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The fact that H2 can't be stored as liquid, even under pressure makes me pretty doubtful. I suspect ethanol or plant-derived oil will beat out hydrogen for as l

The fact that H2 can't be stored as liquid, even under pressure makes me pretty doubtful. I suspect ethanol or plant-derived oil will beat out hydrogen for as long as batteries aren't up to the task.

jeffreyrogers 7y ago
Yeah, I think that's more likely. But for all electric I think hydrogen makes more sense than batteries, since improving batteries enough for real applications requires new chemistries, while I think the obstacles for hydrogen are more about economics.
- ecpottinger 7y ago
  No, look at the prices and requirements for a hydrogen storage tank, you either need a high pressure tank or one that can handle very low temperatures. Neither is cheap or simple.
  - Hypx 7y ago
    For aviation purposes, it's cheap enough.
davedx 7y ago
H2 can be stored as a liquid, it’s more difficult. Check out AeroDelft who are building a liquid hydrogen plane: https://aerodelft.nl/ https://aerodelft.nl/
sa1 7y ago
There was some news about metal sponges earlier that may be able to hold high volumes of H2 under low pressure. https://www.bbc.com/news/science-environment-52328786 https://www.bbc.com/news/science-environment-52328786
- mannykannot 7y ago
  You got me thinking, so I looked for some numbers. Hydrogen has a specific energy of 120 MJ/kg, while Kerosine has 46 MJ/kg. According to the abstract of the paper being discussed here, the new material has a deliverable capacity of 14% by weight, corresponding to about 17 MJ/kg - only a bit better than 1/3 that of kerosine, but considerably better than lithium ion batteries, which apparently achieve less than 1 MJ/kg, while the best-performing lithium-sulfur batteries are at about 1.8 MJ/kg. In addition, we must deal with this material only losing 14% of its weight as its hydrogen is used up, while kerosine loses all of its weight - a combustion-powered airplane becomes more efficient as its fuel is consumed. Furthermore, to get that 14% deliverable capacity, you have to start with it at 100 bar, so the tank containing it will have a substantial weight. So we have progress here, but not yet a substitute for liquid hydrocarbons.
Hypx 7y ago
LH2 is a liquid. It's likely airplanes will use liquid hydrogen as a fuel.

The fact that H2 can't be stored as liquid, even under pressure makes me pretty doubtful. I suspect ethanol or plant-derived oil will beat out hydrogen for as long as batteries aren't up to the task.

jeffreyrogers 7y ago

Yeah, I think that's more likely. But for all electric I think hydrogen makes more sense than batteries, since improving batteries enough for real applications requires new chemistries, while I think the obstacles for hydrogen are more about economics.

ecpottinger 7y ago
No, look at the prices and requirements for a hydrogen storage tank, you either need a high pressure tank or one that can handle very low temperatures. Neither is cheap or simple.
- Hypx 7y ago
  For aviation purposes, it's cheap enough.

davedx 7y ago

H2 can be stored as a liquid, it’s more difficult. Check out AeroDelft who are building a liquid hydrogen plane: https://aerodelft.nl/ https://aerodelft.nl/

sa1 7y ago

There was some news about metal sponges earlier that may be able to hold high volumes of H2 under low pressure. https://www.bbc.com/news/science-environment-52328786 https://www.bbc.com/news/science-environment-52328786

mannykannot 7y ago
You got me thinking, so I looked for some numbers. Hydrogen has a specific energy of 120 MJ/kg, while Kerosine has 46 MJ/kg. According to the abstract of the paper being discussed here, the new material has a deliverable capacity of 14% by weight, corresponding to about 17 MJ/kg - only a bit better than 1/3 that of kerosine, but considerably better than lithium ion batteries, which apparently achieve less than 1 MJ/kg, while the best-performing lithium-sulfur batteries are at about 1.8 MJ/kg. In addition, we must deal with this material only losing 14% of its weight as its hydrogen is used up, while kerosine loses all of its weight - a combustion-powered airplane becomes more efficient as its fuel is consumed. Furthermore, to get that 14% deliverable capacity, you have to start with it at 100 bar, so the tank containing it will have a substantial weight. So we have progress here, but not yet a substitute for liquid hydrocarbons.

Hypx 7y ago

LH2 is a liquid. It's likely airplanes will use liquid hydrogen as a fuel.