this post was submitted on 21 Apr 2026
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Today I Learned

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https://en.wikipedia.org/wiki/Energy_efficiency_in_transport

that table is thoroughly fascinating. i mean all of them, there's more than one table on that article

apparently walking is the most energy-efficient transport mode of all?!?!? apart from bicycles

what i find mind-blowing is that airplanes consume approximately the same amount of energy as cars and trains. I mean i can easily see cars and trains being on the same level, but i always thought that airplanes consumed like an order of magnitude more fuel than cars. considering how everybody keeps saying that "airplanes consume so much fuel" and such. crazy.

and also boats are less efficient than i thought? boats consume 16 L/100 km while cars, trains and airplanes consume 6 L/100 km?

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[–] SCmSTR@lemmy.blahaj.zone 11 points 2 days ago (2 children)

...What's keeping us from having electric planes?

[–] Nighed@feddit.uk 30 points 2 days ago (2 children)

Weight. As you burn down fuel, the plane gets lighter, so requires less fuel/energy for the remaining distance.

With a battery powered plane, the battery is just as heavy all the time. It also has less energy density. This means wayyy less range with current tech.

[–] MurrayL@lemmy.world 30 points 2 days ago (5 children)

Clearly the solution is lots of little batteries, so the plane can drop them as it flies.

[–] AstralPath@lemmy.ca 13 points 1 day ago

Into the ocean, ideally. That way we spur growth in our mining sector to replace them all with new batteries every time. The shareholders are going to love us.

[–] otter@lemmy.ca 4 points 1 day ago* (last edited 1 day ago)

This might actually work? I imagine getting up to altitude is the most difficult and energy intensive step since the engines are operating at a higher power and the air is thicker.

Even if that's only 10% or 15% of the overall energy usage, being able to drop the battery and have it return to the airport on its own for reuse could be a cool concept. You could also optimize that particular battery for take off & climbing, and have the main battery for cruising.

It just needs to be able to pilot itself back to a landing / catching structure 😄

[–] fubbernuckin@lemmy.dbzer0.com 5 points 2 days ago

You made me smile, thanks

[–] Nighed@feddit.uk 3 points 2 days ago (1 children)

There is actually a rocket that does this (the Electron). Uses batteries to power the fuel pumps, drops them as it goes up.

[–] vivalapivo@lemmy.today 2 points 2 days ago

Also there are planes that drop rockets. Do you think we can use them to make the environment more friendly?

[–] AceBonobo@lemmy.world 2 points 2 days ago (1 children)

Dropping them with guided parachutes doesn't sound crazy to me.

[–] Blue_Morpho@lemmy.world 2 points 1 day ago

It does to me.

"Your flight has been cancelled on account of a moderate wind in the forecast somewhere between New York and San Francisco."

[–] birdwing@lemmy.blahaj.zone 0 points 1 day ago* (last edited 1 day ago) (1 children)

I feel something like this could be a way...

Overhaul Planes

What if we had smaller planes? You could end subsidies for plane flights under 1,000/1,500 km, as planes are less energy efficent below those distances than train. You can also abolish flights for planes that are heavier than a certain weight, and subside investing in green plane fuel research. To make the transition smooth, you'd have to do this in phases, and ensuring CEOs are on board with it without corruption.

With flying, the security and having to travel to the airport (the airport requires a lot more specialised infrastructure), a journey for 1,500 km would take at least 3 to 5 hours.


Trains

Train stations by comparison, take up much less space and thus occur more widely. Thus travel time to them is less.

Therefore, accounting for security and travel time towards the station, a train can be equally fast, and doesn't lead to ear pain for passengers. If they don't stray too far, scenic routes are also possible, which is beautiful. As you curve downward a valley, the Mont Blanc reveals itself to you. Driving along rolling hills, past rustic pines and beaches, floral meadows and fair lakes and cities...

They should be massively more subsided to reduce prices. Avoiding overcrowding (which decreases comfort) could be done by only allowing as many to board as there are seats available.

High speed rails could be ideal for daytime travelling. They should be frequent and between many mid-sized and large cities. That is, up until the journey would be longer than a plane flight and its preparations. With longer distances between stops, sleeper trains would be handier, especially if their comfort is seriously improved.


What would sleeper trains need?

Wifi, chargers. You could have cabins for 4 people as the standard, with:

  • banks that can be turned into comfortable beds
  • a foldable table
  • rubbish bin
  • storage space

Interior should be simple, hypoallergenic but 'cosy'. Not claustrophobic, unclean, or metallic.

A more luxurious option might be a private shower (as well baby diaper changing spot) and toilet, with more space. Breakfast served.

A direct journey thus would be handier for sleeper trains, or at the very least the time between transfers should be at least 10 hours (8 sleep, 2 for going to sleep and waking up). There could be transfer hubs for these sleeper trains where you have lounges that are for eating breakfast/dinner, letting children play, or for focusing.

[–] Nighed@feddit.uk 2 points 1 day ago (1 children)

Train stations require train lines between them, that's the crux of the issue.

There is research into electric/hydrogen planes.

[–] klankin@piefed.ca 5 points 1 day ago

Honestly pretty sure their comment is AI generated, so dont waste too much time analysing it

[–] testaccount372920@piefed.zip 3 points 1 day ago (1 children)

Technology, or rather, lack thereof. As others pointed out, planes need to bring their own energy supply and use additional energy for that. Weight is a very big factor for air transport's energy consumption. Fossil fuels have a very high energy density, which make them great for bringing along. Once light weight battery tech (without excessively large sizes) becomes available, it should be no issue to electrify planes. Alternatively, find another source of electricity. E.g. nuclear has a much higher energy density than fossil, but obviously has it's own issues, as do all other currently available tech options.

[–] Trainguyrom@reddthat.com 2 points 19 hours ago

Weight is a very big factor for air transport’s energy consumption. Fossil fuels have a very high energy density, which make them great for bringing along.

Fossil fuels also have the benefit of being weight that's shed (burned) as you fly, so an international flight will be much lighter when landing than it weighs when taking off. It's like the rocket equation but much less severe due to much less energy requirement