Wacky Alternative Energy 5: Pure (Human) Energy

When you're at the gym, do you ever find your mind drifting off to ponder the perils of the planet? Do you feel even the tiniest bit of remorse as your legs pound away on an electric machine that goes nowhere, while the ice-cold air conditioner blows down on your neck? OK, so you're probably thinking of little more than how many calories you're burning, but if you're one of the more eco-conscious exercisers, you may soon be able to let those concerns melt away with the pounds.

Pedal-A-Watt
Photo courtesy Convergence Technologies, Inc.
Hook up your bike to the Pedal-A-Watt bike stand and pedal your way to energy independence.


Several innovative gyms are popping up that convert human energy into useable electricity. One of them, in Hong Kong, has exercise machines that look perfectly ordinary from the outside, but have generators inside that create energy from movement. So while you're busy sweating it out, your efforts are also triggering a generator that creates electricity to both power the exercise console and supplement the electrical juice required to keep the overhead lights on. The owner of the gym maintains that the average person can generate about 50 watts of electricity per hour on the machines [source: Blume]. So unless you like running in the dark, you better get moving.

Pedal generators like the Pedal-A-Watt bike stand use a similar concept but are more powerful. A person in top condition can generate 500 watts of power, while someone in couch-potato condition could generate around 150 watts. Although that may not seem like much, that's enough to power two laptops, two fluorescent light bulbs and a cell phone -- at least until your workout is over [source: Treehugger].

­The Pedal-A-Watt bike­ stand, which works by powering a generator with the movement of the bike's rear wheel, comes with an optional PowerPak that stores the energy you create for later use. The PowerPak has an outlet where you can plug in and power any appliance that runs on less than 400 watts of electricity. For a frame of reference, a large television uses around 200 watts, a stereo 20 watts, a desktop computer 75 watts and a refrigerator 700 watts [source: Convergence Tech, Inc.]. So if you bike for two hours while generating 200 watts, you're not going to be able to keep your beer cold, but you could wind down with a lukewarm Bud while watching the game on television.