Korean nuclear fusion reactor achieves 100M°C for 30 seconds
shiningscience.com
shiningscience.com
> 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.”
Also Texas, another state where they pushed green energy (wind) and slowed the investment in fossil fuels.
We all want cleaner energy, but we must acknowledge that it is not easy.
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.
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.
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.
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 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.
That's why we are considering placing a converter above the sky to more efficiently pierce the sky with energy.
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.
(for the uninitiated: https://youtu.be/3m5qxZm_JqM)
https://energyeducation.ca/encyclopedia/Solar_energy_to_the_... Demonstrates otherwise. About 30% is lost to the atmosphere, 70% reaches the surface.
The UK is building two of these pump uphill things. Four more and it could sustain a 99% carbon free grid on solar and wind alone.
So?
> 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”.
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.
https://ieeexplore.ieee.org/document/9837910
> 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.
Of course, this is actually desirable imho, but yes, both geopolitics as well as cost, stops this from happening.
So, storage is just a part of the grid, and the grid may be fed by wind, solar, hydro, and geo "alone".
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.
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.
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.
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?
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.
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:
https://www.getsunsights.com/will-the-concept-of-space-solar...
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.
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.
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,
> and there are zero physics problems to be solved,
> just practical civil engineering.
[1] https://cleanenergynews.ihsmarkit.com/research-analysis/grid...
> Alchemy is not a solved problem
Ah, trolling. OK.
What form of grid/utility energy storage do you expect will dominate in 20 years?
I provided a reference to back up my assertion. Do you have any?
Everything comes down as manufacturing volume goes up.
I'm seriously hoping that aluminium-chalcogen batteries [https://www.nature.com/articles/s41586-022-04983-9] can be scaled and commercialized soon
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.
We can make it -- in a fusion reactor :)
Oh is that all. How could nobody have thought of this yet?!?!
Remember they were replying to a claim that it would be "inexpensive"
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.
https://ieeexplore.ieee.org/document/9837910
> 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.
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)
https://www.nrel.gov/docs/fy04osti/35097.pdf
"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."
And renewables happily coexist with other uses of the same land, so none is used up.
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.
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.
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.
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.
They require less money to build, and less to operate, than nuclear (per unit of energy output).
So, your talking about land could only be a valid objection if land itself was the constraint. And that's what my snark about eating was aimed at.
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.
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.
A renewable grid includes storage. Storage is cheap and getting cheaper.
In fact, it's long been addressed, and the cost of dealing with intermittency of renewable sources appears acceptable.
https://ieeexplore.ieee.org/document/9837910
> 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.
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.
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).
Actually thinking about it figuring that out would make fission a lot more tenable too
But we already know that fission, too, is uncompetitive, moreso each day as costs for renewables and storage continue relentlessly downward.
Fusion has no chance of ever catching up.
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.
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.
Though you'd need something very different from existing photovoltaics to capture the energy from those x-rays.
It will never produce so much as one kWh of commercial power.
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.
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!
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.
If you're going to compare to utility-scale solar or wind, be sure to include their much lower capacity factor: https://en.wikipedia.org/wiki/Capacity_factor#/media/File:US...
(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)
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.
1. What's the most efficient way to boil water?
2. How do we generate electricity on a population scale without having to boil water?
Question 1 is, apparently, much more tractable. We are still pretty much building the world's most sophisticated tea kettle.
Doesn't need to be the most efficient. Just more efficient per energy transferred to the water than all the other options.
Most efficient conpared to what we have already, but there may still be more efficient ways
https://en.wikipedia.org/wiki/Aneutronic_fusion
Helion Energy is the best known.
https://en.wikipedia.org/wiki/Helion_Energy
HB11 is another one
The others will just spend investors' money until it dries up. Helion too, most likely.
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.
https://en.wikipedia.org/wiki/Tritium#Production
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.
Extracting tritium from a thousand tons of radioactivated lithium hydroxide at PPB concentration is left as an exercise for the ambitious reader.
Good luck.
Other neutron absorbers are contemplated, but extracting tritium from them on PPB concentration is no easier.
Designing the first wall and the volumetric blanket are, indeed, engineering challenges.
They usually can't adequately explain why in a single forum comment.
This topic is not one I'm personally familiar with, so possibly making an ass of myself, but (shrug).
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?".
So it is all castles in the sky.
This problem has been known for decades.
http://orcutt.net/weblog/wp-content/uploads/2015/08/The-Trou...
https://pure.mpg.de/rest/items/item_2131865_1/component/file... (see section 4.1.1)
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.
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.
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.
If you want to talk about "redeeming" then you need to include externalities, and those are pretty bad for coal.
> the human cost of just shutting off power completely if it’s not clean like people seem to want to do.
Nobody wants to do that, stop being weird.
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.
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.
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.
Worse according to who? Climate activists? Or people who are going to freeze to death because those “worse” options weren’t kept online?
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.
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.
Thank you.
The syllogism works the other way too.
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.
Then I pointed out that our electric car does it in both directions too.
electric <-> kinetic - spinning magnets
kinetic <-> pressure - turbine / pump
pressure <- heat - boiler
heat <- chemical potential - furnace
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!
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.
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.
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."
I see what you did there. I feel the same way, though. It feels primitive. But it’s what we’ve got!
"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%."
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.
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.
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.
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.
> I don’t mean to be rude, but to say this without qualification is essentially baseless ignorance or lying.
Your own words can be used back at you.
(Not agreeing with GP, but your zeal in rebuttal falls victim to your own accusation)
We're their pet project, why would they invade?
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 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?
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.
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.
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?
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.
> 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.
I really don't understand why you think this.
(Good thing ʻOumuamua missed. Better luck next time, chumps!)
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.
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.
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.
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.
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.
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.
Interesting times ahead
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.
I need to go hug my wife and children
I guess, if a species used a Dyson sphere for so long, they will certainly have colonized other solar systems, which each have their own star to milk.
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.
The biggest open question with grid storage is which of the many competing technologies will come out on top.
Edit : solar don’t involve having a Dynamo spinning.
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).
It’s a « us » phone born and raise in the US. But I fed him so much French that he is unsure about things.
I let it happen. Accent are fun.
https://solarsystem.nasa.gov/missions/cassini/radioisotope-t...
You can also do hobby-level usage like charging a cell phone with a candle.
