- cross-posted to:
- climate@slrpnk.net
- cross-posted to:
- climate@slrpnk.net
cross-posted from: https://slrpnk.net/post/7273195
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Not trying to be that guy, but do the bike and walking numbers include the energy from the calories you eat, or the energy needed to produce that food?
I don’t think they need to, most people already eat more food than they need to whether they walk or drive. I’d wager the average person wouldn’t need to change a thing in their diet and would overall only improve their health by walking more.
I’ve read that unless the person riding the bike is vegetarian, the ebike actually has a lower carbon footprint than the normal bike. They’re still both far better than the car (ice or EV).
I might dispute the idea that there’s a 1:1 relationship between marginal calories expended exercising and marginal calories eaten.
A UK study showed ebikes have a smaller carbon footprint due to how much meat British people eat.
I’m not sure I understand what you’re trying to say. Do you think you get energy from some source other than food?
If I burn 100 kilocalories pedaling a bike, my body will be using 100 kcal of energy that I got from food. There is a certain amount of carbon dioxide emission associated with the production of 100 kcal of food. That amount varies with what type of food I eat and what farming practices are used. If I choose to simply not eat extra food to replace the energy I used, my body will simply have less stored energy afterwards. My energy absolutely comes 100%, 1:1 from the food I eat, and that food has an environmental impact.
Now, if I ride an ebike, my body will use less energy. I will use energy generated by the power plant. The energy created at the power plant may actually have less environmental impact than the farm creating the food I would have eaten.
Maybe your basal metabolic rate will change because you bike more.
Since you’d have to bike like 30 miles a day for calories from biking to surpass calories from basal metabolism, small changes is basal metabolism will mater a lot
I’m still having a hard time understanding your point. Sure, becoming more fit and replacing fat with muscle may slightly increase your basal metabolic rate but I feel like were onto “I don’t use plastic straws” levels of insignificance.
If you’re biking a few miles to work each day and this ends up being such vigorous exercise that you increase your basic metabolic rate by 50 calories a day or so, you’re still using nowhere near the amount of energy and creating far less pollution than would have been required to drive to work. Small changes in basal metabolism will mean very little.
My point is that measuring energy use from exercise isn’t very meaningful since energy use by animals is so complicated. It seems wrong to say that exercising more increases your carbon footprint.
Maybe studies that meaure the effects long term energy in response to increased exercise. But either way, some amount of exercise is necessary for human health. Biking to work instead of running on a treadmill is clearly carbon negative. Or maybe people biking to work will cause them to get a wasteful biking hobby where they buy a new carbon fiber bike every year.
I see.
Well, I think that the take away message here is that, on average, the energy required for a person to ride their bike (ebike or entirely human powered) to work is so small that the signal gets lost in the noise of normal human metabolism, especially if we take peoples’ exercise routines into account.
On the other hand, driving to work has a large, easily quantifiable energy requirement. It is very obviously costly and unsustainable.
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It says “electric car”
I wondered that too. I imagine it would be very inaccurate to include that as the amount of calories needed would vary wildly person to person. For example, I burned around 2000kcal to cycle 100km in hilly terrain at the weekend, while a friend burned roughly twice that on the same ride.
Fuck cars, but was it really necessary to compare at such different speeds? Air resistance is a big factor and a proper electric bike can go 45kmh as well. Or the car can drive 25kmh
a proper electric bike can go 45kmh as well.
There’s some debate about that. E-bicycles above class 2 (with assistance/drive at over 20mph) are not allowed on a lot of bike lanes, so they’re more like electric mopeds
Yes, they are handled differently in a legal sense. This comes with some small changes to usability of e.g. bike lanes, but in terms of practicality it’s basically still a bike.
Would still be a better comparison, since this is focused on energy consumption. Or just have the car drive slower, as per my other suggestion.
It depends where you live. Here the limit is 400W. Which is probably not quite enough to hit 45km/h in ideal flat conditions.
