Dear Matthew Alice:
I've often wondered, would it be economically feasible to build an exercise machine that could generate electricity? It seems to me that if all the Exercycles, treadmills, elliptical machines, etc., at our local gyms could be hooked up to some kind of turbine, they could generate at least enough energy to power the lights and A/C at the gym and maybe the TVs as well. And could someone invent a television, computer, or video game that can only be powered by an Exercycle or treadmill? This would be a great solution to the lazy, overweight kids who aren't getting enough exercise.
-- LP, Mission Valley
It turns out, everyone in the world has had this idea. Everyone. Everywhere. Many have penciled out the costs vs. the benefits, and, on a large scale, it doesn't seem efficient. Most of the penciling suggests that one incredibly fit athlete pedaling constantly for one hour can generate about a dime's worth of juice. If it's not cycled immediately into some power-eating device, it would have to be stored, so batteries add to the costs. At the moment, small-scale is the way to go. There are self-powered exercise machines, computer monitors that run on pedal-generated power, wind-up-power radios, and pedal-powered fans and lights. The video game suggestion sounds like a winner, too -- except the people who would have to shell out for the device (Mom and Dad) are the same ones letting Lardass eat Hot Chee-tos and sodas in front of the TV all day. A hard market to crack.
My personal fave, though, is an electric backpack developed for the defense department. Foot soldiers carry about 80 pounds of gear; much of that weight is in the batteries needed to run all their digital gadgets. A biologist at the University of Pennsylvania invented a backpack suspended by springs from a rigid frame. The bouncing motion of the pack as the soldier walks generates enough electricity to run a cell phone and night-vision goggles.
It occurs to me that pretty much everybody drives to the gym to work out. This effectively undoes any ecological good achieved by treadmill power.