5 ms·

Don’t forget: - it has an abysmal energy density per unit volume, even as a liquid. E.g. if you used to need 1 tanker or gasoline, you’ll need 18 tankers of co

Don’t forget: - it has an abysmal energy density per unit volume, even as a liquid. E.g. if you used to need 1 tanker or gasoline, you’ll need 18 tankers of compressed hydrogen for the same energy content. - compressing and liquifying it is much more expensive and challanging that natural gas. See this fun little challange [0] - there are currently no odorants available for use in hydrogen (the thing that gives natural gas it’s smell). All the available ones either react with hydrogen or poison your fuel cell - it’s flame is essentially invisible and incredibly hot - it has an explosive range from 4-75% (natural gas for example is 5-17%) [0]: https://en.m.wikipedia.org/wiki/Spin_isomers_of_hydrogen https://en.m.wikipedia.org/wiki/Spin_isomers_of_hydrogen

dmbche 3y ago
I hadn't realised the flame was invisible. It's terrifying to me, after seeing ethanol fires on racecars.
- _aavaa_ 3y ago
  It is! NASA and firefighters had the broom test [0]. Walk with a broom in front of them if they thought there might be a hydrogen fire. If the broom suddenly burst into flames, they knew they had a problem. [0]: https://spinoff.nasa.gov/spinoff1997/ps1.html https://spinoff.nasa.gov/spinoff1997/ps1.html
somewhat_drunk 3y ago
I was a project engineer in a hydrogen fuel cell research lab for a few years. To add to this, hydrogen also: - is the smallest molecule; as such is very difficult to contain - embrittles and degrades most steels - is ignited by a miniscule amount of energy, such as static sparks - has a terribly rapid flame front, which means big boom when it does ignite Everyone has seen the consequences of pilot lights going out while owners are on vacation. House fills with natural gas, fridge compressor kicks on, ignites gas, house explodes. A house filled with hydrogen would not only destroy the house containing it, but the houses next to it as well, and it would be much more likely to ignite due to its much lower ignition energy. I do not trust contractors to install hydrogen piping, and I do not trust homeowners to maintain their hydrogen sensors. I would NEVER live in a building that had hydrogen stored (as in a vehicle tank) or piped inside. There are simply too many ways for that scenario to go wrong, and if it does go wrong, it goes wrong in a very bad way.
- dmbche 3y ago
  Would it be reasonable to reserve hydrogen for electric plants then? Bringing power from far away and burning the hydrogen to power locals?
- senectus1 3y ago
  >Everyone has seen the consequences of pilot lights going out while owners are on vacation. House fills with natural gas, fridge compressor kicks on, ignites gas, house explodes. A house filled with hydrogen would not only destroy the house containing it, but the houses next to it as well, and it would be much more likely to ignite due to its much lower ignition energy. So Its molecule is so tiny it's hard to contain even in specially constructed containers, but in a house leak it'll hang around and build up enough in a house to level a suburb block? You can't have it both ways.
  - somewhat_drunk 3y ago
    An obvious false equivalence. The difference is pressure.
  - dmbche 3y ago
    To clarify with the false equivalence : when pressurized at more than atmosphere, the pressure pushes the hydrogen through containement easily. This is problematic, as we would need hermetic containement. If leaked into a house, the pressure remains 1 atm - the issue is not with the pressure, but with the amount of atoms of hydrogen being close enough that, if one catches fire, it will spread to enough atoms to cause an explosion that will raise a block. The atoms are not moving quickly to escape the house, they observe light motion as particles in the still-ish air of the house, so after some time they overcrowd the house without even having to reach the outside wall, they could all hang around the pipe.
- bjowen 3y ago
  Has there been any serious proposal for hydrogen to replace reticulated gas in domestic supply? The cost to refit existing infra would surely make it less attractive than something like power-to-methane.
deleted 3y ago
[deleted]
_hypx 3y ago
> A liquid hydrogen tanker can carry nearly the same amount of energy as a liquid diesel tanker, noted Mike Roeth, NACFE executive director https://www.trucknews.com/sustainability/nacfe-takes-fresh-look-at-hydrogen-fuel-cells/1003174074/ https://www.trucknews.com/sustainability/nacfe-takes-fresh-l...
- _aavaa_ 3y ago
  A) Liquid hydrogen is stored at 20K, 20 degrees above absolute zero. Compressing and cooling hydrogen gas to 20K consumes ~30% of the energy content of the hydrogen. That tanker has a boil off rate of 0.3-0.6%. The thing you're storing it in is going to have a similar boil off range. B) "No hydrogen option will fully displace BEVs, noted Roeth"
  - _hypx 3y ago
    You don’t consume any of the hydrogen to liquefy hydrogen. That comes from an external energy source. Smartly, it would just be the renewable energy used to make the hydrogen in the first place, making it potentially nearly free. BEVs will still exist as short-ranged urban vehicles. That is a niche, and in trucking that is a very small one too.
    - _aavaa_ 3y ago
      Wherever you get the energy to compress it from, you still need to spend ~30% of the energy content of the hydrogen to compress it to a liquid. There is no evidence to support the idea that BEVs (cars or trucks) will remain short-ranged urban vehicle. Even the "entry" level BEVs in NA, like the leaf, have gotten to EPA ranges of 360 km, a number that is only ever going to go up. Even trucking is slowly getting there as the battery tech improves. In Europe Mercedes is testing trucks, today, which hit 200-400 km before needing to charge [0]. That's not enough for long distance, but that doesn't matter. They can serve this market and when they're ready they can expand to longer ranges. Further, there is even less evidence that in applications where BEVs don't (and won't) work that hydrogen is the winning solution. What is hydrogen's go to market strategy? Introduce trucks for long range that have higher up front costs and higher total cost of ownership that diesel trucks, plus severely limit where you can drive since you depend on a (non-existent) hydrogen network? [0]: https://cleantechnica.com/2023/06/11/electric-semi-truck-drives-from-germany-to-turkey/ https://cleantechnica.com/2023/06/11/electric-semi-truck-dri...

dmbche 3y ago

I hadn't realised the flame was invisible. It's terrifying to me, after seeing ethanol fires on racecars.