The fact remains that cars are faster than bikes. Driving a car usually means going faster and hence wasting more energy. Sure, plenty of people deal with distances that necessitate such speeds to be practical in daily life, but that’s a different problem to be solved.
I agree.
But if it’s a different problem to be solved the comparison is useless from the get go.
Plenty of people drive short distances that could already be travelled by bike or walked. That doesn’t require any new solutions. Reminding those people of how wasteful it is to commute by car is a good way to approach that problem imo.
I think the speeds are the average speed of each transport type, so it’s fair.
The different speeds are to make sure the graph pushes the agenda of the creator. All of them going the same speed would decrease the disparity between walking and driving.
You got lies, damn lies and statistics.
And this is one of those.
It wouldn’t change that much actually. Modern cars are really aerodynamic and the comparatively high weight of electric cars emphasizes the rolling resistance in relation to the air resistance.
This Wikipedia page (https://de.wikipedia.org/wiki/Fahrwiderstand) has an example where 77% of energy goes to air resistance, 23% to rolling resistance - At a speed of 200kmh. Which means rolling resistance requires 5x more energy to overcome than air resistance at 50kmh. (77% -> 77 energy units -> multiply by (50/200)^2 = 1/16, as air resistance depends on speed squared -> 5 energy units, but rolling resistance is independent of speed so it doesn’t change (still 23 energy units))
I really like this graph because it helps visualizes scale. Sometimes, people knock e-bikes by saying they are less efficient than acoustic bikes. While that may be true, it’s another example of, “Don’t let perfect be the enemy of good.” As shown here, e-bikes are literally the 90% solution. I really don’t think it’s worth sweating the potential energy efficiency differences between e-bikes and acoustic bikes. What’s really important is reducing car usage.
Acoustic bikes? I think analog may be more fitting here but honestly I’m not sure. I’ve just never heard acoustic referenced outside of sound.
Acoustic is funnier than analog, and I’m not sure if it’s any less accurate than analog. In analog clocks, the passage of time is represented in an analogous rotation of clock hands. In analog sound, the change in voltage on a wire is analogous to the pressure waves you hear as sound. I don’t know what is analogous to what in biking.
Also, the opposite of analog is digital, and ebikes are not digital bikes.
I’m just happy to be here. I like this conversation.
I’m pretty sure E-bikes are digitally controlled.
Acoustic is definitely funnier, but all definitions I can find about it relate to sound.
Well, if your acoustic bike is not making any sound it’s because you’re maintaining and oiling it too much
Mechanical bikes sounds good.
Motors are also mechanical.
Of course they are. But if we’re being pedantic, flesh is also electric.
It’s a joke. Based on e-guitars / acoustic guitars
It’s… “manual” bikes, right? Or am I taking crazy pills?
You can make anything look bad by removing the next bad comparison though. Like if a pickup truck were there, everything would look good. Remove the car and add a scooter, windsurfing, rollerblading, and rolling downhill, and the e-bike looks bad.
True, but the comparison in this case seems reasonable nonetheless. I just wish they had included fossil fuel cars, too
Not really. The F150 Lightning’s efficiency is ~270Wh/km city which means a small EV is only a 50% improvement vs 95% for ebike.
Also, this graph is helpful given our current situation. Maybe once we’re mostly at the 95% better than an F150 Lightning solution (e-bikes), it might be worth being concerned with energy efficiency, but we’re not there.
I meant a regular pickup truck
So 0Wh/km as they don’t run on electricity? 🤷♂️
One watt is just a joule per second. You can absolutely compute that for gas vehicles, the same way electric vehicles have mpg equivalent
By that logic walking and regular bikes would also be 0Wh/km. But Wh isn’t a unit of electricity
AFAIK, our muscles work by electricity. Soooo…
This chart ignores one very important detail. Exercise is good for you. Those bars should be negative since it’s good energy expenditure.
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kwh per kilometer is the metric on the graph, which is the most relevant to “efficiency”. Speed is shown as a side note, it doesn’t affect the graph.
