Comment on Murica
TDCN@feddit.dk 11 hours ago
Someone can probably do the math, but i have a hunch that humans are technically not very fuel efficient if you look at calories burned pr the total mass being moved along.
But whatever it is biking is awesome, but being technically correct is even better.
I feel like ‘total mass being moved’ is irrelevent if most of that mass is useless (car motor/metal frame/plastic/etc).
Even if a car motor was more efficient per kg, most of the work is wasted on moving the actual car itself, regardless of the passengers & cargo.
Bikes clearly use less energy to displace ‘useful mass’ than a car, so they are more efficient in that sense.
You couldn’t be more wrong. Bicycle is the most efficient way of moving.
If you account manufacturing energy, then in a short time it is overcome by walking.
Interesseret. It just feels so counterintuitive, but as o wrote, it was just a hunch and apparently many telle me now its not so. Do you have any numbers or sources to back up the claim that I can use for future fun facts sessions to annoy my family?
something like 50-80 % of the energy we use (it depends on how active you are,) is used for just sustaining life (AKA your base metabolic rate.)
humans convert a bit less than 50% of the food-energy into a form we actually use- glucose. even though bicycles themselves are fairly efficient with the power put into them, humans themselves are not all that efficient. as for most effecient animals, that would probably be something like an albatross, which extracts energy from the wind to fly. (Specifically using a technique known as ridge lift. in the R/C world, the speed record is 548mph or so- set by a glider using similar techniques, and albatrosses can cross entire oceans.)
Quick math shows I am quite a bit more efficient than a Nissan Juke traveling 150 miles at 19mph. About 50kcal/pound for the car and 8kcal/pound for me+bike to travel the distance.
SoleInvictus@lemmy.blahaj.zone 11 hours ago
Humans are actually unusually energy efficient for mammals when walking and even more so when cycling. Here’s a little info graphic showing a breakdown.
Image
One thing to keep in mind if you have a dog is they’re less energy efficient than humans. While dogs can run faster, a reasonably fit human can easily out distance an equally fit dog when walking or distance running.
milicent_bystandr@lemm.ee 7 hours ago
Also, I love the units. Using miles on one axis and km on the other.
TDCN@feddit.dk 11 hours ago
Nice graphic. But it seems like it doesn’t factor in kg of mass moved. A human and a bike is a lot lighter than a car or a horse. You could also argue that the vehicle weigh should be ignored but then again you could easily argue back that weight of goods move can possibly be a lot higher with a car if you load it up to capacity.
SoleInvictus@lemmy.blahaj.zone 10 hours ago
I’m back with better data. I’m assuming the travel path is perfectly flat because I don’t feel like modeling elevation changes. I’m being energy efficient (read: lazy).
For cycling, I’m using the global average human weight of 62 kg, assuming the cycle is 8 kg, and the pace is 10 kph, which is pretty relaxed.
For walking, I’m using the 62 kg person walking at 4 kph.
For driving with petrol, we’ll use the same spherical 62 kg human and a 2024 Toyota Prius with a fuel efficiency of 4.8 L/100 km and a mass of 1570 kg. One liter of petrol is approximately 8174 kcal. Double the energy expenditure for an estimate for your typical SUV.
For electric, I chose a 2024 Hyundai Ioniq 5 N with an energy efficiency of 21.2 kWh/100km and a mass of 2235 kg. One kilowatt-hour is approximately 860 kcal.
Walking: 0.74 kcal•km^-1^•kg^-1^
Cycling: 0.34 kcal•km^-1^•kg^-1^
Driving(p): 0.24 kcal•km^-1^•kg^-1^
Driving(e): 0.08 kcal•km^-1^•kg^-1^
TDCN@feddit.dk 4 hours ago
Oh really. It seems to contradict the graphics. Cars are also stupid efficient now. I also ran Dom quick calculations on my electric bike and it is crazy how many km*kWh⁻¹ you get and how little it cost to run.
I’ve heard about some research showing that an electric bike over it’s entire lifetime is more environmentally friendly than a traditional one because the amount of extra food you need to consume without the electric help is over time more co2 than the co2 it costs to charge the battery. I don’t know where the research is from since I just heard it from a colleague so don’t quote me on it, but electric motors are really efficient so it sounds very plausible to me.
null_dot@lemmy.dbzer0.com 5 hours ago
Wait so cars are more efficient than cycling now ?
SoleInvictus@lemmy.blahaj.zone 11 hours ago
It still doesn’t give us kcal•km^-1^•kg^-1^, which is what I was looking for. We could do some math to get us some loose estimates, though. I’ll do exactly that and report back shortly.
milicent_bystandr@lemm.ee 8 hours ago
This is very useful. My four friends and I will have to stop swimming to work, and take the car instead.