Recognizing it was first-order approximation, two significant problems with the comparison:
1. E-bike riders likely to travel much faster. Since drag is quadratic, change in consumption significant.
2. The important energy comparison might not be manual bikes, but other modes of transit. A current driver/transit-rider might choose to bike 15 miles each way only if on an e-bike.
The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
31–40 of 46 posts
Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#32They want to sell electric bikes, so they found an obscure point of view from which they may be preferable to the ordinary one. Ignoring the obvious points of view from which they are not - health disservice to the rider, battery tech non-monetary costs, increased electricity consumption of the owner.
Electric bike has its legitimate target group - elderly or ill or handicapped people. If you're fine, get that ordinary bike and build some form.
Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#33Recognizing it was first-order approximation, two significant problems with the comparison: 1. E-bike riders likely to travel much faster. Since drag is quadratic, change in consumption significant. 2. The important energy comparison might not be manual bikes, but other modes of transit. A current driver/transit-rider might choose to bike 15 miles each way only if on an e-bike.
> E-bike riders likely to travel much faster.
I'm not sure that is significant. In most countries e-bikes are constrained not to exceed 25 km/h when under power. I've commuted by bike for some parts of my life (I now work from home) and I usually overtake e-bikes unless I'm climbing a pretty steep hill.
On the other hand your second part is probably correct: I recall reading that when Canada started mandating helmets it had a negative effect on life expectancy because people were using bikes less and that had an impact on cardiovascular health that exceeded the increase in safety. So you might be right that the increase in usage overweights the change in efficiency.
On the other hand I would never leave a bike that is worth more than 100 euros parked outdoors on a pole in most European and American cities even with a decent U-lock. Add to that weather and electrical components and you end up with something you can use only if you have an indoors parking.
Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#34Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#35Recognizing it was first-order approximation, two significant problems with the comparison: 1. E-bike riders likely to travel much faster. Since drag is quadratic, change in consumption significant. 2. The important energy comparison might not be manual bikes, but other modes of transit. A current driver/transit-rider might choose to bike 15 miles each way only if on an e-bike.
"A current driver/transit-rider might choose to bike 15 miles each way only if on an e-bike." This is absolutely the case for me - an e-bike makes the difference between my 27km commute being viable in a sensible time frame, or having to drive.
Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#36anecdotally i get about 60 miles to the burrito.
Depending on the formulation of the burrito, I may produce undesirable hydrocarbon emissions.
Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#37Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#38They want to sell electric bikes, so they found an obscure point of view from which they may be preferable to the ordinary one. Ignoring the obvious points of view from which they are not - health disservice to the rider, battery tech non-monetary costs, increased electricity consumption of the owner. Electric bike has its legitimate target group - elderly or ill or handicapped people. If you're fine, get that ordina…
>health disservice
The point of transportation is to take you places, not to make you healthy.
>increased electricity consumption
The biggest ebike battery you're likely to find is 500 Watt-hours. That's about 6¢ for the average American to fill from zero to full, and that'll carry you 50 miles.
Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#39Earlier quoted context omitted.
Yes, does it take into account the energy cost of the ambulance that comes to collect you after you had a heart attack after getting fat because you didn't burn off what you were eating.... On the other hand, from what I understand in the Netherlands, ebikes help older people keep cycling for longer so ebikes are still good? I would guess overall, the difference between bike and ebike is a rounding error compared to…
In any case I definitely know nobody who ate more because they rode a bike. Some might get a bit more exercise or will get a bit less fat but I m firmly against the assumption that you'll et more if you ride in current wester societies.
My eating logs show a dramatic calorie increase when cycling to work vs not. Eye balling looks like ~20% increases are common
Re: The Energy Cost of Electric and Human-Powered Bicycles (2004) [pdf]
#40"Despite the intuitive sense that electric bikes would require more resources than regular bikes, life-cycle analysis shows that they actually consume 2-4 times less primary energy than human riders eating a conventional diet. This conclusion is largely due to the considerable amount of transportation and processing energy that is associated with our western food system." And obviously, caveat lector: there are huge…
> And obviously, caveat lector: there are huge assumptions going on here, because the "real" cost of stuff like food and batteries aren't trivial to calculate at all. It's not like you can feed em both the same resources anyhow, so at best this is an analysis that the efficiency is sort of comparable. In 2004.
This is what I was thinking as well. My naive guess is that the extra energy expended to build an electric bike blows the efficiency improvement completely out of the water. It would take a truly enormous amount of usage to make up the difference in the expected lifetime of the battery (which then has to be efficiently recycled, else it's yet another environmental hazard).
Of course the real issue is the fact that I can't travel even 1km toward my workplace on a bike without seriously fearing for my life. Cities in the United States are extremely unfriendly to bikes.