I believe the containers would have to be really large.
Also, if we have to continue boiling water at scale, we might reach water crisis some day. Although, it'd take very long time.
I'm being silly, but I'm genuinely curious if there are any plans, even speculative ones, on how to do this.
By the time this could be made to work, nobody will want it at any price.
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.
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.
When it comes to fusion I am always in too minds about statements like this.
On one hand, yeah, it is something that we may be able to wrangle into something useful.
On the other, fusion can be seen as a perpetual motion machine that doesn't defy the laws of physics. It can kind of inhabit that same mind space.
It's so very nearly amazing in several different formats and applications. Net result is it's kinda okayish in a couple of niches.
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.
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.
(If you look at the power density of the plasma alone, or the fission reactor core alone, you get similar wildly discrepant numbers: https://cpb-us-w2.wpmucdn.com/research.seas.ucla.edu/dist/d/... see slide 26)
If you want to make heat to make steam to drive a turbine, a fission reactor will be much smaller, and much cheaper, than a DT fusion reactor.
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.
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.
I would not be excited about attacking the problem of how to safely get energy out of a soup of hot, corrosive, exotic radionuclides.
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.
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...
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.
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.
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.
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.
If you know how to hire well, and have tons of money, it's difficult to do badly.
Overwhelmingly more of success is luck than anybody involved likes to think.
1 out of 4 seems solidly probable to me.
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.
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…
> 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.
[0] https://www.sec.gov/ix?doc=/Archives/edgar/data/0001318605/0...
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.
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.
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.
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.
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.
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.
Edit: Also Jim talks about Elon’s engineering skills at 50 minutes into this interview: https://m.youtube.com/watch?v=1TmuJSbms9c
Disclaimer: I’m not an Elon fan at all.
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.
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.
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.
You are right that the reactor structure costs more. Which is the point I've been trying to make.
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.
What's wrong with a 3-6m size reactor vessel?
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 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.
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%)
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?
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.
Polyimides like kapton are a good example.
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.
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.
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.
Just like it was for experimental reactors for fission.
Sure it might be unfeasible but you gotta give it a try before judging it a failure
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.
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.
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.
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.
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.
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.
If you compute how thick that plasma would have to be to stop neutrons you'll realize this idea is totally unworkable.
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.
Fusion batteries would be cool!
https://docs.google.com/document/d/1B5maRx9w0ahQTqSe6UZ56rd0...
But if it could be made to work, it would be a better prospect than D-T.
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.
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.
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.
The only other major option is using pumped hydro for storage, but not every region has the geography for it.
> 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.
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.
Steam turbines are a substantial fraction of nuke operating cost, but far from the only substantial cost.
I haven't found specific numbers on steam turbines, but this pdf says a gas turbine's maintenance cost over 30 years is 3 to 4 times the capital cost:
https://www.gasturbine.org/papers/GTA%20Comments%20on%20RMRR...
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.
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.
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.
[1] https://www.greentechmedia.com/articles/read/ges-new-gas-tur...
[2] pdf: https://www.energy.gov/sites/prod/files/2016/09/f33/CHP-Stea...
[3] https://www.ammoniaenergy.org/articles/round-trip-efficiency...
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.
Why hasn't this been done? Why do we go to the steam stage when we could just exploit the termoelectric properties of temperature and current?
1. Thermoelectric generator: https://en.wikipedia.org/wiki/Thermoelectric_generator
2. Thermocouple https://en.wikipedia.org/wiki/Thermocouple
A steam turbine is many times more efficient.
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 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?
Is that something that is impossible or not cracked yet?
https://en.wikipedia.org/wiki/Atomic_battery#Radiovoltaic_co...
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.)
This was the first time I heard the "nuclear fusion is 25 years away" joke and it was told as such. We were also shown a graph of how many orders of magnitude away from ignition (for want of the correct word) by date. It had an initial steep decline but then turned right quite sharply and had annoying looking tendency to avoid the magic value.
Now, once you have ignition, you have to sustain it and extract power from it. That's quite tricky too!
See p.4-5 of [1] for more recent plots. It includes earlier runs of both KSTAR (the experiment under discussion) and EAST (the Chinese one mentioned in another comment), but not their most recent ones.
The graph I was shown was more of a "lies to children" job (a Sir Terry Pratchett term for simplification of a concept to enable teaching to happen). It looked more like a somewhat lumpy y=a/log(bt) where a and b are not 1.
I'm just a simple IT bod what studied a fair bit of engineering and a smattering of science back in the day. That graph looks like it forgot to put it's bloody knickers on. The one in the paper https://arxiv.org/pdf/2105.10954.pdf is a bit closer to what I remember.
I do feel that we can relax the 25 year rule a bit these days. I think we can quite confidently allow 20 years and I'm quite cautiously going to suggest 15 instead.
I recall watching "On a Friday" play on the cricket pav. of Abingdon School ("Royce's") at the end of term, summer '87ish. Thom did wear some very colourful waistcoats with his suit and Ed in mufti generally minced around wearing slippers, no socks and an electric blue jumper and a whopping quiff - as was the style in those days ("I fastened an onion to my belt..."). Actually this was the time of the New Romantics so think Culture Club, The Smiths, The Cure, Duran Duran etc.
History is what is written and WP is not keen on first hand experiences: "The band disliked the school's strict atmosphere ..." is writ on WP.
My perspective:
The school is a public school - so borders, dayboys and any school needs some sort of discipline. At the time it was all boys, I think it is now co-ed. However, next door there was the Park which was "no man's land" (master's and mistresses kept away and let the kids get on with it, provided we didn't take the piss) and both Abingdon boys and St Katherine's girls or Fitz Harry's or whomever could meet up and have a fag (smoke) and socialise in general.
We also had a bar in the cellar of School House for the weekends that was run by the boys and financed etc by us. Again, we were given a lot of slack, it was actually educational too - money in - money out etc. There was also the H&J (Horse and Jockey pub) - keep to the snug and look adult was what the owner told me as ordered a pint the first time (bless). I was in Waste Court House at the time.
My memories of Abingdon School are rather golden - I was extremely lucky to go there at the time. The Army paid for quite a lot of it. Nowadays it costs £40,000 a year to go there.
