New power source: wall vibrations
Imagine using a computer that runs on energy generated from your building's wall and window vibrations. Masayuki Miyazaki, a senior researcher at Hitachi Co. Ltd.'s central lab in Tokyo, is trying to do just that.
He recently made a tiny generator that converts building movements into electricity, creating enough energy to run a temperature or light sensor once an hour. Though the output is small right now, only about 10 microwatts, scientists predict the generator's potential could be huge in coming decades - possibly used in battery-free computing systems.
Dr. Miyazaki's work is part of a growing movement by scientists to find, create, or capture alternative sources of energy - even in small amounts much less than one watt. Researchers hope to harvest power from anything from the vibrations of walls and windows to the movements of air and the human body.
While alternative energy sources alone might not produce much electricity, they could help power small devices such as computer chips, wireless sensor networks, or cellphones. The idea is simple. Just as some wristwatches power themselves from the random movements of a person's arm, these devices would capture energy from random movements of other things.
In another approach, Larry Kostiuk at the University of Alberta in Canada, is working on a water-powered battery. Its special trait: creating electricity directly from water on the tiniest scales.
Most people are familiar with hydroelectricity, which uses water falling from a height to drive turbines and generate electricity. Professor Kostiuk's method differs in that water is put under pressure as it moves through microscopic channels within a glass or ceramic-filter tube, allowing electricity to be converted directly from water. The experimental tube, about 2 centimeters in diameter, has about half a million tiny channels or holes through which the water is inserted by a hand-operated syringe.