5 ms·

Ultimately, the answer is fuel density. So, for long distance untethered travel, like planes. Beyond that, it's plastics production and chemical manufacturing.

Ultimately, the answer is fuel density. So, for long distance untethered travel, like planes. Beyond that, it's plastics production and chemical manufacturing. We can switch to hydrogen for lots of stuff that requires carrying your fuel on your back, but some things get tougher because the density is just not the same as a hydrocarbon. These are all surmountable (biodiesel, carbon capture->fuel cycles, bioreactors, etc), but they take time and money. In the end, what will push us to get there are economic shocks. We're getting there, it's just painful.

kelseyfrog 7mo ago
Fuel density wouldn't be such an impactful attribute if the US military and geopolitical situation and strategy were different. Fuel density is logistically important and the US geographical position means that density is more important to the US than other nations. In other words, if we forecast that we'll be fighting foreign wars, fuel transport is an logistical problem that optimises for density.
- kayodelycaon 7mo ago
  Fuel density matters to things like cars and semi-trucks. Right now you can’t build an electric version that can fully refuel in minutes. That makes fast, long-range travel impractical in an electric vehicle.
  - kelseyfrog 7mo ago
    Me searching for the electric tanks. ¯ \ _ ༼ •́ ͜ ʖ •̀ ༽ _ / ¯ Edit: I found them :D
    - ThatMedicIsASpy 7mo ago
      and I wonder which blown up tank would pollute the environment more
      - kelseyfrog 7mo ago
        I don't really think that's really high up on military priorities list. But happy to be proven wrong on that.
      - triceratops 7mo ago
        If you're worried about the environment don't get into wars. If you're in a war, worry about winning. Wars of the future will make heavy use of drones. They don't run on hydrocarbons.
    - kayodelycaon 7mo ago
      They didn’t make it past the drones.
    - make3 7mo ago
      tanks must represent like 0.001% of fuel consumption lol Road uses like cars, trucks and buses is 47% of all oil, and clearly an enormous fraction of that can be converted to use electricity instead
    - adrian_b 7mo ago
      I do not know if any such tanks are in production, but there where experimental electric tanks, just not with batteries, but with turbogenerators.
      - kelseyfrog 7mo ago
        Great question! Turns out there are. The U.S. Military's Abrams Tank Is Going Hybrid [1]. I'm sure we'll get some comments saying why it's a terrible idea[2]. 1. https://insideevs.com/news/784805/abrams-m1e3-hybrid-tank-video-specs-power/ https://insideevs.com/news/784805/abrams-m1e3-hybrid-tank-vi... 2. https://news.ycombinator.com/item?id=47484044 https://news.ycombinator.com/item?id=47484044
  - galago 7mo ago
    https://insideevs.com/news/758625/byd-megawatt-charging-demo-china/ https://insideevs.com/news/758625/byd-megawatt-charging-demo... "It's called Megawatt charging because it delivers 1,000 kilowatts of electrical power at 1,000 volts, which is twice as powerful as the fastest chargers we have here in the United States."
  - adrian_b 7mo ago
    Actually a few other HN threads have just discussed the latest Chinese electric cars that refuel in 5 minutes for a 250 miles range and which have a 500 miles range when fully charged. That makes fast, long-range travel quite practical in an electric vehicle. While this model greatly improves the charging speed, other electric cars introduced this year use sodium-ion batteries, which are heavier than lithium-ion batteries, but they have the advantage that in cold climates they do not lose either capacity or charging speed down to temperatures as low as minus 40 Celsius degrees, removing other limitation of electric cars. So hydrocarbon fuels are likely to remain non-replaceable only in aircraft and spacecraft, where weight really matters. However, hydrocarbon fuels can be synthesized from water and carbon dioxide, passing through syngas, by using solar energy, just not at a price competitive with fossil fuel.
stavros 7mo ago
No, that's fine, I get it that fossil fuels have incomparable density, but we're using them massively for stuff where density isn't that important. Anything inside a city, from transportation to homes to factories are already powered by electricity (or can be, e.g. cars), we're just inexplicably still using fossil fuels to create that electricity. The US grid is still 57% coal and gas.
- BLKNSLVR 7mo ago
