5 ms·

Can we set helium supply aside, though? I really hope we can make airships work, but it seems like the volumes of helium required will be prohibitive for wide-

by lukev 3y ago

Can we set helium supply aside, though? I really hope we can make airships work, but it seems like the volumes of helium required will be prohibitive for wide-scale deployment. Hydrogen works well but remains dangerous... perhaps modern tech can make it "safe enough"?

creshal 3y ago
Realistically, all the other fundamental problems of blimps will limit before the helium supply does — remember that it was artificially crippled by the selloff of the US's strategic helium reserve; it was sold under market value and so all the natural gas producers who could have trapped and sold off their helium production just gave up on doing so. Supply will stabilize again after the last of the reserve is sold off this month.
zyang 3y ago
Hydrogen fusion creates helium as a byproduct. But I don't see why they can't use hydrogen for cargo. We have the tech to make it safer than long haul driving.
- wolfram74 3y ago
  This is a pet peeve of mine when people talk about the advantages of fusion, if you did all of the US power budget with DT fusion that would generate very close to 10 million moles of helium, or 4E7 grams of helium, or 2E8 liters at stp. This is a big number! but it's 2E5 cubic meters and annual US consumption of helium is 40E6 cubic meters, less than 1% of consumption.
  - notfed 3y ago
    I found the last sentence confusing
    - wolfram74 3y ago
      If you produced all the USA's electricity in a year with fusion and collected all the resulting helium with 100% efficiency, you'd have collected less than 1% of the amount of helium we go through in that year.
    - phs2501 3y ago
      A naive translation (not checking facts in any way): Converting 100% of power generation in the US to (deuterium-tritium) fusion would result in 200,000 cubic meters of helium generated per year. But the US currently consumes 40,000,000 cubic meters per year.
    - ooterness 3y ago
      Simplified: If you magically switched every power plant in the USA to fusion, they would make about 200,000 cubic meters of helium per year. But the USA currently consumes 40,000,000 cubic meters of helium per year.
  - perihelions 3y ago
    The helium-3 market makes an interesting comparison: it's sole-sourced from nuclear fission reactors. https://cen.acs.org/materials/3-availability-increase-new-supply/99/web/2021/12 https://cen.acs.org/materials/3-availability-increase-new-su... ("³He availability to increase with new supply deal") It'd cost $30 billion to fill one of OP's blimps with synthetic helium-3 (which—to be fair—is a superior lifting gas to helium-4).
bombcar 3y ago
Hydrogen is "safe enough" if we want to use it, compared to gasoline and other routine hazards. The Hindenburg provided a recognizable meme but even with that, there were things that could have been done differently (with technology of the time) to make even those disasters more survivable. With modern materials, it could be quite safe, indeed.
- messe 3y ago
  > The Hindenburg provided a recognizable meme but even with that, there were things that could have been done differently (with technology of the time) to make even those disasters more survivable. It’s also worth noting that 64% of the crew and passengers survived. I’m not sure how that compares to the average plane crash, but it was certainly not as severe a disaster as it’s usually thought of.
  - dewey 3y ago
    Maybe also worth noting that it was close to the ground, which it would not be in normal operation.
  - rootusrootus 3y ago
    > I’m not sure how that compares to the average plane crash Average plane crash survival rate is about 95%. I'm guessing it's a somewhat bimodal distribution, however.
  - wolverine876 3y ago
    > It’s also worth noting that 64% of the crew and passengers survived. I’m not sure how that compares to the average plane crash, but it was certainly not as severe a disaster as it’s usually thought of. 64% survival would be great for VC investments (depending on the returns); it would be awful for a round of layoffs; for human lives on transportation infrastructure ... maybe we are losing sight of a big picture here! :)
- Aunche 3y ago
  > Hydrogen is "safe enough" if we want to use it, compared to gasoline While I'm inclined to agree with your overall point, intuitively, it seems much more dangerous than gasoline. Gasoline is very difficult to ignite unless if it's vaporized. On the other hand, hydrogen is already a gas so it's significantly easier to ignite and more explosive when it does.
rjmunro 3y ago
I thought that the Hindenburg was more about the materials the airship skin was made of than the Hydrogen itself. If the skin hadn't caught fire, the hydrogen wouldn't have. Also the fuel tanks caught fire, and they could have been better protected. Normally the hydrogen can only catch fire if it leaks out and there is an ignition source near the leak. Even if this happens, if the skin is flame retardant, the hole probably won't grow very fast. You will lose buoyancy, but you'll probably have time to make an emergency soft-ish landing. Helium wouldn't really make any difference because it can leak out and cause loss of buoyancy just as easily.