I would never describe Abingdon School as strict as such in the late 1980s when I was there. The Head was affectionately known as "Freaky Beaky" (a Headmaster is always the Beak) which is pretty standard for any public school. However, Mr Parker was also known as "Miffie" and that was down to someone overhearing his wife using a term of endearment.
At the time, obviously, there was no hint that On a Friday would go on and become a worldwide phenomenon but they were pretty good entertainment for a school band. They clearly had an itch to scratch and buggering off to the US and re-branding etc worked rather well. Well done them. It has to be said that Abingdon school was (with hindsight) extremely supportive. Mr Parker sanctioned On a Friday to play on the cricket pav for end of term entertainment.
Well spotted, and sorry, I seem to have started waffling on a bit ...
Any more to add?
IIUC, France has one of the highest percentages of nuclear energy of any country in the world.
Is this supposed to be bad?
This won't be a problem in the Winter when they're most needed.
Sure, they are necessary.
But if France's existence depended on it - I imagine this is a problem they could solve relatively easily.
On the flip side, Germany is not going to magically generate 80% of their electricity from Nuclear Energy anytime soon. Nor the US or Japan or South Korea for that matter...
> Any more to add?
The Battle of Waterloo?
Germans in Czech tanks went around the end of it, through Belgium.
Without Czech armor, the invasion might have failed. Predicting the Germans would have the full resources of Czechoslovakia would require more prescience than we should demand.
These are just some of the wonderful things the President Moon has accomplished.
Nuclear fission definitely has lots of advantages, but it comes with lots of geopolitical and operational challenges especially if you want to use it for decades, or so called "sustainability". One of the critical factor of "escaping from nuclear fission" was the fact that S Korea is not going to have permanent nuclear waste sites anytime soon; everyone have been talking about that over 30 years and no political party even dare to build the one because in S Korea, every single political issue eventually converges to a matter of real estate. And you know what? The capacity of the existing temporary storage for most plants will be exhausted within 5~10 years.
Now we're talking about the so-called "sustainability"; it's not about environment or whatever liberal propaganda but the dire facts that S Korea will be forced to shut down nuclear reactors unless it finds other ways around. The previous administration couldn't come up with a good solution so decided not to build more reactors. Oh yeah, they didn't even dare to shut down those reactors to earn a little bit more time. It's not even a propaganda, but just a mediocre compromise. Its territory is not big enough to construct just a single waste site.
Oh, then why don't we reprocess the waste? And now we're talking about geopolitical aspects. The US-Korea atomic energy agreement severely constrains what S Korea can do with the waste. Unlike many first world countries, it doesn't have the reprocessing technology and unlikely have the one unless it begins enjoying political tensions with the US.
Nuclear waste is just a tip of iceberg; you're going to find an arbitrary many number of operational and economical challenges on Nuclear fission reactor. And I also want to mention general public reception on nuclear energy, "I trust nuclear energy, but not its operators". Yeah, Korean nuclear industry is well corrupted to its root and it deserves its own reputation. In the era of climate crisis, going to nuclear fission seems no-brainer, but the devil is in the detail.
Which is why all three have/had such strong nuclear expertise.
They are near / wary of China? That is why they have nuclear expertise?
This made me wonder when ITER was going to actually be up and running. From wikipedia:
> "The reactor was expected to take 10 years to build and ITER had planned to test its first plasma in 2020 and achieve full fusion by 2023, however the schedule is now to test first plasma in 2025 and full fusion in 2035."
So, it sounds like it'll start doing something within a few years, but it'll probably be a long time before it produces significant scientific results.
By the time ITER is running, maybe some other group will beat them to it (like the MIT ARC or SPARC reactors, which use more recent, better superconductors and don't need to be anywhere near as big).
Reducing the number of countries involved will probably just speed it up.
The longer it takes, the longer the money flows. The moment its real prospects become clear to everybody, the money stops.
They are not even talking about starting on a power plant before 2050, or finishing before 2070.
It will of course all be dropped long before then, one way or another. Either we build out renewables fast enough, or civilization collapses before we get there. Either way, no fusion power.
I don't think ITER would be dropped because of renewables. Even if we had enough energy to power our civilization, there's always other things we could do if we had more. Civilization collapse could put a halt to ITER, but another possibility is the project could be dropped because someone else beats them to it and they don't need to finish this expensive machine just to find out what everyone already knows about magnetic plasma confinement.
Continuing to spend up until then diverts money from other things not best dropped.
Confining plasma does not suffice to get you power generation.
I guess there's also lot of value in getting the private industry expertise in building the magnents and all of the complicated sub-parts. Basically training a whole generation in practical advanced fusion development. Hopefully there will be some real-world application in time for this knowledge and expertise to be transferable.
https://news.cgtn.com/news/2021-12-31/China-s-artificial-sun...
Half of the engineers on HN right now:
[...as long as the technique used can be scaled up...](PTSD_Chihuahua.jpg)
In other words, are the byproducts able to form back into the "fuel" at a reasonable rate with the energy input of the Sun? I know that a selling point of fusion is that there is such an abundance of fuel that this doesn't matter. But if we treat finite energy sources as infinite, exponential growth in our energy budget means that we will undoubtedly run out of energy, as is being done with forests and such.
After all, I have a feeling people at the dawn of the industrial revolution thought the amount of coal available in the world would serve their needs "practically forever," until energy consumption scaled up by thousands of times.
Tritium, on the other hand, is a problem. It is radioactive with a half life of ~12 years and so the little we have needs to be produced since we can't really accumulate it. Currently it is produced by conventional nuclear reactors. Additionally, breeding tritium is harder than deuterium and requires a blanket around the reactor that uses other materials to multiply the number of stray neutrons. For each atom of Tritium that is fused we could get somewhere between 1.1 to 1.7 with a theoretical maximum of 2 Tritium atoms so, finally answering your question, it is renewable. It's just hard, but a piece of cake compared to actually maintaining a stable fusion.
Intractable in my mind sounds more like something that you don't know how to even start.
Intractable means that anything you try is worse than not starting.
(Damn autocorrect.)
Far more than that is available.
There is no choice about that: it is the only way to get enough tritium to keep operating.
Lithium hydroxide is what you get, as thousands of tons of caustic vapor, when it catches fire.
What that does when you breathe it does not bear contemplation.
The usual designs are things like Li, PbLi, and lithium containing ceramics.
