6 ms·

>There are a lot of examples where something seems perpetually 20 years away. I'd advise tempering the transistor-based optimism with just a skosh of fusion ene

by serf 3y ago

>There are a lot of examples where something seems perpetually 20 years away. I'd advise tempering the transistor-based optimism with just a skosh of fusion energy skepticism. most of the common examples are in-the-works or exist in some form, they just don't satisfy the 'every-person' checkbox yet. AI? sure. Flying cars? sure. Robots? sure. Fusion is in the works, too. Tens of billions of dollars being thrown into the ring by private capital -- and recently -- which is a pretty good indicator of 'perceived realistic' historically. Also, it's kind of apples/oranges. We had equivalent mechanisms before the transistor, transistors just lead to extreme miniaturization of logic gates that we now enjoy. Fusion energy production doesn't (really) have that equivalent. similarly : room temperature atmospheric pressure superconductors are a new thing if proven possible.

jacquesm 3y ago
> Fusion energy production doesn't (really) have that equivalent. It does, actually. It's the miniaturization that's the hard part.
- JumpCrisscross 3y ago
  > it's the miniaturization that's the hard part We don't have a working fusion system to miniaturize. Stellar fusion happens at much lower temperatures than what we're trying to do on Earth.
  - jacquesm 3y ago
    The sun's core is actually very hot, it is the outer layers of the sun that are much cooler. We're trying to do this at roughly twice the temperature than the core of the sun, and I realize the difference is millions of degrees but on a relative scale this doesn't add much complexity, it would be almost as difficult if the plasma would be only half the temperature that they are shooting for. And in a way that higher temp is a result of trying to do this at a smaller scale, if you want to be net-positive it gets easier as you get hotter as far as I understand it. So what we are doing is in fact to re-create conditions roughly on par with what is happening in the core of the sun. And it turns out that doing that small, for extended periods, net positive and reliable (without the machine suffering damage from the process) is a very hard problem. Even so I'm very much impressed with these projects, the engineering and the physics are way over my head but I do hope that one day they'll get it working. But I'm not going to hold my breath. Incidentally, the implications for energy storage if TFA turns out to be on the money are possibly more interesting than fusion in the short term.
    - JumpCrisscross 3y ago
      > what we are doing is in fact to re-create conditions roughly on par with what is happening in the core of the sun My understanding is we are not. (Not an expert!) The Sun's core runs around 15 MK [1]. A tokamak, 150 MK [2]. Orders of magnitude rarely come for free in physics. We need those higher energies because we can't, like the Sun, swaddle with the mass of a hundred thousand worlds a low-temperature, low-frequency weak-force mediated proton-proton reaction [3]. The Sun relies on quantum tunneling to overcome the Coulomb barrier. We humans have to increase the reaction energy so it doesn't all bleed off before anything happens [4], which means using the strong force [5]. [1] https://solarsystem.nasa.gov/solar-system/sun/in-depth/ https://solarsystem.nasa.gov/solar-system/sun/in-depth/ [2] https://euro-fusion.org/faq/what-is-the-temperature-generated-in-a-tokamak/ https://euro-fusion.org/faq/what-is-the-temperature-generate... [3] https://en.wikipedia.org/wiki/Proton–proton_chain https://en.wikipedia.org/wiki/Proton–proton_chain [4] https://en.wikipedia.org/wiki/Bremsstrahlung https://en.wikipedia.org/wiki/Bremsstrahlung [5] https://medium.com/@deepfuturetech/practical-proton-proton-fusion-38b4be10328f https://medium.com/@deepfuturetech/practical-proton-proton-f...
      - jacquesm 3y ago
