We have a winner for our “Hamster-Powered Mansions” estimation contest. The question: How many buff hamsters would it take to completely power a mansion?
Mansions come in a wide range of sizes, and each will have different energy requirements. According to Factcheck.org, Al Gore’s mansion used 191,000 kilowatt-hours in 2006. Dividing by one year, we can compute his average power consumption to be 22,000 W.
From this MAKE magazine video1, we can see that a hamster is at least powerful enough to light up an LED, but this is only a lower bound since he might be able to power even more LEDs if we connected them in the circuit. According to Otherpower.com, their hamster Skippy had no trouble lighting up 6 LEDs, and they estimate he should be able to power 200. Being fairly conservative, I’ll assume our hamsters can power 50 LEDs. According to Wikipedia, the voltage drop across one LED is anywhere from 1.5-4.5 V and the current should be between 1 and 20 mA. Assuming the LED acts like an Ohmic resistor,2 we can estimate the electrical power created by a wheel-spinning hamster,
power = (# of resistors) · (current) · (voltage drop)
= (50) · (10 mA) · (3.0 V)
= 1.5 W per hamster.
From this and the power consumption of Al Gore’s mansion given above, we can estimate the number of hamster’s you’d need to power a mansion,
# of hamsters = (power per mansion) / (power per hamster)
= (22,000 W) / (1.5 W per hamster)
= 15,000 hamsters.
You’d need about 15,000 hamsters to power a mansion. Congratulations to our winner Bryan Merrill. Bryan will be receiving a free copy of How Many Licks? Keep reading for our next contest.
 Speaking of MAKE magazine, check out Maker Faire in Detroit July 31 and August 1. I’ve assumed LEDs require 3.0 V and 10 mA.