Mastodawn

Moritz Negwer 22h ago

𝚃𝚊𝚛𝚊𝚜 𝙶𝚛𝚎𝚜𝚌𝚘𝚎 🚇

"A cyclist can go 3 or 4 times faster than a pedestrian, but uses 5 times less energy. The bicycle is the perfect transducer to match metabolic energy to impedance of locomotion. Equipped with this tool, man outstrips efficiency of not only all machines, but all other animals as well."
—Ivan Illich, 1974.

@straphanger Would love to see ebikes on this chart. Must be somewhere between normal bike and motorbike, but I can't begin to guess where exactly.

Coen Wesselman 1d ago

@nix @straphanger it seems to be close to walking: https://eu.fiido.com/blogs/news/how-much-does-an-electric-bike-consume-per-kilometer

How much does an electric bike consume per kilometer?

Learn about electric bike energy consumption, optimization tips, and Fiido recommendations to reduce costs, extend range, and choose the best commuting option

Fiido EU

trainguyrom 1d ago

@nix @straphanger there's actually research that finds pedal assist ebikes to be more efficient than acoustic bicycles! A laptop battery and a 500w motor combined with muscle power on two wheels make for a very efficient vehicle

@nix @straphanger
The chart backs up other studies that show humans walking or running are as inefficient as automobiles at turning calories into work. If batteries and motors improve on that then replacing all the humans with robots should offer the huge energy savings the future needs.

Donald Ball 8h ago

@nix @straphanger I have read they’re more energy efficient than pure pedal bikes because battery-motor power is much more efficient than digestion-muscle power.

Madagascar_Sky 1d ago

Why are personal cars more efficient than taxis?

I would think taking people to a spot, picking someone up close by, and so on would save on fuel.

Daigoro (he/him) 🌸1d ago

@Madagascar_Sky @straphanger I have the same question. The only reason I can think of why taxis may be less efficient is that they make a lot of stops as they drop off / pick up passengers, which is less fuel efficient than when making long, uninterrupted trips.

Madagascar_Sky 1d ago

@daihard @straphanger

Thanks. Yeah, that seems to make a lot of sense.

Jona Joachim 22h ago

@daihard
Hmm I'm not convinced. Their engine is always warm, the drivers have incentive and expertise to drive economically. Also I don't understand why trains score so bad. Transporting hundreds of people in one go using electricity on low friction rail, that's really efficient in my book
@Madagascar_Sky @straphanger

Matthew Newell 1d ago

@Madagascar_Sky @straphanger not sure about other countries but in UK the long and relatively efficient motorway/autoroute/freeway journeys tend to be made by private cars, the short city trips at a walking pace tend to be taxicabs

Madagascar_Sky 1d ago

@MatthewNewell @straphanger

Thank you. Yeah, that would do it.

Min 🔜 Anthrocon 1d ago

@Madagascar_Sky @straphanger I don't think this chart is taking into account the total amount of distance traveled; i.e., the number of megajoules/passenger-km is the same regardless of whether you drive 5 km or 10 km.

A taxi is likely to travel fewer km total due to fewer round trips, but probably spends more fuel per km on average because taxis spend a lot of time looking for passengers or idling while waiting for somebody.

Madagascar_Sky 1d ago

@minneyar @straphanger

Yeah, that is a lot more logical. Along with the explanation others gave about them doing a lot of short trips whereas personal cars just go to the destination and stop.

Thanks!

Phill Boyack 23h ago

@Madagascar_Sky @straphanger taxis need to travel from wherever they are to the starting point of the journey, before the journey even begins. Then, they're one person heavier than an equivalent private vehicle.

Quinn9282 🖥️🌙✌️1d ago

@straphanger I've seen that chart many times before and it's pretty out-of-date/inaccurate AFAICT. The Boeing 727 is a 40 to 60+ year-old aircraft that hasn't been in passenger service for years, so not a good comparison metric. And I don't really understand how taxis are way less efficient than passenger cars on their own? And how can electric and diesel rail have the same efficiency rating? Isn't electric rail a lot more efficient than diesel rail in practice?

Quinn9282 🖥️🌙✌️1d ago

@straphanger (Obviously the point still stands, but that chart really needs some clarification and updates)

@Quinn9282 @straphanger
Well the taxi is hauling around a driver. Taxis also spend a lot of time travelling about with no passangers. The car is with the owner at home, travels to its destination without the additional weight of a taxi driver, then stays there not moving when passangerless. At times when the owner as ferrying around other people it becomes about as inefficient as a taxi. 99% of the time I drive my car I'm staying at the destination with it.

@Quinn9282 @straphanger For your last question, I suspect by “Electric & Diesel” what they mean is a diesel generator powering electric motors on the wheels. That’s how almost all locomotives for long-haul train routes (think Amtrak) have worked for decades.

I’m not sure how that differs from “heavy rail”, though. The example for heavy rail is a subway, but subways get utility power like light rail, so they don’t have to spend much mass on batteries. Seems unlikely a subway would be less efficient than a train which has to haul its own fuel.

Quinn9282 🖥️🌙✌️4h ago

@bob_zim @straphanger Thanks for the clarification. But yeah, I don't know why they split up rail travel efficiency in that way on the chart. Technically the "heavy rail" terminology as a whole can encompass both subways and commuter/intercity rail, so mentioning it in both contexts probably wasn't necessary since the efficiency is going to be essentially the same either way (assuming we're talking about a fully electrified system; not sure how that pairs up with diesel in practice though).

Morten Grøftehauge 14h ago

@Quinn9282 @straphanger If the chart is old then there's probably not a lot of renewable energy in the mix. So the efficiency is the same whether you burn the fuel in the train or a power plant.

Matthew Newell 1d ago

@straphanger as a mad-keen cyclist I don't wanna argue. But water-borne transport is missing (planes there so not all land). Canal boat shifting tonnes powered by a horse. The old tea-clippers are still close to record holders for lots of searoutes (only beaten by speedboats).

But the point stands. Bikes are cheap, simple, available (hopefully) to all, and eco-friendly. Doesn't get better than that.

babble encat 1d ago

@MatthewNewell Well there's another dimension to the Pareto frontier, canal boats are slow. If I want to get somewhere quick an e-bike would be high on the list

Matthew Newell 1d ago

@babble_endanger oh definitely. I was just a bit surprised that water-borne transport was omitted. I should probably check out the original article

Smoljaguar 22h ago

@straphanger I will say that the Elizabeth line has significantly lower energy usage than the London underground train figure, probably about 0.8MJ/km estimated pessimistically with public data but the overall message still stands

@straphanger ... What are lorries doing in a chart about transporting humans? *Confused*

Jon Sullivan 22h ago

@straphanger I wonder where an albatross or shearwater would fit on that graph. They travel extraordinary distances expending little energy.

I guess wind power is cheating though. A land yacht would also be more energy efficient than a bicycle, as long as the wind was blowing in the direction you wanted to go.

@straphanger The car value of 2.1 here seems based on combustion-based cars, which is fair because the vast majority of cars still burn fuel. But it would have been nice if they had also added (battery-)electric cars as its own category, since they clock in at a much lower 0.7 MJ/km (approximately: I converted 0.2 kWh/km which is about 3.1 miles/kWh).

Rodrigo Santamaría 11h ago

@straphanger doesn't consider the need of a infraestructure (plain surface), i guess, but good to know!

Petr Skála 1h ago

@straphanger 👍