        If you start to think of 'temperature' of individual particles as 'speed with which they move' that is a useful rough approximation of trying to figure out what it means that something has a particular temperature. Containing the plasma is hard not just because of the temperature it is at but simply because it tends to destroy anything that contains it and that doesn't really change all that much for 15 million degrees Celsius, 30, 100 or 150. What it does change is that at 150 million degrees Celsius you have some hope of extracting useful work from a very small quantity of plasma. If you don't get it up to those temperatures - again, as far as I understand it - then you will always be putting in more energy than you are gaining because of some fundamental physics limitations. So the smaller you make your reactor the hotter you'll have to make it to make it net positive. This leads to the counter intuitive result that making a much larger reactor is actually quite possibly easier than making a really small one. The rate of heat loss is much smaller for a larger reactor and so it becomes easier to sustain the reaction and to extract useful energy from it. It is very well possible that none of the reactors currently on the drawing board and under construction are going to be working well enough to give us a sustained reaction resulting in net yield. But we're getting closer and closer to that and there is some (small) chance that I will still see this in my lifetime. The catch is that as long as you can't get a small reactor to work getting funding for a much larger one (which you actually may be able to get to work) is going to be extremely difficult. We like to see proof before we scale up. In this case it may well be that such small scale proof can't be done or can't be done in a way that it it will convince backers that a larger scale device will work.
  - avalys 3y ago
    He’s referring to a “Hydrogen bomb”.
- wbl 3y ago
  We miniaturized fusion 70 years ago and they named a bathing suit after it. Keeping it going is the hard part, and it was messy.
  - mjlawson 3y ago
    I'm quite happy it didn't keep going, though not for lack of trying.
    - wiz21c 3y ago
      Some how, I read : "I'm quite happy it didn't keep going, though not for lack of _f_rying." Besides, what's the bathing suit name reference ? I don't get it.
      - Filligree 3y ago
        The bikini islands.
      - narism 3y ago
        The bikini swimsuit was named after the Bikini Atoll. A bit of a mixup from OP though: it wasn’t named after fusion bombs. The bikini swimsuit was announced a few days after the first public fission bomb test there (Crossroads Able) in 1946. The first fusion bomb test there (Castle Bravo) wasn’t until 1954.
  - jacquesm 3y ago
    Fair enough. I should have written 'controlled fusion'. But you're 100% right.
jjoonathan 3y ago
My favorite example is the hydrogen fuel cell. It was invented before the lead acid battery back in the 1800s. PEM gave it a boost around the Apollo era, but that wasn't enough to make it widespread either. Lead-Acid went through its whole 100+ year character arc and hydrogen fuel cells still haven't found product market fit. Sometimes that's how it is.
- jacquesm 3y ago
  There are plenty of commercial applications of hydrogen fuel cells though. The biggest issue has been pretty much a constant over the time since it has been invented: keeping the membranes free from impurities is hard. But there are all kinds of transportation devices using hydrogen in production today.
  - Turskarama 3y ago
    Sure, but the point is that they hardly caused a revolution in energy storage. If fuel cells didn't exist, for the average person life would be exactly the same. Revolutionary tech does change normal peoples lives, and sometimes very rapidly, but a lot of stuff that looks revolutionary just kind of never works out. I'd say nuclear power is probably the prime example of this. It was supposed to bring us electricity too cheap to meter, but it's actually the most expensive form of generation that anyone bothers to build.
    - jacquesm 3y ago
      Fuel cells are just another transformer like the dynamo, or any kind of motor. They turn one kind of energy into another and in the context of hydrogen (which you could produce out of water using electricity as a means of storing energy) it serves to reverse the storage step. This is nice to have but just like nuclear power it's a variation on stuff that we already have, it is at best a quantitative change (and hopefully an improvement). Room temperature / ambient pressure super conductivity is something we do not currently have. The difference between having that and not having that is a qualitative difference and hence it will enable a whole raft of applications for which we currently do not have a solution.

