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Alternative fuels for airplanes?? I’m curious what you propose to haul 200 people across the Atlantic. Batteries? Solar?

JumpCrisscross 7y ago
> Alternative fuels for airplanes? Synthetic jet fuel can be out of atmospheric carbon. (Chemically, it's jet fuel. Just synthesized instead of being pumped out of the ground.) It's more expensive than the out-of-the-ground stuff. But a lot of the price premium is currently due to a lack of economies of scale. Airlines could go carbon neutral within a few years. Replacing the power plant is overkill.
- seiferteric 7y ago
  This sounds like pure fantasy. A quick google search says the industry uses ~6.9*10^10 liters of jet fuel per year. Energy density of jet fuel is ~35 MJ/L. You would need at 100% efficient conversion ~76GW of continuous power to produce that. Realistically probably like 10x that... Current installed solar capacity is like 650GW world wide and it is not sunny all the time.
  - beatgammit 7y ago
    And solar isn't "synthetic fuel". I don't think anyone is seriously recommending solar planes, at least not in the short term.
    - seiferteric 7y ago
      I was talking about using solar (as an example) as the energy input to produce synthetic fuel, not solar planes.
  - JumpCrisscross 7y ago
    > Current installed solar capacity is like 650GW world wide Synthetic fuel is derived from hydrocarbons assembled from atmospheric C02. It can be powered by anything. Installed solar is irrelevant.
    - seiferteric 7y ago
      Where does the energy come from? CO2 is already "burned" you can't make an energetic hydrocarbon without providing energy, effectively "unburning"/reducing it.
      - JumpCrisscross 7y ago
        > Where does the energy come from? Anywhere. Nuclear. Wind. Waves. Initially, fossil fuels, because most energy comes from fossil fuels.
        seiferteric 7y ago
        If nuclear is on the table, then okay maybe but it would take decades and many billions of $ to ramp up capacity. Solar was just an example, but all of the renewables will have the same problems I mentioned, there is no way you are going to get that scale of renewable capacity installed and running just for the aviation industry any time soon. And as for fossil fuels... what? I don't even understand, why would you use fossil fuels to extract CO2 out of the air, that makes no sense...
        JumpCrisscross 7y ago
        > it would take decades and many billions of $ to ramp up capacity. As would re-tooling (a) the economy to be less reliant on travel or (b) the entire aviation fleet to be e.g. battery-electric. Change is expensive. We're comparing costs, and when I've done that, synethetic fuel is the best near-term, i.e. within 50 years, solution. > why would you use fossil fuels to extract CO2 out of the air Big plants (can) burn much cleaner than jet engines. (Also, it's an interim step.)
        seiferteric 7y ago
        > > why would you use fossil fuels to extract CO2 out of the air >Big plants (can) burn much cleaner than jet engines. (Also, it's an interim step.) Please show me how you extract more CO2 out of the air by burning fossil fuels than you release.
- ars 7y ago
  > Synthetic jet fuel made out of atmospheric carbon. What's your energy source? And once you've specified your energy source why are you using that source to make jet fuel instead of directly powering things like the electric grid? Once the world is 85%+ on alternative energy we can worry about Jet airplanes.
  - JumpCrisscross 7y ago
    > once you've specified your energy source why are you using that source to make jet fuel instead of directly powering things like the electric grid Because we need planes. Or, to put it more simply, countries that fly will outperform those that don't. Hydrocarbons are a great energy store. And we have a global fleet that burns them. For cars, we can go electric. But for weight-sensitive uses, it doesn't make sense to go battery. There will always be Luddites who advocate a permanent quarantine. But if that's the only solution, we'll stick with the status quo. And the status quo is untenable.
    - ars 7y ago
      You misunderstood my question. The question is why use synthetic fuel for airplane, and natural fuel for ground stations? Only once you are no longer using natural fuel (pumped oil) for ground stations anywhere in the world, only then does it make sense to start making synthetic fuel for airplanes.
- petre 7y ago
  Sorry mate. It's cheaper to make it from syngas, cow poo and other biomass. Even cheaper yet to buy it from the Saudis. It's doable but not from atmospheric CO2. We need algae of floating ferns to fix that one.
  - JumpCrisscross 7y ago
    > It's cheaper to make it from syngas, cow poo and other biomass Agreed. > cheaper yet to buy it from the Saudis Agreed. This would need to be a cost caused by regulation.
deleted 7y ago
[deleted]
Sharlin 7y ago
Zero-net-carbon synthetic fuels if nothing else. Hydrocarbons will have their place in the future as well, but we have to start think of them as an energy storage medium rather than an energy source.

