It being officially spring (albeit with so much rain that even the ducks get depressed), I broke out the bike and bopped around a bit. There’s a nice rail trail near me (the Minuteman Bikeway) that covers about 2/3 of the way to work, so I often commute that way in the summer. Google’s new bike map option actually showed me a route I didn’t know about, thus showing how AI is creeping into our lives. It won’t be long before the Googleplex figures out the nuclear launch codes, so it’s a good thing they’re officially not evil.
It’s about a ten-mile bike ride as compared to a twelve-mile commute by car. Is that worth it in greenhouse terms? The car drive takes about half a gallon of gas, or about 60 Mjoules. Bike riding is said to take about 400 Kcalories/hour, and the ride takes 45 minutes, so that’s 300 Kcalories, or 1.3 Mjoules. That’s 45X less energy! Bikes rule! In straight energy terms 300 Kcalories is the energy in about 1/100 of a gallon of gas, so on my 10 mile ride I’m effectively getting 1000 miles/gallon. Beat that Toyota!
This isn’t too surprising when you consider that my car weighs about 15X what my bike and I weigh. It goes about 3X faster on average (40 mph vs 13), so 15X * 3X = 45X the power needed. That’s suspiciously close, actually.
Unfortunately, it takes fossil fuel to make food. I haven’t seen a clear breakdown of where it goes, but most of the claims refer to this study by Prof David Pimentel of Cornell. The claim is that it takes 7 to 10 calories of fossil fuel to produce each calorie of food. Each of the major steps – fertilize, harvest, package, ship, and refrigerate – takes its share, with fertilizer being the largest piece. Growing organically and buying locally helps, but it’s still going to be a few calories in per calorie out.
So those 300 Kcal of bike effort really represent more like 2000 Kcal of gasoline. That drops my effective mpg from 1000 down to ~150. Still pretty good, but within striking distance of a Lovins-style hypercar.
So maybe this:
Will ultimately lose to this: