5 ms·

Of course there is green hydrogen. First of all, the green aspect of it is that the source is renewable. That's what makes it green. It's not correct to call i

by chicob 4y ago

Of course there is green hydrogen. First of all, the green aspect of it is that the source is renewable. That's what makes it green. It's not correct to call it a net loss, because no one wants to produce power from hydrogen in order to harvest more hydrogen. There would always be a renewable input somewhere. About losses. There are always losses on each energy transformation step. The same thing applies to electricity generated with fossil fuels, or heat generated with electricity generated from heat, or light generated with electricity produced with light. The fact that the source is renewable means we can probably afford that loss in the long term. Using green hydrogen as fuel for far-from-grid cases still makes sense. Electric tractors are not feasible yet, given the required power×autonomy. Also, consider Iceland, were electricity is cheap and produced via geothermal sources, but exporting it is impossible: producing green hydrogen would make that energy exportable. And consider also the Haber-Bosch process, where ammonia production requires hydrogen that currently comes from fossil sources (natural gas) which implies carbon emissions. Shifting to green hydrogen would be a game changer in the production of fertilizers. Remember farming is one of the major sources of CO₂ emissions.

kkfx 4y ago
It's not a matter of efficiency but of scale: we can't produce enough hydrogen by hydrolysis even with all the electricity we can produce. On contrary probably we can made electric tools to substitute tractors. Something that demand a bit of investment but last FAR longer and can run only on p.v. the hard part there would probably be convincing farmers that they do not need tractors anywhere but only for very specific activities... If you use all Island electricity you can't even produce enough hydrogen to power a hypothetical nations-wide fleet of cars...
- lukeschlather 4y ago
  This EU study suggests that we could produce enough hydrogen to fuel air travel with about 32 Pwh annually, which is maybe 20% of current global energy production. I am pretty sure your assertion is simply wrong. Converting to hydrogen would be expensive, possibly dramatically more expensive than other solutions, but it seems totally achievable. https://www.fch.europa.eu/sites/default/files/FCH%20Docs/20200507_Hydrogen%20Powered%20Aviation%20report_FINAL%20web%20%28ID%208706035%29.pdf https://www.fch.europa.eu/sites/default/files/FCH%20Docs/202...
  - kkfx 4y ago
    This honestly is not a study, in the scientific sense, it's a McKinsey made scenario (and they are definitively not skilled in anything industrial, they only deal with finance) of something McKinsey want and present in nice, high paid brochures to offer politicians a way to justify spending in this or this other area. So far the very few experimental plants we have made have proven the fact that, yes, the process work on solar, eolic ec, but also the fact that producible volumes are FAR BELOW the demand, not because we do not have enough plants so far on scale, but because we can't have them on scale on Earth at the actual state of tech. Beside that so far we still completely miss the hydrogen storage issue: we can't store hydrogen in ANY known form. We can fill tanks of it, it will leak out slowly with relevant safety issues, and with the biggest issue that a just filled tank will be essentially empty in few days. People like to dream, like to deny the reality following dreams pushed by interested parties, but they are just dreams, with good outcome for some scammers for some period of time, disasters for the dreamers.
- ncmncm 4y ago
  You insist on this, but it is not, in fact, true. All that is true is that we have not yet built out enough electrolysis equipment to produce much hydrogen. But that is an empty fact; of course, before you build something, you don't have it yet.
  - kkfx 4y ago
    Let's made a game: how much electricity in kWh you need to extract a liter / gallon of H₂? How fast H₂ leak from a generic tank/in what form you propose to contain it and how much energy such form demand. With this data we can discuss scalability.
    - ncmncm 4y ago
      Let's make a game: you collect actual figures instead of just making shit up.
      - kkfx 4y ago
        Ok, from a conference not much time ago I've noted, but unfortunately fail to recover linkable reference, around 67kWh to extract 1kg of H₂ if there are no losses in the process. I can't estimate losses but I can imaging are there in a relatively relevant percentage. The there is the storage issue: H₂ goes trough essentially any tank, no matter how we store it in practical ways, and that's another loss hard to be computed but there. I've found this old report https://www.nrel.gov/docs/fy04osti/36734.pdf https://www.nrel.gov/docs/fy04osti/36734.pdf and I doubt we really have made significant advance since it.
        ncmncm 4y ago
        You imagine that hydrogen cannot be stored, yet we handle tens of millions of tons every year. Do we vent it and then gather it from the air when we need some? No, we store and transport it. Some is stored in underground cavities, places where we put NG today. Some is liquified. Some is in, yes, tanks at 700atm. You can buy electrolysers on the open market, cash on the barrel head. Need more hydrogen? Buy more electrolysers. Where does this fail to "scale"?

