Daniel Convissor's Web Site (is in the midst of reconstruction):
Energy Consumption: Bikes v Cars
Bicycling requires 35 kcal/mi. Cars require 1,860 kcal/mi. [Both of
those figures are from Marcia Lowe of the World Watch Institute.] Someone
here suggested it takes 10 kcal of energy to produce 1 kcal of food.
[This is inflated. I remember hearing it takes just under 5 kcal of
energy to grow 1 kcal of vegetarian food, sorry I don't have the
reference in my possession. Of course, a vegetarian diet is a whole
other argument we can get into :) .] Yet another person mentioned there
is ~25% efficiency in converting eaten food to useful work. [Note:
that's kcal eaten to joules of work; I think Ms Lowe's calculation above
is different, referring to kcal eaten to go a mile.]
The average diet is about 2,000 kcal/day.
Now for the math.
Either way you look at it, bikes are more efficient. Now, factor in that
both the cyclist and auto driver are going to eat about 2,000 kcal
anyway. To go a mile, I'd only have to eat between 2% and 7% more food, if I eat
anymore at all.
WORST CASE SCENARIO [using 10 times figure and 25% energy conversion]:
---------- = 140 kcal's of food need to be eaten to bike one mile
140 kcal/mi * 10 = 1,400 kcal to grow food to bike 1 mi.
1 - ------------- = .25 = Bikes are 25% more efficient
BEST CASE SCENARIO:
140 kcal/mi * 5 = 700 kcal to grow food to bike 1 mi.
1 - ------------- = .62 = Bikes are 62% more efficient.
This page was written by Daniel Convissor as a posting to ba.transportation on
3 July 1994
Up to the Bicycle Page or to it's Planning Section.
Are you having a hard time printing this page? Read the Printing FAQ.
This page is hosted by Daniel Convissor
Home Page: http://www.panix.com/~danielc/
This URL: http://www.panix.com/~danielc/world/carvbike.htm
Last updated: 7 April 1999