As a newbie in nuclear fusion, this explanation is the most interesting part:
> Lee Margetts at the University of Manchester, UK, says that the physics of fusion reactors is becoming well understood, but that there are technical hurdles to overcome before a working power plant can be built. Part of that will be developing methods to withdraw heat from the reactor and use it to generate electrical current.
> “It’s not physics, it’s engineering,” he says. “If you just think about this from the point of view of a gas-fired or a coal-fired power station, if you didn’t have anything to take the heat away, then the people operating it would say ‘we have to switch it off because it gets too hot and it will melt the power station’, and that’s exactly the situation here.”
And the engineering here is very problematic. Indeed, the issue mentioned may be a showstopper for DT fusion.
The problem is limits on power/area through the wall of the reactor. Because all the produced energy has to go through the wall, and because the area of the wall grows as r^2, the volumetric power density of a DT reactor (that doesn't exceed the power/area limit on the wall) must decline with increasing size.
This leads to DT fusion reactors having horrible volumetric power density. ITER, for example, has a volumetric gross fusion power density of 0.05 MW/m^3. The 2014 ARC design, 0.5 MW/m^3. A PWR's reactor vessel? 20 MW/m^3.
On the other hand, basically every complicated bit of engineering on the PWR is due to the fact that it does have such a high volumetric power density. A PWR is basically a fancy (very fancy) pressure vessel which is cheap (in relative terms) and then parallel redundant cooling systems and containment buildings because dealing with such high power density is hard. Right after shutdown, the power density from decay heat is still 1.3MW/m3 and dealing with that decay heat in all currently conceived circumstances is where all the money goes.
Essentially. The CO2 cooled AGR has much lower power density and was thought by its designers to be a much superior design to water cooling for safety and cost reasons.
It turns out, definitely not on cost grounds and the AGRs are all reaching technical end of life a few years after their original rated lives whereas light water reactors are getting life extensions basically everywhere for decades beyond that.
Light water thermal reactors are the worst kind of nuclear reactor except for all the other ones which have been built.
No, it does not have to be high within the core. A reactor can be operated at a low power level. This is not like a fire that goes out if the flame is too weak.
The problem with that is that cores are very expensive. They require 100s of kgs of enriched uranium. If you run them at half power, you need twice as many and your cost goes up dramatically.
What's wrong with pulling the energy from the magnetic containment system?
We already are using the magnetic containment system to redirect charged particles in the plasma back into the plasma. If we do so less forcefully than they were heading out, but still enough to stop them from leaving, we can convert particle velocity directly into electricity (AC with a relatively linearly decreasing frequency distribution, I think). This also has the effect of cooling the plasma (since temperature is related to average particle velocity).
The challenges I see here are:
1) The faster the control system, the more efficient it is at extracting energy -- it can extract the energy of higher frequency components.
2) You may need a very large magnetic field (larger than needed for containment) to make this practical
3) Coil geometry and efficiency becomes critical.
80% of the fusion energy from DT fusion comes out in fast neutrons, which ignore magnetic fields.
The other 20% has to come out somewhere. If it could be converted to electrical energy maybe it could avoid surfaces (Helion plans to do this, with DD + D3He) but when it's just 20% of the output that doesn't buy you much.
And DT fusion neutrons are even worse than fission neutrons, since they are much more energetic (and because only 3% of the energy in a fission reactor is released in neutrons.) The 14 MeV DT neutrons are above the threshold for (n,p) and (n,alpha) reactions, which cause gas to accumulate in reactor materials. The helium produced by (n,alpha) reactions accumulates in tiny bubbles that would reach extreme pressures and rip materials apart.
Well, no, not completely solving it. There are limits to neutron fluence materials will withstand. Even neutron heating can't be too nonuniform in the blanket.
I see there the same relationship. If you have a fixed surface temperature then you have to decrease volumetric intensity when increasing volume (the ITER and further case). If you have a fixed volumetric intensity then increasing volume results in higher energy flux per unit of surface and thus results in surface temperature increase to increase the intensity (T^4) of radiation away of that energy - that is the Sun case.
I like this term ‘volumetric intensity’. I don’t know how common the term is, (some cursory googling just turned up one fusion paper from the 1990’s)) but it would make appreciating Gauss’s Law in E+M much easier from the outset than the typical surface integral calculus typically used to introduce the subject.
The overwhelming majority of the sun is made up of hydrogen, and specifically the isotope protium, which is just a proton with no neutrons.
When two protons collide, the overwhelming majority of the time they just bounce off eachother. The diproton (a particle with two protons and no neutrons) isn't just unstable, it's basically forbidden.
However there is an incredibly rare chance that when two protons come together instead of just splitting up, one of the protons will turn into a neutron, thus producing deuterium, the hydrogen isotope with one proton and one neutron. Deuterium is much more capable of fusing.
Now when I say incredibly rare, I mean like "unlikely to happen to any given hydrogen atom over the lifetime of a star" rare. Luckily stars are big, and dense, and thus contain a lot of hydrogen atoms hitting each other very frequently. Thus you have a slow but consistent burn of hydrogen over billions of years. Once it's converted to deuterium, it fuses within about 1 second. This produces helium-3 (2 protons, 1 neutron), which is also capable of fusion, but not with the abundant protium[1], so it takes some time to find something to fuse with. A helium-3 will on average survive about 200 years before it fuses, which is still pretty short as far as the sun is concerned.
This slow burn means that within any given chunk of the sun there aren't that many fusion events occurring. Even in the deepest core of the sun, power densities never exceed 275 Watts per cubic meter. By comparison, compost releases about 7000 Watts per cubic meter at its peak decay rate and even over longer time periods averages around 600 Watts per cubic meter. Human metabolism releases about 1600 Watts per cubic meter. But since the sun is so immensely large, it has a lot of cubic meters of fusing hydrogen. Overall, it's producing 3.8x10^26 Watts.
[1] Actually helium-3 can (at least in theory) fuse with a proton, it's just extremely rare. In fact it is so rare we've never actually observed it.
It should be noted that in stars slightly larger than the Sun, fusion energy production becomes dominated by the CNO cycle, which has a much stronger temperature dependence than the PP cycle.
Euh ? In a few paragraph you basically say that even if fusion works, getting energy out of it will be almost impossible in a meaningful way (you're showing order of magnitudes of difference). But, don't the engineers at ITER and other facilities have already though about that ? It'd be very irresponsible to start such a project knowing in the beginning that, at the end, there's a high chance of failure...
That's a good question. Why do fusion people not pay attention to this issue?
The answer is some do. And those people tend to get frustrated and quit the field (or, if they are lucky, notice the problem early and never go into fusion at all.) Lidsky is a famous example; Pfirsch and Schmitter in Europe are others. Others bottle up their objections and only let them out as they retire.
The more common coping mechanism is just to assume someone else is going to solve it and not pay too much attention while working on other issues. It helps to focus on physics issues -- which are very interesting, after all -- and tell yourself that this problem is "just engineering" and can't be too hard to solve, in comparison, and that anyway telling yourself it's bad to think about it before the physics is nailed down (which is wrong, but lets you stop worrying that you've wasted your career.)
As for ITER specifically: ITER is costing > $20B for something that could produce maybe 400 MW gross fusion power (and isn't engineered to produce tritium, electrical power, or to survive more that a few weeks at full power). Industrial levels of denial are needed to tell oneself something like that is on a trajectory to relevance.
Perhaps an even better question is: why are people funding DT fusion? For governments, I think it's because in many cases the purpose of government research funding isn't to solve problems, it's to be seen working toward solutions in the distant future (and that perception can be achieved even if there is no actual chance of success, if the public is sufficiently unaware, which it is.) For venture capital I'm not clear what the explanation is. Spinoff technologies like high Tc superconducting magnets, maybe?
And yet history has usually proven them right to have this kind of attitude. The first instance of everything is ludicrously expensive and commercially non-viable as it is. Then it gets cheaper and easier and eventually commonplace and boring.
It's often the case that the commercial applications for a technology are not apparent to the researchers doing the research. They're focusing on the science/engineering challenges. Later, sometimes much later, it becomes part of an economically-viable product or service.
Sure, for successful technologies, naysayers were wrong. But almost all technologies (sufficiently finely defined) fail. The naysayers are usually right.
compare it to the space program. that didn't really have any directly useable goal. but the technology produced in the process is used everywhere.
DT fusion may or may not work. maybe the problems may get solved some day, maybe not. we'll never know if we don't try. and the technology we get in the process is valueable regardless.
Spinoff technologies from space are another "sell the perception" thing. There's a lot of BS there. But as long as the public swallows it, it works to justify the program.
Even if you choose to ignore all that has come from it.. Space is quite possibly the most important thing we can be investing time, money and research into in terms of future advancement and sustainability of the human race.
Tell me: what exactly would have been worse if the US had never had a manned space program? The whole thing feels like a vanity project, not something that delivered value. It could all have been delayed while launchers got cheaper without loss, as far as I can tell.
Kapton is a great example of the spinoff racket. You take something that was USED in the space program (but not invented by NASA; Kapton came from Dupont), you carefully blur the story, and now you claim it was the RESULT of the space program. It doesn't help that the marketing of these things often used the space program, calling them "Space Age", trying to mooch off the glamour Apollo had at the time. Integrated circuits, teflon, velcro, glass ceramics are other examples.
Moonshot programs are what create demand for the sort of R&D that Dupont did to bring kapton to market.
Polyimides date back to 1902, but you couldn't buy anything like kapton tape before the space programs created a need for such materials and capital to build out plant for them.
I promise you there was enormous demand for products to stimulate R&D outside of NASA. Orders of magnitude more. That's why technology was leaping ahead even before NASA existed, and even after NASA's budget shrank. It's also why all that new technology came out of countries without manned space programs.
To make a valid spinoff argument, you have to show that the particular technology would not have come about without NASA. That sort of contrafactual, alt-history argument is really hard to do. It's why alt history has such a bad name in history circles -- you can't really show anything. This means all spinoff claims are dubious. Not only are they presented without the necessary evidence, it's difficult to see how the evidence ever could be acquired.
No, it's just saying they we haven't really done the serious work and engineering yet required to have an answer for this yet. Remember, we still aren't even sure which type of reactor design will work/be used. These are the type of problems that we can't seriously deal with until we have at least the basics down.
This is the "ignore the engineering until we get the physics to work" mantra. There are generic problems that can kill DT fusion independent of the physics, and these need to be investigated to see if a solution is even plausible. If one is not, then continuing to invest in the physics for DT fusion reactors is a complete waste of resources.
ITER is a technology demonstrator intended to show sustainable fusion. The amount of power it generates is lesser than it will require to operate. The physicist Sabine Hossenfelder has a great video on her YouTube channel that I highly recommend watching.
It’s also a large international collaboration, a study on the engineering challenge involved with building a fusion reactor and a way to improve the technological know how of some participants.
The truth of ITER is that the way the work is shared slow down the project considerably. It would have been much faster as a collaboration between the three or four countries in the world with actual hands on experience on large scale reactor building but ITER is first and foremost a political thing.
The cost of the reactor vessel is directly related to how large it is (and how complex). The larger object uses more material, has more parts, has more joints between parts. Its reliability decreases along with its size, increasing cost even more (as all those parts and joints must now themselves have lower failure rates to maintain a given system failure rate.)
This is an incredibly naive bordering on "probably just dishonesty masquerading as ignorance" thing to say.
Of course cost goes up fairly linearly with size. More rebar, more pipes, more materials, more diesel in the bulldozer, more man hours, more welding rods, more welds to inspect, more money.