by serf 3y ago

jacquesm 3y ago

> Fusion energy production doesn't (really) have that equivalent. It does, actually. It's the miniaturization that's the hard part.

JumpCrisscross 3y ago
> it's the miniaturization that's the hard part We don't have a working fusion system to miniaturize. Stellar fusion happens at much lower temperatures than what we're trying to do on Earth.
- jacquesm 3y ago
  The sun's core is actually very hot, it is the outer layers of the sun that are much cooler. We're trying to do this at roughly twice the temperature than the core of the sun, and I realize the difference is millions of degrees but on a relative scale this doesn't add much complexity, it would be almost as difficult if the plasma would be only half the temperature that they are shooting for. And in a way that higher temp is a result of trying to do this at a smaller scale, if you want to be net-positive it gets easier as you get hotter as far as I understand it. So what we are doing is in fact to re-create conditions roughly on par with what is happening in the core of the sun. And it turns out that doing that small, for extended periods, net positive and reliable (without the machine suffering damage from the process) is a very hard problem. Even so I'm very much impressed with these projects, the engineering and the physics are way over my head but I do hope that one day they'll get it working. But I'm not going to hold my breath. Incidentally, the implications for energy storage if TFA turns out to be on the money are possibly more interesting than fusion in the short term.
  - JumpCrisscross 3y ago
    > what we are doing is in fact to re-create conditions roughly on par with what is happening in the core of the sun My understanding is we are not. (Not an expert!) The Sun's core runs around 15 MK [1]. A tokamak, 150 MK [2]. Orders of magnitude rarely come for free in physics. We need those higher energies because we can't, like the Sun, swaddle with the mass of a hundred thousand worlds a low-temperature, low-frequency weak-force mediated proton-proton reaction [3]. The Sun relies on quantum tunneling to overcome the Coulomb barrier. We humans have to increase the reaction energy so it doesn't all bleed off before anything happens [4], which means using the strong force [5]. [1] https://solarsystem.nasa.gov/solar-system/sun/in-depth/ https://solarsystem.nasa.gov/solar-system/sun/in-depth/ [2] https://euro-fusion.org/faq/what-is-the-temperature-generated-in-a-tokamak/ https://euro-fusion.org/faq/what-is-the-temperature-generate... [3] https://en.wikipedia.org/wiki/Proton–proton_chain https://en.wikipedia.org/wiki/Proton–proton_chain [4] https://en.wikipedia.org/wiki/Bremsstrahlung https://en.wikipedia.org/wiki/Bremsstrahlung [5] https://medium.com/@deepfuturetech/practical-proton-proton-fusion-38b4be10328f https://medium.com/@deepfuturetech/practical-proton-proton-f...
    - jacquesm 3y ago
      If you start to think of 'temperature' of individual particles as 'speed with which they move' that is a useful rough approximation of trying to figure out what it means that something has a particular temperature. Containing the plasma is hard not just because of the temperature it is at but simply because it tends to destroy anything that contains it and that doesn't really change all that much for 15 million degrees Celsius, 30, 100 or 150. What it does change is that at 150 million degrees Celsius you have some hope of extracting useful work from a very small quantity of plasma. If you don't get it up to those temperatures - again, as far as I understand it - then you will always be putting in more energy than you are gaining because of some fundamental physics limitations. So the smaller you make your reactor the hotter you'll have to make it to make it net positive. This leads to the counter intuitive result that making a much larger reactor is actually quite possibly easier than making a really small one. The rate of heat loss is much smaller for a larger reactor and so it becomes easier to sustain the reaction and to extract useful energy from it. It is very well possible that none of the reactors currently on the drawing board and under construction are going to be working well enough to give us a sustained reaction resulting in net yield. But we're getting closer and closer to that and there is some (small) chance that I will still see this in my lifetime. The catch is that as long as you can't get a small reactor to work getting funding for a much larger one (which you actually may be able to get to work) is going to be extremely difficult. We like to see proof before we scale up. In this case it may well be that such small scale proof can't be done or can't be done in a way that it it will convince backers that a larger scale device will work.
- avalys 3y ago
  He’s referring to a “Hydrogen bomb”.
wbl 3y ago
We miniaturized fusion 70 years ago and they named a bathing suit after it. Keeping it going is the hard part, and it was messy.
- mjlawson 3y ago
  I'm quite happy it didn't keep going, though not for lack of trying.
  - wiz21c 3y ago
    Some how, I read : "I'm quite happy it didn't keep going, though not for lack of _f_rying." Besides, what's the bathing suit name reference ? I don't get it.
    - Filligree 3y ago
      The bikini islands.
    - narism 3y ago
      The bikini swimsuit was named after the Bikini Atoll. A bit of a mixup from OP though: it wasn’t named after fusion bombs. The bikini swimsuit was announced a few days after the first public fission bomb test there (Crossroads Able) in 1946. The first fusion bomb test there (Castle Bravo) wasn’t until 1954.
- jacquesm 3y ago
  Fair enough. I should have written 'controlled fusion'. But you're 100% right.

jjoonathan 3y ago

My favorite example is the hydrogen fuel cell. It was invented before the lead acid battery back in the 1800s. PEM gave it a boost around the Apollo era, but that wasn't enough to make it widespread either. Lead-Acid went through its whole 100+ year character arc and hydrogen fuel cells still haven't found product market fit. Sometimes that's how it is.

jacquesm 3y ago
There are plenty of commercial applications of hydrogen fuel cells though. The biggest issue has been pretty much a constant over the time since it has been invented: keeping the membranes free from impurities is hard. But there are all kinds of transportation devices using hydrogen in production today.
- Turskarama 3y ago
  Sure, but the point is that they hardly caused a revolution in energy storage. If fuel cells didn't exist, for the average person life would be exactly the same. Revolutionary tech does change normal peoples lives, and sometimes very rapidly, but a lot of stuff that looks revolutionary just kind of never works out. I'd say nuclear power is probably the prime example of this. It was supposed to bring us electricity too cheap to meter, but it's actually the most expensive form of generation that anyone bothers to build.
  - jacquesm 3y ago
    Fuel cells are just another transformer like the dynamo, or any kind of motor. They turn one kind of energy into another and in the context of hydrogen (which you could produce out of water using electricity as a means of storing energy) it serves to reverse the storage step. This is nice to have but just like nuclear power it's a variation on stuff that we already have, it is at best a quantitative change (and hopefully an improvement). Room temperature / ambient pressure super conductivity is something we do not currently have. The difference between having that and not having that is a qualitative difference and hence it will enable a whole raft of applications for which we currently do not have a solution.