But whatever you use, you have to get extremely low concentration tritium out, somehow, to run the reactor on tomorrow.
That seems like the least of our problems.
https://cpb-us-w2.wpmucdn.com/research.seas.ucla.edu/dist/d/... (see slide 21)
"40 years away and increasing" is an eye-opening admission. They have no plan for how to produce more tritium than they consume, never mind any way to collect it. And they don't expect to have access to enough tritium to even start operations on the successor to ITER.
Another startling omission is that Tokamak and stellarator designs are unsuitable for a production reactor, and there are no alternatives under consideration.
Finally, they have not identified a structural material that will stand up to the neutron bombardment and continue to hold the reactor together.
It makes the fusion startup companies look even more like out-and-out scams.
1000 tons of lithium deuteride (half 6Li, half 7Li, all 2H) would cost ~$2B for the deuterium, plus a smallish fraction of that for the 6Li-enriched lithium. Any deuterium that picks up a neutron would become tritium, adding to what is got by fooling with the lithium. Maybe you economize with half-H, half-2H, for only ~$1B.
You have many reasons not to let your LiH catch fire, beyond that it cost you $1-2B and would totally destroy your $50B reactor and be deucedly hard to put out. It burns in air to LiOH, Li3N and H2, and reacts with any water, CO2, or nitrogen you might have hoped would douse it. Li3N further reacts with the hydrogen making lithium amide LiNH2, thence various unpleasant peroxides.
Regular LiH is solid at a more-familiar operating temperature under 400C, and liquid at what might thought an extreme 700C. The deuterides would raise the melting point some. You really want something in there to scavenge any metallic lithium, if molten, because that corrodes steel and silica.
However, for all practical intents and purposes, solar energy is renewable. The same holds true for nuclear fusion for at least a couple of hundred years, even considering growing energy consumption.
Deuterium fuel is the most abundant. There's enough in your morning shower to supply all your energy needs for a year. There's enough in the oceans to last for billions of years. Fusion is as close to renewable as anything, because it'll last until the sun goes out.
Right now most projects are also using tritium fuel, which has to be made from lithium. That's plenty abundant but not to the extreme of deuterium. But pure deuterium fusion is possible, just a little harder. And one prominent fusion startup, Helion, is actually using deuterium (along with helium-3, which is the waste product of deuterium fusion).
We should switch a good chunk of fussion funding towards 'clean' fission; travelling wave reactors, molten salt, small modular reactors, thorium, etc, etc. Some of these have a chance at being commercially viable and making a real impact this decade, not half a century or more hence.
Fix the NRC, and we might get somewhere with fission.
This is where much of the energy debate in Europe is at now. It is exactly the same argument being used against fission.
Pick any technology that has come to fruition in the last decade. Video streaming as a substitute for cable and terrestrial TV. Mass adoption of Smart Phones. EVs becoming a viable option for broad populations of car owners. A space startup that came from nowhere and rapidly out-competed the incumbents. All of them.
Remember the Apollo astronauts who walked on the moon shitting on private space companies on C-SPAN not that many years ago?
Look at the time span between people dismissing these technologies as off in the distant future and when they arrived. People have a tendency to assume that tomorrow will be the same as today.
Affordable nuclear is still some years away. I think the events in Europe actually shortened that distance into the future by a significant amount just in the last 6 months. But fission power is still "too slow". Fusion is even more years away into the future. If/When it comes to fruition people are going to be surprised, and none more so than the experts.
Because the experts are almost always wrong for a good while after disruptive breakthroughs have already happened.
It means we have to think ahead and make sufficient bets on technologies that exist at all time scales. And the more potential they have for delivering stable base load, the higher the payoff.
Yes we have to invest in both fission and fusion. And we have to invest a lot more than we already do.
But in this case the 'experts' seem to be putting all the funding toward fusion, which is likely decades away, if at all, and almost not at all toward new fission, which could be viable this decade.
No new nuke design begun today could produce any power before 2035. The money spent building it, spent on renewables instead, would produce immediately, displace CO2 immediately, and produce more.
Small modular reactors could well be operating before the end of the decade, with government assistance, esp. regarding permitting.
But that's beside the point, and your argument is exactly that criticized above - ie we should spend today on current tech rather than research for tomorrow. Renewables are now essentially 'baked', and from the government pov it's just a matter of tweaking regulations etc to encourage further commercial rollout.
But we should also be researching for the future, and new nuclear needs help to actually develop the technology to commercial viability, along with say, deep geothermal. In comparison fusion is pie-in-the-sky, and doesn't warrant it's outsized funding - some funding (for the science), yes.
Please do not pretend not to have heard of storage. It fools no one, but makes you look foolish.
I agree we should be investing in storage technologies too, just not to the exclusion of other options.
https://ieeexplore.ieee.org/document/9837910
> 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.
Note that other western industrialized nations are significantly less wasteful with residential electricity; the same storage would last the average german household already over 2 weeks for example. Part of the difference might be explained by air conditioning-- but this conveniently requires very little storage anyway.
That sentence doesn't make a lot of sense to me.
Meaning that on average, each household requires ~1kW of electricity.
I've spent much of my life listening to what people say various things can't be done. And then either seeing people do what was "impossible" or, in a few cases, participating in doing what other people said couldn't be done. It is the same kind of mental pitfall that magicians exploit: the audience fail to imagine the amount of effort that can be brought to bear and hence make assumptions about what is possible within a scope that wasn't as limited as they thought.
It doesn't happen often, but it happens often enough that I'm disinclined to dismiss possibilities before they have been properly explored.
I'm not saying fission can be accelerated to, say, a sub decade path to realization. I'm saying that categorically stating this timetable can't be accelerated is a bit premature before anyone has made a serious attempt.
So what do I mean by "serious attempt"?
If you look at investment in fission over the past decade, in my book that qualifies as the world not having made a serious attempt. The level of investment needs to be perhaps on the order of 2-3 magnitudes higher for it to be a "serious attempt". And it doesn't have to be a null sum game in the sense that it would all have to come from reallocating investments from other energy sectors - it could be that we allocate more resources to the energy sector.
The most reliable prediction, historically, has been that they were lying about costs. No fission project has ever been gone forward without massive public subsidy. There are no projects in progress now or proposed that do not rely on massive subsidies. These go back to the first "too cheap to meter" claims.
