Hyundai’s Hydrogen System Will Power Aussie Startup’s Electric Plane Trials

[artee]

https://www.gizmodo.com.au/2023/06/hyundai-dovetail-hydrogen/

"Dovetail Electric Aviation, an Aussie electric aviation startup currently working with airliner Rex to retrofit planes with electric motors, has announced that it will be using Hyundai’s hydrogen fuel cell system to power its electric powertrains.

In case you didn’t know, hydrogen powertrains and systems are basically electric systems. The big difference is that, for example, where an electric car is powered by a battery, a hydrogen car is powered by a hydrogen battery. The hydrogen is converted into electricity, which powers the motor. The same goes for planes, and now, Dovetail Aviation has selected the Hyundai ‘HTWO’ system for its trials (HTWO doesn’t actually spell anything out, but it symbolically is meant to represent the hydrogen molecule and humanity).

Hyundai’s HTWO system is actually quite versatile. Over on the carmaker’s website, it’s shown as a potential powertrain for cars, trams, buses, boats, and power generators. Planes aren’t mentioned on the website, but I guess there’s space to add more after this announcement.

Dovetail said that the Hyundai HTWO system will be integrated into the ‘Iron Bird’ plane, which was successfully tested back in February with a 250kW battery. The HTWO will be used as a prior step to full-scale trials of the electric-powered trains, with the first flights expected in early 2024..."

[HOVIS]

It doesn't say how or where the hydrogen will be stored.

[artee]

It doesn't say how or where the hydrogen will be stored.
A trivial detail - not.

[IBMJunkman]

Count Ferdinand von Zeppelin had an idea on storage. :)

[Null Orifice]

And look how that ended!

[Winemaker]

And look how that ended!
The issue with hydrogen is not weight of the fuel, but rather volume and storage method. If it's gaseous compressed hydrogen the tanks weigh a ton and you need a lot of them. If it's liquid hydrogen there are other issues storing and using a cryogenic fluid, as well as volume. I've run the numbers several times and I just don't see how it will be a viable aircraft fuel source. Buses and trucks, yes; flying things not so much.

There is also the issue of hydrogen production. The most common method is a steam reforming reaction with natural gas (methane), stripping the carbon and producing H2. The is a high temperature energy intensive process and produces carbon monoxide as a by-product. There is of course electrolysis, breaking down water molecules to produce hydrogen and oxygen, the reverse of the reaction in the fuel cell that produces electricity. Again, this requires large amounts of electricity - at least the same amount as that produced by the fuel cell when it recombines the hydrogen with oxygen to produce water.

[jolihokistix]

Green hydrogen production, using solar-powered electrolysis, is admittedly in its infancy, but it can only grow from here.

Slowing that inevitable growth will be cheaper sources from already-established but less environmentally-friendly methods, and negativity from certain competing sectors, (Musk battery EV inter alia).

Wishing good luck and power to the elbows of those pioneers trying to make hydrogen work for us. Let's see what they can do.

[tdracer]

The issue with hydrogen is not weight of the fuel, but rather volume and storage method. If it's gaseous compressed hydrogen the tanks weigh a ton and you need a lot of them. If it's liquid hydrogen there are other issues storing and using a cryogenic fluid, as well as volume. I've run the numbers several times and I just don't see how it will be a viable aircraft fuel source. Buses and trucks, yes; flying things not so much.

Exactly. The storage issues with H2 on an aircraft are simply insurmountable for anything approaching "long range". You must have spherical or cylindrical tanks (either gaseous or liquid), so it's not going in the wing. Putting it in the fuselage means it's in close proximity to passengers - plus even with it's light weight, enough H2 to fly thousands of miles needs to be close to the CG, so it needs to be over the wing - would you want to be a passenger in an aircraft with a massive tank of H2 in the middle? So it needs to be in massive pods outside the fuselage - meaning lots of extra drag.

Taking 'green' H2, combining it with CO2 and making it into a hydrocarbon 'e-fuel' is a far more viable solution than H2 powered long range aircraft.

[jolihokistix]

Mmm...yes, I like it, TDR, though a Bologna/Beluga sausage of H2, with side passages, could be a convenient way to separate first and business class from cattle economy class.

[procede]

Again, this requires large amounts of electricity - at least the same amount as that produced by the fuel cell when it recombines the hydrogen with oxygen to produce water.

Electrolysis has an efficiency of about 70%, fuel cells about 60%. Overall that is just under 50%, not taking into account losses due to compression, liquifaction and heating and/or cooling (which is an issue with fuel cells).

I feel that especially due to logistical challenges liquid hydrogen is practically unusable for anything else than rocket propulsion. And even for that it is not exaclty ideal.

[ATC Watcher]

I tead a few months ago a very educative article from a French researcher who demonstrated that H2 does not decarbonise at the moment ( create more CO2 than it saves under current and near future production methods) and so cannot be used for the "net" zero deadline of 2050. He also mentioned the impractibilities to use this for aircraft for the very same reasons explained here already , mainly size and weight of tanks, not to mention certification which is likely to take many years. VTOL prototypes with 30min autonomy for 4 pax maybe but not for carrying 100-200 pax over long distances. Electric with new generation batteries (not Lithium) with less weight and longer capacity ,and with fast recharges cycles is most probably the way it will go for aviation .

The recent news coming out about how the "Titan" subsersible lost over the Titanic was built , operated and (never) certified will most probably remind our regulators that there is a big difference between encouraging innovation , buiding prototypes and proposing safe transportation of paying passengers .