But there are also a ton of one per instance overhead paper pushing costs, especially with something as onerously regulated as nuclear that are a large fraction of overall costs and will be roughly the same whether you're building a 1kw facility or a 1gw facility. All of that has to be amortized over your reactor. So if you build a small reactor each dollar of reactor might have $10 of overhead it needs to amortize. If you build a big one each dollar of reactor might only have another $1 it needs to amortize.
Of course there's a sweet spot before the reactor is so massive the part count grows so high that the MBTF starts getting you. That sweet spot also has a low end below which the fixed regulatory and palm greasing costs are so high that your tiny reactor can never hope to pay them back in it's lifetime.
The argument being made doesn't require a linear relationship between size and cost. Remember, we're looking at two objects with the SAME power output, one much larger than the other.
The MTBF/MTTR of fusion is actually looking like an extremely serious problem. Fission reactors can operate with 2% of their fuel rods leaking. A single leak through the vacuum boundary of a fusion reactor will contaminate the plasma and shut things down. And repairs on a fusion reactor are going to be much more difficult than simply replacing fuel rods. The innards of any fusion reactor will be so radioactive that hands-on maintenance will be impossible.
I specifically said “at full tilt” to try and avoid an unnecessary debate about capacity factors, but I guess someone couldn’t resist.
Would it have helped if I had compared the output of this proposed fusion reactor against a large base load biomass station like Drax (UK, 3900 MW) instead ? (0.03%)
An idle thought I had related to this is that the real trick to scaling up fusion power may be to not try and extract the energy "through the walls", as you said.
You know how they tell you to "visualise success" because you need to know what it looks like to aim for it?
Along those lines I was visualising what it would look like if someone like Elon Musk was on YouTube showing off some sort of future fusion reactor that's "not just a piece of lab equipment", but something that would be dramatically better than any extant fission reactor or similar technology.
I visualised it as an enormous stationary rocket engine, where cooling water was pumped through a relatively narrow (~50cm) "reactor tube". The water needs leave a hole in the middle for the fusion fuel gases. The hole is achieved by imparting a rotation to the water, so it "spins out" to the sides. Fusion would occur not throughout a large volume, but at a small number of "pinch points" along the axis set up using powerful magnets -- and not necessarily superconducting magnets! To get sufficient current through the coils, the charged exhaust is allowed to expand through a magnetic "rocket engine bell", producing moving (and accelerating) electric charges. This current is recirculated through the engine to provide the enormous magnetic field strengths required, via thick copper conductors aggressively cooled with water.
Essentially it would be a magneto-hydrodynamic-fusion jet engine, using fields instead of impellers to achieve compression, expansion, and energy recovery to run the whole cycle.
The bulk of the energy would be in the super-heated steam produced, which could be used as in traditional power plants, or used as a bone-fide rocket in space.
Obviously there would be "challenges" to making this work, to put it mildly!
But consider that with the kind of computer power we can throw at modelling physics these days, it may be possible to use "topology optimisation" style tricks to figure out the required geometry of the parts to achieve the conditions required for fusion while staying within material design constraints.
If you ask me, a Manhattan-project style attempt at something like this would be a better way to "waste money" than yet another aircraft carrier, or whatever...
I like the visualization. There’s too many hyperrationalist over analytical minds here to appreciate it.
Tesla could imagine his inventions and leave them running in his imagination and if they still worked a few weeks later he knew it would work in the real world. Allegedly anyway.
Your visualization reminds me of some geometry I’ve seen and studied in ancient Vedic architecture/temples. There is this cavern with what looks like something is poured into in a cylindrical room, with holes in various places. The Egyptian story is also peculiar as some areas also complement this visualization. Especially the granite statue that was “never completed” and has a hole on its side next to a trench and is quite long vertically. Probably for water, but either way just reminded me of what you said. I personally think you’re onto something with the pinch.
> “You know how they tell you to "visualise success" because you need to know what it looks like to aim for it?
Along those lines I was visualising what it would look like if someone like Elon Musk was on YouTube showing off some sort of future fusion reactor that's "not just a piece of lab equipment"”
The money went to his head, he’s not the innovator he was, now he’s just a billionaire that got bored with Mars and wants to own social media instead.
I do wonder how much of an innovator he actually is on his own. He's known for his time at Paypal, but he was only there for 6 months, during which his big effort was to switch their Unix servers to Windows NT. He bought his way into Tesla.
And speaking as somebody who used to work at Twitter in anti-abuse engineering, I can confidently say that he displays a very poor understanding of the problems he's in theory buying Twitter to solve. And that's before we even get to his terribly handled attempt to buy the company, which could literally cost him billions to get out of, or billions more if he's forced to buy and run the company.
He bought his way into Tesla very early on, oversaw the design of the first Roadster, and took over as CEO before the first Roadster launched. He’s also been at SpaceX from the start and has apparently been involved at a technical level from the start.
I've had some bosses/clients that were "involved at a technical level". Let's just say that their being "involved" in a successful project is not a perfect indicator that they are particularly skilled innovators.
For example, consider Steve Jobs. He was hugely involved, but not particularly technical. He was very strong at marketing, and also very strong at understanding certain kinds of user need and then berating people until he got something that met his high standards.
Yes, he was definitely fired after a short stint. Stories on why don't totally line up for me, but incompetence is one of the explanations, and I feel like it's pretty hard to get fired from a CEO spot that quickly.
All the success he has had comes from lots of bucks to start from, and lucky hires. You can tell from all his obvious duds, and the idiotic things he says whenever he goes off-script.
Gwynne Shotwell probably deserves the credit for SpaceX, and probably all of that for her personnel actions.
And yet every biography and early employee of SpaceX will say otherwise about Musk's importance to the success of the company. Shotwell however does not get enough credit in the eye of the general public (she's quite popular among people who keep up with SpaceX), Musk has always emphasized how important she was/is for securing contracts for them and keeping engineering from going too wild.
Like when Musk wanted to cancel Falcon Heavy because it was turning out to be much more challenging than expected, was a dead end in terms of Mars ambitions and Falcon 9 had improved enough that it basically took most of the launches FH had been intended for, but she pushed for them to work on it anyway because IIRC they had enough potential customers lined up to go forward with it.
One, saying that he was important to the success of the company is not the same thing as saying he's a particularly good technical innovator on his own. Take Steve Jobs as an example: important to the success of the Mac, but as a visionary who was also enough of an asshole that he got fired.
Two, what people will say about an egotistical, litigious billionaire is limited. Even more so when he controls their income and/or they still hold a lot of illiquid stock. Note, for example, that Musk fired 5 people just for internal criticism: https://www.reuters.com/technology/spacex-fires-employees-in...
I saw a lot more negative accounts about Steve Jobs starting a few years after his death than I did in the years leading up to it. I expect to see something similar with Musk.
I'm not arguing that he's flawless, I just get annoyed when people try to suggest that he simply lucked out in making the right hiring decisions in an industry where "How do you become a millionaire in aerospace? Start with a billion" was (and to an extent still is) a common adage. I feel that boiling it down to luck is pretty insulting to all the work people have put into putting SpaceX a decade or two ahead of the rest of the world.
That said, the people who I'm referring to aren't really in the position you describe. Most of them have either retired or are doing their own thing and having been early members of SpaceX are pretty much the best rocket engineers around (eg Tom Mueller), so I doubt that they have any concerns about their income.
Musk appears to at least be able to keep up with technical details enough to be able to discuss them with technically oriented YouTubers. So while it's hard to say if he's a particularly good technical innovator on his own, he's capable of understanding various design decisions, discussing tradeoffs, questioning assumptions and thus appropriately leading his engineers. I believe that is a big aspect of why SpaceX has been so successful. Shotwell also has an engineering background, so the same probably goes for her ability to balance business and technical considerations.
Nobody is suggesting that he "simply" lucked out. But this part makes no sense: "I feel that boiling it down to luck is pretty insulting to all the work people have put into putting SpaceX a decade or two ahead of the rest of the world."
One, there's no conflict between believing that Musk was lucky and other people worked hard. Two, if the hard labor of "the best rocket engineers around" was what made SpaceX successful, then that helps prove the point that Musk's reputation as a genius technical innovator is perhaps overblown.
> I doubt that they have any concerns about their income.
That is spoken like somebody who has never been through a lawsuit. Or incurred the disfavor of somebody powerful. You can bet that every one of the people who has worked for Musk has signed agreements that would let him brutalize them in court for years. Lawsuits, even ones you are confident of winning, are incredibly stressful and draining. If Musk is happy to fire people just for criticizing him privately, there's no reason to think he wouldn't sue somebody for publicly making him look like an asshole. So as with Jobs, they tell the positive stories loudly and the negative ones quietly or not at all.
> Musk appears to at least be able to keep up with technical details enough to be able to discuss them with technically oriented YouTubers.
Oh dang, YouTubers? Well then.
As a person who has spent years doing anti-abuse work, including at Twitter, I can tell you that what he's been saying about Twitter's issues has a plausible gloss but is both ignorant and wrongheaded. Musk is happy to pretend to be an expert genius when he doesn't know shit. That gets lots of Twitter/YouTube likes, but that's not what matters when running a real business.
Or we could look at his attempts to automate the Tesla factories. Tesla almost went bankrupt because this nominal genius vastly overestimated what was possible, ignoring decades of manufacturing experience in favor of huffing his own... vapors. This was a multi-billion dollar error.
So is it possible that he was helpful technically at SpaceX? Sure. But it's also possible that the difference at SpaceX is that he had a stronger staff that kept him at bay while they did their "best rocket engineers" thing.
And yet there have only been 2 commercial launches of Falcon Heavy launches. There are more on the manifest but I wonder how many of those would be served by Starship, especially if the effort put into FH had been used to pull forward Starship.
There should have been a few more by now but they keep getting delayed. Overall though, I think FH might have been made worth developing because of Europa Clipper, NSSL launches and Dragon XL despite not necessarily making back R&D yet. Falcon Heavy is easier for risk averse government agencies to choose.
Remember that Lunar Starship winning HLS was not at all expected, most people assumed NASA would consider it too radical, going for the other more conservative proposals.
In that environment, FH offers best in the world capability at low costs while still being pretty close to what people (especially uninformed politicians and bureaucrats) think of as a rocket.
I don’t understand the discussion people are having here.
Musk is demonstrably good at identifying interesting problem spaces, finding things a new company could do better in them, convincing people who have capital to invest, building, growing and leading a team able to successfully tackle the challenge and communicating with the outside world in a way generating a tone of interest and buy in. In short, he is very good at his job which is being a CEO. Musk is not working in engineering.
Someone in this discussion said he lucked out on the team at SpaceX. That’s a gross misunderstanding of why he is good. The managing team of SpaceX and especially Shotwell is Musk great achievement.
Gwynne absolutely is the unsung hero. (Though in truth I think more spacex fans know about her importance than it would seem. Not sure about the outside world.)
Oh yeah totally? Just luck! Wow, what a lucky man right? Probabilistically nearly impossible but hey? Statistically it’s still possible as a fluke. Super rational thinking that’s applicable to increasingly well understood mental modes of reality. Bravo!
Probabilistically it's not that implausible. Musk has what, one successful company he founded himself - SpaceX? The hyperloop is flop, the boring company is a flop too, so is SolarCity, and the sucessful one came with a lot of exceptionally great hires. I'd say empirically his skill at hiring competent people that are willing to work hard is higher than average, while his engineering skills don't seem to be particularly special.
Yeah, many people don't get how much the world is tilted in favor of the rich. Look at Jared Kushner's ability to keep failing upwards, for example.
Musk is an amazing hype man; the way he talked Tesla's stock price into the stratosphere gave him incredibly cheap capital. And he was correct in thinking that electric cars were a coming thing that the major auto companies were sleeping on, so he gets points for insight. But now that the majors are in the game, over the next decade we'll see how much Tesla's built on skill vs luck.