And yet, this appears to be happening.
The thing is, arguing that "X can't happen because X hasn't happened before" isn't a proper argument because everything around you has spent more time not happening than happening.
A compelling argument is one that argues how X can't happen for reasons we can know. For instance if we bang up against hard limits imposed by natural law that we just can't get around.
Electric cars were not, in fact, a practical prospect until lithium battery technology improved radically. It was not the prospect of electric cars that drove the improvement. It was cell phones. As soon as the batteries got good enough, practical electric cars started to be offered, cash on the barrelhead, what you see is what you get.
Nuke experience resembles this in exactly zero details. It is frankly weird you thought otherwise.
Each dollar diverted from renewables build-out to nukes brings climate catastrophe incrementally nearer.
Also, if we are going to be super optimistic about fission we can also be optimistic about battery storage and solar.
Let me give you an example. Right now I have at least half a dozen 6-9 channel IMUs on my person. Most of which cost from a couple of dollars to a few cents apiece. When I was a kid a much less precise IMU could cost more than a decent car. If you asked people who worked on equipment containing IMUs back then they would probably not have predicted today's price point and the fact that billions of these devices are owned by people of all levels of wealth.
Before the advent of MEMS devices, cheap chip manufacturing and a mobile market to drive up volumes and drive down costs it was fairly hard to envision that you could make a decent precision IMU and make a profit selling it for pocket change.
In fact, when I was a kid, nobody very few people who ran numbers really believed that mobile phones could be had for less money than a dinner at a not-even-fantastic-restaurant within our lifetime.
If you are to argue that something can't happen, you kind of have to find compelling argument rooted in fundamental limitations.
I don't think fission is ever going to be cheap as it deals with materials that are tricky. But I'm not ready to make the assumption that they can't be made cheaper per kWh than, say wind or solar (as you have to combine these with storage to solve the same problem).
That wasn't the point. The point is that right now people can't even envision that nuclear can be done more efficiently because there isn't being invested much in nuclear. Just as people couldn't imagine cheap IMUs or electrical cars that were actually as good, and often better, than cars with combustion engines.
It was an observation about people. Not things.
If you look at the current energy crisis in Europe, that's one of those wakeup calls that could, and should, change our awareness of energy mix. Even before the Ukraine war, Europe was heading for an energy crisis because it was not investing enough in constant power sources. Focus has been on renewables, which is well and good, but wind and solar are intermittent. And as Norway is discovering, with changing weather patterns, hydroelectric becomes a challenge as well.
To illustrate how serious the crisis is: a lot of businesses are energy intensive. For instance a grocery store requires enormous amounts of cooling. Bakeries require electricity to drive huge ovens. Some of these businesses see nearly an order of magnitude higher electricity costs. There are farms where crops get plowed into the ground because farmers can't afford the energy to process the produce and bring it to market.
This doesn't scare people nearly as much as it should. So the value is rather obvious at this point.
I mean, doesn’t the atmosphere in our big greenhouse always retains a non-zero amount of energy, no matter the CO2 etc. in the air? If that is true, then so far the net energy out flux was positive, but now we see with rising greenhouse concentrations that it’s turning. If we then raise the stock of energy inside the greenhouse, it overheats, no?
In any case this stuff will never produce so much as one solitary kWh of commercial power, so the question is wholly academic. Fusion heat would cost much, much more to extract in usable form than fission, and fission is already not competitive.
The dream of unlimited power without spending on fuel -- capex but no opex -- is already here, and we call it renewables + storage. We just need to build it out fast enough that civilization doesn't collapse first. Fusion is a pernicious distraction, in present circumstance.
This is inaccurate, both production and storage have service lives (in years, cycles or both) so need to be continually replaced. This is opex in practice
We currently generate most of this power in exactly the same way, but by burning coal and gas to make heat rather than by nuclear fusion.
The difference would be that no CO2 is released with a fusion power plant.
5W/m^2 or 0.5% is enough forcing to be catastrophic which puts us roughly in the 20x current consumption or 2100-2140 range if we don't stop growth.
So yes. We're in exactly the same position now WRT heat as we were when scientists first started warning about greenhouse gases. Ironically switching to PVs and starting the transition was an option then too even though the first commercial PVs were thought to be thermoelectric.
We can all live well, but we can't all live in an air conditioned uninsulated mcmansion with a 9 tonne electric suv each going everywhere via highway and throwing out half our appliances which we move by truck every year.
10 billion or so people can live at current average western levels without it being a problem.
It's part of the reason fusion's so sought after - it doesn't result in anything bad or that has to be carefully sequestered.
(Apart from extraordinary heat I suppose. Perhaps there's an argument the actual reactor would always be a pretty risky place. But any incident isolated at least, worst case a remote industrial building burns down beyond economical repair.)
Also, if I understand correctly, the waste products are a lot less nasty.
I'm rather glad that doesn't apply to the fusion reactor in the sky that we'll be fully dependent on for a while yet.
Public perception > reality.
Look at hydroelectric. Terrible for ecosystems, decent number of deadly failures over the years, way better perception and less pushback from the public than fission.
https://www.businessinsider.com/dam-safety-statistics-risk-o...
As demand goes up, so does supply, as additional reserves are prospected for and more costly uranium sources become economically viable.
There's not much reason to prove reserves if you won't be able to profitably mine them.
There just isn't much at current prices, but fuel costs are not significant so prices cam rise.
With that assumption, fission can last for a very long time if we get uranium from the oceans, and burn it in fast reactors. The oceans hold four billion tons of uranium, and with fast reactors we'd use it a hundred times more efficiently than we do today.
As nuclear fission, nuclear fusion might simply not be used because of that scary word alone.
So it's still very challenging.
Fuel cost is a substantial fraction of exactly none of the generation methods in use.
Direct thermal climate foring is a couple of orders of magnitude out from current energy use.
Classical computing is almost finished.
Many minerals are at the point where extraction takes a rapidly increasing amount of energy per tonne.
Land used for grazing and agriculture is over half of habitable land.
Fishing is wiping out entire ecosystems.
It's time to think about moving earth to a steady state economy.
(with some input to kick it off possibly)
regardless, the earth receives 173,000 TW of solar radiation from the sun
we have a way to go yet
You need to build out the sequestration plants, maintain and run them, only one of those inputs is cheap energy. You need to move the carbon to a safe storage facility etc.
