nuclear, despite nuclear having received a massively larger amount of subsidies over the years, there are still many parts of the world that are building nuclear so it's not like we're losing the technology, but really, there doesn't currently seem to be a good reason for building new nuclear.
Let me put it another way, a relatively small island like Ireland is going to be capable of going 100% wind/solar relatively soon. They are not strongly connected to the EU grid. Smaller disconnected islands already have gone 100% renewable. So we will have plenty [1] of test cases of increasing size as we ramp up renewables. Conveniently, electricity is also much more expensive on small islands, so it's also economical to test every technology you want to bring to maturity there first.
If we find that beyond a certain size it doesn't work we'll have a decade of warning before we hit that wall with the big continental size grids.
[1] 2200 EU Islands: https://ec.europa.eu/energy/en/topics/energy-strategy-and-en...
But maybe a group like the Citizen’s Climate Lobby can pull something off (they suggest using the revenue of the tax as a monthly dividend for all citizens. Never underestimate the power of a monthly bribe in generating consensus in the American public).
Indeed, wind and solar can produce power very cheaply nowadays, which is awesome. We should definitely build more of them. OTOH, due to their variable nature, their value to the grid reduces as their penetration increases, so it's a race of declining costs vs declining value due to increasing penetration.
Nuclear, being somewhat dispatchable, doesn't suffer from this.
Given the magnitude of the climate crisis, IMHO we should build about every low-carbon source we can, as fast as we can. Including wind, solar, and yes, nuclear.
> China is ramping up investments in renewables (including crucial grid strengthening measures) and hasn't approved a nuclear power station in two years (as of beginning of this year, I haven't heard if it has resumed building them now).
According to http://world-nuclear.org/information-library/country-profile... China has 20 nuclear plants under construction. AFAICT China is investing heavily in both renewables and nuclear.
The variability of renewables is of course a well studied problem [1] and exactly why, after a certain point, we need transmission capacity (or, more expensive, local storage). The variability averages out on large scales.
[1] I posted this elsewhere already: https://arxiv.org/pdf/1801.05290.pdf
Personally I'm with Bill Gates on this one: we basically need an innovation miracle to solve our energy and climate problems, but probably just one, and it can be in any of four or five different fields (renewables + storage, fission, fusion, biofuels, carbon capture, etc.). Success in any one of those spaces is far from guaranteed, so we shouldn't put all our eggs in one basket, and should be aggressively pursuing all of them in the hopes that at least one will pan out.
There is a big Initiative with that goal, desertec. But unfortunately it got very quiet around them.
For renewables not.
And the storage is a problem yes, but not one that requires miracles. Just investing.
(And there are much more technologys around than just batteries. Air-pressure storages for example. Or hydrogen. Or different H2 based ones like Methan, etc. or artifical lakes for water pump storage, etc.)
But to make Fusion work any time soon, there are indeed miracles required. If it works one day, nice. But I would not bet on it, to solve any problems we have today.
Renewable storage and transmission requires some breakthroughs. Maybe we could do it Soon, maybe in decades.
Fission requires political will, no miracles, no breakthroughs. We could have been doing it last year.
Fusion is not possible now. As climate change is happening now, any delay in transitioning to clean and available solutions is purely ideology driven.
The wider it is avaiable, the easier it is for certain groups to get more dangerous.
But I don't know much about the topic. Short google search shows that your claims are not proven and at least controversal:
https://theecologist.org/2017/oct/03/james-hansens-generatio...
Proliferation resistance is trickier, and not all gen IV designs focus here. There are a couple of areas of attention here. The first, and probably more mature development-wise, are alternative fuel cycles like the Thorium fuel cycle that don't produce easily usable fissile material out the other end (and do produce a bunch of U232, which in addition to being non-fissile is also difficult to steal because it's super-dangerous to handle). Secondly, there are designs that breed and then immediately burn fuel in situ without reprocessing, such that there's no point during which the fissile material exists outside the reactor to be stolen. I don't think any of this class have actually been built yet, but the Traveling Wave design is probably furthest along, and TerraPower is building one of those in China with a target completion date of ~2025.