> I'd say empirically his skill at hiring competent people that are willing to work hard is higher than average…
He wasn’t competent at hiring the right people, his ideas in the beginning looked amazing and drove the best minds to apply there. Now they’re leaving…
Right right, "they're leaving", exactly who is they and how mow many is that?
> Tesla revealed in its 10-K filing with the SEC that it employed 99,290 employees as of December 31, 2021. This is a substantial increase from how many people the company had employed at the end of 2020. Tesla reported an employee headcount of 70,757 people at the end of 2020.
Also, it's often that those who leave, should leave, as there is a mismatch.
To generalize and extrapolate a minority percentage of misfits that you clearly are focusing on is quite the error.
Let's see Tesla's growth year over year:
Tesla revenue for the quarter ending June 30, 2022 was $16.934B, a 41.61% increase year-over-year.
Tesla revenue for the twelve months ending June 30, 2022 was $67.166B, a 60.45% increase year-over-year.
Tesla annual revenue for 2021 was $53.823B, a 70.67% increase from 2020.
Tesla annual revenue for 2020 was $31.536B, a 28.31% increase from 2019.
Tesla annual revenue for 2019 was $24.578B, a 14.52% increase from 2018.
Yep, sounds like you know what you're talking about.
Could the part of the plasma be diverted into heat exchanger and back into the stream somehow ? I guess problem there would be having one that doesn't just melt away. Maybe shoving water into it so it flash-evaporate and we're back to the ye olde steam?
Doesn't help much in DT fusion, since 80% of the produced energy immediately leaves the plasma in neutrons.
For non-DT fusion, there are alternatives, which is why I was explicitly saying "DT" in the critical comments. This is also why I consider Helion's the least dubious fusion effort out there today.
Stellarators do not solve the problem, they would heat evenly too. (TRIZ drums) What is needed is some sort of "abblative" migrating system, that leaves behind its heat to harvest, while the fusion process travels onwards, stressing other rejuvinated parts of the containement vessel. Basically, a series of reactors, pumping the plasma in circles once ignited.
Or we dump the whole idea, call it a day and pump all the money into musks larange solar power plant. Which ironically is a fusion containement in the distance power scheme. Which then will have problem with solar winds. Funny how the small plant mirrors the problems of the larger soon to be plant.
Very wild idea: gaining electricity by induction instead heat since its charged matter.. but I know it doesnt make sense, as it only yields the kinetic energy which has too high entropy to be yieldable (no directed movement)..
Can the wall be baffled like an air filter to increase area? I get that the flux through it in total at a given radius would be the same, but is the heat being pulled out through plumbing or something?
That only works to increase the surface area in materials with poor heat conduction, such as an aluminium-air interface on an air-cooled motor (air is a poor conductor of heat). Poor heat conduction is not the problem here.
Actually, heat conduction is something of a problem here in at least one way.
Some of the energy going to the first wall impinges on the surface of the first wall and becomes heat there (photons from the plasma, direct impact of charged particles from the plasma on the surface). This must be conducted through a vacuum-tight barrier layer before reaching a coolant channel. The ability of this layer to dissipate heat (before stress from differential thermal expansion of the inner hot/outer cold parts cause it to fail) is proportional to its thermal conductivity.
For ITER, the relevant layer of the first wall armor is a CuCrZr alloy. However, this alloy is unsuitable for use in a production DT reactor due to activation. For DEMO, this layer is going to have to be made of RAFM steel, which has an order of magnitude lower thermal conductivity.
This problem MIGHT be solvable with a liquid first wall (flowing liquid lithium), but it's not clear all the penetrations of a fusion reactor can be shielded in that way -- and any that are not will face this issue. And the lithium doesn't solve the neutron wall limit problem unless its very thick.
As you have noted elsewhere, molten lithium would interfere with magnetic containment. Lithium hydride melts at a rather higher temperature. I don't know how reactive molten LiH would be with pipes. I know letting any air into contact with molten LiH would be, as we say, bad.
Taking your number of 0.05 MW/m^3, Back of the napkin calculation is that the USA would need ~8,000 gigafacory-sized reactors to meet 100% of electricity demand.
Similar to how energy is extracted from fission reactors currently: the heat is used to boil water which makes large turbines spin and produce energy. It's dumb engineering. (I don't mean that in a bad way.)
I always find it slightly amusing how there's remarkably few forms of power generation that don't eventually boil down to "use water/air/steam to make a turbine spin".
I like to think they're saying "We'll make contact when they realize they don't have to build a fusion reactor because there's already one in their sky."
It's interesting how you're assuming that a species which obviously has been navigating way past the point where any useful power can be extracted from their star would not see the utility of developing fusion power
I'm assuming that such a species would themselves have fully exploited the energy output of their local star(s) before they embarked on building an artificial one. And that they would view any species trying this in reverse order as unintelligent.
That's assuming a lot I think. Having the ability to create a large amount of power on demand is a lot more useful than it's popular to think these days.
On a lower end medium time scale maybe.. but the kind of power we're talking about here and needed by society, is still a few discoveries and a few decades away from actually being, let alone being practical on a large scale. And the worst part is that only then does the discussion even begin about adopting, using and manufacturing/installing it at scale.
Large scale HUGE capacity electricity storage is a LOT further away than a lot of people and interests are willing to... well.. as we see in europe.. allow for. We are going ahead with the first half of a system that isn't even complete in theory.
Large scale electricity storage is just waiting for the economic conditions that would justify rolling it out. Once those conditions arise, storage will pop up like mushrooms after a hard rain, and will move down experience curves, and become cheap.
The biggest open question with grid storage is which of the many competing technologies will come out on top.
No, hydro is mostly solar - the water wouldn't be flowing downwards to the sea if it wasn't for weather caused by the sun.
Solar isn't less steam and less engine, it's literally just solar, whereas everything else but geothermal and nuclear is solar with more steps. Natural gas and oil is just solar stored in paleo compost.
Interestingly, the authenticity and legitimacy of UFO disclosures has been ramping up recently, right as we come closer to the cusp of fusion, AI and quantum computing breakthroughs. We’ve gone from stories in pulp magazines to reports in NYT and the Congress.
These are the super-advanced aliens, that can travel all the way to Earth and secretly observe us, but accidentally come into the field of view of a random jet plane?
While I do not follow these discussions I'd argue that the advent of drones plays a major role in that. Additionally as long as our space tec remains as primitives we are quite boring as a civilisation
Aliens may exist, but the phenomena people are reporting as UAP are not from aliens. There is money to be made by selling the idea of aliens and alien visitors to the public and to government (who go along with the idea because it can lead to more funding).
They may not think of it as an invasion if they are exponentially more advanced than we are. Any more than I worry about bugs I might step on and kill walking across the lawn.
I don't know that would be representative of the potential gap between us and them. We seem pretty far from faster-than-light travel or whatever other thing would allow them to visit.
It’s irrelevant what they think. We care about us and our well-being.
Invasion does not mean prejudiced extermination. If they ignored us as we might ignore insects when we discover new habitat then, yeah, I’d want to keep them from coming.
The cosmos is not startrek -one doesn’t travel vast multigenerational distances in space and time to “just observe”. If we could travel to an extra-solar habitable planet. Do you think we’d be like, huh, nice carbon based life, just like us. Awesome now let’s go back “home”.
Or if we let off some earth mammals the beasts would be like, you know what, humans, take me and my descendants ten/a thousand generations down back to earth.
This does make the assumption of aliens having similar lifespans. A life form that might live 500 or 10k years would view the personal cost of those distances much differently than humans, who view it as suicide.
It also assumes similar moral and cognitive processes of what to do when encountering another planet's life, neither of which must hold true for a society or species to become spacefaring. Likewise, an alien's AI probe could be effectively immortal and that would drastically shape its opinions on a return trip.
Or maybe they're intergalactic mayflies with innate knowledge for reaching orbit or relativistic speeds but they die each day and a new generation takes over tomorrow. All distances are suicide missions, even trips across their own planet. It would totally normalize multigenerational trips.
I think it's short sighted to make any assumptions of human similarities when it comes to first contact. Cephalopods have independently developed significant intelligence in parallel here on Earth and they might as well be aliens to us despite a common evolutionary ancestor way back. A completely independent evolutionary path leading to intelligence could be incredibly counter to our expectations.
We only know what we know. This is what we build off of. Also there are physics limits. We cannot go FTL and even getting to light speed would mean vast quantities of energy. Could there be new physics? We can’t make decisions on something so far seems quite unlikely.
Speaking of cephalopods, do they seem less aggressive than other species? Have they gone vegan?
Is it more or less likely the species that goes vegan wins the race? And even if they did it would mean that they had to subdue a more aggressive species. In other words, pacifists cannot unilaterally (en)force peace.
You don't need FTL or even near C speeds to traverse a galaxy. We only pursue those ideas because it's the only way for humans to send off a request for information and get something back before our great great great great grandchildren die of old age.
For the traveler's frame of reference interstellar travel with current technology is within reach of single human lifespans if you're fine with a one way trip (and extreme cost without an expected payoff). If a species lucked out with some right-sized planets and orbital arrangements they could end up with a great gravity slingshot by happenstance that drastically reduces their energy needs in space.
The awareness of the tyranny of the rocket equation again assumes human sized likeness of aliens. If human-like intelligence arises in ping-pong ball sized beings on a low gravity planet they could have a much easier time than we do escaping their planet and physics would be on their side for extreme-G launches that would otherwise be fatal to us.
So much discussion about aliens is hinged on them just being a copy of us but located somewhere else. It doesn't take a ton of imagination to envision plausible and entirely different starting scenarios that enable greater success in space travel without inventing new physics or exotic engineering.
> The cosmos is not startrek -one doesn’t travel vast multigenerational distances in space and time to “just observe”. If we could travel to an extra-solar habitable planet. Do you think we’d be like, huh, nice carbon based life, just like us. Awesome now let’s go back “home”.
This sounds awfully knowledgeable about travel over multi-generational distances when neither you, nor I, nor any other human has ever done it. Maybe you're right that it's not what we would do, but how can you, I, or any human possibly know whether it's what an alien species would do?
Neither people, nor animals, nor plants travelled long distances to habitable places to then be satisfied and turn back. It doesn't happen on a continental scale so it's even much less likely to happen on an interstellar scale. If it's half habitable, you're gonna make that place a "home".
It's a nice fantasy to think you can zip back to the home planet after prancing around the galaxy making discoveries and reporting consequential and timely information back home.
First - there’s plenty of evidence of intercontinental trade prior to colonization/ migration in Humanity’s past.
Second, you have a very anthropomorphic perspective built in to your thinking. What if they had lifespans measured in centuries or longer? What if they had radically different views of life and death and generational cooperation? Alien life is, by definition, alien. It’s hard to say what would/wouldn’t be true.
>there’s plenty of evidence of intercontinental trade prior to colonization/ migration in Humanity’s past.
What? How is it possible to trade intercontinentally without there being a colony to trade with first? that makes no sense. One does not go to a deserted island to do trade, with whom, the birds?
With the inhabitants who are already there, of course. Your contention is that intelligent life wouldn’t travel long distances without the intent of colonization. Human history sort of argues against that to a point. Europeans were trading broadly before developing colonial empires. Travel wasn’t the thing that ensured colonization.
Yep, and we are humans with a track record of breaking the prime directive everywhere we went on earth, so why not other worlds? If there is microbal life on mars, we will kill it soonish.
I find it bizarre that you would jump in here to caution about the limitations of our knowledge, and not jump in in response to the previous commenter who proposed that visitors would just be observing.
If anything, this is the commenter that is being more careful not to entertain familiar science fiction presumptions and is exhibiting the discipline that you're asking for.