It's still a huge undertaking, but would be way simpler if we had cheap electricity (which it seems like we will get via solar anyways, carbon sequestration could probably be turned on and off as needed for grid conditions)
fortunately we already have millions of holes we drilled in the ground to get the stuff we burnt originally
Cheap energy doesn't need to come from fusion, wind and solar are getting quite cheap, I suspect it'll take a loong time for fusion to get as cheap even after it's wall plug positive.
https://www.lazard.com/perspective/levelized-cost-of-energy-...
28 - 37 $/MWh for solar 26 - 50 $/MWh for wind
This includes the maintenance and operating costs.
Their estimate for maintenance costs of a pre-existing nuclear plant is 29 $/MWh. That means there are cases where it'd make financial sense to shutter a pre-existing plant to build a new solar array (obviously not all cases, the generation profile of nuclear is very nice for base load)
Fusion is 10 years away from being able to generate more energy than it consumes, how far away is it from being able to be cost competitive with solar & wind?
(where implemented)
with unlimited clean energy you'd be able to print carbon credits as a result of direct hydrocarbon sequestration
the economic infrastructure already exists today, but the cost structure doesn't work
my town's anti-dog fouling laws aren't a failure because there exist other towns that permit dog fouling
in terms of contribution to global emissions everything is dominated by Chinese growth
but that doesn't mean that it hasn't curtailed emissions significantly where implemented
The fundamental appeal of these carbon schemes is that they can permit a theoretical decrease in greenhouse gases while keeping the current economic model alive and well. But despite being greatly amenable to the way things currently are, with few extra efforts or changes needed in comparison to other types of plans for the climate, they were not widely adopted at all.
The system these schemes were designed to save was unable to pick even the lowest-hanging fruit that could have potentially saved it.
So yes, it might work with unlimited clean energy, but if we have that we are already in a different arena altogether with entirely new problems and solutions and where carbon credits are unnecessary anyway.
The fact that the cost-structure doesn't work now is the indictment. Cost structures is how we got into all this mess to begin with. Saying carbon credits work is like saying a healthy lifestyle can prevent obesity. It's of course true on its own, but also fairly useless since the problem is that people are very resistant to adopting such a lifestyle.
given this entire thread is about a hypothetical future where we have unlimited clean energy I'm not sure why this is a problem
IMO this is wishful thinking, and the wrong attitude to solve a problem that is right here right now.
We should focus on reducing emissions, not on hoping that a technology that is not yet proven will be available soon
EDIT: sorry for the tone, I just re-read what I wrote. Anyhow what I wrote still stands: we have no proof that fusion will ever bring unlimited cheap energy, if ever viable.
It poses many problems, from neutron activation of the blanket to energy extraction, problems that we don't know yet how to solve, to solve them in a economically viable AND with neutral carbon footprint... well seems just unfeasible to me (hope to be proven wrong). Therefore I might suggest to pursue more understood ways to mitigate the huge problem we have
What has decreased the quality of life, which offsets the above slightly and makes it appear as thought things aren't improving much, is goods that require domestic labor, such as education, whose price has outstripped CPI, and goods that have artificial regulatory capture which cause their price to be artificially high, such as insulin, and demerit goods such as opioids which detract from the utility of the customer.
Greenhouse gases retain heat. Sea level temperature is a function of ambient heat due to sunlight and other heat sources, minus the rate at which it dissipates into outer space, mediated by the insulation effect of the atmosphere.
Projects that try to reduce the carbon intensity of energy are focused on changing the denominator in the equation. The current aim of these projects is to produce a cheap and plentiful energy source, via a heat engine. What they are actually chasing, whether they admit it to themselves or not, is a cheap and plentiful heat source. If they succeed they change both the numerator and the denominator, which ends up partially cancelling each other.
Wind and solar are different because they tap into an existing heat engine, instead of trying to build a new one.
What we as a people need is a fusion plant that costs less per KWH than a fossil fuel power plant with tariffs to account for the cost of the carbon dioxide, but still about as expensive as a fossil fuel plant where the carbon is free. If we actually got a fusion plant that was 10x more cost efficient then we'll just introduce the concept of heat pollution to the conversation, swapping out the villain in the story but keeping the same outcome.
edit: conclusion
edit again: I'm extrapolating from https://en.wikipedia.org/wiki/Jevons_paradox but didn't remember what it was called
> The growth in Earth's energy imbalance from satellite and in situ measurements (2005-2019). A rate of +1.0 W/m2 summed over the planet's surface equates to a continuous heat uptake of about 500 terawatts (~0.3% of the incident solar radiation).[2][35]
https://en.wikipedia.org/wiki/Earth's_energy_budget
I found a chart that says we’re producing about 25,000 TWh per year of power now, or 2.9 TW continuous to put it in the same units. But what is the efficiency of those plants? 35%? That’s 8.3 TW of heat, which is already 1.6% of our budget surplus. If we dogleg our energy production while thinking it virtue signaling, that quickly becomes 5% of a number that is slowly cooking us. That brings doomsday in by years.
We can’t endlessly dump heat into the atmosphere any more than we can continuously dump mercury into the oceans.
I’m getting 1.6% of our heat surplus at present power production rates, and I’m saying what if we triple our power production because it’s cheap and clean now?
Wind doesn’t increase this number. Nor does hydro. Solar only does if the albedo is lower than ambient. Tidal… I wouldn’t even know where to start calculating that. Heat engines increase it by something like 300% of the power that gets to your light switch.
Fusion and fission are bad ideas on their own merits, regardless of heat they might produce.
> What we as a people need is a fusion plant that costs less per KWH than a fossil fuel power plant with tariffs to account for the cost of the carbon dioxide, but still about as expensive as a fossil fuel plant where the carbon is free
That the fusion plant can't be too expensive, or too cheap.
Not really. It'll just be another tool for the fossil fuel lobby to use to misdirect attention from what will make them irrelevant forever (reduction and sunlight).
Even if the reactor part is free and 100% reliable. Getting heat out of a 100 million degree chamber that is spewing neutrons everywhere and turning it into electricity is much much harder and more expensive than collecting some photons and building a train.
https://www.economist.com/the-world-if/2020/07/04/what-if-ca... (not sure how to overcome the paywall)
Pretty interesting article.