_aavaa_ 3y ago
It is! NASA and firefighters had the broom test [0]. Walk with a broom in front of them if they thought there might be a hydrogen fire. If the broom suddenly burst into flames, they knew they had a problem. [0]: https://spinoff.nasa.gov/spinoff1997/ps1.html https://spinoff.nasa.gov/spinoff1997/ps1.html

somewhat_drunk 3y ago

I was a project engineer in a hydrogen fuel cell research lab for a few years. To add to this, hydrogen also: - is the smallest molecule; as such is very difficult to contain - embrittles and degrades most steels - is ignited by a miniscule amount of energy, such as static sparks - has a terribly rapid flame front, which means big boom when it does ignite Everyone has seen the consequences of pilot lights going out while owners are on vacation. House fills with natural gas, fridge compressor kicks on, ignites gas, house explodes. A house filled with hydrogen would not only destroy the house containing it, but the houses next to it as well, and it would be much more likely to ignite due to its much lower ignition energy. I do not trust contractors to install hydrogen piping, and I do not trust homeowners to maintain their hydrogen sensors. I would NEVER live in a building that had hydrogen stored (as in a vehicle tank) or piped inside. There are simply too many ways for that scenario to go wrong, and if it does go wrong, it goes wrong in a very bad way.

dmbche 3y ago
Would it be reasonable to reserve hydrogen for electric plants then? Bringing power from far away and burning the hydrogen to power locals?
senectus1 3y ago
>Everyone has seen the consequences of pilot lights going out while owners are on vacation. House fills with natural gas, fridge compressor kicks on, ignites gas, house explodes. A house filled with hydrogen would not only destroy the house containing it, but the houses next to it as well, and it would be much more likely to ignite due to its much lower ignition energy. So Its molecule is so tiny it's hard to contain even in specially constructed containers, but in a house leak it'll hang around and build up enough in a house to level a suburb block? You can't have it both ways.
- somewhat_drunk 3y ago
  An obvious false equivalence. The difference is pressure.
- dmbche 3y ago
  To clarify with the false equivalence : when pressurized at more than atmosphere, the pressure pushes the hydrogen through containement easily. This is problematic, as we would need hermetic containement. If leaked into a house, the pressure remains 1 atm - the issue is not with the pressure, but with the amount of atoms of hydrogen being close enough that, if one catches fire, it will spread to enough atoms to cause an explosion that will raise a block. The atoms are not moving quickly to escape the house, they observe light motion as particles in the still-ish air of the house, so after some time they overcrowd the house without even having to reach the outside wall, they could all hang around the pipe.
bjowen 3y ago
Has there been any serious proposal for hydrogen to replace reticulated gas in domestic supply? The cost to refit existing infra would surely make it less attractive than something like power-to-methane.

deleted 3y ago

[deleted]

_hypx 3y ago

> A liquid hydrogen tanker can carry nearly the same amount of energy as a liquid diesel tanker, noted Mike Roeth, NACFE executive director https://www.trucknews.com/sustainability/nacfe-takes-fresh-look-at-hydrogen-fuel-cells/1003174074/ https://www.trucknews.com/sustainability/nacfe-takes-fresh-l...

_aavaa_ 3y ago
A) Liquid hydrogen is stored at 20K, 20 degrees above absolute zero. Compressing and cooling hydrogen gas to 20K consumes ~30% of the energy content of the hydrogen. That tanker has a boil off rate of 0.3-0.6%. The thing you're storing it in is going to have a similar boil off range. B) "No hydrogen option will fully displace BEVs, noted Roeth"
- _hypx 3y ago
  You don’t consume any of the hydrogen to liquefy hydrogen. That comes from an external energy source. Smartly, it would just be the renewable energy used to make the hydrogen in the first place, making it potentially nearly free. BEVs will still exist as short-ranged urban vehicles. That is a niche, and in trucking that is a very small one too.
  - _aavaa_ 3y ago
    Wherever you get the energy to compress it from, you still need to spend ~30% of the energy content of the hydrogen to compress it to a liquid. There is no evidence to support the idea that BEVs (cars or trucks) will remain short-ranged urban vehicle. Even the "entry" level BEVs in NA, like the leaf, have gotten to EPA ranges of 360 km, a number that is only ever going to go up. Even trucking is slowly getting there as the battery tech improves. In Europe Mercedes is testing trucks, today, which hit 200-400 km before needing to charge [0]. That's not enough for long distance, but that doesn't matter. They can serve this market and when they're ready they can expand to longer ranges. Further, there is even less evidence that in applications where BEVs don't (and won't) work that hydrogen is the winning solution. What is hydrogen's go to market strategy? Introduce trucks for long range that have higher up front costs and higher total cost of ownership that diesel trucks, plus severely limit where you can drive since you depend on a (non-existent) hydrogen network? [0]: https://cleantechnica.com/2023/06/11/electric-semi-truck-drives-from-germany-to-turkey/ https://cleantechnica.com/2023/06/11/electric-semi-truck-dri...