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Clothes slow Lance down
The Tour de France is in its final week and while I cheer Lance Armstrong to a victory (hopefully) I enjoy watching the coverage and seeing the cyclist’s wattage as they race away from the peloton or climb the Alps. By understanding how much power a person can produce, it should give you a good frame of reference on the scale of electric power production!
As I watch the Tour they occasionally display a rider’s instantaneous power output on the screen. They are able to do this because the cyclist has a power meter on their bike and this transmits data to the broadcasting network. So just like the TED can monitor my home’s power consumption, the bicycle power meter measures a cyclist’s power production. This power usually ranges anywhere between 250 Watts if they are just cruising along with the pack, or 400-500 Watts if they are pushing hard up a steep climb.
If you were one of the lucky few to read my What’s a Watt post (click through the slideshow at the end that I spent waaaaay too much time making) you know that a Watt is an instantaneous measure of power and is a product of force and speed. In electrical terms, the force is Voltage and speed is current (Amps); therefore, electrical power is Voltage * Current. For a cyclist, the force is how hard he pushes on the pedals and the speed is how fast he turns the crank (rpm). The combination of these two things results in the cyclist’s power output, which is usually expressed in watts. For more on this topic, see the great FAQ section that has been put together on this page dedicated to bicycle power generation.
The International Cycling Union (UCI) maintains records for the Hour Record, which is an ongoing contest to see who can ride the farthest in one hour. To get a good estimate of the maximum energy a person can produce (these are elite athletes after all), we’ll figure out the average wattage of someone competing for the Hour Record, and since it lasts an hour, this average wattage will be the total energy the rider expended over that hour. Therefore, the energy they expend over the time they compete can be presented in Watt-hours.
The current record holder for the Hour Record is Ondrej Sosenka and the website BikeCult.com has an estimate of his average wattage during his Hour Record at 430 Watts! If Ondrej’s bike were attached to a bicycle generator and it was super efficient, Ondrej would have been generating enough power to light up 7 60-Watt light bulbs! Since I pay about 10 cents/kWh, if I were to pay Ondrej for the energy he produced over the hour he was pedaling he would have almost earned a whole nickel (430 Watts • 1 hour = 430 Watt-hours = .43 kWh)!
The cycling blogger Alex Simmons has a great article on the current Masters Men (35-39) Hour Record holder Jayson Austin and his power output over his attempt at the Master’s record in 2009. Jayson’s average power output was 302 Watts over the hour he rode. The year before Jayson tried to go for the record but was only able to produce an average of 241 Watts (he wasnt feeling too well, so you can see his power output decline the longer he rode). The graph of the two attempts can be seen at the right.
As you can see, the best human efforts at producing power over the course of an hour on a bicycle are around 300-400 Watts. To put this in perspective, when my AC is running full blast my house can consume about 4,000 Watts or 4 kW. I would need over 10 of the best cyclists in the world attached to bicycle generators to power my house when it is consuming this much power! While this doesn’t diminish the effort of the cyclists, it does demonstrate that powering our future by pedal power doesn’t look like an option, unless they want to work for nickels…..
***Update – 10/03/09 – November’s issue of Bicycling magazine has an excellent article on human powered bicycle generators that I highly recommend. As someone who is passionate about renewable energy and cycling, I get very excited reading this stuff. The article mentions two companies that are trying to retrofit gym equipment and spin classes to produce and display cyclists power output. ReRev is retrofitting gym equipment to produce clean energy and The Green Revolution is doing something very similar and targeting spin classes. I’ve wanted something like this in my gym for awhile. I’m not a big fan of spin class currently because there is no feedback on how I’m performing and improving. These companies can provide valuable feedback on your power output AND produce clean, renewable energy for the grid. This is win-win stuff.
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Plus, you have to feed, water, and cool the human generator – further diminishing the efficiency.
Electricity is great for moving power long distances, but when you are converting rotational energy into electricity and then back to rotational power again all within a couple of feet (assuming you park the cyclists in your driveway next to your AC compressor), then there must be a better way.
You should try hooking up the bikes DIRECTLY to the compressors with a drive belt, eliminating the inefficincies of all those dynamos and motors.
I bet this would drop your requirements to perhaps only 3-4 of the world’s best cyclists, which should be much easier to pull off (heck, that’s less than half a team!).
Seriously, this might actually be fun and not-so-hard to rig up, if only for demonstration purposes.
-josh
Unfortunately I dont think that would work. In my simple comparison, I assumed there was no inefficiency between the power output of the cyclist and creation of electrical power, so this is already the maximum power expected.
I agree that it would be very cool to see a demonstration of a bunch of riders powering some devices!
Don’t forget about the pollution (CO2 and more) from this generator……………….
For 270 Watts you can cruise for an hour on a bike. Two small 12 V / 15 AH batteries can provide 2×12x15=360 watt for 1 hour.
Makes you wonder why do we need a 2.8 liter 200 hp car engine to drive within the city.
Let us all use a battery powered bike and save all that fuel!
During the 2001 OLN coverage Chris Carmichael said that Armstrong’s power output during the tour could light the city of Austin for 2 hours and 15 minutes.
A marketing banner in the window of Austin’s Barton Creek Mall’s Nike Store proclaimed that
“Over the 20 states of the Tour, Lance produces 97,175,983 total Watts of power – That’s enough power to light his hometown of Austin, Texas for 2 hours and 18 minutes, or the entire state of California for just over 3 seconds”
Guess this proves that a high school diploma isn’t worth much anymore.
It’s always frustrating how often people get Watts and Watt-hours mixed up. Hmmm..I’m a little skeptical of the 97,175,983. Let’s say Lance was always peddling at his highest output and let’s say that’s around 400 Watts. If Nike meant Watt-hours and not watts, then Lance was peddling for 242,940 hours!
Further, for every one calorie on the U.S. plate, 8 calories of petrochemicals are used to produce the fertilizers, cultivation and transportation to get it there…
NO NAKED MEN PLEASE
Yeah, that’s bad math re: Lance. Riding the TdF takes ~80 hours, not all at full output. So call it 300W x 80 hours = 24,000 W-h = 24 kWh. That will supply my house for about a day. There have been ~100 TdFs, and each one has ~150 finishers, and that gets you a total of 360,000 kWh of output. As CA uses about 360,000 GWh in a year (http://www.energyalmanac.ca.gov/electricity/total_system_power.html), and 1 GWh = 1,000,000 kWh, we find that all riders from all Tour de France performances could power CA for about 30 seconds (ballpark).
The take-home is that our energy consumption drastically exceeds the human scale.
[...] Lance Armstrong could power an entire building. And well, none of us are Lance Armstrong. Sure, mapawatt says Lance can produce 400 to 500 watts while climbing up the French mountains, but he only [...]