My ebike goes 40 km/h.
this post was submitted on 03 Mar 2024
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I believe most e-bikes in Europe are limited to 25km/h. 32km/h in Canada.
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The car is correctly represented, about 0.15 KWh / km is what one gets.
However, the positioning of the e-bike looks strange to me. I've looked at previous studies and the e-biker has always been first in efficiency - because the efficiency of a motor far exceeds the efficiency of human digestion and muscles, while weight and speed remain comparable to an ordinary cyclist.
I think someone has calculated food energy incorrectly, or assumed that e-bikes move faster than they do. :)
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Now do it at the same speed.
What sense would that make?
Kinetic energy is E=1/2mv^2 and because of aerodynamics and friction factors, energy efficiency (or, consumption) varies a lot at different speeds.
This graph has a nonlinear x scale because each vehicle’s entry is at a different speed, therefore the energy scale is nonsensical.
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Interesting. I've never owned an electric car, but just guesstimating based on those numbers, my daily commute would cost something like 25 cents in electricity. Not too shabby.
I did buy an ebike a few years back and watched to see how much the bill went up, but frankly never noticed any change. At 2 cents per day, it's basically a rounding error relative to other electrical usage, so that makes sense to me now.
Energy efficiency and carbon footprint are very different things - pretty sure the carbon footprint of 15 big macs (8500kcal) is substantially greater than 1L of gasoline (let alone an electric grid equivalent)
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This should be shown in Km/Wh so the more efficient the modes of travel show as bigger bars.
yes, I thought it was backwards and was quite surprised
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Let me just travel 30km to the shops by foot and carry shopping home another 30km back again
Have you heard of this miraculous thing called public transit? And there are things called panniers which are pretty cool too.
But frankly, if you don't have groceries within walking distance, your neighborhood and your zoning laws are very poorly designed.
And that's deliberate. Neighborhoods around the world are designed to require cars to live in, because of oil company lobbying, and also for "security", in order to keep out people too poor to own cars.
Getting rid of cars requires changing the various ways our cities are designed to make cars necessary. That's worth doing too.
In this graph a bus would be a lot worse than a far given the massive size, aerodynamic brick wall, and constant stops.
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Can confirm. It takes an hour to walk to the city. I have 3 grocery stores within 10 min of walking (checked with Google maps too)
Living outside land of the free, I have like 4 grocery stores and 1 supermarket within 15min walking distance, and I don't live in a dense neighborhood.
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Now do one where you A) normalize this to the same trip distance (not speed, so that these choices for a single trip become meaningfull) and B) convert the kWh into CO2 emissions, including the emissions in growing and transporting the various power and food production methods used (coal to solar, locally produced veggies-air shipped beef)
Trip distance is dependent on methods of transportation at the aggregate level. That's only relevant for policy decisions or collective actions, not individuals of course, but if we are going to deal with climate change, collective action is necessary.
Given the graph is normalized by km traveled, its overly generous to cars.
It's already normalized to distance, the graph is showing kWh/km. The speed is just there for additional context.
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This data needs to be normalized by speed or realistic range/day. Otherwise it's pretty meaningless.
It is totally pointless, I am totally on side of bikes and walkable cities, but this chart is pointless. What battery stores and what humans use is not comparable, and adding combustion engine car/bus/train here would throw the chart to totally other scale. Train has enough kWh to power a small town, but it carries shit ton of load.
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Where's the gas car on here? How about steam locomotive?
If I've got to go 300+ miles through the US I'm probably not going on foot or by human power.
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Based on this chart, electric car is a best way to burn calories
If you're charging it with your own muscles, sure. Or you could just put rocks in your panniers.
The joke is that calorie is a unit of energy, and it's the car that's "burning the calories" instead of your body
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Maybe the most surprising thing here is that regular biking is still twice as efficient as e-biking even given our mediocre metabolic efficiency and a physique that isn’t exactly designed for the bicycling motion.
it also has the Ebike going ~40% faster which means almost twice as much friction to overcome.