JumpCrisscross 7y ago

> Alternative fuels for airplanes? Synthetic jet fuel can be out of atmospheric carbon. (Chemically, it's jet fuel. Just synthesized instead of being pumped out of the ground.) It's more expensive than the out-of-the-ground stuff. But a lot of the price premium is currently due to a lack of economies of scale. Airlines could go carbon neutral within a few years. Replacing the power plant is overkill.

seiferteric 7y ago
This sounds like pure fantasy. A quick google search says the industry uses ~6.9*10^10 liters of jet fuel per year. Energy density of jet fuel is ~35 MJ/L. You would need at 100% efficient conversion ~76GW of continuous power to produce that. Realistically probably like 10x that... Current installed solar capacity is like 650GW world wide and it is not sunny all the time.
- beatgammit 7y ago
  And solar isn't "synthetic fuel". I don't think anyone is seriously recommending solar planes, at least not in the short term.
  - seiferteric 7y ago
    I was talking about using solar (as an example) as the energy input to produce synthetic fuel, not solar planes.
- JumpCrisscross 7y ago
  > Current installed solar capacity is like 650GW world wide Synthetic fuel is derived from hydrocarbons assembled from atmospheric C02. It can be powered by anything. Installed solar is irrelevant.
  - seiferteric 7y ago
    Where does the energy come from? CO2 is already "burned" you can't make an energetic hydrocarbon without providing energy, effectively "unburning"/reducing it.
    - JumpCrisscross 7y ago
      > Where does the energy come from? Anywhere. Nuclear. Wind. Waves. Initially, fossil fuels, because most energy comes from fossil fuels.
      - seiferteric 7y ago
        If nuclear is on the table, then okay maybe but it would take decades and many billions of $ to ramp up capacity. Solar was just an example, but all of the renewables will have the same problems I mentioned, there is no way you are going to get that scale of renewable capacity installed and running just for the aviation industry any time soon. And as for fossil fuels... what? I don't even understand, why would you use fossil fuels to extract CO2 out of the air, that makes no sense...
        JumpCrisscross 7y ago
        > it would take decades and many billions of $ to ramp up capacity. As would re-tooling (a) the economy to be less reliant on travel or (b) the entire aviation fleet to be e.g. battery-electric. Change is expensive. We're comparing costs, and when I've done that, synethetic fuel is the best near-term, i.e. within 50 years, solution. > why would you use fossil fuels to extract CO2 out of the air Big plants (can) burn much cleaner than jet engines. (Also, it's an interim step.)
        seiferteric 7y ago
        > > why would you use fossil fuels to extract CO2 out of the air >Big plants (can) burn much cleaner than jet engines. (Also, it's an interim step.) Please show me how you extract more CO2 out of the air by burning fossil fuels than you release.
ars 7y ago
> Synthetic jet fuel made out of atmospheric carbon. What's your energy source? And once you've specified your energy source why are you using that source to make jet fuel instead of directly powering things like the electric grid? Once the world is 85%+ on alternative energy we can worry about Jet airplanes.
- JumpCrisscross 7y ago
  > once you've specified your energy source why are you using that source to make jet fuel instead of directly powering things like the electric grid Because we need planes. Or, to put it more simply, countries that fly will outperform those that don't. Hydrocarbons are a great energy store. And we have a global fleet that burns them. For cars, we can go electric. But for weight-sensitive uses, it doesn't make sense to go battery. There will always be Luddites who advocate a permanent quarantine. But if that's the only solution, we'll stick with the status quo. And the status quo is untenable.
  - ars 7y ago
    You misunderstood my question. The question is why use synthetic fuel for airplane, and natural fuel for ground stations? Only once you are no longer using natural fuel (pumped oil) for ground stations anywhere in the world, only then does it make sense to start making synthetic fuel for airplanes.
petre 7y ago
Sorry mate. It's cheaper to make it from syngas, cow poo and other biomass. Even cheaper yet to buy it from the Saudis. It's doable but not from atmospheric CO2. We need algae of floating ferns to fix that one.
- JumpCrisscross 7y ago
  > It's cheaper to make it from syngas, cow poo and other biomass Agreed. > cheaper yet to buy it from the Saudis Agreed. This would need to be a cost caused by regulation.

deleted 7y ago

[deleted]

Sharlin 7y ago

Zero-net-carbon synthetic fuels if nothing else. Hydrocarbons will have their place in the future as well, but we have to start think of them as an energy storage medium rather than an energy source.