How much work to run particular items?
In my online futzing, I came across this nifty bike-driven generator. It generates 150 to 200 watts at 12 to 20 volts DC. So once I saw that, I looked at the electronic bill for the Smallcave and calculated that I’d need three of ‘em running all day to power this place. Barring an influx of very cheap labor, that’s not going to happen. However, I figured it’d be interesting to see how long that would run various appliances. We’re assuming 150 watts/hour here:
| Microwave (1000 Watts) | An hour on the bike gets you 9 minutes of cook time. Enough for two lean cuisines. |
| Laptop (45 Watts) | 3.3 hours. |
| One 18 watt cfl bulb | 8.3 hours. Not bad! 18 watts of cfl is equivalent to 100 watts of incandescent. |
| Fridge: (500 watts) | 20 minutes per hour. |
| LCD TV: (200 watts) | 45 minutes. |
| Cellphone: (0.75 watts) | 200 hours. |
What amazes me about this list is a) that anything got done before electricity, b) how traditionally lousy battery power has made for incredibly efficient portable devices, and c) how efficient it makes solar look. A 3 kilowatt system at the latitude and cloud cover of New York will tend to generate 11-12 kwh per day on average. That system would take up about 360 square feet. So putting panels on your roof is like hiring 3 bikers to go 24 hours a day, but without the backtalk. Or, considering that a horsepower is 746 watts, it’s like having Secretariat on a treadmill all day, and without the poop. More incredibly, consider that at peak sunlight, a single panel like this can generate 150 watts. Point that thing into the sun and save a bike ride. Or take a look at this map, which shows how much land you’d need to generate the world’s power needs with solar:
Bonus: Here’s video of a guy running a 32 inch TV with a bike. And here’s a hand-cranked ipod shuffle.
May 11th, 2007 at 3:09 pm
what the??
why the hell aren’t we doing it?
May 11th, 2007 at 3:12 pm
High up-front costs. Plus, transmission of power is very lossy, so a huge station in the Sahara wouldn’t necessarily be able to power Europe. But those are solvable problems. (I assume your question was at least in part rhetorical)
May 13th, 2007 at 11:35 am
[…] information. For instance: a normal biker going 14 miles per hour uses about 100 watts of power. (That suggests the bike generator people are really sweatin’ it to get 200 watts.) Meanwhile, Lance Armstrong can provide about 500 watts for a burst of 20 […]