Two important caveats though: these are "proilferation-resistant" in the sense that fuel would be hard for non-state actors to steal; state actors are another concern as that article points out, but they also don't really need to breed fuel, and can just enrich uranium directly without that much difficulty, as Iran and North Korea have both demonstrated, if they're willing to pay for it. At this point the physics are very well-understood, so this is a problem in need of diplomatic solutions more than technological ones. And second, the focus here is on material for fission weapons. I don't think any nuclear technology has good defenses against using material for dirty bombs.
All of that said, I'd still stand by my original point that newer designs are well-understood and dramatically better in these respects than most currently operating plants, and are only not being built (at least in the US and Europe) for political reasons.
Well your original point was written a bit more absolute...
With this I go along. And as I said, I also prefer fission as the short term solution. But only as a transition on the way to fully renewable (or allmost full, I am for pragmatism). As there are just many problem involved with nuclear power, like danger and waste and the need for uranium, etc. that you would not have with solar energy. So this is the goal for me, fission power only as a way to get there or where there are not really other options. (submarines, spacemissions, etc.)
https://en.wikipedia.org/wiki/AVR_reactor
But there were incidents when the plant was basically out of control. Worse, the design is based on graphite spheres which contain the fuel. That is only safe as long as the spheres in the hot reactor do not come into contact with air, which will cause them to burn, or with water, which will form hydrogenium-oxygen mixtures. Burning graphite was both a main ingredient in the Windscale fire, and in the Chernobyl disaster. There were also important mechanical problems with the spheres. In retrospect, these claims for passive security were unwarranted and the plant was dangerous. With the experience from the AVR, one can also say, that the nuclear industry is not transparent at all about safety problems. Also, it is not only very hard to make such plants inherently safe, if this also very expensive. Unfortunately, this conflicts with the goal of every company, which is to make a profit which is as large as possible.
https://en.wikipedia.org/wiki/Westinghouse_Electric_Company#...
Assuming you are in the US, you forgot how close the Three Miles Island accident was to cause an US version of Chernobyl in the East coast.
For the critical issue of tritium breeding, it is more like non-existing technology. What is meant to bridge the gap between today's plasma physics experiments and working power plants includes a large amount of fairy dust. It is not a valid comparison to compare that against the advantages and disadvantages of the existing renewable sources. Even the Pelamis wave power plant (which was discontinued for whatever reasons) is far far closer to large-scale energy generation than any nuclear fusion process could be in the next 50 years.
Even for extremely high carbon reductions (95% on 1990) the best models I've seen consider transmission lines and sector coupling considerably cheaper. And these models make very aggressive assumptions on the fall of battery prices. E.g.:
https://arxiv.org/pdf/1801.05290.pdf
Edit: The thing to look at is figure 11. on page 16. It gives a policy trade off. Given political limits on the amount of transmission grid extension (x axis) what is the cost of the economically optimal mix of technologies (y axis). Left graph shows sector coupling, right graph shows sector coupling. The second graph almost completely eliminates the need for battery storage.
Nuclear is not in this mix, partly because this is exploring policy constraints on transmission capacity in the context of Europe (and nuclear is pretty much a non-starter politically) but it clearly shows that the idea that large amounts of battery are inevitable is outdated.
I'll leave you with a quote from the conclusions:
"The All-Flex-Central scenario with optimal transmission costs just 13% more than today’s system [even when excluding health benefits]"
https://www.sciencedirect.com/science/article/pii/S136403211...
Which I find considerably more convincing, given that it addresses the concerns raised in detail and gives a much wider overview of the literature and ideas around.
In my view the response article actually demonstrates that Heard et.al. had an ideological motivated conclusion they wanted to get to and chose evaluation criteria to fit their desired outcome.
Yes, I am. I'm not particularly convinced by it, it seems to largely repeat the same claims made previously. Anyway, there's a preliminary informal response to that at http://4thgeneration.energy/response-to-brown/
> In my view the response article actually demonstrates that Heard et.al. had an ideological motivated conclusion they wanted to get to and chose evaluation criteria to fit their desired outcome.
