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... and not a single word about how the necessary electricity needed to make this "zero emission fuel" is supposed to be produced. Plus, all I know about hydro

by lutorm 12y ago

... and not a single word about how the necessary electricity needed to make this "zero emission fuel" is supposed to be produced. Plus, all I know about hydrogen points to it not being anything close to "an ideal fuel for powering vehicles, buildings and storing renewable energy". It has very low density, requires cryogenic storage or very heavy pressure vessels, migrates through materials, and is explosive when mixed with air.

digikata 12y ago
See also "hydrogen embrittlement" http://en.wikipedia.org/wiki/Hydrogen_embrittlement http://en.wikipedia.org/wiki/Hydrogen_embrittlement Many materials you might select to carry hydrogen are weakened by it.
Crito 12y ago
Even when cryogenic (and hydrogen needs to be deeply cryogenic to remain liquid. 20K compared to liquid nitrogen's 77K) it is not particularly dense. It barely makes sense to use it in rockets since it has such poor density, causes embrittlement, and requires a great deal of insulation if you want to store it for any reasonable amount of time. If it is a chore to use the stuff for rocket science, I don't see it becoming a reasonable power source in more casual applications. If I am factually incorrect about anything here, I honestly do want to be told so.
nardi 12y ago
This is like commenting on a battery tech article with, "Yes, but how are we going to charge all of those batteries?!" Or power grid technology, "Great, but where is the electricity going to come from?!?!"
- aidenn0 12y ago
  There is no mention of efficiency either; the efficiency of hydrolysis is often around 50% which means that almost anywhere you live it would be better from a CO2 standpoint to just put gas in your car.
- lutorm 12y ago
  Well, if they claimed that using batteries was "emissions free", I would complain about that, too. With hydrogen, the issue issue is that (at least to my understanding) if you have electricity, we already have a far more efficient solution: put the electricity directly into a battery and use it to power a motor. Going the route over electrolysis->hydrogen storage->fuel cell imposes such efficiency penalties that it would need extremely compelling other advantages to be competitive, and I don't see them.
  - nardi 12y ago
    Hey, I like chemical batteries too, but they're not capacitors. You don't put electricity into them. You drive an electrochemical reaction with them, which is subject to its own inefficiencies, as well as wear and tear on the battery, which isn't a problem with hydrogen fuel cells. Hydrogen fuel cells also tend to be highly efficient.
    - lutorm 12y ago
      Sure. Are you saying the fuel cell cycle is actually more efficient than the battery cycle? The long-term performance question is interesting, though. Any idea how long the time scale would have to be before the fuel cell wins?
    - seanflyon 12y ago
      > wear and tear on the battery, which isn't a problem with hydrogen fuel cells. Sadly this is not the case. Fuel cells have similar lifespans as batteries.
  - epistasis 12y ago
    Using the batteries is emissions free. Claiming anything else is just bringing emotional baggage and irrationality to the situation.
    - lutorm 12y ago
      It is anything but. It's like saying "gasoline is emissions free, it's the burning of it that's the problem." If we're going to have a rational discussion about various forms of emission, we need to talk about total fuel cycle emissions, otherwise it's meaningless. Touting one small section of a fuel cycle as emissions free is at best confusing, at worst misleading.
justin66 12y ago
> ... and not a single word about how the necessary electricity needed to make this "zero emission fuel" is supposed to be produced. At some point you have to trust the reader to understand things that are completely obvious. That's a necessary quality of good writing, even if you're adhering to the newspaper standard of targeting someone at the 8th grade reading level.
- jacquesm 12y ago
  But in the case of Hydrogen such 'completely obvious' things are actually not all that obvious to the target audience. So it's ok to spell it out to avoid the risk of overselling a new technology and thus create a situation where it will fail to deliver due to unrealistic expectations. Hydrogen is not exactly the easiest compound to work with and how it is generated is a huge part of equation.
  - lutorm 12y ago
    Exactly. If you haven't come across people who think hydrogen is "the solution to global warming", you need to talk to more people.
  - justin66 12y ago
    The article did not claim the energy used to proceed the hypothetical AAA battery was free. That certainly would oversell some things. On the contrary, if they'd demoed the thing with a small solar panel I might have had some issues with it, and wanted to see some elaboration. The fundamentally good thing about the battery example is that everyone understands that making a battery costs something. IMO it's a better example than you give them credit for. Certainly everyone reading here understands that it takes energy to make a battery, that the creators of the gadget haven't defeated the laws of thermodynamics, and so on. Hence my comment about trusting the reader.
mikexstudios 12y ago
They didn't comment about it because it's not relevant. As nardi and others have said, think of water splitting as a battery... or a way to store energy as a chemical fuel (i.e. hydrogen gas). Because your energy input can come from any source, it doesn't matter. Agree that hydrogen isn't an ideal fuel though. They're overselling that point. But the science is about how to split water efficiently. It's outside the scope of this research to address how to handle and use hydrogen after that.
digikata 12y ago
I'm skeptical of hydrogen infrastructure using direct hydrogen too, and assume you need some other way to store and release the hydrogen. http://en.wikipedia.org/wiki/Hydrogen_storage http://en.wikipedia.org/wiki/Hydrogen_storage I would think it would be more interesting to electrolyze directly into some storage material. But then, I'm just a casual observer in this topic area...

by lutorm 12y ago

digikata 12y ago

See also "hydrogen embrittlement" http://en.wikipedia.org/wiki/Hydrogen_embrittlement http://en.wikipedia.org/wiki/Hydrogen_embrittlement Many materials you might select to carry hydrogen are weakened by it.