by chicob 4y ago

kkfx 4y ago

It's not a matter of efficiency but of scale: we can't produce enough hydrogen by hydrolysis even with all the electricity we can produce. On contrary probably we can made electric tools to substitute tractors. Something that demand a bit of investment but last FAR longer and can run only on p.v. the hard part there would probably be convincing farmers that they do not need tractors anywhere but only for very specific activities... If you use all Island electricity you can't even produce enough hydrogen to power a hypothetical nations-wide fleet of cars...

lukeschlather 4y ago
This EU study suggests that we could produce enough hydrogen to fuel air travel with about 32 Pwh annually, which is maybe 20% of current global energy production. I am pretty sure your assertion is simply wrong. Converting to hydrogen would be expensive, possibly dramatically more expensive than other solutions, but it seems totally achievable. https://www.fch.europa.eu/sites/default/files/FCH%20Docs/20200507_Hydrogen%20Powered%20Aviation%20report_FINAL%20web%20%28ID%208706035%29.pdf https://www.fch.europa.eu/sites/default/files/FCH%20Docs/202...
- kkfx 4y ago
  This honestly is not a study, in the scientific sense, it's a McKinsey made scenario (and they are definitively not skilled in anything industrial, they only deal with finance) of something McKinsey want and present in nice, high paid brochures to offer politicians a way to justify spending in this or this other area. So far the very few experimental plants we have made have proven the fact that, yes, the process work on solar, eolic ec, but also the fact that producible volumes are FAR BELOW the demand, not because we do not have enough plants so far on scale, but because we can't have them on scale on Earth at the actual state of tech. Beside that so far we still completely miss the hydrogen storage issue: we can't store hydrogen in ANY known form. We can fill tanks of it, it will leak out slowly with relevant safety issues, and with the biggest issue that a just filled tank will be essentially empty in few days. People like to dream, like to deny the reality following dreams pushed by interested parties, but they are just dreams, with good outcome for some scammers for some period of time, disasters for the dreamers.
ncmncm 4y ago
You insist on this, but it is not, in fact, true. All that is true is that we have not yet built out enough electrolysis equipment to produce much hydrogen. But that is an empty fact; of course, before you build something, you don't have it yet.
- kkfx 4y ago
  Let's made a game: how much electricity in kWh you need to extract a liter / gallon of H₂? How fast H₂ leak from a generic tank/in what form you propose to contain it and how much energy such form demand. With this data we can discuss scalability.
  - ncmncm 4y ago
    Let's make a game: you collect actual figures instead of just making shit up.
    - kkfx 4y ago
      Ok, from a conference not much time ago I've noted, but unfortunately fail to recover linkable reference, around 67kWh to extract 1kg of H₂ if there are no losses in the process. I can't estimate losses but I can imaging are there in a relatively relevant percentage. The there is the storage issue: H₂ goes trough essentially any tank, no matter how we store it in practical ways, and that's another loss hard to be computed but there. I've found this old report https://www.nrel.gov/docs/fy04osti/36734.pdf https://www.nrel.gov/docs/fy04osti/36734.pdf and I doubt we really have made significant advance since it.
      - ncmncm 4y ago
        You imagine that hydrogen cannot be stored, yet we handle tens of millions of tons every year. Do we vent it and then gather it from the air when we need some? No, we store and transport it. Some is stored in underground cavities, places where we put NG today. Some is liquified. Some is in, yes, tanks at 700atm. You can buy electrolysers on the open market, cash on the barrel head. Need more hydrogen? Buy more electrolysers. Where does this fail to "scale"?