The previous commenter was being silly, in response to mc32 being silly, then mc32 switched to making a serious claim in response.
> If anything, this is the commenter that is being more careful not to entertain familiar science fiction presumptions and is exhibiting the discipline that you're asking for.
It's just a version of the Dark Forest problem. It is possibly much safer to drop an asteroid on any newfound civilization's head than to travel hundreds or thousands of years (at light speed) just to observe someone and try to figure out if they are going to drop an asteroid on your civilization's head first. IOW, the first-mover, the one who pulls the trigger first, the side that pushes the doomsday button first, etc ... the surprise attacker has a better chance of victory.
(Good thing ʻOumuamua missed. Better luck next time, chumps!)
What if the alien civilization is so advanced that a jump across the cosmos takes about as much effort as driving a couple of miles down to the mall for us?
The physics that we currently understand does not allow that.
Our current model of physics is barely a few hundred years old. We’re talking about a civilization that’s potentially hundreds of thousands of years ahead of us.
We're millions of years ahead of slugs never the less our advanced intelligence is incapable of changing physics. I doubt alien intelligence even if further advanced can change the nature of physics.
Yes, there is a possibility we will learn more and there are other pathways, but at the moment, that is fantasy, so it would all be speculative.
Yep. Besides the common exception of photovoltaics, the only other method I'm aware of is "Direct energy conversion" which generates electricity by catching fast moving charged ions. But this only works with select fusion fuels / reactions such as protium–boron-11.
I don’t want to be rude but to say solar is ‘inefficient’ without qualification is essentially baseless ignorance or lying.
PV/wind turbine efficiency and Rankine cycle efficiency are basically entirely different concepts physically and economically. Highly efficient rankine plants might turn 35% of the potential energy of expensive nuclear/coal fuel (which costs money) into electricity. In the process they produce waste heat and waste (dealing with those things is typically kicked down the road). Solar turns 20% of something that is free (being pointed at the sun modulo land use) into electricity with zero waste and zero additional waste heat. How is that inefficient (even if it were half that)? You can and should say lots of things about scale or nighttime but none of those have to do with prime mover efficiency.
Now consider economic efficiency. The denominator of economic efficiency for solar/wind is financing charges and the numerator is multiplied by a lower capacity factor whereas for everything else the denominator is financing charges plus fuel costs. Fuel costs are expensive and boom/bust volatile creating huge economic uncertainties. These uncertainties increase financing charges further reducing economic efficiency. This is before you get to waste or waste heat.
I don’t think 100% solar is a realistic option but neither are baseless claims of inefficiency.
was curious about mirrors, which are used to boil water, "most concentrated solar power technologies will have an efficiency somewhere between 7 and 25 percent."
"Though most commercial panels have efficiencies from 15% to 20%, researchers have developed PV cells with efficiencies approaching 50%."
"Both nuclear and coal plants show a range of efficiencies. Nuclear plants currently being built have about 34-36% thermal efficiency, while one of the new reactor designs boasts 39%. In comparison, new coal-fired plants approach 40% and CCGT plants reach 60%."
Coal is "40%", less the energy used in mining and transporting the coal, less the energy used in coping disposing of the ash and coping with the environmental and health harms arising from burning coal.
For PV, a higher "efficiency" means less land is used for a given nameplate power output. Desert land is not in noticeably short supply, though.
Or it might mean that PV is economically feasible in high-latitude or chronically cloudy areas.
I'd have to think that any water mill over a couple hundred years old would give a circa 2000 solar panel a run for its money; they weren't particularly expensive, and amortization adds up.
The amount of power your traditional water mill extracts would be exceeded by solar panels on its roof, which would be cheaper than the building under them, not even counting the cost of the water wheel and weir. The mill might last centuries, but only with continuous maintenance.
A weir way uphill with a penstock and Pelton wheel could do better than the old mill, but both depend on landform features with limited distribution. If you needed twice the power, you would be stuck. But you can put out more panels.
It's not clear to me why the reference points need to be a couple hundred years ago, and a couple decades ago. Was the intent to point out that the dollars are a one-off, where the kWh's keep on coming as long as the equipment works?
Even in my relatively wet and grey corner of the world, I'm confident that if I spent $X on PV vs hydro, the PV would produce more electricity and require less maintenance.
> It is amusing. But it's just because that is the most efficient way we know to turn heat into electricity at scale.
Despite the 'but', I don't think you are disagreeing with your parent (who I took to be saying that they found it slightly amusing that we haven't discovered any more efficient ways to turn heat into electricity). If you meant that steam turning a turbine is the most efficient way that we know to turn heat into electricity, then it seems that you're saying the same thing as your parent, and it's not clear what 'just' adds. If you meant that it's the most efficient way that exists, then, first, I wonder how you know; and, second, I think that far from this being 'just' anything, it's pretty remarkable that we stumbled on the literally most efficient possible way so early in our history of working with electricity!
If you read what he wrote, your question is answered already.
Saying the best way we know is the best way we know is vacuous. Nothing about steam is especially good except that water is cheap. It was cheap before, and still is. Its problems are problems we have learned to live with.
But it costs more than wind or solar, even with free heat. So it is a dead end.
> If you read what he wrote, your question is answered already.
You are right; I missed "that we know". That is entirely my mistake. But then it seems to make gridspy's comment rather content-less.
If someone says "I always find it slightly amusing how there's remarkably few forms of power generation that don't eventually boil down to "use water/air/steam to make a turbine spin".", then what does saying "it's just because that is the most efficient way we know" contribute? The 'because' suggests some justification, but it appears just to be re-stating what it's justifying. A re-statement can be valuable, but combining it with 'just' seems to be dismissing an observation that I, at least, found interesting enough not to dismiss, even if it is 'just' a description of existing facts.
I find some merit in your argument. I feel like the GP said "We use lots of turbines, isn't that interesting" and I said "It's nice to see the common factor here is a translation of pressure -> electricity" or "temperature -> energy."
So what I thought I was contributing here was an explanation of why we like steam and turbines so much.
I'm pretty sure that steam, turbines, etc have a big efficiency loss. Like you guessed, I meant "the best way we know of to do it at industrial scale now."
Thank you for your constructive engagement with my question! As ncmncm pointed out, you clearly said that you were referring to the best way currently known, and it was my fault for simply misreading.
Not as amazing as PV. From milliwatts (microwatts even, if you wannt) to Terawatts. And only stopping at Terawatts because we'd get bored going bigger.
Since I can't imagine any easy way to have produced that as a typo, you may like to know that the spelling is actually 'rhetorical' (no accent in English, despite 'rhétorique' in French).
If you want to maximize pointlessness, Energy Vault is right there. But defrauding investors doesn't seem like a great choice to enable.
Maybe it would be better to do what might help avert global civilization collapse, thermonuclear war, and mass starvation?
Investing in practical energy-storage tech factory build-out, solar farms co-sited on reservoirs and pastures, cost-effective hydrogen and ammonia synthesis tech are all overwhelmingly better uses, and can all be equally as cool.
HB11 strikes me a nonstarter. Their proposed direct conversion mechanism is obvious nonsense, and the putative "avalanche" mechanism they want to use to make the nuclear reactions go has been savagely critiqued in the literature.
I think there is a zeroth problem here, which is how to get the heat from the plasma to the water. You have a fusion reactor making hot plasma that also needs to have water circulating in the right way. From what I gleaned from some fusion presentations the solution to this is itself an engineering challenge.
Fusion plants also need to absorb the neutrons coming out of the reactor and secure themselves a supply of tritium for their reaction. The most common solution is to do all three with a blanket of molten lithium that can absorb neutrons and heat from the reaction, transmute into tritium, and go through a heat exchanger with water to heat it up.
Lithium fission would be into Hydrogen and Helium - definitely not releasing energy. Do you mean that Lithium fusion with a proton or neutron releases energy?
There's a lot of lithium being mined for batteries. Just centrifuge out Li-6 or isolate it with some other clever means. Not much is needed for fusion fuel compared to industrial scale consumers of lithium and it's a healthy boost to heat output.
"Fusion Reactor First Wall Cooling" https://www.youtube.com/watch?v=bHJyoqDO0zw talks about the steady-state heat transfer out of a proposed tokamak design. Around 1:09:23 they show "1.5 GW" deposited as "0.3 GW from radiative photons -> surface heating" plus "1.2 GW from 14.1 MeV neutrons -> volumetric heating".
Designing the first wall and the volumetric blanket are, indeed, engineering challenges.
1.2 GW worth of neutrons is rather a lot. Neutrons cause damage to materials (e.g. disrupting the microstructure) and also make elements radioactive through neutron capture (activation products). It's a pretty complicated issue really.
Generally somebody should have explained somewhere. But it is not considered very interesting, because nobody seiously expects to ever need to solve it.
Indeed. As I mentioned upthread, the limits on power/area at the first wall of the reactor lead to DT fusion reactors having horrible volumetric power density. Their "figure of demerit" vs. fission is roughly (radius of plasma)/(radius of a fuel rod).
It's a fusion reactor, so how do you get the water into the part with the hot stuff? That's all inside a magnetic field, I think. Also, you have to consider the neutron radiation's effect on the pipes that carry the water into the core, it's going to activate several metals in there, and cause weakening of the pipe wall, which will necessitate inspections and replacements.
It's a way harder engineering problem than you're letting on. Your comment is like a software user saying "How hard could it be just to add feature X?".
The heat transfer is not (will not be) directly from the plasma to the water. The fusion neutrons will impact a "blanket", which is water-cooled, and kept at a temperature of around 600-800 C. Weakening of the pipes and all other structural components will primarily be from neutron irradiation. Not to say that any of it's easy, just not for the reasons you suppose. :)
Exactly! Unlike in a fission reactor, where you can flow the coolant through the core, in a fusion reactor the energy has to be radiated through the surface of the reactor. The square/cube law comes into play: the surface area you can radiate through goes as r^2, while volume (and cost) of the reactor goes as r^3.
Could be interesting if they couple it with a Closed Cycle Gas Turbine [1] and a tiny steam plant, like the gas CCGT plants of today. Then the heat engine part should see similar, or even higher, efficiencies compared to gas based CCGT plants.
Boiling water using the Rankine cycle [2] and it will be as dead in the water as nuclear and coal is today.
A thing to keep in mind though is that it is very hard to compete with the engineering of an axle straight into a generator like wind turbines or a solid state system like solar PV. Working fluids, cooling loops and what not are awful to build and maintain.
If you think nuclear is dead in the water you haven't really been following where the energy debate is heading these days. Especially in Europe, where we no longer have the luxury of plugging the holes left by renewables with gas.
Nuclear has a 15-20 year delay from political decision to generating power. Color me surprised if there's still an ongoing energy crisis in Europe by 2037-42.
Well the Energy Department just approved a new nuclear design for testing. Not sure how long it was in the works. If there is enough money to be made, you better believe it will get done faster that 15 years.
> Especially in Europe, where we no longer have the luxury of plugging the holes left by renewables with gas.
We don't have the luxury to wait on nuclear either. A large part of the current French electricity crisis is "thanks" to the cost and time budget overruns of Flamanville - they had gambled on Flamanville being ready in time to replace the old unreliable clunkers that, surprising nobody, now have massive corrosion issues.
The solution is to massively over-build on renewables - wind and solar most obviously as well as trans-continental ultra-high-voltage links, but also biogas plants that convert the millions of tons of cow dung and other bio waste into gas that can then be used during low availability of renewable electricity. On the other side we also desperately need actually smart grids and consumers that can dynamically act based on the power available in the grid.
