Wednesday, December 19, 2007

Transportation Energy

Way back in July, I posted some information on how much energy is generated by a cyclist.

(An anonymous commenter reminded me of it just recently, whe s/he questioned the numbers. Click here to link to the original post... it might be worthwhile just to see the awesome Tour de France photos that are attached.)

According to David Perry, author of a fantastic book, Bike Cult, an average person can produce 75 watts of power (0.1 horsepower) for several hours. A top-tier racing cyclist can produce 375 watts for several hours. It takes about 33 watts to putt along the Greenbelt at 7 mph (12 km/h).

Anyway, I got to thinkin'... and would like you to consider:

A normal car headlight burns 55 watts lo-beam, 60 watts hi-beam. Most cars have 2 of 'em. Sometimes 4. (The "dually-diesel J.C. Whitney macho monster truck crowd" likes to have 8, or 10, or 16.)

So... if you're driving with your headlights on (which many people do this time of year, what with the short days and long nights), your two headlights are burning more energy (110 watts) than a bicyclist is burning for propulsion (33-75 watts)! If you've got that heater/defrost going, you may be using 5 times more energy when you're sitting at that stoplight, than I do crankin' along.

(Sure, you don't notice it, because your engine is doing all the work. But when it has to spin the alternator, your fuel consumption will reflect the extra load.)

Think of the energy it takes to push that hulking hunk of metal and plastic down the road!

Speaking of sitting at stoplights... I sure see a lot of folks doing that. (It reminds me of one of the main reasons I gave up driving. I hate being stuck in traffic! And don't they have highly-paid traffic engineers who should be trying to minimize the amount of red-light waiting? Maybe those folks are taking too many donut breaks.)

When you're sitting at that stoplight, Mr. or Ms. Motorist, unless you shut your car off you are getting ZERO miles per gallon! OUCH! By contrast, when I'm sitting at that stoplight on my bicycle, I'm still getting 119,000 (so far) miles per gallon!

Yep... warm thoughts on a chilly day.

2 comments:

Anonymous said...

http://www.computerworld.com.au/index.php?id=312084283

MIT students powered a supercomputer with bicycle power! Right up your alley.

Bob T said...

Speaking of stoplights I find that when I'm on a bike I have no problem waiting as long as necessary for a green light but when I drive a car I tend to get impatient waiting the same amount of time. I wonder why that is?