  Slightly tangential, we bought a 2014 Nissan Leaf about 18 months ago, against howls of protest from parents-in-laws and brother- and sister-in-laws with all the regular electric car FUD you hear (can't drive interstate on a single tank, can't tow a trailer, will explode and burn your house down). For our use-case, 95% of our trips are to the shops, to various kids sports, to school, to the bus/train station, visiting (local) family, and all are very short trips easily within the relatively short range of the Leaf: ~100km. We still have our existing cars, they just get used less in favour of the cheapest option for the job at hand. Even with our son being newly able to drive independently (so essentially needing to have three cars, rather than two, on the go at any one time), over the 18 months of owning the Leaf we've saved about 25% of the purchase price of the Leaf in spending less on petrol (including the electricity cost to charge the Leaf - which gets charged using the solar panels during the day, but more commonly using cheaper grid electricity non-peak overnight - yes, likely primarily off fossil fuels but from what I've read is more energy efficient than using petrol to power the car). My point being, analogous to the "right answer" being to only using energy-dense fuels when necessary, we use the cheaper electric vehicle option when applicable, and only burn the expensive stuff when the better option is unavailable. P.S. Looking at buying a newer EV with longer range, so there are additional and more flexible "better options", plus coming up to having a daughter who is also able to drive unaccompanied (four cars? :grimacing face:)
  - stavros 7mo ago
    I really don't understand how people offer "but that ten-hour trip I take once a year will be 40 minutes longer!" as criticism and completely ignore "my EV TCO will be half of an ICE". Humans really do not like change, the problems you have now are swept under the rug but tiny new problems are made into massive, insurmountable ones.
chrysoprace 7mo ago
In Australia the answer is political lobbying, without a doubt. We had an emissions trading scheme[0] in 2012 meant to help in a transition to clean energy sources that was aggressively lobbied against by Australia's largest polluters and lasted only 2 years before being repealed by the incoming government by labeling it a "tax" that citizens would pay for. This led to a decade of policy stagnation[1] where we could've been transitioning away from fossil fuels. So while energy density is definitely a factor, political lobbying is absolutely a factor. [0] https://en.wikipedia.org/wiki/Carbon_Pollution_Reduction_Scheme https://en.wikipedia.org/wiki/Carbon_Pollution_Reduction_Sch... [1] https://www.ft.com/content/0a453f5c-e859-4300-9355-46822c45172b?syn-25a6b1a6=1 https://www.ft.com/content/0a453f5c-e859-4300-9355-46822c451...
- dmix 7mo ago
  > by labeling it a "tax" that citizens would pay for. Are the quotes here implying there wasn't a cost imposed on the public to artificially speed up a transition to green energy? Might as well be honest about it and say it's a "temporary sacrifice for the greater good" or something. Otherwise it's just another form of political spin.
  - BLKNSLVR 7mo ago
    It was an enforcement of paying a (small) portion of the externalities as a result of the use of fossil fuels. The "tax" was to be paid by the largest polluters, hence their lobbying against it. It wasn't something the citizens had to pay for unless the largest polluters decided to raise their prices as a result of this "tax". Asking polluters to decrease their profits, as it becomes increasingly obvious that their profits are based on making life worse for the entire planet for the future, I think, is not too grand an ask. "That's how it has always been" is not a reason not to act to improve "how it could be".
    - dmix 7mo ago
      Those schemes always seemed to me like a whole lot of lipstick and pretty packaging on something that could just be pitched with more honesty, and without creating a maze of extra corporate accounting costs and loopholes. Just raise a tax to pay for investment in green energy that will eventually compete on price and be self-sustaining, while also providing lots of environmental benefits and potentially increase industrial competition with China. The only reason a politician would come up with a complex carbon scheme like that is if they knew a tax would be unpopular with the public. Which mostly translates to a lack of good communication or a disregard for the public's intelligence.
api 7mo ago
Aviation is a few percent of global emissions. All aviation. It’s probably the hardest thing to replace but if we can’t we will be okay. Long haul trucking and shipping and remote site power are probably the next hardest things, and maybe coal for metallurgy, but these are also small compared to emissions from electricity generation and routine car transit. The big sources can be completely converted.
- andriy_koval 7mo ago
  I suspect even if all oil will be gone, it will be possible to maintain some solar -> synthetic fuel chain for aviation on large scale.
  - api 7mo ago
    You could probably fill a 737 with biodiesel today and fly it. A jet will run on anything combustible within the right ignition temperature, density, and viscosity ranges and diesel is not far from kerosene aka jet fuel. I mean, you could probably almost run a jet turbine on bacon grease if you kept it warm to keep it from solidifying. Some military stuff is intentionally made to be as “flex fuel” as possible in case you are cut off from official supply lines and have to do something like gas up a plane with road diesel of unknown quality. You wouldn’t just do things like that with a million dollar plane since it might be bad for the engine but if the engine were tuned for it it’d be fine.
GorbachevyChase 7mo ago
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kelseyfrog 7mo ago

