Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

ZEROe: Hydrogen-hybrid aircraft concept

airbus.com

Post reply on HN
Print view View original

11–20 of 111 posts

Re: ZEROe: Hydrogen-hybrid aircraft concept

#11

Post by Hypx »

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.…

> The infrastructure has no multiple use, unlike improvements to the grid.

You need hydrogen for steel production, ammonia, and synthetic hydrocarbon production. Likely cement, glass, and plastic production too.

> So why not just do full manufacture of regular fuel? I've never understood where hydrogen fits between improving batteries/capacitors and synthetic hydrocarbons.

Because fuel cells are batteries themselves, and synthetic hydrocarbon needs hydrogen.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#12

Post by unchocked »

In a world where existing natural gas infrastructure transitions to hydrogen, securing sufficient hydrogen fuel at airports seems totally practical.

Due to the fuel's low density, the conventional fuselage designs lose a lot of load capacity.

The blended wing body looks practical, with plenty of interior volume. Hearing people complain about passengers not wanting to sit in a stadium, or that their inner ear will be unmitigatedly upset by roll changes remind me of historical folks who said cars would never take off because they'd scare the horses.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#13

Post by xoa »

Yetanfou wrote: post #6
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.…

An advantage of hydrogen is that it can be used in fuel cells, producing only water as reaction product. Using hydrocarbons of any sort in existing engines leads to the production of nitrogen oxides due to the presence of nitrogen in the air.

Thanks for this reply as well. But batteries will cover most land use, and going by sources like the EIA [1] the primary source of anthropogenic N2O emissions is overwhelmingly agriculture, at 70+%. Other sources indicate that may have fallen somewhat since then, but even so everything I can find indicates fossil fuel combustion is still only around 10%. And of that air travel will be single digits. Not nothing, but I'm not sure it'd justify massive effort alone.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#14

Post by outworlder »

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…

> 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.

Sure.

Here's the thing though: we can efficiently store those complex hydrocarbons. We can't efficiently store hydrogen. It destroys containers, and can escape any container we have devised(unless in liquid form?)

Many of the proponents of electrolysis claim that renewables will make energy a non-factor(or they'll propose nuclear power, etc). If that's the case, then add another step to capture CO2 as well.

> Finally, hydrogen has a great energy / kg ratio

Yes but energy per unit of volume is terrible.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#15

Post by outworlder »

schainks wrote: post #7
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.…

This is a simplification, think about this: You can manufacture hydrogen anywhere as long as you have water, an electrolyzer, and a power source. Oil can only be pumped out of the ground in certain places, water is technically _much_ more abundant everywhere. Hydrogen storage tech has improved in the last twenty years. It's becoming affordable and "as safe" to store hydrogen at fuel densities similar to that of petro…

> It's becoming affordable and "as safe" to store hydrogen at fuel densities similar to that of petroleum based fuels.

Have we solved hydrogen embrittlement issues? What about hydrogen leaking out of containers?

Re: ZEROe: Hydrogen-hybrid aircraft concept

#16

Post by mayama »

xoa wrote: post #10
schainks wrote: post #7

Earlier quoted context omitted.

This is a simplification, think about this: You can manufacture hydrogen anywhere as long as you have water, an electrolyzer, and a power source. Oil can only be pumped out of the ground in certain places, water is technically _much_ more abundant everywhere. Hydrogen storage tech has improved in the last twenty years. It's becoming affordable and "as safe" to store hydrogen at fuel densities similar to that of petro…

> You can manufacture hydrogen anywhere as long as you have water, an electrolyzer, and a power source. I don't understand what you're arguing with here? You can manufacture synthetic hydrocarbons anywhere so long as you have water, carbon dioxide, and a power source too. So I'm not sure why you see this as an advantage for hydrogen. > but shouldn't we attempt to engineer huge carbon emitters like container shipping…

> You can manufacture synthetic hydrocarbons anywhere so long as you have water, carbon dioxide

You need coal or some biomass to manufacture synthetic hydrocarbons. And tail emission is still a concern.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#18

Post by kolinko »

mayama wrote: post #16
xoa wrote: post #10

Earlier quoted context omitted.

> You can manufacture hydrogen anywhere as long as you have water, an electrolyzer, and a power source. I don't understand what you're arguing with here? You can manufacture synthetic hydrocarbons anywhere so long as you have water, carbon dioxide, and a power source too. So I'm not sure why you see this as an advantage for hydrogen. > but shouldn't we attempt to engineer huge carbon emitters like container shipping…

> You can manufacture synthetic hydrocarbons anywhere so long as you have water, carbon dioxide You need coal or some biomass to manufacture synthetic hydrocarbons. And tail emission is still a concern.

You can extract carbon from atmosphere.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#19

Post by usrusr »

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.…

Manufactured fuels have two main economies: one is energy input per energy output (usually bigger than one and the goal is to get that number as close to one as possible) and the other is transformer system cost, particularly cost that even applies when idle. If this number is very high fuel manufacturing won't be opportunistic at all and will keep the conversion systems at high utilization, offering input energy prices as needed and selling at prices depending on demand. A very low investment/idleness cost on the other hand would lead to wildly variable utilization depending on output demand and input availability.

Hydrogen is usually considered a very simple conversation (e.g. compared to synthetic hydrocarbons) that would be very open to opportunistic transformation utilization.

"Only fire up the converters when there's an open order for synfuel and the grid has excess power", that's the dream. I'm not convinced that this dream is significantly more viable for simple hydrogen than for more complex synfuels (particularly factoring in the many ways hydrogen isn't easy to store), but I can easily see how some people might want to believe that.

Re: ZEROe: Hydrogen-hybrid aircraft concept

#20

Post by Robotbeat »

Not as helpful for reducing effective emissions as you might think.

High altitude water vapor is just as big of a problem as CO2 as the lifetime of water vapor in the stratosphere is measured in years, not days or hours like it is in the lower troposphere. Water vapor is, after all, a much stronger greenhouse gas than CO2, it's just that normally its lifetime in the atmosphere is so short so as not to matter.

So unless we can be certain these planes will fly solely in the lower troposphere (unlikely, considering the aircraft presented), then hydrogen is not actually necessarily a silver bullet and in some situations (i.e. very high altitude flight, ala Concorde) could actually be worse than kerosene.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...

Post reply on HN