this post was submitted on 15 Jul 2024
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Hydrogen

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A community about hydrogen and its use as a way to fight climate change.

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With government entities rolling back EV regulations, now is the time to take a second look at hydrogen.

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[–] [email protected] 2 points 1 month ago

If the goal is reducing CO2 emissions, then electricity will be used to break H2 from water. Currently most H2 is extracted from natural gas, which produces CO2 as a by-product. That is, H2 needs to be used as a chemical energy storage mechanism for low-carbon energy sources such as solar, wind, or (ick) nuclear.

Problem with this is that the round trip efficiency of electricity to H2 and back is around 30%. If you use the H2 in a combustion system then you might get 35-40% efficiency. LiION batteries are around 90%.

So once you solve the materials handling problems with H2 you are still left with a very expensive energy storage mechanism.

Of course, Lithium is a limited resource so we are going to need more storage mechanisms anyway, but pronouncing H2 as the future is misleading at best.

[–] [email protected] 1 points 1 month ago (2 children)

I used to think it was the future. But I realized it takes too much electricity to create hydrogen.

Better, solid state batteries are the future.

Better yet, widespread electrified mass transit is even better.

[–] [email protected] 2 points 1 month ago

It takes the same amount of electricity in theory. Even in practice it is not a major issue since an all renewable grid needs energy storage, such as hydrogen based energy storage.

[–] [email protected] 1 points 1 month ago

A lot of wind energy is wasted when there's "too much" wind and it there's too much energy to feed into the grid. From I understand, it would destabilise the grid. At the moment, that energy goes nowhere - and it's a lot. That could be used to generate hydrogen instead.

Hydrogen is great for storage. It could also become the future for planes are it has more energy than kerosene, however no jet engines exist that can take advantage of it due to a lack of investment (which is changing rapidly). It is also lighter than kerosene, which would allow planes to fly longer or use less fuel to fly.

Finally, electrolysis is also used to generate deuterium/heavy water, which is critical for nuclear fusion. If we ever invest as much in nuclear fusion as we did in photovoltaic or even combustion engines, generating enough energy to reach a 1 on the Kardashev Scale might actually be possible within our lifetimes.

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