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The drawbacks are as follows. To convert hydrogen back into electricity you need to either use a gas turbine or a fuel cell. Fuel cells are expensive, so you h

The drawbacks are as follows. To convert hydrogen back into electricity you need to either use a gas turbine or a fuel cell. Fuel cells are expensive, so you have capital cost problems. Additionally fuel cells have problems providing variable power output. For this reason you often couple the system with a battery. Gas turbines running on hydrogen have some engineering challenges. In particular the gas turbine technology needs to be re-engineered because hydrogen burns differently from natural gas. Secondly NOx emissions are an issue that needs to be addressed. Moreover, if one is to store and transport hydrogen as a gas or a liquid, the infrastructure is more challenging than with a natural gas pipeline. If one is to further convert hydrogen into a synthetic fuel, you get additional conversion losses.

dmbche 3y ago
Thanks for the explanation, clear and to the point.
_aavaa_ 3y ago
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
- 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...
ikekkdcjkfke 3y ago
If you have an accident at a filling station it will go boom real loud
bwanab 3y ago
Wouldn't the cost of fuel cells come down, as happened with PV, once they are mass produced? Or, is there some inherent high cost to them?
- dmbche 3y ago
  I think it's inherent from the danger of hydrogen and I imagine it's extremely reactive, it might interact with most materials used to hold it.
- jgamman 3y ago
  currently use a lot of rare metals like platinum. inc vol of fuel cells will drive up price of fairly inelastic supply of rare metals. or require step change in anode/cathode catalysts to cheaper metals
  - _hypx 3y ago
    Not all fuel cells use platinum, and those that do use very small amounts of it: https://www.cnet.com/roadshow/news/bosch-ev-fuel-cells-less-platinum-report/ https://www.cnet.com/roadshow/news/bosch-ev-fuel-cells-less-... > The major auto supplier, which recently partnered with Sweden's Powercell, is working on a new fuel cell architecture that, according to Reuters' report, will "use only as much platinum as a diesel catalytic converter."
- _hypx 3y ago
  That is what is happening now. Critics of this idea are just repeating the same arguments that where used against PV too.
- _aavaa_ 3y ago
  There isn't an inherent cost, just an inherent inefficiency in the electricity -> hydrogen -> electricity process. So the price would come down if they were massed produced. Except you would need a market that is willing to pay the high cost until it comes down. Such a market segment has yet to materialise. If you build satellite you need a source of energy that doesn't depend on your bringing fuel for it. So you're willing to pay the obscene starting price of PV. If you needed/wanted clean electricity made off-grid you're willing to pay for PV since it had many benefits over the alternatives (if they even existed in your situation). What is the same starting market for fuel cells? It would have to: 1. Not care that the hydrogen is difficult to transport to that location, or be willing to invest in the costly equipment to make and store it on site. 2. It would have to be willing to put up with the poor end-to-end efficiency, both in absolute and relative terms. 3. It would need to be isolated from a grid such that you would require storage in the first place. 4. It would need to be long term and isolated enough such that batteries, pumped hydro, connection to the grid, and overbuilding of renewable are not a viable/cheaper alternative.

dmbche 3y ago

Thanks for the explanation, clear and to the point.

_aavaa_ 3y ago

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
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...

ikekkdcjkfke 3y ago

If you have an accident at a filling station it will go boom real loud

bwanab 3y ago

Wouldn't the cost of fuel cells come down, as happened with PV, once they are mass produced? Or, is there some inherent high cost to them?

dmbche 3y ago
I think it's inherent from the danger of hydrogen and I imagine it's extremely reactive, it might interact with most materials used to hold it.
jgamman 3y ago
currently use a lot of rare metals like platinum. inc vol of fuel cells will drive up price of fairly inelastic supply of rare metals. or require step change in anode/cathode catalysts to cheaper metals
- _hypx 3y ago
  Not all fuel cells use platinum, and those that do use very small amounts of it: https://www.cnet.com/roadshow/news/bosch-ev-fuel-cells-less-platinum-report/ https://www.cnet.com/roadshow/news/bosch-ev-fuel-cells-less-... > The major auto supplier, which recently partnered with Sweden's Powercell, is working on a new fuel cell architecture that, according to Reuters' report, will "use only as much platinum as a diesel catalytic converter."
_hypx 3y ago
That is what is happening now. Critics of this idea are just repeating the same arguments that where used against PV too.
_aavaa_ 3y ago
There isn't an inherent cost, just an inherent inefficiency in the electricity -> hydrogen -> electricity process. So the price would come down if they were massed produced. Except you would need a market that is willing to pay the high cost until it comes down. Such a market segment has yet to materialise. If you build satellite you need a source of energy that doesn't depend on your bringing fuel for it. So you're willing to pay the obscene starting price of PV. If you needed/wanted clean electricity made off-grid you're willing to pay for PV since it had many benefits over the alternatives (if they even existed in your situation). What is the same starting market for fuel cells? It would have to: 1. Not care that the hydrogen is difficult to transport to that location, or be willing to invest in the costly equipment to make and store it on site. 2. It would have to be willing to put up with the poor end-to-end efficiency, both in absolute and relative terms. 3. It would need to be isolated from a grid such that you would require storage in the first place. 4. It would need to be long term and isolated enough such that batteries, pumped hydro, connection to the grid, and overbuilding of renewable are not a viable/cheaper alternative.