If we generated enough spare power to run lots of carbon capture equipment, and removed enough carbon, the planet would cool.
There are fantastic reasons to abandon fusion, and even better reasons to accelerate build-out of renewables, but that is not one of them.
We already have proven basically unlimited electric energy in the form of PV panels (and batteries if you need it stored). So far, that tech has not solved climate change at all, because actually building enough of these things is something that people need to be willing to pay for.
As i understand it, nuclear fusion could (as soon as really achieved, i.e. there exist commercial plants) provide more energy than we are currently producing by all other methods. And if we can produce it, I have no doubt we would use more and more energy.
Which would mean that all this energy must end up somewhere somehow. What I would like to know is, don' we then (just in another form) contribute to the heating of the planet again? Are there any studies/theories about that? What would the impact of the ever increasing energy release/production be?
Also I don’t think it’s true that commercial fusion power plants would in the near term produce extraordinarily high energy levels compared to a large hydroelectric or fission nuclear power plant. The thing that’s great about fusion is that it requires very little fuel and doesn’t produce nuclear waste.
https://dothemath.ucsd.edu/2012/04/economist-meets-physicist...
If we invent fusion, I think we could grow exponentially for quite a while, but it'll mostly happen in space. Controlled fusion makes a really great rocket.
> There was a chorus of 'What do you mean?'s around the table.
> 'Well, as soon as the so-called Age of Infinite Power got under way, and everyone had thousands of kilowatts of cheap, clean energy to play with - you know what happened!'
> 'Oh, you mean the Thermal Crisis. But that was fixed.'
> 'Eventually - after you'd covered half the Earth with reflectors to bounce the Sun's heat back into space. Otherwise it would have been as parboiled as Venus by now.'
-- 3001: The final Odyssey, Arthur C. Clarke
Accuracy not guaranteed!
[0] https://dothemath.ucsd.edu/2011/07/galactic-scale-energy/
How is the heat controlled? Is there any resource that explains this thermal part?
The sun is immensely powerful, and any heat generating activity done by humans is negligible compared to the sun. Except for activities which increase the suns effects, such as creating greenhouse gasses.
Was it hosted at the facility?
https://en.wikipedia.org/wiki/DEMOnstration_Power_Plant#Time...
ITER is doing that NOW and NONE of headline-generating startups have even started...
So it seems to me that ITER is both contributing more engineering insights and closer towards a full-fledged fusion power-plant, and unlikely to be overtaken in these regards anytime soon, if ever.
We have superconductors now that can support much stronger magnetic fields than ITER uses. That lets us build smaller tokamaks with the same output as ITER. Several startups are using them, led by MIT spinoff CFS. Their SPARC reactor should have output similar to ITER's, in a reactor half the size of JET, which was built in a year. They expect to attempt net power in 2025 and a lot of researchers think they'll succeed.
Assuming that works, as similar reactor the size of JET gets them to commercial output levels.
So even IF the whole SPARC thing goes according to play, it's going to be miles away from anything resembling a competitive power plant, while ITER is potentially something like a quarter way there (assuming that operating at 2GW thermal begins being somewhat attractive/feasible for a fusion-powerplant).
Personally, I strongly doubt that fusion power is EVER going to be an option because of simple economics; I just don't really see how a vacuum chamber surrounded by superconducting magnets, cooling systems, turbines and turbogenerators is ever going to compete (financially) with just slapping PV panels on a roof, putting some battery banks in the basement, hooking it up with an inverter and just repeating as necessary until power demands are met...
A bigger research reactor is simply better in that it enables you to investigate/solve problems that are related to scale, and all those MUST be solved before a commercial plant can be built.
Until ARC or an even further removed successor catches up to ITER in size/power, the SPARC project is just yet another toy reactor IMO.
https://www.gem.wiki/Existing_U.S._Coal_Plants#Size_comparis...
Coal plants of course use steam turbines:
https://www.tva.com/energy/our-power-system/coal/how-a-coal-...
Because your chart cements my point: Power produced by coal plants smaller than ITER (<500MW thermal output, or <250MW electrical power in your chart) is negligible because building those makes evidently no sense economically (almost all installed capacity is in big plants).
And thats with coal where building smaller actually reduces operating cost from fuel (unlike fusion) plus needs no vacuum chamber, cryocooling or dealing with neutron activation...
Getting D-T fusion competitive will be a challenge for everyone, but SPARC/ARC has an obvious advantage over ITER/DEMO by having way, way lower capital costs.
This isn't entirely ITER's fault. The superconductor technology SPARC is using didn't exist when ITER was designed.
Most likely - fusion ignition in the 2030s. Fusion supplying 10% of global electricity in the 2050s.
https://www.metaculus.com/questions/?order_by=-rank&main-fee...
There is not obviously lots of money to be made in rapidly building out fusion power plants.
Achieving stable fusion does not make practical power from it possible. It would necessarily cost >10x fission, and fission is not competitive.
We can be absolutely ,confident that by 2100, there will have been zero kWh of commercial power from Tokamak fusion. It is just barely possible that D-3He fusion might work by then, but it would still struggle to compete. It might find use in outer-solar-system spacecraft.
I doubt a regular thermometer will scale at such levels.
https://www.scienceinschool.org/article/2013/fusion-4/
Incidentally, the plasma is of such low density (ie. few particles) that it has little stored heat energy. As soon as the plasma touches anything it cools down and fusion stops. You're unlikely to get a mushroom cloud out of today's fusion reactors, as there is just not enough stored energy in them. (Might that change if they are scaled to the point where large amounts of energy can be extracted, a bit like the bang out of a large charged capacitor?)
I believe the chambers are operated at a pressure of 1/10,000th of an atmosphere.
Edit: A bit more searching turned up an answer. It's a neutron absorber. So it's used as a shield to stop the neutrons leaving the reactor?
Extracting parts-per-billion of tritium distributed throughout thousands of tons of hot, brittle, radioactive, super-flammable LiH would be no picnic. Melting it probably would not make that easier.
Fortunately, no one will need to.
Hundreds of tons of deuterium in your thousands of tons of terrifyingly inflammable LiD would be expensive. But if we balk at expense, we won't get fusion power.
