Originally Posted by
mschwett
did you read what i wrote? the carbon ”cost” of producing and delivering the energy is exactly what i compared to the corresponding carbon “cost” of the food.
i was speaking of operational carbon, which is of course totally different from embodied carbon. rather than saying something is nonsense, let’s see the evidence which refutes the point, which is simply that depending on the food source, human energy may not have a lower carbon footprint than electrical energy.
the embodied carbon question is an important one and is entirely variable on how long the vehicle is kept for and a million other variables, but here’s a good estimate for the battery, which probably represents the majority of the difference between a bike and an eBike:
so, a typical 500Wh ebike battery is around 80lb of CO2e. if it lasts 10,000 miles that’s actually a very, very tiny amount per mile, even if you just chuck it in the landfill after, which i hope people aren’t doing anymore.
as for gaining or losing weight, yes, of course, over time that happens. but nobody loses weight forever, which means that at some point energy in and energy out are approaching balance. more energy expended = more energy consumed. where that energy comes from matters.
So, let's get this straight, because the main point I made about food consumption seems to have gone over your head, you're assuming that people will eat less if they pedal less. This is just likely wrong. Basically, you're asserting that the carbon footprint of humans is best limited by a completely sedentary lifestyle, when all you're really showing is that you get ridiculous numbers when you assume an all-beef diet and 10,000 mile bike batteries.
Look, all your chart shows is differences between the carbon footprint of servings of different kinds of foods. This has absolutely nothing to do with ebikes vs people-powered bikes and more to do with getting our protein from eggs instead of beef.
BTW,
your figures don't add up even with the all beef diet. You forgot to add the half demand of calories back into the total co2e with the pedal assist. So if the 20 mile unassisted co2e is 18 pounds, the half reduced human demand is 9 pounds, add that to the 12 pounds co2e for the 140 watt hours assist (your figures, not mine), and you get 21 pounds co2e, a net gain of 3 pounds. In other words, the e-assist replaced 9 pounds of co2e caused by human effort with 12 pounds. Oops.
And people do tend to get heavier as they age, btw. Heavier people expend more energy just moving around. Like I said before, just because you're pedaling less does not mean you're likely eating less.
If you want to argue for reducing beef consumption, just do it. Don't make convoluted nonsense calculations about ebikes vs human-powered.