Wot do we know about the 'ecological footprint' of cycling and wot does an electric motor add to this footprint'?
These are questions I promised to address when I got my new ebike a few weeks ago, and here we go.
Right off the top, we know that a 5-mile commute by regular bicycle has a footprint of only 2,103 sqft (.05 acres), versus 5,186 sqft (.12 acres) by bus and 54,679 sqft (1.25 acres) if driving in a car alone (via answers.com).
Yet, how much energy does an electric-assist bike use? How much does it cost to charge?
We know from calculations by Electrobike that the footprint from making the battery and motor and re-charging the battery constitutes about half of their bikes emissions.
So, let's say my ebike footprint is twice that of a regular bike. Guess wot...that's still less than 10% of a car and 80% of a bus. Yeah!
Alternatively, simply comparing the 20 lbs of CO2 per gallon of car driving (from EPA)-- which equates to 0.67 lb/mi @ 30 mpg-- with the 0.02 lb/mi from ebiking at 15 watts per mile (using the emissions data from KIUC), we're looking at a 33-to-1 advantage. And yeah!
'Course that makes me feel even better when I'm riding.
Yet, wot about the footprint from the extra calories I'm burning to pedal this puppy? Here's where the calculations get a bit tricky. Neil Hunt estimates that, because of the oil used to produce the food burned in bicycle commuting, there's only a 40% net savings over a car commute.
Still, with my Bionx "intelligent biking" system (which includes regenerative braking) I'm using perhaps one-third of the energy in peddling a regular bike. So, that's an 80% savings.
Hey, do any of these fine points matter to me? Heck no! I'm in love with cycling all over again.