Fuel density wouldn't be such an impactful attribute if the US military and geopolitical situation and strategy were different. Fuel density is logistically important and the US geographical position means that density is more important to the US than other nations. In other words, if we forecast that we'll be fighting foreign wars, fuel transport is an logistical problem that optimises for density.

kayodelycaon 7mo ago
Fuel density matters to things like cars and semi-trucks. Right now you can’t build an electric version that can fully refuel in minutes. That makes fast, long-range travel impractical in an electric vehicle.
- kelseyfrog 7mo ago
  Me searching for the electric tanks. ¯ \ _ ༼ •́ ͜ ʖ •̀ ༽ _ / ¯ Edit: I found them :D
  - ThatMedicIsASpy 7mo ago
    and I wonder which blown up tank would pollute the environment more
    - kelseyfrog 7mo ago
      I don't really think that's really high up on military priorities list. But happy to be proven wrong on that.
    - triceratops 7mo ago
      If you're worried about the environment don't get into wars. If you're in a war, worry about winning. Wars of the future will make heavy use of drones. They don't run on hydrocarbons.
  - kayodelycaon 7mo ago
    They didn’t make it past the drones.
  - make3 7mo ago
    tanks must represent like 0.001% of fuel consumption lol Road uses like cars, trucks and buses is 47% of all oil, and clearly an enormous fraction of that can be converted to use electricity instead
  - adrian_b 7mo ago
    I do not know if any such tanks are in production, but there where experimental electric tanks, just not with batteries, but with turbogenerators.
    - kelseyfrog 7mo ago
      Great question! Turns out there are. The U.S. Military's Abrams Tank Is Going Hybrid [1]. I'm sure we'll get some comments saying why it's a terrible idea[2]. 1. https://insideevs.com/news/784805/abrams-m1e3-hybrid-tank-video-specs-power/ https://insideevs.com/news/784805/abrams-m1e3-hybrid-tank-vi... 2. https://news.ycombinator.com/item?id=47484044 https://news.ycombinator.com/item?id=47484044
- galago 7mo ago
  https://insideevs.com/news/758625/byd-megawatt-charging-demo-china/ https://insideevs.com/news/758625/byd-megawatt-charging-demo... "It's called Megawatt charging because it delivers 1,000 kilowatts of electrical power at 1,000 volts, which is twice as powerful as the fastest chargers we have here in the United States."
- adrian_b 7mo ago
  Actually a few other HN threads have just discussed the latest Chinese electric cars that refuel in 5 minutes for a 250 miles range and which have a 500 miles range when fully charged. That makes fast, long-range travel quite practical in an electric vehicle. While this model greatly improves the charging speed, other electric cars introduced this year use sodium-ion batteries, which are heavier than lithium-ion batteries, but they have the advantage that in cold climates they do not lose either capacity or charging speed down to temperatures as low as minus 40 Celsius degrees, removing other limitation of electric cars. So hydrocarbon fuels are likely to remain non-replaceable only in aircraft and spacecraft, where weight really matters. However, hydrocarbon fuels can be synthesized from water and carbon dioxide, passing through syngas, by using solar energy, just not at a price competitive with fossil fuel.

stavros 7mo ago

No, that's fine, I get it that fossil fuels have incomparable density, but we're using them massively for stuff where density isn't that important. Anything inside a city, from transportation to homes to factories are already powered by electricity (or can be, e.g. cars), we're just inexplicably still using fossil fuels to create that electricity. The US grid is still 57% coal and gas.

