Viewing a single comment thread. View all comments

ok46reddit t1_iyd0slb wrote

Can you even load enough hydrogen onto a jet for this to be practical?

Why not methane, or ammonia?

https://h2sciencecoalition.com/blog/hydrogen-for-aircraft-number-crunching-the-solution-or-the-hoax/ >When you crunch the numbers it’s clear that hydrogen is not suitable for transportation. It requires too much energy to produce it without CO2 emissions (green hydrogen) and there is a significant storage problem, even for grey hydrogen. 

0

Enchydrogen t1_iyd4z3u wrote

Hydrogen gas is the obvious choice and the technology is improving everyday which will eventually lead to a more efficient storage method to solve the "transportation" issue. As for the production, yes it take more energy to create than is extracted but leave that issue to the producers, if it is a competitive price and its green, why not. There is a TON of unused power around the world that could be used to produce H2, transportation is the only hurdle and we look to be able to clear it soon.

5

ok46reddit t1_iyd6r23 wrote

>which will eventually lead to a more efficient storage method to solve the "transportation" issue.

You will not 'eventaully' change the physics of hydrogen's energy density. Liquid ammonia has twice the energy density of 69MPa gaseous hydrogen. LNG/Liquid methane has four times the energy density. And commercial jets will not be using cryogenic hydrogen, not that this would solve the energy balance problem either.

2

Enchydrogen t1_iyd8bii wrote

I was not saying you can change the physics of hydrogen's density, rather the way in which it is currently stored in gaseous form will improve as technology progresses. I agree that ammonia is a viable green alternative but as I understand it is not the best for combustion and adds to engine complexity and cost. LNG is not a green alternative.

1

ok46reddit t1_iyda979 wrote

LNG is not currently a viable green alternative just like Hydrogen isn't.

There is no limitation of either chemistry or physics that would prevent totally green LNG from becoming a thing, like there is for practical hydrogen stroage for transportation.

And many of the limitations you mention of ammonia can be overcome by adding a small percentage of hydrogen to the fuel mix. A much more ready to go alternative than hydrogen alone. And the hydrogen can be obtained by cracking the ammonia itself as needed as part of the engine system's operation, using waste heat.

https://newatlas.com/aircraft/aviation-h2-ammonia-fuel-jet-aircraft/

1

Vickrin t1_iyf4pmm wrote

> rather the way in which it is currently stored in gaseous form will improve as technology progresses

Technology cannot change the laws of physics.

There is a base minimum amount of space requires to store gaseous hydrogen, if you go below that you get liquid hydrogen and even bigger storage problems.

1