4 ms·

Incidentally, leaked hydrogen is substantially worse, as a greenhouse gas, than methane.

fomine3 3y ago
Is it? https://en.wikipedia.org/wiki/Global_warming_potential#Values https://en.wikipedia.org/wiki/Global_warming_potential#Value...
morsch 3y ago
In the atmosphere? No. The GWP of methane is about twice as high as hydrogen, as far as we know. https://en.m.wikipedia.org/wiki/Global_warming_potential https://en.m.wikipedia.org/wiki/Global_warming_potential
semi-extrinsic 3y ago
Nope, the GWP of methane is 2x larger than hydrogen, both on 20 and 100 year time scales. And that's on an equal-mass basis. If you consider an equal-energy basis (which is what we actually care about), methane is 5x worse than hydrogen. Finally, hydrogen has wider flammability limits than methane, so from a safety perspective you have to make hydrogen systems even more leak-proof than methane/natural gas systems.
- angiosperm 3y ago
  The atmosphere has a limited capacity for turning H2 into H2O. As more H2 is released, each molecule takes longer to be neutralized.
  - pfdietz 3y ago
    It may be possible to increase this capacity, for example by releasing iron salt aerosols. These would generate additional OH and Cl radicals by photochemical reactions in sunlight. It would be better to use that increase to destroy methane, though. I also wonder if it could be better to make hydrogen by electrolysis of salt water and produce chlorine instead of oxygen. Released into sunlit atmosphere, chlorine is rapidly decomposed to Cl radicals which will rapidly react with methane (or hydrogen). You'd want to release it at sufficiently low dilution that there's enough methane in each air parcel to consume all the chlorine, though.
pfdietz 3y ago
Only if you presume that considerably larger fraction of the hydrogen would leak, which is not a bad assumption. Anyway, use of hydrogen for grid storage does not require its transmission or distribution in pipelines, especially in the small pipes of local distribution networks for home/small business use where one might expect the most leakage.

Is it? https://en.wikipedia.org/wiki/Global_warming_potential#Values https://en.wikipedia.org/wiki/Global_warming_potential#Value...

morsch 3y ago

In the atmosphere? No. The GWP of methane is about twice as high as hydrogen, as far as we know. https://en.m.wikipedia.org/wiki/Global_warming_potential https://en.m.wikipedia.org/wiki/Global_warming_potential

semi-extrinsic 3y ago

Nope, the GWP of methane is 2x larger than hydrogen, both on 20 and 100 year time scales. And that's on an equal-mass basis. If you consider an equal-energy basis (which is what we actually care about), methane is 5x worse than hydrogen. Finally, hydrogen has wider flammability limits than methane, so from a safety perspective you have to make hydrogen systems even more leak-proof than methane/natural gas systems.

angiosperm 3y ago
The atmosphere has a limited capacity for turning H2 into H2O. As more H2 is released, each molecule takes longer to be neutralized.
- pfdietz 3y ago
  It may be possible to increase this capacity, for example by releasing iron salt aerosols. These would generate additional OH and Cl radicals by photochemical reactions in sunlight. It would be better to use that increase to destroy methane, though. I also wonder if it could be better to make hydrogen by electrolysis of salt water and produce chlorine instead of oxygen. Released into sunlit atmosphere, chlorine is rapidly decomposed to Cl radicals which will rapidly react with methane (or hydrogen). You'd want to release it at sufficiently low dilution that there's enough methane in each air parcel to consume all the chlorine, though.

pfdietz 3y ago

Only if you presume that considerably larger fraction of the hydrogen would leak, which is not a bad assumption. Anyway, use of hydrogen for grid storage does not require its transmission or distribution in pipelines, especially in the small pipes of local distribution networks for home/small business use where one might expect the most leakage.