7 ms·

I don't believe regular planes to ever run on hydrogen and be commercially viable. Hydrogen is not very dense, even in liquid form (to be compared with the volu

I don't believe regular planes to ever run on hydrogen and be commercially viable. Hydrogen is not very dense, even in liquid form (to be compared with the volume already taken by kerosene on a plane). And requires very strong -and thick- container walls. However with dwindling fuel supplies, I'm pretty positive we'll see the return of glorious, massive blimps. Powered by a fraction of the hydrogen it uses to float in the air, savvy meteorology, and thin solar panels.

tormeh 4y ago
Can't the low density be taken advantage of, producing aircraft with blimp-ish characteristics? Not sure how practical that is... And given how big % of fuel is needed for ascending to cruise height, I'd imagine you could have a decent % of the fuel in take-off tanks with thin walls, since those tanks only need to contain the fuel for less than 10 minutes anyway. I could imagine future planes using hydrogen for take-off and batteries for cruising.
- nomel 4y ago
  > producing aircraft with blimp-ish characteristics Drag nearly directly proportional to the cross section of the craft. Something blimp like would be necessarily slow, to stay efficient.
  - coderenegade 4y ago
    This is true, but depending on how you use the hydrogen, you can fly much higher than you would with kerosene. Hydrogen burning jets would fly at around 70-80k feet, not the usual 35k that we're used to. Not to mention, the weight savings mean you cut down on the amount of fuel you need to carry, so the 'blimp' effect is overstated. One third the energy in LH2 gets you around half the distance as an equivalent volume of kerosene, because the volume of hydrogen only weighs one tenth the mass of the kerosene. So getting the same range means you need more volume, but you need less total energy to get you to the same destination because you're lofting less mass.
- tragictrash 4y ago
nix23 4y ago
>I'm pretty positive we'll see the return of glorious, massive blimps Na thanks i take the train ;) But for good's i could image that.
kurthr 4y ago
Not really, it's more likely to be stored at low temperature to avoid embrittlement. Liquid Hydrogen has an energy density of approximately 120 MJ/kg, almost three times more than diesel or gasoline. Even with the cryogenic storage and reheating equipment it has comparable power to weight ignoring electrical motor efficiency advantages. Comparable flight hours do take up 2-3x more volume than diesel (including pumps and fuel cells), but at larger sizes (e.g. 737 and larger) most commercial flight distances are limited by weight rather than volume. A lot of things come down to scale. Small drones can run reasonable distances on LiPo, which scales very badly to larger vehicles.
- kristopolous 4y ago
  Right. The strongest evidence is commercial planes will be exclusively hydrogen powered. Airbus is working on one right now https://www.airbus.com/en/innovation/zero-emission/hydrogen/zeroe https://www.airbus.com/en/innovation/zero-emission/hydrogen/... (I think 2035 is way too long - it needs to be done 10 years ago) What more there will be hydrogen fuel plants onsite at the airports Additionally you'll see hydrogen in similar large systems such as rail and earth moving equipment. Honestly the only question I have in the large vehicle systems is cargo ships. There's plenty of space and benefit to large solar wings expanding the vessel surface area that can fold up when necessary If you see the efficiency gains and cost reduction in commercial grade PV continue, it's going to be unit cost economically superior fairly soon. Alternatively there could be some mystery device that can get a net energy gain by processing sea water to hydrogen fuel. This doesn't look physically impossible but I haven't heard of any serious efforts to do so yet and personally I'd need a lot of convincing to be assured it wouldn't just be doing a new flavor of ocean polluting
  - coderenegade 4y ago
    Cargo ships will go with methanol or ammonia, both of which are easy to synthesise from green hydrogen. I'm more partial to methanol since it can be carbon negative and provides a market for the tremendous amount of waste we generate, but ultimately the most effective solution will win.
clouddrover 4y ago
Air Nostrum has ordered some airships: https://edition.cnn.com/travel/article/airlander-10-air-nostrum/index.html https://edition.cnn.com/travel/article/airlander-10-air-nost...

tormeh 4y ago

Can't the low density be taken advantage of, producing aircraft with blimp-ish characteristics? Not sure how practical that is... And given how big % of fuel is needed for ascending to cruise height, I'd imagine you could have a decent % of the fuel in take-off tanks with thin walls, since those tanks only need to contain the fuel for less than 10 minutes anyway. I could imagine future planes using hydrogen for take-off and batteries for cruising.

nomel 4y ago
> producing aircraft with blimp-ish characteristics Drag nearly directly proportional to the cross section of the craft. Something blimp like would be necessarily slow, to stay efficient.
- coderenegade 4y ago
  This is true, but depending on how you use the hydrogen, you can fly much higher than you would with kerosene. Hydrogen burning jets would fly at around 70-80k feet, not the usual 35k that we're used to. Not to mention, the weight savings mean you cut down on the amount of fuel you need to carry, so the 'blimp' effect is overstated. One third the energy in LH2 gets you around half the distance as an equivalent volume of kerosene, because the volume of hydrogen only weighs one tenth the mass of the kerosene. So getting the same range means you need more volume, but you need less total energy to get you to the same destination because you're lofting less mass.
tragictrash 4y ago

nix23 4y ago

>I'm pretty positive we'll see the return of glorious, massive blimps Na thanks i take the train ;) But for good's i could image that.

kurthr 4y ago

Not really, it's more likely to be stored at low temperature to avoid embrittlement. Liquid Hydrogen has an energy density of approximately 120 MJ/kg, almost three times more than diesel or gasoline. Even with the cryogenic storage and reheating equipment it has comparable power to weight ignoring electrical motor efficiency advantages. Comparable flight hours do take up 2-3x more volume than diesel (including pumps and fuel cells), but at larger sizes (e.g. 737 and larger) most commercial flight distances are limited by weight rather than volume. A lot of things come down to scale. Small drones can run reasonable distances on LiPo, which scales very badly to larger vehicles.

kristopolous 4y ago
Right. The strongest evidence is commercial planes will be exclusively hydrogen powered. Airbus is working on one right now https://www.airbus.com/en/innovation/zero-emission/hydrogen/zeroe https://www.airbus.com/en/innovation/zero-emission/hydrogen/... (I think 2035 is way too long - it needs to be done 10 years ago) What more there will be hydrogen fuel plants onsite at the airports Additionally you'll see hydrogen in similar large systems such as rail and earth moving equipment. Honestly the only question I have in the large vehicle systems is cargo ships. There's plenty of space and benefit to large solar wings expanding the vessel surface area that can fold up when necessary If you see the efficiency gains and cost reduction in commercial grade PV continue, it's going to be unit cost economically superior fairly soon. Alternatively there could be some mystery device that can get a net energy gain by processing sea water to hydrogen fuel. This doesn't look physically impossible but I haven't heard of any serious efforts to do so yet and personally I'd need a lot of convincing to be assured it wouldn't just be doing a new flavor of ocean polluting
- coderenegade 4y ago
  Cargo ships will go with methanol or ammonia, both of which are easy to synthesise from green hydrogen. I'm more partial to methanol since it can be carbon negative and provides a market for the tremendous amount of waste we generate, but ultimately the most effective solution will win.

clouddrover 4y ago

Air Nostrum has ordered some airships: https://edition.cnn.com/travel/article/airlander-10-air-nostrum/index.html https://edition.cnn.com/travel/article/airlander-10-air-nost...