"Have to" is ill defined. On paper they could say "leaving the Soviet union was a terrible idea, we want back in" but many have lived experience of living under soviet (or soviet-allied) rule and hated it. On paper they could give Russia a ultimatum of "withdraw or face open war", but Russia has more nukes and they may well still function. Boycotts are the current choice.
I suppose I’ll bite here. We don’t need “fancy” energy production as Southern California and the Midwest becomes uninhabitable, you serious? Coal power should be dead in the water if it isn’t. It’s bad for workers, bad for the air we breathe, water we drink, bad for the people who live around plants. That has been well established. It actually kills more people than nuclear, solar and wind combined. There’s no redeeming quality to it other than being plentiful and cheap. It shouldn’t be cheap based on the externality of the destruction it causes here and around the world.
It being plentiful and cheap is a pretty damn important and redeeming quality.
In most western countries we can afford to transition to other solutions, and it is far healthier for both the people around it and the environment, but I don’t think most of the people on this site really understand the ramifications of not having cheap reliable power. There’s a reason people left the farms and flocked to dirty hellish cities during the industrial revolution and still flock to cities and build coal plants today. It’s less hellish than living without reliable modern amenities.
Southern California and the Midwest aren’t going to become uninhabitable even if we continue pumping out as much CO2 as we are currently. I know of no reasonable projections that predict anywhere near the human cost of just shutting off power completely if it’s not clean like people seem to want to do.
That does NOT mean we can’t reduce CO2 emissions while meeting increasing energy demands. But we should be striving to do both. And given a choice between living next to a coal plant and having reliable lighting, heating, air conditioning and food refrigeration or living next to a clean but unaffordable and unreliable plant, most people would choose the coal plant. We’ve been running that experiment globally since the industrial revolution, the answer is clear. Even when taking the health effects and climate change projections into account, that choice would be reasonable. Dying of cold, dying of disease due to unrefrigerated food, dying due to inability to call for help… these are all things very distant from the minds of most people fortunate enough to be on this site. They are very real ramifications of not having reliable power. And those severe ones I just mentioned are just the tip of the iceberg.
Lets just please, please, please finish the new stuff before turning the old stuff off. Build as many solar farms and wind turbines and nuclear and hydro and battery parks and hydro batteries and natural gas lines as we need, and only turn the old stuff off when we’re actually ready. If we turn off everything not clean preemptively we’re going to kill way more people than climate change. If we were reasonable and sought to actually solve emissions problems as fast as possible there is no reason not to aggressively pursue wind AND solar AND hydro AND nuclear fission AND natural gas.
It’s sad I can make this prediction about your opinion, but I’m assuming you are probably not an advocate of fracking or nuclear power or hydro. Please correct me if I’m wrong. A lot of people apocalyptic about climate change are quite picky and refuse to pursue solutions that don’t conform to a perfect vision of a star trek like future where everything looks like the apple campus. It’s delusional.
It speaks to the privilege of those advocating green energy “at all costs” (which is not actually at all costs and maximally translates to “at the cost of the poor” due to the aforementioned pickiness) and reflects a severe lack of appreciation for the ramifications of less reliable and more expensive power on the poor.
The fact that most people on this site are surrounded by opulence and excess is creating a severe disconnect with the reality of the wider world. That default reality is that the only reason the climate isn’t killing way more people in the here and now is cheap power.
It did strike me as a pretty egregious straw man. I don't think I've ever heard anybody argue for just turning off coal plants and sitting in darkness, certainly not the poster being replied to.
In the last 20 years, the percentage of US energy coming from coal has fallen in half. Eliminating is entirely achievable.
People don’t think that’s what they’re arguing for, but that’s what happens when you go green too optimistically and aggressively. If you sacrifice reliability and robustness for being green, your grid becomes vulnerable.
From what I understand it seems reasonable to get rid of coal in the US over a reasonable time frame with appropriate replacements. I’m not arguing in favor of coal. I’m arguing in favor of going with cheap reliable energy and whatever the best and actually practical solutions are for a given area.
The fact that coal has fallen by half in 20 years doesn’t mean the other half is just as easy, either. You need a certain amount of supplemental power at night, during bad weather, during usage spikes, etc. The remaining percentage of coal use is going to be more and more concentrated in the supply areas that are harder to replace. That doesn’t mean it can’t all be replaced or that we shouldn’t pursue replacing all of it, all I’m advocating is for a sane transition that takes practical constraints like that into account and doesn’t get perfectionistic about solutions. Frankly I don’t often see considerations like that being made, I see a lot of hysterics and dogmatic assertions about how everything needs to be solar panels and wind turbines yesterday and everyone who wants moderation or other green solutions and more gradual phase in is a greedy oil shill.
> I’m arguing in favor of going with cheap reliable energy and whatever the best
Then you're not doing a very good job of it. For all that you accuse others of "hysterics and dogmatic assertions", I think your posts earn that label way more than the comments you replied to.
The transition will perforce be very far on the side of what you call "sane", to a pathological degree. There is no merit in arguing for what must certainly happen anyway.
Germany already did that. They shut down a whole bunch of power plants to meet emissions quotas thinking they could meet demands with renewables. They made their grid fragile and dependent on the Russians, and now they can’t. They’re planning on rationing and building warming shelters: https://m.dw.com/en/german-residents-make-plans-amid-fears-o...
> It’s sad I can make this prediction about your opinion, but I’m assuming you are probably not an advocate of fracking or nuclear power or hydro. Please correct me if I’m wrong.
Lol yeah you’re wrong. We’re on HN after all, everyone loves nuclear. Fracking is also horrible for the environment and for climate change. Most wells leak methane which is a 6x worse greenhouse gas than CO2. Hydro and nuclear are fantastic, although we’ve dammed most places we can in the US already. Anyway I’m against coal, the climate is a cost of coal, it isn’t cheap for society. I’m for investing in doubling the nuclear capacity of this country to eliminate coal completely. Or spend the trillion dollars we’ve dumped on wars to build a superconducting power grid and save the transmission waste. Also as others have said your argument is a ridiculous straw man. Nobody is talking about going back to the Stone Age. Just talking about how to build cleaner sources of energy. If the weather of the past year hasn’t convinced you of the necessity of this, I’m afraid for the future of the world.
I’m glad you are willing to invest in other forms of clean energy.
That argument is not a straw man. I know very few want to go back to the stone age (some radicals do), that’s not my argument. A lot of people vastly overestimate the ease of transitioning and are making laws and goals and plans that are wildly optimistic and out of touch that will in effect lead to unstable grids and more people without power. No one sane wants that, but that’s already happening because a lot of places that have been aggressive about transitioning have done it poorly and without proper backup power generation options.
If COVID hasn’t convinced you rushed and panicked centralized interventions make things worse, and you’re willing to engage in even more of the kind of massive disruptions that we’ve only begun to see the full effects of because of a heatwave, you’re likely to kill more people with rushed intervention: https://nypost.com/2017/07/10/heat-death-hysteria-the-wrong-...
I meet a lot of people that are dogmatic about wind and solar and think it’ll work by itself and that the whole world needs to transition to that alone right now. In combination with other sources, in the US and rich countries we can afford to build all the clean energy we need, if all options are actually on the table. But doing that globally and doing it too fast will kill people.
This guy [1] is definitely an independent thinker and pretty regularly beats the "air quality" drum. Burning coal puts a massive amount of particulate matter into the air. That alone should disqualify it.
Hey mate, I've been going through a bout of depression recently, and I wanted to thank you for your comments on HN, this one and many of your other posts have made me laugh so much and have put a proper smile on my face, I'm sitting at my desk in such a good mood. I enjoy your form of comedy.
It's also very expensive engineering. That's how a coal plant works, and the last coal plant that the US built cost $2B for a 600MW plant. Given how much cheaper solar & wind are, fusion will be dead in the water if it doesn't come up with a cheaper way of extracting energy from the reaction.
I'm not sure where your numbers are from, but just because $2B sounds like a big number, it isn't inherently a dealbreaker.
If that's 600 MWe, running at 80% capacity factor, amortized over 30 years, then the $2B becomes: 2e9/(600 * 1000 * 0.8 * 24 * 365 * 30) = $0.0158 / kWh -- the $2B capital cost amortizes to 1.6 cents per kWh of electricity sold. Not zero, but 1.6 cents is far less than the current market price of a kWh.
(Admittedly: we don't yet know the capital cost of a working fusion heat source, or its capacity factor. Both will determine whether this is economically competitive.)
On page 15 note "This analysis does not take into account potential social and environmental externalities or reliability-related considerations", and that solar and wind do not get the checkmark for "baseload" -- only "intermittent".
Pages 13 and 14 show Fuel Costs as:
Wind: 0
Solar: 0
Coal: $13-$18/MWh ($0.013 - $0.018 per kWh)
Fission: $9/MWh ($0.009 per kWh)
Natural Gas: $21-34/MWh ($0.021 - $0.034 per kWh)
As a retail consumer, I'm paying about $0.15 per kWh, though I know that includes transmission and distribution and retail markup.
Fusion has the potential to be very low on fuel costs. But the capital costs are an unknown. In my original comment, I tried to show that when amortized over enough kWh for sale, even $Billions in capital costs could make sense, if they give us a machine that produces zero-carbon baseload electrical generation at scale.
Yes, but most of the time that fusion reactor is behind a giant hunk of iron covered in various other matter. Even when in the sky, the sky itself is an effective insulator that only allows 1/4 of the energy through.
That's why we are considering placing a converter above the sky to more efficiently pierce the sky with energy.
I always liked how NASA realised in 1970 that the moon is a sandpit of fusion-converter material. It's such an awesome reason to build houses above the sky.
The moon is high in silicon. You can make solar panels from mostly moon dust. Then build solar panels in orbit which are 4x the power generation of sea level panels and they experience less shading.
I agree with you relating to our existing energy problems. However I expect that humanity will be attempting to use as much energy as it can possibly create for at least the next 1,000 years.
I hope we have a bright future growing into space, creating a Dyson ring, orbital habitats, etc.
Replacing our current use of fossil fuels has plenty of strong ground-alternatives. I like the idea of Thorium salt reactors for base load, hydro stored energy and lots of local wind and solar.
I support moving all the smoking buildings outside the environment also. Then many of them can use the fusion reactor directly, with the aid of mirrors and lenses.
Speaking of solar it would be nice if we could just plate the inside of a reactor with photoelectrics instead of blowing all the budget on a clusterfuck of a steam system. Too bad silicon doesn't like 100M degrees...
Actually thinking about it figuring that out would make fission a lot more tenable too
Are you honestly suggesting that we place photovoltaics (which perform worse when they get hot, and can only absorb a narrow spectrum of the energy emitted by the reactor) inside a fusion reactor instead of using a very well understood and efficient heat -> electricity technology (steam)? I'm pretty certain they would just simply melt at the temperatures that a tokamak is subjected to, even if there weren't other issues with efficiency.
This is nothing more than an engineering challenge, looking at it seriously.
Cooling? an IR barrier in the reactor to stop IR from reaching the cells should solve about 80% of the issue - assuming you can make something transparent at the right wavelengths for the cells - and capable of withstanding the heat of the reactor. The other 20% is already doable with current technology, and we do it from large-scale solar farms to single-family homes - water tubing on the backs of the devices to a radiator or storage tank. Hell, while using them to harvest light energy, that water loop can be used to harvest heat energy, thus improving the overall system efficiency!
IR as in infrared? Nonono, at 100 million kelvin, if I’ve done the maths right, a blackbody spectrum peaks somewhere around the x-ray band, and about one part in a trillion of the energy is in the IR band or lower.
Anything hot produces photons, and a working reactor would necessarily produce a lot of heat.
