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ZEROe: Hydrogen-hybrid aircraft concept

airbus.com

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Re: ZEROe: Hydrogen-hybrid aircraft concept

#101

Post by AtlasBarfed »

mattashii wrote: post #8
xoa wrote: post #4

I'll admit I really don't get the fascination with hydrogen as an energy storage medium. It has to be manufactured, so how green it is depends on whatever the power input is coming from. It's not any inherently greener then synthetic hydrocarbon production, which can be produced from atmospheric carbon for zero net carbon impact, and of course has no sulfur or aromatics. It also works fine with existing engineering.…

> It's not any inherently greener then synthetic hydrocarbon production, which can be produced from atmospheric carbon for zero net carbon impact As I understand it, the production of complex hydrocarbons that can be used as a replacement for jet fuel is even more inefficient when compared to the production of hydrogen, as many of the known processes that start from CO2 actually use hydrogen in the process. So, altho…

algae biofuels is what I'm hoping for.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#102

Post by jabl »

Qwertious wrote: post #81
jabl wrote: post #54

Earlier quoted context omitted.

> Perhaps the efficiency to produce methane is not so bad, but a chain with 6 or 7 carbons like gasoline is very complicated. The Fischer-Tropsch process is almost a hundred years old, and has been used on an industrial scale. E.g. Nazi Germany used it to produce a non-trivial fraction of their liquid fuels during WWII. Similarly South Africa used it during Apartheid. Now FT itself is better suited for producing most…

"The Fischer-Tropsch process is almost a hundred years old, and has been used on an industrial scale. E.g. Nazi Germany used it to produce a non-trivial fraction of their liquid fuels during WWII." I know it's not an argument against, but the Nazis lost WW2 because they ran out of oil. They invaded Russia at the last moment they could before they wouldn't have the oil to invade, and when they invaded they made a beel…

> I know it's not an argument against, but the Nazis lost WW2 because they ran out of oil.

Well, they would most likely have lost anyway, but failing to capture the Caucasian oil fields as well as the Allies attacking their fuel infrastructure certainly hastened their demise.

One can make a good argument that the strategic bombing on the western front in WWII was largely ineffective, but there were parts that were wildly successful, like attacking the fuel infrastructure.

As for why they didn't just use synthetic fuel all the way instead of just a fraction of the total use, I don't know. I guess they just couldn't scale it up fast enough. And certainly getting oil from the ground is much cheaper than creating synthetic fuel from coal in huge industrial parks.

> ...also, the main non-fossil fuel the nazis used was probably hay. For their horses. It's just a super weird example.

Sure. Blitzkrieg captured the public imagination, but in reality only a small fraction of the German army were these mechanized shock troops. Most were infantry that moved by train or marched with horses carrying equipment.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#103

Post by ncmncm »

liability wrote: post #100
ncmncm wrote: post #44

Earlier quoted context omitted.

Maximum efficiency of 2%. Even the worst electrolysis driven by cheap solar does better.

You've forgotten that we have a limited capacity for solar cell production and those solar cells are put to better use replacing coal plants than synthesizing something plants can synthesize.

Biofuel is just very, very expensive. The only reason it is used at all is heavy, heavy subsidies, often connected with corruption. (Cf. Archer-Daniels-Midland.)

Re: ZEROe: Hydrogen-hybrid aircraft concept

#104

Post by jackdeansmith »

ib84 wrote: post #70

A side-question on the perspective of battery-driven electric-flights: when electric cars can recuperate power instead of breaking, why can't airplanes do the same on descent? Couldn't they build a propeller at the rear, which does propulsion and recuperation? Energy-wise, that would certainly be attractive...

You need battery mass to capture energy on decent, why lug that mass around when there's cheap energy available down on the ground where you're going?

Re: ZEROe: Hydrogen-hybrid aircraft concept

#105

Post by liability »

ncmncm wrote: post #103
liability wrote: post #100

Earlier quoted context omitted.

You've forgotten that we have a limited capacity for solar cell production and those solar cells are put to better use replacing coal plants than synthesizing something plants can synthesize.

Biofuel is just very, very expensive. The only reason it is used at all is heavy, heavy subsidies, often connected with corruption. (Cf. Archer-Daniels-Midland.)

And hydrogen or synth fuel aren't expensive? If these alternatives weren't more expensive then the problem would be moot because the industry would be voluntarily using them already.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#106

Post by Aperocky »

ncmncm wrote: post #98
Aperocky wrote: post #94

Earlier quoted context omitted.

OK So this is just about conversion. H2 doesn't need solar, it needs power, it doesn't care where that power came from. It's essentially a disconnected system, to sell it as if H2 somehow means solar (which I get from earlier threads) is a little bit disingenuous.

Not even a little bit. Wind and solar are the cheapest source of power, with their usability reduced only by surge demands. Liquifying H2 would absorb peak production and be unaffected by temporary lulls. Unless you think it would be natural to use the more expensive power instead?

That makes much more sense, was not thinking in terms of surges.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#107

Post by Hypx »

liability wrote: post #95
jabl wrote: post #52

Earlier quoted context omitted.

Society uses absolutely mind-gobbling amounts of energy, mostly from fossil fuels. There's just not enough land available to produce even a significant fraction of that from biofuels. Never mind the ecological devastation that would be caused by converting the little wilderness left to intensive biofuel cultivation. That is not to say biofuel don't have a role to play. Agriculture and forestry wastes, municipal biowa…

But this is my point; biofuel makes a ton of sense for aviation. Biofuels would be used in cases where there is no realistic alternative, particularly with airplanes. It's more practical and likely to succeed in this domain than hydrogen, and isn't a total pipe dream like battery powered planes. In other domains, like grid power or automobiles, solar/wind/etc are the way to go (I never suggested we run power plants o…

The problem is twofold: The first is that biofuel doesn't scale. Maybe if we shifted all biofuel production to aviation we could do it. But the market is growing over the long term. Which means biofuels will eventually stop being a solution.

The other problem is that biofuel isn't actually all that green. It still needs lots of fertilizer, pesticides, farm equipment, etc., that ultimately gives it a relatively high GHG output.

At some point, we need to bite the bullet and go with hydrogen or one of its derivative fuels (e.g. ammonia, methanol, etc.). People are constantly trying to imagine a solution that avoids this outcome, but no one has come up with anything that looks like a viable alternative.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#108

Post by ncmncm »

liability wrote: post #105
ncmncm wrote: post #103

Earlier quoted context omitted.

Biofuel is just very, very expensive. The only reason it is used at all is heavy, heavy subsidies, often connected with corruption. (Cf. Archer-Daniels-Midland.)

And hydrogen or synth fuel aren't expensive? If these alternatives weren't more expensive then the problem would be moot because the industry would be voluntarily using them already.

They have always been more expensive than petroleum, and anyway would be made with power generated from petroleum or coal, or (in the case of hydrogen) from natural gas.

But that was before solar and wind became substantially cheaper than petroleum.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#109

Post by aero-glide »

Robotbeat wrote: post #93
ncmncm wrote: post #51

Earlier quoted context omitted.

Batteries are way, way, way worse than you imagine. Their energy density would need to get >10x better, when 2x is a miracle. Furthermore, without internal combustion, you are limited to ~350 knots.

i study this professonally. batteries are sufficient if we make other improvements as well. and not true about combustion being essential.

Do you have any links where I can read more about this?
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