Interest of hydrogen as fuel?

[laurent_caen]

good evening everyone
I wonder about the interest of an energy that is presented as the energy of the second half of the 20th century, namely hydrogen: indeed, I absolutely do not see the interest of this energy as fuel insofar as the size of the molecules generates big storage problems, that this molecule is not naturally present (except in specific places like Iceland) and therefore that its production itself requires a large quantity of energy, so that I absolutely do not see the advantage of this energy over electricity for example. This is all the more so as the vehicles would then reject water (2 H2 + O2 -> 2 H20O), which is a greenhouse gas with a heating power twice that of CO2! I hope you can light up my lanterns ... and I apologize in advance if this information is present on your site.
Good night
Laurent

[Flytox]

Hello Laurent Caen

I wonder about the interest of an energy that is presented as the energy of the second half of the 20th century, namely hydrogen.

Agree with you, the only interest which I see there, it is to move away the sources of pollution (engines) of the cities. But in any case it will be necessary to pollute somewhere to produce this hydrogen.

We can just hope that if there are infinitely fewer hydrogen manufacturing centers than there are engines in circulation, it will be easier to absorb heavier systems capable of treating pollution at the source (trapping CO2, particulates thinner etc ...)

This is all the more so as the vehicles would then reject water (2 H2 + O2 -> 2 H20O), which is a greenhouse gas with a heating power twice that of CO2!

This is a damn interesting question, I have never read anything well documented on this aspect pollution by water vapor. Is this negligible or on the contrary should we urgently look into it before it colonizes the planet and produces urban highway fog?

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[laurent_caen]

Water vapor is the FIRST greenhouse gas present in the atmosphere; but this is completely normal since it is of natural origin, although ... its concentration in the atmosphere increases due to global warming (increase in condensation) but it is an indirect effect of greenhouse gases greenhouse produced by humans; However, if we produced water vapor in an artificial way, we would then create an excess of water vapor in the air exactly as we currently do for CO2! We would then only change enemies ... This is why I cannot understand the current craze for hydrogen

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[Cuicui]

If we increase the amount of water vapor in the atmosphere, there will simply be more precipitation (rain, fog, dew). Hydrogen could be interesting for the propulsion of planes if we manage to solve the problem of storage.

[laurent_caen]

"If we increase the amount of water vapor in the atmosphere, there will simply be more precipitation (rain, fog, dew)."

Not exactly, water is a greenhouse gas in the same way as CO2 and just as an excess of CO2 disrupts the climate, an excess of H2O does the same, especially as the power of warming of this gas is twice that of CO2. I have the impression that everyone thinks that CO2 is a pollutant (it is true that it is so clubbed at the moment and rightly so) unlike water; CO2 is a natural component of the atmosphere, just like water vapor! It is the EXCESS of man-made CO2 that disrupts the climate and which we must fight against. In this perspective, we would have the same problem if we develop hydrogen, it would then be necessary to fight against the EXCESS of H2O emitted in the atmosphere. Have I made myself understood?

[Cuicui]

The difference between CO2 and water is that the atmosphere can get rid of its excess water by condensation and precipitation, which is not the case for CO2.

[laurent_caen]

Again, same problem as for CO2: just as from a given threshold of CO2 in the atmosphere, vegetation cannot capture all the CO2, there is a breaking point from which the concentration There would be too much water vapor in the atmosphere for all of the water vapor produced to condense and return to a liquid state. There would then be an increase in the concentration of H20O in the atmosphere (which is already the case at the moment, as I said earlier) with therefore an increase in the greenhouse effect.

[delnoram]

Water vapor has been debated here

In particular this passage:

Water vapor is indeed a GHG, it is even the first contributor to the greenhouse effect.
But there are several things which it is necessary to take into account to properly estimate its possible action, it is that water vapor does not accumulate in the atmosphere (because of the saturated vapor pressure) and that '' it shows both positive (blocking outgoing IR) and negative (blocking incoming radiation) feedbacks on the Earth's radiation balance ...

So it seems to me that a little more caution would be desirable when it comes to this type of instrument.

[laurent_caen]

Thanks for the link, I'll take one last look before I sleep

[Flytox]

Bonjour à tous

Anyone have an idea of ​​the volumes of water or water vapor that could be thrown into the atmosphere by all vehicles in the world equipped with hydrogen. I think we have to relate it to the amount of water naturally present in the atmosphere. (is the percentage significant or totally derisory?)

It should also be taken into account that current engines already throw about as much water into the atmosphere as the amount of fuel they consume.

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