BLKNSLVR 7mo ago
Slightly tangential, we bought a 2014 Nissan Leaf about 18 months ago, against howls of protest from parents-in-laws and brother- and sister-in-laws with all the regular electric car FUD you hear (can't drive interstate on a single tank, can't tow a trailer, will explode and burn your house down). For our use-case, 95% of our trips are to the shops, to various kids sports, to school, to the bus/train station, visiting (local) family, and all are very short trips easily within the relatively short range of the Leaf: ~100km. We still have our existing cars, they just get used less in favour of the cheapest option for the job at hand. Even with our son being newly able to drive independently (so essentially needing to have three cars, rather than two, on the go at any one time), over the 18 months of owning the Leaf we've saved about 25% of the purchase price of the Leaf in spending less on petrol (including the electricity cost to charge the Leaf - which gets charged using the solar panels during the day, but more commonly using cheaper grid electricity non-peak overnight - yes, likely primarily off fossil fuels but from what I've read is more energy efficient than using petrol to power the car). My point being, analogous to the "right answer" being to only using energy-dense fuels when necessary, we use the cheaper electric vehicle option when applicable, and only burn the expensive stuff when the better option is unavailable. P.S. Looking at buying a newer EV with longer range, so there are additional and more flexible "better options", plus coming up to having a daughter who is also able to drive unaccompanied (four cars? :grimacing face:)
- stavros 7mo ago
  I really don't understand how people offer "but that ten-hour trip I take once a year will be 40 minutes longer!" as criticism and completely ignore "my EV TCO will be half of an ICE". Humans really do not like change, the problems you have now are swept under the rug but tiny new problems are made into massive, insurmountable ones.

chrysoprace 7mo ago

In Australia the answer is political lobbying, without a doubt. We had an emissions trading scheme[0] in 2012 meant to help in a transition to clean energy sources that was aggressively lobbied against by Australia's largest polluters and lasted only 2 years before being repealed by the incoming government by labeling it a "tax" that citizens would pay for. This led to a decade of policy stagnation[1] where we could've been transitioning away from fossil fuels. So while energy density is definitely a factor, political lobbying is absolutely a factor. [0] https://en.wikipedia.org/wiki/Carbon_Pollution_Reduction_Scheme https://en.wikipedia.org/wiki/Carbon_Pollution_Reduction_Sch... [1] https://www.ft.com/content/0a453f5c-e859-4300-9355-46822c45172b?syn-25a6b1a6=1 https://www.ft.com/content/0a453f5c-e859-4300-9355-46822c451...

dmix 7mo ago
> by labeling it a "tax" that citizens would pay for. Are the quotes here implying there wasn't a cost imposed on the public to artificially speed up a transition to green energy? Might as well be honest about it and say it's a "temporary sacrifice for the greater good" or something. Otherwise it's just another form of political spin.
- BLKNSLVR 7mo ago
  It was an enforcement of paying a (small) portion of the externalities as a result of the use of fossil fuels. The "tax" was to be paid by the largest polluters, hence their lobbying against it. It wasn't something the citizens had to pay for unless the largest polluters decided to raise their prices as a result of this "tax". Asking polluters to decrease their profits, as it becomes increasingly obvious that their profits are based on making life worse for the entire planet for the future, I think, is not too grand an ask. "That's how it has always been" is not a reason not to act to improve "how it could be".
  - dmix 7mo ago
    Those schemes always seemed to me like a whole lot of lipstick and pretty packaging on something that could just be pitched with more honesty, and without creating a maze of extra corporate accounting costs and loopholes. Just raise a tax to pay for investment in green energy that will eventually compete on price and be self-sustaining, while also providing lots of environmental benefits and potentially increase industrial competition with China. The only reason a politician would come up with a complex carbon scheme like that is if they knew a tax would be unpopular with the public. Which mostly translates to a lack of good communication or a disregard for the public's intelligence.

api 7mo ago

Aviation is a few percent of global emissions. All aviation. It’s probably the hardest thing to replace but if we can’t we will be okay. Long haul trucking and shipping and remote site power are probably the next hardest things, and maybe coal for metallurgy, but these are also small compared to emissions from electricity generation and routine car transit. The big sources can be completely converted.

andriy_koval 7mo ago
I suspect even if all oil will be gone, it will be possible to maintain some solar -> synthetic fuel chain for aviation on large scale.
- api 7mo ago
  You could probably fill a 737 with biodiesel today and fly it. A jet will run on anything combustible within the right ignition temperature, density, and viscosity ranges and diesel is not far from kerosene aka jet fuel. I mean, you could probably almost run a jet turbine on bacon grease if you kept it warm to keep it from solidifying. Some military stuff is intentionally made to be as “flex fuel” as possible in case you are cut off from official supply lines and have to do something like gas up a plane with road diesel of unknown quality. You wouldn’t just do things like that with a million dollar plane since it might be bad for the engine but if the engine were tuned for it it’d be fine.

GorbachevyChase 7mo ago

[dead]