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Comment by ummonk | Hacker News Reader

> It’s long been known that an average person on a bicycle is a more efficient translator of energy per gram per kilometre than any other machine or animal

This seems highly questionable. I would hazard a guess for example that cargo ships are significantly more energy efficient per gram per kilometer.

Edit: indeed my intuition was right, going by Wikipedia. Domestic waterborn and rail can transport a metric ton (i.e. 1000 kg) of freight 4-6 km using 1 MJ of energy. By contrast, a velomobile can transport a person ~12 km using 1 MJ of energy, but a person weights only about 70 kg.

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Cargo ships are terribly inefficient on roads and trails. Likewise for bicycles on ocean.

> bicycles on ocean

This made me consult a search engine and I was not displeased.

https://www.toxel.com/tech/2018/07/09/ocean-bicycle/

Yeah, seems to be a common misinterpretation of this Scientific American article from the 70s (only unlocked source i could find) https://cdn.antymateria.com/wp-content/uploads/2020/04/Histo...

On page 10 in the pdf you can see the vehicles and animals compared.

Thanks yeah. Even ignoring the claim that it's the most efficient per mass, even on a per passenger basis there appear to be modern rail lines that beat velomobiles (let alone bicycles) for energy expenditure per passenger-mile.

I think this is getting into somewhat nitpick territory. If we include per passenger we could just use bikes with 10 riders (extreme tandems). On a flat road the increase of energy for more people is very minor so you can just divide by the number of people.

Yeah but that's basically what a peleton is but without the bikes being physically connected.

Point taken. Although the original statement was about single bikes.

Well I was very excited to learn about velomobiles and then very disappointed to learn how much I'd have to pay and how hard it would be to get my hands on one.

Moving over a solid in air vs moving a boat through water already involves talking about movement through media with vastly different coefficients of friction, so comparing them isn't really "fair". After all, if I'm in space, I can move nearly infinite miles with the only energy needed being that which got me started going in the first place.

I choose "distance to Voyager 1" as my frame of reference: according to NASA's status website I've traveled about one thousand miles since I started writing this sentence. After such an effort it's clearly time for a coffee break!

The question is if one should include cargo transport into that equation. I think that becomes a very different question. I mean I think it's pretty obvious that the statement is meant in the context of moving oneself around, not stacking 100 people into a container. .

A statement that chooses to say "per gram" rather than "per person" sounds like it's intentionally about cargo, and not people.

Also, riding a bicycle (even while coasting and not expending energy) is not exactly comfortable, so stacking people into a container might not be all that unreasonable a comparison.

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

If we speak of individual transport that means: bicycles or public transport. Which is precisely what we know should be done for 30+ years to tackle the climate crisis

Focusing on individual transport is not the most efficient way to tackle the climate crisis.

Focusing on any single thing is not the most efficient way to tackle the climate crisis. We need to focus on everything we can do in any sector.

Not subsidizing the bad and subsidizing the good would be a very low hanging fruit to start with.

If we want to minimize energy usage from individual transport, we should lock people in their homes.

Ah the good old "there is no perfect solution, so we shouldn't even start trying"-argument. Perfect for when you already decided you don't want to fix an issue and you want to end an discussion without putting in the mental legwork.

You might want to consider that there is actual value in searching solutions that still allow people to maintain their mobility, while reducing the negative impact on everything.

My bet is on freight trains.

Neither of those translate energy from the human to the conveyance though.

> any other machine or animal

It doesn't say it's limited to humans.

Peregrine Falcon in a dive?

If you're only going to count the "going with gravity" part, a ball falling out of the sky is very efficient too.

Mountain bikes are most efficient when you ride them off a cliff.

If you count the gravitational energy extraction, it's probably not too efficient. Very streamlined shape but the high speeds cause a lot of drag.

My bet is on sailing ships in the 16th-18th centuries.

They could reach up to around half a million miles per galleon.

With sailing you have to account for energy extraction from the wind.

I would think water resistance would be worse than air resistance.

But I guess the massive size of freighters allows them to still be more efficient than trains.

Ships typically travel slower and have flatter terrain (which matters since regenerative braking on trains is not 100% efficient). Turns out both freight trains and cargo ships are in the same ballpark though, so efficiency probably depends more on specific route and model.

Considering cycling vs walking only, I always thought this depends heavily on how steep the terrain is. So cycling is more efficient than walking on a flat road without headwind (which feels intuitive: give half a stroke on the pedal and you're moving several meters forward, whereas for walking you need several steps moreover you're essentially moving your complete body weight up by a couple of centimeters on every step). But uphill that's just completely different, wfor cycling having one major muscle group which needs to develop quite a lot of power. tldr; statement indeed needs some clarification.

> But uphill that's just completely different

Yeah, if it gets steep enough, walking is less effort than cycling. But downhill is essentially free for cycling and definitely not free for walking.

And of course if you introduce grass or other even thicker vegetatation, then the advantage of a pair of wheels diminishes further.

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