How green is blue hydrogen?

Re:How green is blue hydrogen? by dTal on Thursday August 12, 2021 @06:10PM (#28162223)

Sure, but when people say "hydrogen fuel" they usually mean pure H2. Trouble is, those carbon atoms everyone's so keen to get rid of are damn useful, chemically speaking. I actually think there's a lot more mileage in synthesizing hydrocarbons from biowaste. There's nothing inherently wrong with burning hydrocarbons - the problem is that we're lazily digging historical supplies out of the ground, instead of keeping the carbon cycle closed.

Really, we should just put massive tax levies on fossil fuel extraction operations and call it a day. The market will sort the rest out.

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Re:How green is blue hydrogen? by the_third_wave on Thursday August 12, 2021 @06:31PM (#28162447)

> There's nothing inherently wrong with burning hydrocarbons

...if and when you burn them with pure oxygen like done in rockets. Mostly they're burnt using using atmospheric oxygen though, leading to the production of nitrogen oxides (NOx) which come with their own problems [1]. It is possible to reduce the emission of these gases [2] at the cost of increased complexity and cost.

[1] https://en.wikipedia.org/wiki/NOx#Health_and_environment_eff...

[2] https://en.wikipedia.org/wiki/NOx#Regulation_and_emission_co...

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Re:How green is blue hydrogen? by diarrhea on Friday August 13, 2021 @05:52AM (#28167158)

NOx (and PM) is a local, temporary consequence. Catalysts exist to remove NOx out of exhaust gasses. They are perfectly serviceable.

Carbon dioxide is a permanent, global issue, where no (large-scale) capturing/cleaning methods exist.

NOx removes itself out of the atmosphere through natural means, CO2 does not.

You can close the cycle, hence 'ignore' CO2 emissions since they cancel out, and deal with NOx using today's existing technology. Same thing for PM and sulfur.

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Re:How green is blue hydrogen? by the_third_wave on Saturday August 14, 2021 @11:54AM (#28181629)

Tell that to the Dutch authorities who are using NOx emissions to restrict industry and agriculture...

> NOx removes itself out of the atmosphere through natural means

...because of this [1], among others.

[1] https://en.wikipedia.org/wiki/Human_impact_on_the_nitrogen_c...

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Re:How green is blue hydrogen? by AYBABTME on Thursday August 12, 2021 @08:13PM (#28163556)

CO2 is a greenhouse gas, and combustion of hydrocarbons emits it.

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Re:How green is blue hydrogen? by dTal on Thursday August 12, 2021 @09:07PM (#28164042)

And creation of hydrocarbons consumes it, so it all evens out in the long run. The problem is that we're digging up deposits hundreds of millions of years old, so evening out over the long run means atmospheric CO2 goes back to what it was back then, which is much higher. But if you burn vegetable oil that you only grew this year, that doesn't emit any net CO2.

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