by lukev 3y ago

creshal 3y ago

Realistically, all the other fundamental problems of blimps will limit before the helium supply does — remember that it was artificially crippled by the selloff of the US's strategic helium reserve; it was sold under market value and so all the natural gas producers who could have trapped and sold off their helium production just gave up on doing so. Supply will stabilize again after the last of the reserve is sold off this month.

zyang 3y ago

Hydrogen fusion creates helium as a byproduct. But I don't see why they can't use hydrogen for cargo. We have the tech to make it safer than long haul driving.

wolfram74 3y ago
This is a pet peeve of mine when people talk about the advantages of fusion, if you did all of the US power budget with DT fusion that would generate very close to 10 million moles of helium, or 4E7 grams of helium, or 2E8 liters at stp. This is a big number! but it's 2E5 cubic meters and annual US consumption of helium is 40E6 cubic meters, less than 1% of consumption.
- notfed 3y ago
  I found the last sentence confusing
  - wolfram74 3y ago
    If you produced all the USA's electricity in a year with fusion and collected all the resulting helium with 100% efficiency, you'd have collected less than 1% of the amount of helium we go through in that year.
  - phs2501 3y ago
    A naive translation (not checking facts in any way): Converting 100% of power generation in the US to (deuterium-tritium) fusion would result in 200,000 cubic meters of helium generated per year. But the US currently consumes 40,000,000 cubic meters per year.
  - ooterness 3y ago
    Simplified: If you magically switched every power plant in the USA to fusion, they would make about 200,000 cubic meters of helium per year. But the USA currently consumes 40,000,000 cubic meters of helium per year.
- perihelions 3y ago
  The helium-3 market makes an interesting comparison: it's sole-sourced from nuclear fission reactors. https://cen.acs.org/materials/3-availability-increase-new-supply/99/web/2021/12 https://cen.acs.org/materials/3-availability-increase-new-su... ("³He availability to increase with new supply deal") It'd cost $30 billion to fill one of OP's blimps with synthetic helium-3 (which—to be fair—is a superior lifting gas to helium-4).

bombcar 3y ago

Hydrogen is "safe enough" if we want to use it, compared to gasoline and other routine hazards. The Hindenburg provided a recognizable meme but even with that, there were things that could have been done differently (with technology of the time) to make even those disasters more survivable. With modern materials, it could be quite safe, indeed.

messe 3y ago
> The Hindenburg provided a recognizable meme but even with that, there were things that could have been done differently (with technology of the time) to make even those disasters more survivable. It’s also worth noting that 64% of the crew and passengers survived. I’m not sure how that compares to the average plane crash, but it was certainly not as severe a disaster as it’s usually thought of.
- dewey 3y ago
  Maybe also worth noting that it was close to the ground, which it would not be in normal operation.
- rootusrootus 3y ago
  > I’m not sure how that compares to the average plane crash Average plane crash survival rate is about 95%. I'm guessing it's a somewhat bimodal distribution, however.
- wolverine876 3y ago
  > It’s also worth noting that 64% of the crew and passengers survived. I’m not sure how that compares to the average plane crash, but it was certainly not as severe a disaster as it’s usually thought of. 64% survival would be great for VC investments (depending on the returns); it would be awful for a round of layoffs; for human lives on transportation infrastructure ... maybe we are losing sight of a big picture here! :)
Aunche 3y ago
> Hydrogen is "safe enough" if we want to use it, compared to gasoline While I'm inclined to agree with your overall point, intuitively, it seems much more dangerous than gasoline. Gasoline is very difficult to ignite unless if it's vaporized. On the other hand, hydrogen is already a gas so it's significantly easier to ignite and more explosive when it does.

rjmunro 3y ago

I thought that the Hindenburg was more about the materials the airship skin was made of than the Hydrogen itself. If the skin hadn't caught fire, the hydrogen wouldn't have. Also the fuel tanks caught fire, and they could have been better protected. Normally the hydrogen can only catch fire if it leaks out and there is an ignition source near the leak. Even if this happens, if the skin is flame retardant, the hole probably won't grow very fast. You will lose buoyancy, but you'll probably have time to make an emergency soft-ish landing. Helium wouldn't really make any difference because it can leak out and cause loss of buoyancy just as easily.