Seems to be meaningful that all of the speeds should be the same.
To be meaningful, they should reflect the real-world imo. Which I they attempt to do? 18km/hr seems really slow for non-ebike (my last commute home by acoustic bike before I got an ebike was 27.0 km/hr), but I guess casual riders might go that speed?. If you use a class 3 ebike in the US, the ebike speed is also really slow (for class 1/2, its about right - I typically get 26km/hr). In Europe, speeds are typically less than the US for ebikes. And I think European urban speed limits tend to be less than US? Of course there's also traffic, so there are times when cars average less speed than bikes. Depending on location and time of year, how intensely the AC/heater in the car is running may significantly impact traffic fuel efficiency. They could have just included a few different speeds for each option, I suppose.
If you want to apply it to CO2, you need to convert that energy into CO2, but that's also really dependent on energy source. Coal power will be a lot worse than solar and wind. Typical US beef will be a lot worse than chicken or wheat or solar/wind energy. So, you would need a second chart and then do the calculations. For the average person whose ebike speed and acoustic bike speed are nearly the same, the ebike is better in terms of CO2. If someone gets specifically cleaner energy sources, then it would be a lot better. OTOH, someone connect to a grid that's mostly fossil fuels, but eats a low-CO2-emitting diet, the acoustic bike might be slightly better.
It makes sense to me...
For example if the the e-bike rider had to spend 1/5 of the energy of the unpowered cyclist (numbers chosen for the example's sake) that would be 1.1Wh/km they exert.
The remaining 12.9Wh/km would be what was discharged from the battery while riding (from using pedal assist and/or throttle features). This can be measured when you charge it back up at the end of the trip to the previous level.
Looks like trains are about 50wh/km
https://www.linkedin.com/pulse/most-energy-efficient-mode-zero-emission-urban-transport-kme%C5%A5
I couldn't find any info on planes, but that'd be interesting to see how massive that would be too.
It's that normalized by passenger or is that just the train?
The 50 is normalized to passenger. I think it's 30 per seat, but I guess they don't fill all the seats usually.
Normalized by passenger, certainly. However, it's easier to hit passenger capacity in a train than in a (private) car.
Wait the private car isn't normalized as 1 person per car or 1.2 average people per car?
Deeply suspicious framing if that's the case.
You misunderstood me. For one, I simply assumed that locomotives have big engines for a reason and thus the number can't be calculated for the entire train. For two, when I mentioned the capacity of cars, I meant maximum passenger capacity. I said that because at maximum passenger capacity, cars become a reasonable means of transportation whereas normally, they are ridiculously inefficient.
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Really had to drop that car speed down to make a meaningful chart huh?
What would the energy usage be if all of them were going the same speed?
More importantly, the KWH used to go the same distance. Sure a car uses more power... It's going faster, and gets to its destination faster, therefore using power for less time.
Energy is measured in KWH, people. But yeah, your point about normalizing to the same speed to make the comparison fair is good.
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Besides the other comment being right about air resistance, a speed of around 40 km/h is considered safe in urban environments and artificial obstacles are now being placed to lower traffic speed to about that limit. Also, the mean speed is also around that in towns where you either go faster than the limit or go 0 in a traffic jam
Wdym? The faster a car moves (or anything, not just a car) the less efficient it's gonna be, because it has to fight against more and more wind resistance.
The measure of productivity of transportation is distance traveled, not speed (unless this were some time race). Comparing kw/speed tells you nothing about the kWh used to make the same trip as alternative modes of transportation.
In theory I agree, in practice other stuff, as the need for heating/cooling, really muddled the theory and puts the sweet spot speed way up. And if we turn the Aircon off, 150 is a really high number.
They're saying that at highway speeds the cars energy usage would be off the chart, or if they scaled the chart to that usage, everything else would be too small to discern the differences.
You guys are in agreement.
Aaah, I get it now, thanks!
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