February 29, 2008
Scientists have made an exciting breakthrough in the perennial human search for renewable energy sources by venturing into new and undiscovered territory — the human body.
A team of Canadian and U.S. researchers has found a way to capture human energy that conceivably could help people with prosthetic limbs, artificial pacemakers or insulin pumps power these devices using their own energy. The energy is produced by the simple act of walking.
"The main idea is to harvest energy from walking in a manner that you can get electricity without increasing effort," explained study author Max Donelan, a professor in the school of kinesiology at the Simon Fraser University in Burnaby, British Columbia, and chief science officer of a company formed to develop the energy-harvesting device.
Much like a hybrid car that captures energy that is normally dissipated, the biomechanical energy harvester captures energy from the normal stop-and-go of walking, more specifically, from the deceleration phase of walking.
"The generator helps slow the motion of the knee at the right time, and you can get substantial electricity with minimal effort," said Donelan. While the technology is probably too expensive to be practical in its current state, Donelan says that its price will inevitably come down.
An adult walking at a brisk pace wearing the harvester — which attaches to the knee and weighs just over three pounds -- can generate 13 watts of electricity in one minute. That means you could get about six minutes of laptop computer time with every minute of fast walking. A low-effort walk would produce about five watts of power, which would give you roughly two and half minutes of laptop time. The study is published in the Feb. 8 issue of Science.