Clearly Heard is a nuclear advocate, yes, but AFAICT the criteria they chose aren't unreasonable. OTOH it's hard to argue Jacobson, Breuer, Brown et al. aren't pushing an ideology either, since they claim to be motivated by decarbonizing the energy supply, yet they are excluding one of the very few sources which, historically, has provided large-scale low-carbon energy.
> Despite the sustained and growing cost-competitiveness of certain Alternative Energy technologies, advanced economies will require diverse generation fleets to meet baseload generation needs for the foreseeable future
with specific numbers in the actual report.
It's easy enough to focus on Europe or the Americas where the rich have the comparable luxury of being able to overpay for generation if the political will is there, but the overwhelming majority of new generation capacity brought online globally in the next century won't be in these places, it will be in Asia, Africa, and South America, as these countries work towards developmental parity with the West. We need to come up with solutions that aren't just possible, but cheap, and deployable in places that are starting from basically nothing in terms of modern grid infrastructure, and where hyper-inefficient diesel generation is currently the norm, to the extent that electricity is broadly available at all (as is the case in large parts of Africa in particular today).
Again: this isn't to say that renewables can't work, or that any other particular technology will or won't be the solution. We just don't know yet, both in terms of feasibility and economics.
Also, once you go into the developing world context a lot of things change. What is difficult and expensive in the European context is to guarantee the last few hours of electricity a year. If you can take an area that has a few hours of electricity a week to that point, you have a massive win already. Plus you can build sector coupling in from the beginning.
In a green field scenario you _really_ want wind/solar as a decentral bootstrapping technology that scales down, that can get you a really long way.
Bangladesh has >5 million solar home systems installed. That's a Norway or a Denmark population running 100% on decentral off-grid solar.
Edit:
An important point here is to be aware of time horizons. A study looking at a 2025 or a 2030 system looks very different from one that looks at a 2050 system. If the foreseeable future means the next ten years, then sure.
Renewable energy sources are already cheaper than traditional nuclear energy, in many parts of the world already cheaper than fossil sources, and rapidly getting even cheaper:
https://en.wikipedia.org/wiki/Grid_parity
And at the same time, Westinghouse had to file for chaper 11 bankruptcy because ... well, nuclear power does not seem to be so economical at all.
As an interesting side note, both nuclear power as well as renewable energy sources have the cost structure that almost all investments are up-front, while the relative amount of running costs is very small. Because in a market system, the marginal cost of production per unit determines the market price, and the market price is therefore close to zero, both technologies have the problem that they actually need subsidies and incentives to be created. In other words, while renewable power sources definitively need incentives, nuclear power also can't exist without huge subsidies.
Again: only when looking at the cost of generation alone. It's more expensive if you factor in the storage and/or long-distance transmission necessary for high utilization (even the study I'm responding to says so, though by a smaller amount than I've seen elsewhere -- ~13%).
> well, nuclear power does not seem to be so economical at all.
Nuclear power isn't economical under the current regulatory environment and set of political realities. There's no fundamental reason that that need be the case. More people die from wind and solar per year than nuclear (mostly installers and technicians falling off of things), and obviously both are dwarfed by orders of magnitude by coal once externalities are factored in. If we were as risk-averse with those sources as we are with nuclear, they would be expensive too. Coupled with the slowness of construction eliminating economies of scale or effective market competition, and you don't have a great situation.
https://www.businessgreen.com/bg/news/3029756/scottish-wind-...
And it works pretty well. The last power failure I can remember which was in any way related to wind energy was in 2006:
https://en.wikipedia.org/wiki/2006_European_blackout
(but wind energy was not the primary cause, the main cause was bad planning)
What happens at large scale is that the fluctuations induced by variable wind speeds smooth out over larger regions. And having a large, interconnected grid is usually much cheaper than battery storage.