These photons can’t usefully be converted directly into electricity with the photoelectric effect, but they sure could be converted indirectly via the same mechanism that the fusion in the core of the sun is reduced to the band that current PV runs at.
Not sure if it’s worth doing that (may well be such a diffuser would be so large it would be easier to do something completely different), but that’s very different thing to your dismissal.
Maybe a dumb question, but could one use bricks of depleted fission fuel as the neutron shield in a fusion reactor, and swap them back into a fission reactor every time they become fuel-grade again?
Sorry, maybe I was unclear. I wasn't asking about using the fusion reactor just to produce fission fuel. I was asking "if the fusion reactor produces a bunch of extra neutrons as a side effect, is this a way to use them to produce more energy later instead of throwing away that energy, or letting the neutrons actively damage the fusion reactor?"
i.e. one needs to prevent the neutrons from escaping or degrading the material the reactor is made out of, so instead of just adding a throwaway shielding layer, would it work to use something that is not only super dense, but is currently a waste product[1], and also becomes more valuable in the process of being used as the shield? Seems like it would be vaguely equivalent to a photoelectric collector for neutrons, but I am not a physicist or reactor engineer.
[1] I do think it's a shame that we stopped building breeder reactors, but that's a separate discussion.
Breeder reactors are not used because refining the bred fuel costs more than processing mined uranium.
The overarching requirement on fusion neutron absorption material, besides delivery of heat to process steam, is that it needs to produce more tritium to burn. You don't get that if the neutrons are absorbed in something other than lithium.
This is absolutely not true. My day job is designing control systems for renewable generation so I certainly don't have a bias against renewables - the opposite in fact.
The fact remains that the physics of a grid powered only by distributed non-dispatchable wind and solar resources simply does.not.work. full stop without massive investments in storage and transmission upgrades. The physics isn't even debatable - it's simple. You only have to look at the very limited transmission infrastructure that currently exists and understand the simple fact that the power grid is a zero sum game. Power in = Power out or very bad things happen that lead to power out = 0. Zero sum generation + aging transmission = not enough power where you need it, when you need it if you get rid of traditional baseload sources.
It's good to champion renewable generation, storage, and transmission upgrades. It's necessary infrastructure for the economic and actual health of our nation. It is not going to be inexpensive by any definition of the term. It's going to be monumentally expensive even if it's completely necessary.
I honestly think this is one area which should be nationalised rather than left to the private sector. Yes, the investment will be massive, on the trillions scale. But:
a) Once it's done, you're pretty much self sufficient energy wise. Sure, you may need the raw materials from other countries to make panels, turbines and batteries. But once you've achieved a 100% renewable clean energy grid, you're getting a fairly decent lifespan out of everything so you're not going to be as subjected to the whims of the market like most of Europe is experiencing with gas. The market should generally be more stable.
b) Once your citizens have free energy, they have a massive chunk of disposable cash they were once spending energy. They will spend that or invest it: and both general spending and investing are taxed at higher rates than fuel spending (5% VAT on fuel spending in UK compared to 20% general VAT rate). Yes that is a massive loan for the government to put on the books, but they will probably get it back much quicker than expected.
If you give people a limited amount of free power that's equivalent to giving them some free money. Which is fine and dandy but it's rather unrelated to how the grid works.
If you give people an unlimited amount of free power they're going to use it to mine cryptocurrency in a massively wasteful and expensive way.
I didn’t mean unlimited free power. I’d basically propose that the government would pay for as many solar panels as you can fit on your roof plus a battery in the garage or in a utility room. For apartments, the government would pay for some solar panels installed on a solar farm and you’d get a certain amount of energy for free covering the typical energy use of the size of your apartment. So we’re mainly just covering normal domestic usage. Of course if you’ve got anything spare you’re free to use that mining crypto but I don’t think that’s what the majority of households are really going to be doing.
The surest way to make someone not value something is to give it to them for free. Giving away energy is a good way to make sure that we use as much energy as we produce, and then some. The key, I think, is to make energy usage painful, but make that pain proportional to your resources. A big power bill to a billionare and a big power bill to a single mom on food stamps should result in the same level of emotional distress to both - hopefully very little.
Normally I would agree with you but not on this. There is a giant nuclear reactor in the sky giving out as much energy as we could ever possibly want. Literally all energy on this planet came from it: sunlight feeds the plants which are turned to oil or feed the animals which feed us.
Once we have built the machinery to harness that energy, it does become pretty much free and we can use as much or as little of it as we like. The cost of maintaining the machinery will become ever cheaper due to the amount of power we can get for little to no effort. It becomes self sustaining.
There are literally ongoing efforts right now to replicate Asimov’s vision which was to create space based solar farms and transmitting the energy back down in radio waves to specific points. We could literally harness our entire planets energy use from just a few of these in strategic locations if it was done right:
Yes, there is a great deal of energy at the core of the milky way galaxy as well. Unfortunately my ability to use it to make toast in the morning is quite limited.
It turns out your ability to harness energy is kind of important. We're nowhere near that level of energy capture. We can't even handle transmitting solar from one corner of one smallish continent to the other, we're nowhere near the level of technology and infrastructure development you're talking about.
> Once it's done, you're pretty much self sufficient energy wise.
What arm of the USA government do you trust most to get this job done efficiently and fairly? What do you think will happen when you use "more than your share" of electricity for a month or two and your (undoubtedly centrally controlled) account is deemed unacceptable? Or is it your thought that providing electricity free will reduce consumption?
I’m in the UK so I don’t know which branch of the US government I’d trust to get it done. What I do know, is that you guys have done some incredible things, look at your railways, roads, cities, subways, internet, space program. You have done massive scale programs in the past and I have no doubt that you could do it again in the future if the political will was there.
As for the second part, privately owned houses would get as much energy as the solar panels and battery on their property can provide. Additional power would come from the grid and would have to be paid for as normal. For people in apartments, presumably you have records of normal energy usage for every house and apartment, you could use those to work out the amount of solar panels needed to add to a solar farm or the equivalent for wind. The government pays for the installation of that and the citizen gets the energy generated for free. Additional energy they use is then paid for out of their own pocket.
> without massive investments in storage and transmission upgrades
So, we build storage and transmission. Storage cost is falling even faster than generation, and there are zero physics problems to be solved, just practical civil engineering.
The cost of this much civil engineering will be very large, but much smaller than e.g. for that much nukes, and we will pay it, because the only other choice is global collapse when the degraded biosphere becomes unable to sustain our population.
> Storage cost is falling even faster than generation,
Citation please. The high demand for EVs and other battery-hungry devices has led to a situation where grid scale energy storage costs are currently increasing year over year and expected to continue doing so [1]. And pumped hydro storage is not something that will flexible enough for general deployment.
> and there are zero physics problems to be solved,
> just practical civil engineering.
Alchemy is not a solved problem, and there is only so much lithium to go around.
Batteries are the most expensive storage. The overwhelming majority of storage will not be batteries. Of what is batteries, the overwhelming majority will not be lithium. Lithium batteries are well adapted for cars and phones. Other qualities are favored for utility storage.
There are lots of exciting battery chemistries, and some boring ones. It is impossible to say which ones will win out, in the end. The one thing certain is that whichever wins will have the best performance per unit cost, and thus better than all the others.
Other exciting chemistries include molten antimony/calcium, zinc/bromine, and iron/air. The antimony/calcium one would never wear out or catch fire. Zinc/bromine is most compatible with current lead/acid battery tech. Iron/air is very, very cheap. None are very attractive for cars, so utilities will not be in competition with the car industry for access to batteries.
a mix of hydro and non-lithium batteries. for grid scale batteries, you don't care about weight, and if you make it big enough can hear the battery if it helps. as such there are a lot of very cool battery technologies in various stages of commercialization that will never go in a phone, but make a lot of sense when you scale them up to a few thousand pounds.
The absolute cost of anything world-scale is unavoidably very large. Pretending serves no one.
At issue is how this cost compares to that. Renewables and storage costs, as big as they will be, will be overwhelmingly less than alternatives, and can be fielded faster.
Seriously though. Maybe, if we solve the large capacity storage issues and are able to build a storage system to scale. So 3 or 4 decades if we are extremely lucky. But right now in reality....
And it's still not clear if it would be enough in the end. We'd need cover everything in panels and put towers everywhere. The amount of resources needed for solar and wind is actually realistically insane at the scales needed. (one of the many problems usually ignored by wind/solar evangelism)
A peer reviewed study? Come now, this is a profit seeking book. In order to verify these claims I would have to read an entire book. It’s preposterous to cite as evidence what is basically a novel.
> Even former critics must admit that adding e-fuels through PtX makes 100% RE possible at costs similar to fossil fuels. These critics are still questioning whether 100% RE is the cheapest solution but no longer claim it would be unfeasible or prohibitively expensive.
Anyway, I now expect you will apply the same level of skeptical criticism to anyone stating renewables are insufficient, and demand they supply peer-reviewed references.
Solar and wind _alone_ means no storage (otherwise, it's not _alone_!). This means you need to build at so very many locations as to have consistent power for baseload, and a transmission infrastructure to distribute across that location, that it becomes almost a global problem. Aka, a global grid spanning continents.
Of course, this is actually desirable imho, but yes, both geopolitics as well as cost, stops this from happening.
strictly speaking, sure. But it's a source for all intents and purposes, because in order to achieve the same outcomes using renewables as with fossil fuel powerplants, you'd need to pair it with storage. Or produce so much renewables, and be able to distribute it so widely, that no single location would lack power at any given time.
Over a short timeframe storage can be a sink or a source of energy. The grid needs to be managed both over short and long timeframes - you can't just say "100MWh in = 100MWh out over the last 24h", it also needs to be balanced so that the input and output is constant on a per-millisecond basis.
Nobody has done it. Nobody has put forth a credible theoretical model on how to do it. If you believe otherwise please show how it can be done. With details. Things like frequency regulation, reactive power and all that stuff that makes the grid work. And include the economic calculations. The burden of proof is on you.
> Nobody has put forth a credible theoretical model on how to do it.
HVDC global grid, mentioned loads of times on this forum. 60% antipodal loss with existing components that were optimised for much shorter connections, but even that loss is fine given how cheap optimally placed PV is. Cost about a trillion USD (ok) and a few decades of current global aluminium and copper production (meh), but that’s still absolutely in the realm of the “we could afford it, shame about the politics”.
Lots of people have put forward credible models of how to do it. The key is to include power-to-X to provide dispatchable demand and a buffer for rare prolonged outages of the renewable sources.
> Even former critics must admit that adding e-fuels through PtX makes 100% RE possible at costs similar to fossil fuels. These critics are still questioning whether 100% RE is the cheapest solution but no longer claim it would be unfeasible or prohibitively expensive.
It is, in fact, not. And, you are no reliable judge of it. Your assessment will have exactly zero effect on how the transition to renewables plays out.
Either we transition to renewables fast enough, or global civilization collapses first. Nobody can say which.
Microgrids and storage cost way more than any method of generating power we are currently using. Please stop using buzzwords and look at the actual numbers.
At grid scale, batteries were about the same cost as a functionally equivalent fission reactor last time I looked (a few years ago). Despite which, batteries are one of the more expensive ways to store energy at scale.
I don't know where you looked then because batteries are not anywhere near low cost enough to be deployed at grid scale at the amounts required to run a grid of wind and solar. Even in a sunny climate with reliable solar output, if you assume that there is a 10% chance that in any year you will have a 10 day period of cloud cover and 50% lower solar output and your entire grid cost goes up by 5x! The math for storage is BRUTAL.
I don't think anyone was arguing that, it's more that geographic distribution of solar panels and windmills isn't a silver bullet and there's a reason solar and wind need expensive storage.
