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Stepping up to a bright idea

POSTED November 1, 2011 6:28 p.m.

At first I wasn’t sure I was reading the CNN report correctly. The story hinged on special pavement that uses the impact of human feet to generate electricity.

That’s right. A young man in Britain has invented a device that harvests the energy from a footfall hitting the pavement to power things like LED lights.

Talk about a bright idea.

The “PaveGen” project is the brainchild of Laurence Kemball-Cook, age 25 years. He’s an engineer who built a prototype of the device during his last year in school and is now working to make and market his creation.

The PaveGen tiles work because they have a bit of “give” in them. When you step on one, it’s depressed a little bit by your body weight. That motion can be used to generate a small but measurable bit of electricity. If the paving tiles are in an area of heavy foot traffic – like the stairs down to a subway station – in total they can make enough electricity for some useful applications.

Using human muscle to generate electricity is not completely new. I’ve seen students in teaching demonstrations pedaling hard on stationary bikes to light up a relatively low-watt light. In short, it takes a lot of oomph to power a standard bulb – us old ladies need not apply for any job requiring that much work on a regular basis.

But walking is one of the most efficient things we humans can do. And by stepping on the paver of the PaveGen devise, a person exerts considerable downward force – full body weight. Each step on one of the pavers generates enough juice to power an LED bulb for 30 seconds. The generating device can be linked to a battery to even out the flow of the electrical current between footfalls.

Kemball-Cook had a second bright idea as he designed his device. In addition to contributing electric power to devices outside the paver, he engineered the tiles to retain 5 percent of their oomph. That bit of power is used to light up a LED bulb in the paver itself. This means the device lights up as you walk in it, giving you positive feedback that you’re really making electricity as you walk across the pavement. People really like that, it’s clear from the news reports.

Some 20 of the tiles will be installed around London’s Olympic Stadium where foot-traffic is going to be high.

The pavers have already been tested at a school in southeast Britain.

“1,100 kids have devoted their lives to stamping all over them for the last eight months,” Kemball-Cook said.

On a shorter-term test, Kemball-Cook says he took the pavers to an outdoor festival where 250,000 footsteps created enough juice to charge 10,000 cell phones.

The pavers are a bit like social media, harnessing the individual contribution of many people in ways that generate value. That’s part of the appeal of the devices.

Each PaveGen tile can be made to the size of existing pieces of pavement so they can be substituted in for what’s already in a sidewalk.

Like with everything in this world, the economics of the pavers will determine if you see them on a city sidewalk near you. At this point Kemball-Cook won’t say what it costs him to make each PaveGen slab. He notes instead that once they go into mass production, the costs will fall.

Time will tell if this idea has legs. But I for one am rooting it does. And I’m glad to note some members of the next generation are thinking outside the box and creating some delightful devices.

Keep it up, kids!

 

— Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. Follow her on the web at rockdoc.wsu.edu and on Twitter @RockDocWSU. This column is a service of the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.

 

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