What would also help is diversification. In Scotland, there was a fascinating project to generate electricity from wave power, the Pelamis wave power converter. It had working 500 kW installation but was scrapped then.
https://www.youtube.com/watch?v=JYzocwUfpNg
Fortunately, some Chinese companies seem to have copied the design:
http://www.dailymail.co.uk/news/article-3832029/Chinese-wave...
> If we were as risk-averse with those sources as we are with nuclear, they would be expensive too.
A wind power plant blowing up will not cause half of Europe to be contaminated with huge costs to agriculture, like it happened in 1986. You must also not forgot the extreme health costs of uranium mining.
https://www.ipp.mpg.de/15144/zuendbedingungen
Unclear where in that shaded region the new result lies.
Based on this information, I conclude that nuclear fusion is probably only about 20 years away.
Down from the '25 years away' it has been for the last 50. I'm not being facetious, I actually think that's huge win and we should all be happy.
Edit: Addendum: I vividly remember images with visualization results for numerical simulations on the reactor vessel shape for Wendelstein 7-X. That was back in 1992 or so. This just shows how long this experiment was in the making.
https://hardware.slashdot.org/story/12/04/11/0435231/mit-fus...
It's just disrespectful to all the brilliant physicists and engineers who work on the topic to belittle their efforts like that.
That's a surprisingly small number for the impact nuclear fusion could make. I wonder why we haven't seen any billionaires taking up the challenge, even though this might be more impactful than space tourism or people on mars.
Note that SpaceX is set up as a business, not a charity; Musk may talk a lot about Mars but that's not really where the money goes.
By contrast, fusion will only be a scientific research project for many years and many billions.
It's like Manhattan project, you can do it if you want it bad enough.
The basic problem is that heat transfer limits guarantee that fusion reactors will be big and expensive (meaning: power density an order of magnitude worse than a fission reactor core, and probably worse than that.)
The core of a PWR fission reactor that one can build today has a power density of 100 MW per cubic meter. The power density of ITER (dividing the gross fusion power by the volume inside the cryostat) is 0.05 MW per cubice meter, 2000x worse. Other fusion designs aren't quite as ludicrous, but will still be much worse than fission.
The problem is that heat in the PWR has to get out of fuel rods that are 1 cm in diameter. The heat in a fusion reactor has to get out of a plasma vessel that is meters in diameter. The ratio of surface area/volume is orders of magnitude higher for the fission reactor.
I understand that there is a level of experimentation and R&D that is guaranteed not to generate viable results but at some point you need to trim the fat, get everyone moving in one direction etc. This grand project has been going on for over 50 years at this point, It seems like we should at least have one design that everyone should be focusing on. If they had real, defined commercial goals (even if they miss the goals) it might be easier to secure funding because your average politician would see the benefit to them.
I'm not a nuclear engineer so take that all with a grain of salt.
As they say - if we knew what we were doing it wouldn't be research.
the other rapid development scenario would be some sort of fusion arms race between asia (ch/kr/jp) and the rest of developed world.
On which reference frame?
If you spare half an hour to Google, you can find out what we want collectively;
1) Find global spending on fusion research and note it down.
2) Pick some other stuff to compare it to. Like global annual military budget. Annual profits of the largest companies and what they sell to make it. Or how much do we spend on 'entertainment'. Or popularity of Kardashians(given even I know that f#cking name...) or whatever.
You'll be quick to realize that the fusion is sitting in the corner, waiting for us to "want to have it".
It makes me feel depressed to see on every fusion article in 2018, there is a paragraph allocated to explain how fusion is different from fission and how it is not... basically not a bomb.
The topic feels home in HN, but I do not know if you ever brought up fusion in a talk with family or even among your young friend circle. I certainly have engaged in that experiment myself. People do not even know what the heck is fusion, let alone lobbying to fund it with tax money. In this state, I say, the advancement on fusion is rather stellar, I congratulate wholeheartedly anyone putting sweat and money in it to bring things to this level.
Rather, funding for fusion is low because fusion is marginal.
The money would be there if the technology warranted it. But examined closely, fusion doesn't appear promising, so people close their checkbooks.