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An advantage of hydrogen is that it can be used in fuel cells, producing only water as reaction product. Using hydrocarbons of any sort in existing engines lead

An advantage of hydrogen is that it can be used in fuel cells, producing only water as reaction product. Using hydrocarbons of any sort in existing engines leads to the production of nitrogen oxides due to the presence of nitrogen in the air.

xoa 6y ago
Thanks for this reply as well. But batteries will cover most land use, and going by sources like the EIA [1] the primary source of anthropogenic N2O emissions is overwhelmingly agriculture, at 70+%. Other sources indicate that may have fallen somewhat since then, but even so everything I can find indicates fossil fuel combustion is still only around 10%. And of that air travel will be single digits. Not nothing, but I'm not sure it'd justify massive effort alone.
- Yetanfou 6y ago
  I don't think hydrogen is a good energy storage solution. I do see its advantage over hydrocarbons for certain applications but the difficulties in storing hydrogen - a small molecule which is sort of an escape artist - make it less than ideal for many purposes. Fuel cells can get contaminated unless they're run with pure hydrogen and oxygen. In applications where hydrogen is already available - e.g. H₂-LOX fuelled rockets - it makes sense to use fuel cells. It might be possible to run aircraft using H₂-fed fuel cells if these can be made powerful and light enough to fit the application, the advantage over battery-electric here is that the energy density of liquid hydrogen is much higher than that of current battery technology. For the rest - cars being a good example - I think batteries are currently a better solution. Large scale energy storage is probably handled better using either redox flow batteries [1], hydro storage systems or energy storage vaults using concrete blocks which are lifted when there is too much energy available, lowered when energy is needed. [1] https://en.wikipedia.org/wiki/Flow_battery https://en.wikipedia.org/wiki/Flow_battery

xoa 6y ago

Thanks for this reply as well. But batteries will cover most land use, and going by sources like the EIA [1] the primary source of anthropogenic N2O emissions is overwhelmingly agriculture, at 70+%. Other sources indicate that may have fallen somewhat since then, but even so everything I can find indicates fossil fuel combustion is still only around 10%. And of that air travel will be single digits. Not nothing, but I'm not sure it'd justify massive effort alone.

Yetanfou 6y ago
I don't think hydrogen is a good energy storage solution. I do see its advantage over hydrocarbons for certain applications but the difficulties in storing hydrogen - a small molecule which is sort of an escape artist - make it less than ideal for many purposes. Fuel cells can get contaminated unless they're run with pure hydrogen and oxygen. In applications where hydrogen is already available - e.g. H₂-LOX fuelled rockets - it makes sense to use fuel cells. It might be possible to run aircraft using H₂-fed fuel cells if these can be made powerful and light enough to fit the application, the advantage over battery-electric here is that the energy density of liquid hydrogen is much higher than that of current battery technology. For the rest - cars being a good example - I think batteries are currently a better solution. Large scale energy storage is probably handled better using either redox flow batteries [1], hydro storage systems or energy storage vaults using concrete blocks which are lifted when there is too much energy available, lowered when energy is needed. [1] https://en.wikipedia.org/wiki/Flow_battery https://en.wikipedia.org/wiki/Flow_battery