Most of us do, in fact, balk at expense, for reasons. But the topic here is what would be needed for fusion to be made to work at all. $2B worth of deuterium to help breed tritium is not much for a $100B fusion plant.
Extracting your few grams of tritium every day from a thousand tons of LiD may be called somebody else's problem.
The blanket is lithium hydride, not hydroxide.
Some people talk about adding beryllium.
BTW I had to vouch for your comment to reply because you have a history of making short and sometimes brusque comments and HN has punished you for it. If you would make slightly longer comments in the future more people will engage with you and it will be more fun for you.
If ITER succeeds (proves that fusion in a magnetic confinement device can be used to produce net electricity and it's "just" a matter of scaling things up that is holding fusion back), then sure, investors are going to line up, even for alternative designs. Fusion will be all the rage. But until then, I doubt anyone is scaling anything fusion-related up. Well and if ITER fails, then we are all fucked, and we can turn the fusion "are we there yet" clock back 50 years.
Seeing as ITER doesn't even exist yet, I fail to understand how it can be old news or how we can innovate beyond it.
In short, we have diminishing returns for giant reactors, and instead need to have plants that can be mass produced, fast.
Higher quality source: https://www.newscientist.com/article/2336385-korean-nuclear-...
1. Containing a hydrogen plasma involves containing a superheated turbulent fluid. This is inherently unstable that will be sensitive to very minor defects;
2. A superheated plasma produces a lot of high velocity particles. Those not contained by magnetic containment tend to destroy the container (ie "neutron embrittlement"); and
3. Possibly the biggest problem of all: neutrons represent energy loss by the system and there's no currently viable way of solving this problem.
To solve (2) and (3) various groups research so-called "aneutronic" fusion. I put that in quotes because it's just a lot less neutrons generally, not no neutrons.
Helium-3 fusion is one possibility but He-3 is exceedingly rare. The best source may be from the solar wind being collected on the Moon's surface. As you can imagine that presents it's own set of challenges to mine, contain and return.
Hydrogen fusion uses heavier isotopes of hydrogen (ie deuterium with 1 neutron and/or tritium with 2). Why? Because we currently need these neutrons to feed the fusion reaction.
And after all this we extract heat to boil water to turn a turbine. This too adds to cost and complexity.
Personally I think the future of humanity's energy production is space-based solar power collectors.
They use a hybrid D-D/D-He3 reaction. The He3 is the waste product of the D-D reactions. They say the combination will release only 6% of its energy as neutron radiation, which is why they can skip the turbine.
(I'm also a fan of space solar though.)
Right now things are bad in this world and will get worse but the future is filled with abundance and new levels of comforts not seen in human history.
I'm all for new tech but we should at least try to project the cost to build a working fusion power plant. Fusion not only has to work, it has to be at least somewhat cost-competitive with other forms of energy generation.
Perhaps silly, but I wonder how this comparison would shape up if we were capable of calculating reasonably-accurate long-term figures about effects of pollution, mining for resources, construction costs, etc. in the process of producing each form of energy. I'm really curious what that'd look like.
Physicist having fun with other people's money?! On top of the fact that this demo reactor costs a fraction of the development cost of the F-35.
Eric Weinstein: "We can't afford to pay these people. We can't afford to give them an accelerator just to play with in case they find something at the next energy level, these people created our economy. They gave us the rad lab and radar, they gave us two atomic devices to end World War Two that created the semiconductor and the transistor to power our economy through Moore's Law as a positive externality of particle accelerators that created the World Wide Web.
And we have the insolence to say, why should we fund you with our taxpayer dollars? Now, the question is, are you enjoying your physics dollars?"
So, how are you having fun with your physics dollars?
I would rather the other ones get it, because maybe something of value might come from that.
That said, plasma fluid dynamics physicists are chronically underfunded, and they can often use money from fusion projects for their experiments. I never begrudge money to plasma fluid dynamics physicists. But we shouldn't expect to get useful fusion out as a result.
In one sentence you suggest funding one group without the expectation anything will come from it. And then the next you say we shouldn't fund one group because there is no expectation anything will come from it.
You are just anti-fusion.
Kinetic neutrons are almost the worst energy delivery vehicle conceivable, even worse than gamma rays. (Only neutrinos would be worse.) Visible photons are good.
Oh, and about 160M times bigger in diameter.
You can safely ignore all future fusion announcements.
"Grossly extreme cost"? Shell made more money than ITER costs in the Q2 of 2022
https://www.shell.com/investors/results-and-reporting/quarte...
Hint 2: the sun already works. Solar panels already work, and are cheap and getting cheaper.
Hint 3: ITER is not a power plant. It is not even planned to ever produce so much as one kWh of electrical energy. It will burn GWh, if ever finished.
Hint 4: a working fusion power plant would necessarily cost many times as much to operate as a fission plant of the same capacity.
Hint 2: We should invest heavily in solar; they aren't exclusive. I am a massive, massive fan of solar, and tidal, and hydro, and wind.
Hint 3: ITER was never intended to be a power plant. This is a hacker forum, one assumes you know about iteration.
Hint 4: That's an untested assertion which I would dispute, and the cost will come down with more research and experience.
Also, I'm taking exception with you regarding the cost. This is pittance for humanity to spend.
Yes to solar and renewables, that's a no-brainer.
Arguing against fusion because of that is not even a straw man. They are not mutually exclusive, and you are thinking too short term.
ITER, even at tens of $Bs, is small potatoes compared to what a real plant would have to cost.
So fusion then steam.
Fusion reactors make nuclear power plants marginally smaller.
Dispatch and transmission costs are still a thing.
Dispatch and transmission are a thing even if all the software developer/ECE/Physicist folks downvote my comments.
Also, I'm not a fan of tinkerbell engineering, where anything is possible if we just believe hard enough.
Tinkerbell engineering which has increased confinement time during its period of research faster than Moores law increased transistors on a chip.
It's not like we haven't achieved nuclear fusion from MCF. We have. So maybe you are trying hard to believe it's not possible when already proven.
The main problem holding back nuclear is its cost. Fusion, at least of the DT kind, makes this main problem worse.
What matters most, always, is cost. Things that cost more lose. Renewables, here, win.
There's a wide variety of storage options for renewable energy with varying cost and efficiency characteristics. The ultimate solution will likely be some combination of these, along with overprovisioning, dispatchable demand, and transmission.