It has become clear that we need to figure out greener, renewable sources of energy. Well, what if we could produce our own damned power? Walking’s about as carectomy-friendly as it gets. Below are some concepts in the works that will allow us to crank out some electricity while keeping healthy, happy, and pollution-free out on our strolls.

We featured NanoSonic Inc’s piezoelectric backpack concept in an earlier article. In a nutshell, the backpack’s straps, which feel just like nylon, are made from polyvinylidene fluoride (PVDF). The material harnesses the static electricity created by the user’s walking motion. This power can either be used directly by electronic devices or stored in batteries for later use. The power such a device generates isn’t huge: about 45.6 milliwatts of power while walking. However, it’s enough to power an LED headlamp or an ipod and it’s “free power” in the sense that there’s no extra effort required by the walker.

Researchers at the Georgia Institute of Technology are taking the piezoelectric idea one step further; they’re embedding nanotechnology fibers into fabric and making power-generating duds. Simply by moving around and jostling the clothing, the wearer is cranking out power.

From the AP:

Zhong Lin Wang and colleagues at the Georgia Institute of Technology covered individual fibers of fabric with nanowires made of zinc oxide. These wires are 50 nanometers in diameter, 1,800 times thinner than a human hair.

Alternating fibers are coated with gold. As one strand of the fabric is stretched against another, the nanowires on one fiber rub against the gold-coated ones on the other, like the teeth of two bottle brushes. The resulting tension and pressure generate a piezoelectric charge that is captured by the gold and can be fed into a circuit.

The allure of the idea is that it doesn't take unusual movement to generate usable electricity. Pretty much anything someone does while wearing a piezoelectric shirt would be productive.

Our friends at EcoGeek recently ran a story on a “knee dynamo” that harnesses energy directly from the walking motion.

From EcoGeek:

It actually uses the energy of the leg swinging forward at the beginning of the stride to generate the power.

This energy would otherwise need to be counteracted by the leg muscles to keep the leg from jarring the knee. This way, the dynamo can actually produce more power than the extra energy the wearer spends to use the device. Think of it like regenerative breaking in hybrid cars. Every time you take a step, your thigh has to both speed up and slow down your lower leg. This thing just helps your leg slow itself down, and captures some of that energy. There's an excellent video of the thing in action at BBC news, I suggest you check it out.

Not quite “free power,” as there’s still a little extra effort required by the user. However, the energy gained is greater the extra energy expended. Sounds a bit like perpetual motion - as long as you keep walking!

Or, perhaps the next step in self-contained power is to carry mini-solar panels around with us. Computer bags and backpacks with solar panels have been around for a while. Well, why not dispense with the luggage and put the panels right on our bods? Groovy Green recently featured a stylish little number from Studio 5050 made up of solar-cell-packing tiles. Somewhere in the scanty outfit is a USB interface to charge your accessories on the go.

As Hank Green of EcoGeek said, “..if I can't power my own iPod 15 years from now, I give up on this planet...thanks to these guys for getting this technology another step (or half-stride) closer to reality.”

Comments (2)

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frisbee said:

How about the amount of kWh's to be generates throughout the lifetime of such features compared to the total amount of energy to produce, transport, maintain en dispose/recycle them? Is there any figure that shows a net gain? In that case great! Otherwise of no help at all.

March 07, 2008

Carl Foner said:

Also worth checking out is M2E (http://m2epower.com/). They're also harnessing kinetic energy generated by just walking around and using it to power handheld devices.

March 12, 2008 | url

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