I worked for years in a business providing support services for maintaining the distribution network to rural areas. The distribution network was run at a loss by the government. Please look at the numbers and stop reactively responding.
Solar and wind are not serious solutions to the energy needs of the planet today or in the future. As billions more people become part of a global middle class our energy requirements will expand dramatically from today.
"In the United States, cities and residences cover about 140
million acres of land. We could supply every kilowatt-hour
of our nation’s current electricity requirements simply by
applying PV to 7% of this area—on roofs, on parking lots,
along highway walls, on the sides of buildings, and in other
dual-use scenarios."
"We would
need only 10 million acres
of land—or only 0.4% of the
area of the United States—to
supply all of our nation’s electricity using PV."
Isn't the intermittency of the energy source the issue? And there's currently no scalable solution to efficiently store excess energy generated from solar panels?
> Even former critics must admit that adding e-fuels through PtX makes 100% RE possible at costs similar to fossil fuels. These critics are still questioning whether 100% RE is the cheapest solution but no longer claim it would be unfeasible or prohibitively expensive.
I really wish this sort of thing would either be better thought through or better articulated. 10 million acres is enormous. And is it continuous supply (if so, how?) Or just supply when it's sunny?
> Everybody has known all along that renewables generation is intermittent
That doesn't mean it's made clear in statistics. I've read plenty of people say "X generates as much as Y", where X is intermittent and Y is suitable for base load. Certainly enough to disagree that everyone knows it and is able to discern that from context-free statistics.
Literally every single person on Earth who even knows what renewables are knows they are intermittent. No one imagines solar panels produce peak power all the time, or any power at night.
You've missed my point again. Every time someone says "renewables supply 80% of power required" or similar, without stating the context of what that means, it creates false impressions in people's minds. Is it 80% on the sunniest day ever? 80% of actual load but using storage? 80% of the load 5% of the time?
I'm not saying if people think it through they won't understand it, I'm saying that context-free stats like that create false impressions in some people's minds based on whatever the assume about the stat, and annoy people like me who'd like to know where the stat came from.
0.4% of the entire country is a massive amount of land.
That’s 10 million acres of wires, maintenance, habitat and all kinds of mischievous creatures, not least of which are humans. And it only works when the weather is good. And not all countries have the grid or engineering and maintenance capacity of the United States.
It’s not a realistic solution.
By all means, lets put solar panels everywhere we already have buildings and roofs and power hookups and make a dent. Maybe at some point it’ll be possible to use solar alone, and we can keep up the maintenance.
Going all in on solar right now would be suicide. It’d be worse than the effects of anthropogenic warming. People are going to freeze to death this winter in Germany because they bought into the promise of renewables before it delivered and didn’t diversify their energy supply.
You should only phase something out when you can meet demands without it. Nuclear is a way to do that. Natural gas is a way to do that. Renewables are a way to do that. But you have to actually exceed demand and have a solid diversified base before you panic switch because of climate change. Otherwise you kill and impoverish more people than climate change.
I'm waiting for him to realize that agriculture will use two orders of magnitude more land than is needed to power the US with renewables. Will he conclude that eating is impossible?
One of the things I like about this site is the restraint (at least in comparison to other places) in substituting an argument this kind of snarky scoffing and engagement. It’s brainless.
Agriculture is already working, or was until its been starting to be shut down and curtailed due to alleged environmental issues like in the Netherlands. You can manage much larger chunks of land with plows and combines and other vehicles because of how you interact with the land when farming.
You can’t plant solar panels and have them just grow out of the ground and repair themselves and reproduce largely independently. It’s a totally different type of land use. Managing solar farms is magnitudes more effort to build and maintain than agriculture.
Costs on paper, cost in reality over time, and cost due to physical and manpower constraints vs cost due to government subsidies and regulation are not equivalent.
This claim that 10 million acres of solar panels is cheaper to build and maintain and actually put into use and store power from vs extremely high energy output nuclear plants with tiny footprints that can produce continuously reeks of extremely biased accounting.
The arrogance and presumption is the issue. I don’t think it’s a conspiracy at all. Frankly I don’t trust people who aggressively point to models and facts and figures and don’t actually engage with the WHY and the caveats and actually think about the risk of non correspondence between the figures and the real world.
That does not mean you’re wrong, I simply don’t trust your hand wavy dismissive argument about it being cheaper.
If I see a report that looks at the long term maintenance cost of an actually deployed modern solar farm, not hypothetical ones, and compares it to an actually deployed modern nuclear reactor, I’ll take that one.
I have an affinity for whatever actually works, the main reason I think nuclear looks good is I trust basic physics and understand how much astronomically higher the energy density of nuclear power is in comparison to like everything else.
I think the truth is in the middle. Solar is becoming ridiculously cheap, but even if the panels were free there's still a lot of other costs to factor in.
As explained elsewhere, a mix of energy sources is necessary.
And your statement is devoid of context. Solar is already working well in North America (and elsewhere), and uptake will continue to increase. It won't be a panacea for the rest of the world, and solar+wind won't replace all other generation types.
It's an important component of a strategic solution. Where it makes sense, aka: not in the artic circle.
Not sure why you're dismissing it so out of hand. I agree it's not the panacea that many want it to be, but it's still very important, especially given its recent cost declines (solar specifically here).
Can you provide any sources on Texas having grid issues because of renewables? The biggest publicized issue I'm familiar with was caused by inadequate maintenance of fossil-fuel-based generation facilities - during that period of time renewables produced the expected amount of energy for the weather conditions. Of course that expected amount wasn't their peak output, but that's something you plan for if you're competently managing your grid.
When you invest a lot in renewables and neglect investment in other plants, then I find it fair to blame some of it on the investment in renewables.
It's like buying a BMW and then not having enough money for groceries...it's not just the groceries being too expensive, the nice shiny car might have something to do with it.
On the contrary, California is struggling with with electricity generation during times of high A/C loads due to a heat wave. Those times correspond with high solar power generation, without solar they'd be doing a lot worse.
On the contrary, Germany has met their goal of 80% full natgas storage several weeks early despite the French nuclear reactors being offline due to higher than expected renewable energy supplies.
You're saying that Germany and California are not struggling with the electric grid...now I believe you're trolling
They invested a lot in solar power, which is expensive, so they couldn't afford to invest enough in transmission and backup generators, and now they have expensive electricity and unreliable grids. Ignoring current year, I think Germany is second in the world in regards to expensive electricity (after Denmark) and California is one of the most expensive states in the US.
They invested a lot in solar power because it is cheap. It is the cheapest method of generating power every fielded. They got far more power by investing in solar than they would have spending anywhere else.
Of course they have not finished building out, which takes time. And, Germany counted on access to NG as backup while they build out. The war interfered. Had they invested any other way they would be even worse off.
> invested a lot in solar power because it is cheap
This is an outright lie, let me dig in a bit. They're cheap only if you look at watts generated, if you ignore extra grid costs and backup supply. For 1 MW of solar, you need 1 MW of backup. If you use solar for most of the day and use the backup just for 20% of the total electricity required, then the backup plant will look like it's very expensive to build and operate, while the solar seems cheap. But solar cannot operate without backup.
What needs to happen is that you have to transfer some of the money generated by the solar plant to the backup plant. How you do that will make it look like solar is either very cheap, or expensive - and this is all political and a PR move. In the end, consumer will pay for both anyway, which is why Germany and California have such high electricity bills.
A real life equivalent example would be to say that your truck can downhill with 100 MPG and very cheap to run, and this is absolutely true...if you ignore that the truck must also climb the hill.
> Had they invested any other way they would be even worse off
Germany is lucky that EU just implemented the unified energy market, otherwise they would have been absolutely obliterated this past winter + wartime.
It's not my area, but I suspect that the heat extraction rate for a fusion reactor must be several orders higher than current fission reactors if we are to run them continuously. Fission reactions can be actively controlled by using reaction moderating material (control rods), which means we can tune the reactor activity to match the amount of heat extraction available.
Fusion plasma must be sustained at a few million Kelvin or it shuts down again, and I'm not sure how finely we can control the operating temperature without either overheating the reactor or shutting down the plasma. I think it will take a lot more than dumb engineering to accomplish this.
The heat flux management from the plasma is certainly not dumb engineering, true. However, the actual heat transfer technology is, I think it's fair to say, "dumb" compared to all of the plasma physics that has to enable the reactor in the first place. It's more or less just running cold water through the lithium blanket, which they hope to keep under around 1000 Celsius or so.
I was talking about this with the my kids (10, 7) the other day. Blew their minds a little that pretty much every power source comes back to the same central thing: moving magnets.
Then I pointed out that our electric car does it in both directions too.
Assuming we can run an actual fusion reactor consistently, how is the power taken out? I've seen lots of comments about water/steam, but we're talking 100M°C degrees here, that's insane! Do we bury this thing in the ocean?
I'm being silly, but I'm genuinely curious if there are any plans, even speculative ones, on how to do this.
I haven't actually read the announcement, but I assume the tremendous temperature is in a tremendously small quantity of plasma. Basically, it's a few extremely fast nuclei.
Well, when it's that much heat, you're going to need a lot of water.
Also, when dealing with that much high energy radiation, your metal has a tendency to wondrously become another metal, with all the problems that comes with.
> Well, when it's that much heat, you're going to need a lot of water.
we want a lot of water! That's a lot of energy!
> Also, when dealing with that much high energy radiation, your metal has a tendency to wondrously become another metal, with all the problems that comes with.
That's kinda problem with anything fusion or fission, wherever neutrons hit things get weird. Probably much worse for fusion tho.
The question is more how you get the heat to the water in a sensible way. It's _probably_ just engineering, but it's still something that needs to be worked out.
To put that into perspective, we need about a thousand gallons of water to produce a megawatt-hour of power. We can desalinate a thousand gallons of water out of the ocean by spending about ten kilowatt-hours. So that's a 1% energy overhead.
So we think about the engineering problem and reject the entire concept on that basis.
Even if I give you a magic box full of near vacuum 100 million degree plasma that emits 1MW/m^3 in the form of neutrons whenever you want as long as you stop it from touching the sides with supercooled magnets. How do you turn that into a remotely viable power station?
Just the heat exchanger and steam turbine portion is going to be uneconomical against renewables+storage.
Yes. Just just keeping a steam turbine up and running, completely ignoring where the heat comes from, costs more than both building out and operating wind and solar.
Sure, as long as you skip storage. Batteries are really expensive if you're using enough to get through windless nights instead of just compensate the duck curve. Long-distance transmission is expensive too, and to get through winter you need either huge storage or lots of overcapacity. It all adds up.
At this point someone usually says "we don't need batteries for long-term storage, we can just make hydrogen and burn it later" but then oops, you're back to using a turbine.
It is correct that batteries are the most expensive storage. One corrolary is that other storage is cheaper. Another is that other methods will be used instead.
Storage is an integral part of a renewable-powered grid. It is figured into all the cost analyses. Insisting otherwise is promoting known falsehoods. Lying is unwelcome here.
> At this point someone usually says "we don't need batteries for long-term storage, we can just make hydrogen and burn it later" but then oops, you're back to using a turbine.
There are various experimental options too but I don't think any have deployed at scale, so their costs are uncertain. And some of them, like thermal storage, will still use a turbine.
I'm gonna need a source on that. It seems to me that turbine cost is mainly capital cost, and if you're not running it continuously then your cost per kWh is higher.
After all, that's the argument you renewables folks make when you say nuclear plants can't load-follow economically. So tell me why a turbine run intermittently is cheaper, and prove it with a source.
Allow me to invite you to look up steam turbine overhaul cost and frequency. Do mothballed turbines need frequent overhauls? Or will they need overhauls after N hours' use at intensity Y, or after M > N operated at intensity X < Y?
