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drsnafu t1_ix5eymw wrote

Isn't hydrogen the favourite green energy source of the fossil fuel industry since it uses a lot of the same infrastructure, when in reality is not actually very 'green'?

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HodorFirstOfHisHodor t1_ix5hyv3 wrote

Hydrogen can be grey, blue or green. The article says the electricity comes from renewable sources which makes it green hydrogen.

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The_Countess t1_ix64cm9 wrote

or red, which is a 'new' flavour they are developing in japan where its generated by heat from a nuclear reactor.

(A reactor that can't melt down because among other things, it doesn't use water for cooling, and can withstand temps up to 1800 degrees C. They have a test reactor up already, and they let it melt down deliberately, and nothing happened. The reaction stopped on its own.)

So far that's one of the few climate neutral large scale hydrogen generation techniques that has looked at all feasible to me. For everything else the efficiency just isn't there. For example if you use renewable electricity to create hydrogen to fuel a car (even a fuelcell powered one (60% efficiency), not ICE (25% at best), a battery car would go 2.5 to 3 times as far on the same amount of renewable energy.

efficiencies like that would always relegate it specific parts of the market were batteries are just too heavy (aviation) or near instant refueling is a requirement.

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Exotria t1_ix7r07l wrote

There's some interesting work being done with green hydrogen in ammonia production, which is used to make fertilizer. With recent innovations, ammonia production plants can be scaled at smaller sizes, so you've got the use case of an island with lots of solar being able to produce its own fertilizer without fossil fuel shipments.

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HertogJan1 t1_ix83tzo wrote

wouldn't it just be blue like regular nuclear power?

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The_Countess t1_ix8c7ut wrote

They went with red, because its the heat that separates the oxygen from the hydrogen.

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netz_pirat t1_ix8cubp wrote

Green hydrogen only makes sense if you scale your generation for winter needs, and therefore have excess in summer that you can't use otherwise.

And it only makes sense for stuff that you can't power otherwise. (ie efuel kerosene for aviation)

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einmaldrin_alleshin t1_ix8glyp wrote

Well with renewables, there's a lot of fluctuation all the time. If solar and wind are able to power the entire country on a calm and cloudy day, there's going to a lot of excess during windy sunny days. Green hydrogen generation would ideally utilize these peaks.

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carlosvega t1_ix5qxaz wrote

Hydrogen is not a source of energy. Is an energy carrier. The main sources of energy are nuclear and solar. All others derive from these two. Exceptions may be tidal and geothermal but they constitute a very small fraction. Green hydrogen could be useful for industry but I have yet to see a big scale plan for it.

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69tank69 t1_ix68ki2 wrote

Right now a huge chunk of it comes from natural gas

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carlosvega t1_ixaaymz wrote

Indeed. But natural gas is just another carrier, the source of it is solar anyway. That’s why usually we speak about sources of electricity, types of electricity production or electricity mix.

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69tank69 t1_ixaj5n3 wrote

Most SMR plants I have seen burned fossil fuels do you have any source that says otherwise

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carlosvega t1_ixao8nz wrote

I haven’t said otherwise. I just said that fossil fuels are not a source of energy, just a carrier, it embodies solar energy captured millions of years ago.

https://www.resilience.org/stories/2018-04-26/there-are-just-two-sources-of-energy/

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69tank69 t1_ixbfj41 wrote

Solar comes from nuclear fusion so there is only type of energy if you want to use that logic, but calling fossil fuels solar energy is deliberately misleading

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