Crito 12y ago

Even when cryogenic (and hydrogen needs to be deeply cryogenic to remain liquid. 20K compared to liquid nitrogen's 77K) it is not particularly dense. It barely makes sense to use it in rockets since it has such poor density, causes embrittlement, and requires a great deal of insulation if you want to store it for any reasonable amount of time. If it is a chore to use the stuff for rocket science, I don't see it becoming a reasonable power source in more casual applications. If I am factually incorrect about anything here, I honestly do want to be told so.

nardi 12y ago

This is like commenting on a battery tech article with, "Yes, but how are we going to charge all of those batteries?!" Or power grid technology, "Great, but where is the electricity going to come from?!?!"

aidenn0 12y ago
There is no mention of efficiency either; the efficiency of hydrolysis is often around 50% which means that almost anywhere you live it would be better from a CO2 standpoint to just put gas in your car.
lutorm 12y ago
Well, if they claimed that using batteries was "emissions free", I would complain about that, too. With hydrogen, the issue issue is that (at least to my understanding) if you have electricity, we already have a far more efficient solution: put the electricity directly into a battery and use it to power a motor. Going the route over electrolysis->hydrogen storage->fuel cell imposes such efficiency penalties that it would need extremely compelling other advantages to be competitive, and I don't see them.
- nardi 12y ago
  Hey, I like chemical batteries too, but they're not capacitors. You don't put electricity into them. You drive an electrochemical reaction with them, which is subject to its own inefficiencies, as well as wear and tear on the battery, which isn't a problem with hydrogen fuel cells. Hydrogen fuel cells also tend to be highly efficient.
  - lutorm 12y ago
    Sure. Are you saying the fuel cell cycle is actually more efficient than the battery cycle? The long-term performance question is interesting, though. Any idea how long the time scale would have to be before the fuel cell wins?
  - seanflyon 12y ago
    > wear and tear on the battery, which isn't a problem with hydrogen fuel cells. Sadly this is not the case. Fuel cells have similar lifespans as batteries.
- epistasis 12y ago
  Using the batteries is emissions free. Claiming anything else is just bringing emotional baggage and irrationality to the situation.
  - lutorm 12y ago
    It is anything but. It's like saying "gasoline is emissions free, it's the burning of it that's the problem." If we're going to have a rational discussion about various forms of emission, we need to talk about total fuel cycle emissions, otherwise it's meaningless. Touting one small section of a fuel cycle as emissions free is at best confusing, at worst misleading.

justin66 12y ago

> ... and not a single word about how the necessary electricity needed to make this "zero emission fuel" is supposed to be produced. At some point you have to trust the reader to understand things that are completely obvious. That's a necessary quality of good writing, even if you're adhering to the newspaper standard of targeting someone at the 8th grade reading level.

jacquesm 12y ago
But in the case of Hydrogen such 'completely obvious' things are actually not all that obvious to the target audience. So it's ok to spell it out to avoid the risk of overselling a new technology and thus create a situation where it will fail to deliver due to unrealistic expectations. Hydrogen is not exactly the easiest compound to work with and how it is generated is a huge part of equation.
- lutorm 12y ago
  Exactly. If you haven't come across people who think hydrogen is "the solution to global warming", you need to talk to more people.
- justin66 12y ago
  The article did not claim the energy used to proceed the hypothetical AAA battery was free. That certainly would oversell some things. On the contrary, if they'd demoed the thing with a small solar panel I might have had some issues with it, and wanted to see some elaboration. The fundamentally good thing about the battery example is that everyone understands that making a battery costs something. IMO it's a better example than you give them credit for. Certainly everyone reading here understands that it takes energy to make a battery, that the creators of the gadget haven't defeated the laws of thermodynamics, and so on. Hence my comment about trusting the reader.

mikexstudios 12y ago

They didn't comment about it because it's not relevant. As nardi and others have said, think of water splitting as a battery... or a way to store energy as a chemical fuel (i.e. hydrogen gas). Because your energy input can come from any source, it doesn't matter. Agree that hydrogen isn't an ideal fuel though. They're overselling that point. But the science is about how to split water efficiently. It's outside the scope of this research to address how to handle and use hydrogen after that.

digikata 12y ago

I'm skeptical of hydrogen infrastructure using direct hydrogen too, and assume you need some other way to store and release the hydrogen. http://en.wikipedia.org/wiki/Hydrogen_storage http://en.wikipedia.org/wiki/Hydrogen_storage I would think it would be more interesting to electrolyze directly into some storage material. But then, I'm just a casual observer in this topic area...