Steam turbines are a substantial fraction of nuke operating cost, but far from the only substantial cost.
So taking the worst case, capital plus maintenance for a continually-running turbine is 5X its capital cost, to get 30 years of power output. For each year of power, the total cost is 5/30 or 1/6 of the capital cost.
Now lets take your 4 hours/day example. That's 1/6 as much running time, so only 5 total years of power output. It's also 1/6 as much maintenance cost, so maintenance is 4/6 of the capital cost, for a 30-year total cost of 1.66 times capital cost. Total cost per year of power is 1.66/5 = 1/3 of the capital cost.
That puts the cost per kWh for energy storage at double the cost of the continuously-run turbine.
We mostly already have the combined-cycle gas turbines, and are burning NG on them, so their capital cost is already sunk.
Until enough renewable generation is built out, it will be silly to build storage, so the turbines will continue burning NG, just increasingly mainly at night and on dark, calm winter days. As their duty cycle declines, their total annual operating cost falls in proportion. As chemical synthesis and compressed or liquified air storage gets built out, later, the fraction of their (reduced) operating time they spend driven by those instead of NG increases. As non-synfuel storage capacity (battery, pumped hydro, mineshaft gravitic, buoyancy) increases, running time and maintenance load declines further, as those pick up more load. Synfuel and compressed air will be mixed into NG in proportion increasing with stock on hand, rather than running on one fuel for a while and then another. Eventually NG falls out of the mix.
Operating the turbines only when the renewables and non-fuel storage are not supplying enough power cuts the maintenance load, therefore operating cost per unit calendar time. Not running does not mean you are not getting revenue: revenue comes in for the renewable-generated power, produced at near-zero marginal cost.
Running a turbine only sometimes extends its total life, so its capital cost is amortized over just as many kWh produced, either way, just longer in, again, calendar time.
You could model it roughly as adding the capex cost of half a turbine or so and x% of uptimes to your solar/wind capacity. Lifetime would also be longer but anything after 2060 or so is largely irrelevent for slowing climate change so we'll ignore it.
IIRC O&M + Capex for a CCGT is about $20/MWh and fuel is around $30 which would put the capital around $5 and we don't expect to operate it for long as it's a backup.
So the generator should cost us <$10 per MWh of solar + wind we use (with the majority being used directly or via batteries/hydro). Green fuel will cost about 2x the renewable energy with capex/O&M on the same order as the turbine or maybe a bit lower (ammonia electrolyzers are estimated about $1000/kw with current tech but you'd only need to put half or less of your peak capacity through it. Additionally they will run most of the time producing fuel if the target is using the fuel as the last resort backup).
With projected solar + wind costs around $20/MWh using chemical storage for winter would then have a total cost of $60/MWh for energy that has been stored as ammonia and $40 for energy that has not in a somewhat pessimistic ballpark with price dominated by fuel generation. On par with some current full time gas, but at the upper end. Far less than fission if we use the same 'joules before 2060' constraint, but enough to cause difficulty building out new gas turbines if we don't presently have enough.
Fusion isn't really in the running as a steam turbine is much more expensive than a gas one so we're getting close to parity with the renewable + battery + gas turbine just from the steam turbine step.
From a quick google, steam turbines cost about 50% more than gas turbines.[1][2] Gas is $500-700/kW, steam is $670-1140/kW.
That's easily compensated by the higher capacity factor of non-storage applications (since storage turbines, calculated above, cost 100% more per kWh due to idle time). Also, storage has to add the cost of the electrolyzer and ammonia storage tanks.
On top of that, round-trip efficiency of energy storage via ammonia is only about 30%.[3] So if your solar farm costs $20/MWh, your cost of stored energy is over $60/MWh before accounting for turbine/electrolyzer costs.
This means you can easily be competitive with a steam turbine plus a heat source that costs $60/MWh, at least for baseload.
Right, steam turbines cost about 50% more. But a turbine for energy storage is likely to get a much lower capacity factor than a turbine on a generator, so it evens out. (Sources and math in another thread below my above comment.)
TEGs are pretty neat, but the temperature and energy flux is very hard on the materials.
If only there was some way to get energy from a fusion reaction via a semiconductor junction by running them in parallel at low temperature rather than in series at extremely high temperature, and a long way away so the neutrons could thermalize and you could absorb much easier to handle photons. Oh well.
A study device and thinking from first principles about the reaction.
There are higher energy reactions like proton-boron that emit only light and charged particles. Eric Lerner's Focus Fusion approach taught me about that.
I'm looking at parallel delivery of single photons and how that scales as laser systems develop. Lasers themselves are on an exponential curve, so that seems promising.
1) don't try to achieve a chain reaction, but do single atom reactions and fully cycle the energy. Simpler to think about, and raw energies add up (see link).
2) if chain reaction needed, orient the reaction to aim the outputs towards their secondary targets e.g. with a crystal lattice fuel package.
The usual place. Surround your fusion reactor in a very thick blanket of opaque hydrogen plasma so the neutrons can bump into something.
Contain the whole thing in some kind of force field (if only there was some alternative to the EM force for this purpose), then when the photons hit your photon electric generators you get electricity.
If you arrange things such that the outside of the opaque hydrogen blanket is about 5800 Kelvin and your photon-electric generator panels are spread out in parallel to...let's say about a kilowatt of energy per square metre they should last a couple of decades and your efficiency will be okay, maybe around 20-30%
There. Fusion power plant invented. Sadly it's just a pipe dream though because we couldn't roll it out without first waiting for a stable fusing plasma source on earth.
It heats them up (The joke is I'm describing the sun and solar panels as the end state of trying to overcome the technical hurdles of building a heat engine to extract electricity from fusion if you're not just playing along).
Jokes aside, TEGs are pretty neat. In addition to harvesting what is currently waste heat in someplaces or having applications in geothermal or solar collectors they might even make fission not-stupid. Can't forsee any way fusion works as practical power generation this century though. It has worse power density than chemical and much higher temperatures to deal with and much higher neutron flux than fission as well as needing massive 2 kelvin magnets right next to the 100 million degree plasma that explode if they warm up to 3 kelvin.
Right. It's not physics (though arguably plasma isn't that well understood but let's ignore that) it's just incredibly difficult engineering and needing to solve multiple extremely difficult engineering problems. In that same sense reversing climate change is just an engineering problem, populating Mars is just an engineering problem, a space elevator to orbit is just an engineering problem, quantum computers etc. etc. ;)
There are other competitors in those niches. Some of which are just indirect ways of storing hydrogen depending how you use it. Ammonia, methane, dimethyl ether, methanol, and longer chain hydrocarbons. All have positive and negative tradeoffs
Similarly there are other competitors for fusion. The difference here is they are orders of magnitude better in most ways. Fission and chemical reactions have much higher power density and vastly lower cost (and fission is already cost prohibitive), renewables are vastly cheaper even with battery or chemical fuel storage. There's not really a good niche for D-T fusion even if we had it today rather than in 50 years.
All the alternatives have serious efficiency penalties. All the alternatives that have carbon atoms in them require either atmospheric CO2 capture (expensive) or capture and storage of CO2 from combustion (and now we're back to storage of a gas, and also we've just increased the per-output-power cost of the system, which is very bad.) Hydrogen is unique in requiring none of that and allowing cheap underground storage.
It's been considered, for a variety of heat sources. I'm long-term bullish on a related technology (thermophotovoltaics), although presently the efficiencies are not great & the compatibility with nuclear radiation is probably poor.
It seems relatively accessible too, at least as a technology and conceptual model it shows a simplicity that allows the majority to get their hands on it and thus a potential for more growth and innovation. It’s interesting that it also allows refrigeration.
If we could combine heating, refrigeration, with a configurable output of either end on top of it being a generator of voltage… is quite amazing.
The power density is much higher than traditional photovoltaics (more in line with concentrating photovoltaic power), so in theory the cost should be low, although one probably needs more sophisticated cells to achieve reasonable efficiencies. On the other hand, since there are no moving parts, the temperature can be very high, which increases the maximum theoretical efficiency. (Carnot limit applies.)
The major issues I can see are (1) achieving sufficient efficiency at a reasonable cost, by recycling the low-energy photons instead of absorbing them as heat (2) avoiding radiation damage to this sophisticated device - maybe this isn't too hard with a liquid salt heat exchanger?
I still don't understand why we don't really have a reliable and good way to convert chemical bond/radioactive energy into electrical energy directly? Why do we still require 2 conversions of Chemical -> Heat -> Electrical ?
Is that something that is impossible or not cracked yet?
Fuel cells convert chemical -> electrical directly, batteries go both ways.
For nuclear fusion, the only practical reaction releases 80% of the energy as uncharged particles (neutrons), for which the only way to harness their energy is to convert it to heat. The 20% of the energy that is emitted as charged particles could in principle be converted with high efficiency, but the other 80% dominates.
For fission, more of the energy is emitted as charged particles, but it's not clear how one would harvest it directly in bulk. (It can be done on small scales, but not efficiently.)
Some examples exist for directly converting alpha, beta, and gamma particles into electricity, but I didn't find anything for neutrons in my brief search.
Why is there no image of the sinking ship? Because at sea in war zone? Wouldn't Ukrainian army want to show image from their drone after hit? New satellite image coming soon?
Apparently it sank during a storm so probably getting visual confirmation to share was though. The drone was used to distract the radar, probably got shot down.
(Publicly accessible) satellite images weren't immediately available because of cloudy conditions, from what I read on news reports about the incident.
Cool but ISP and others can still spy on IPs you make requests to and simply ask for reverse DNS of that IP to still get a good idea of what you are doing? Not sure how we could really achieve 100% privacy from the ISPs.
Isn't this more to prevent ISPs from modifying the results of your DNS queries? Also, in the future when we get encrypted SNI, users of websites behind CDNs like CloudFlare or similar (where the website you are visiting will not be discernible from the IP you're connecting to) will benefit from DoH + eSNI.
Another goal is to deal with the problem of "no log" VPN providers being forced to tag all internet-bound traffic on port 53 with the customer IP it originated from.
This has evolved into the universal compromise, since the VPN provider still gets to claim that they themselves aren't doing any logging. But of course their upstream ISP is now easily able to do so.
This is why mullvad intercepts all DNS queries (even to 8.8.8.8 or 1.1.1.1). Try using OpenNIC from behind mullvad: you won't get the extra TLDs.
Logging DNS makes it easy to selectively deanonymize people. All you have to do is get them to browse to a website that resolves a weird domain name.
Then, start a VPN provider and wait for the NSL to arrive, like Mozilla did.
Not a coincidence that they suddenly started pushing DoH hard shortly after launching their own VPN. Before that it was just another protocol; after the VPN they suddenly were in a big huge hurry to put people on DoH by default whether the system resolver supported it or not.
If your ISP is running the DNS with DoH/DoT then those queries can still be modified. Encrypted DNS does not solve the problem of DNS record manipulation.
For the rest, encrypted SNI might help, but it's still a draft so not really in use. Also 95%+ of sites are identifiable by IP only.
You could be using a VPN. I always found DNS with VPN messy, how not to leak queries, how to resolve internal records, how to react to the VPN servers dhcp info.
Never send DNS queries into a VPN. They are all logged along with the originating client IP.
If your VPN provider claims they "don't log" it just means they're tagging the query with your IP as it leaves their network and letting their upstream ISP do the logging.
Indeed, however there are more use cases for VPNs.
You might run a "road warrior"-setup, connecting to the company network for services and accidentally leaking company DNS info to the airports WLAN provider.
I think its the opposite: things are slowed down on S62 so they can’t reach speed of light. That is how you could (in theory) go in the future because earth time would go faster if you were on S62. So if you could watch it, it would be slower?
