Originally Posted by
kiwi grey
That will depend almost entirely on fuel cost assumptions:
- Battery electric: the battery will probably be semi-consumable, with a limited number of cycles, so it's "fuel" of a sort. How many cycles/years?
- Fuel-cell electric: cost of hydrogen fuel - I don't think anyone has now a clear view of the likely costs of bulk supplies of green LH2 in the 2030s & 2040s
- Hydrogen-fuelled turboprop: cost of hydrogen fuel (see above)
- SAF conventional turboprop: will the SAF be 1.5x, 2x, or 3x the 2024 cost of fossil fuel?
- Fossil-fuelled turboprop: cost of fossil fuel. I expect this will probably be still available until 2050-ish, but I expect carbon taxes to make this more and more expensive, then eye-wateringly more expensive, at least in "Western" nations.
Electric propulsion aircraft should be a bit cheaper in maintenance costs than turboprop aircraft, because there a so many fewer components - particularly rotating components - in their engines, but I doubt this will be significant in the whole picture.
A couple of comments. Re hydrogen fueled turboprops, the issue with hydrogen is storage; tankage, whether liquid or gaseous will require a pressure vessel as normal wing tanks are sealed areas in the wing structure. Volume is a huge (ha ha) issue also, as the energy density of hydrogen/volume is low compared to jet fuel. Yes, n a weight/energy analysis hydrogen is great, but on a volume analysis it falls down vs jet fuel.
Also, hydrogen production is and issue; most hydrogen is now produced by a steam process breaking down natural gas, this requires more energy input than the fuel produces when used. Yes, if there were a large infrastructure of solar cells hydrogen could be produced by electrolysis, but if there weren't (and there isn't) electrolysis would require electricity generated by some sort of power plant, again negating any energy advantage of hydrogen. I won't go into the numbers here, but hydrogen fueled passenger aircraft just don't pen out.