Brian Fuller: June 18, 2009, 12:30 PM

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The Pounding Promise of Piezoelectric

They say innovation stands on the shoulders of our predecessors. For Elizabeth Redmond and Andrew Katz, it stood in Trevor Baylis' shoes.

Baylis is a noted U.K. inventor and greentech guru who nearly 10 years ago walked across a desert to prove piezoelectric technology could power a cell phone. He rigged his shoes with a piezoelectric subsystem which transformed the vibrations of his footfalls into electricity that powered his cell phone.  It was the latest in a long career of bright ideas from Baylis, who also invented the wind-up radio.

Flash forward nearly a decade to the University of Michigan. Redmond, an art student, is trying to pull together a green-centric design project for her graduate thesis.  Katz had already published his thesis after participating in a Home Depot-sponsored project at Duke on the home of the future. Redmond came across the paper, "Residential Piezoelectric Energy Sources," which was published in July 2004.

Redmond had been inspired in part by Baylis' work on piezo-ped power. Coming across Katz's paper helped her connect the dots.

Now Redmond and Katz are building a company, PowerLeap LLC, working with flooring manufacturers and architectural designers to commercialize piezo-based flooring for high-foot-traffic areas like train stations and nightclubs.

The piezoelectric effect has been known for more than a century: When compressed or tensile stress is induced in a material, an electric field is generated across it, creating a voltage gradient and a current. Crystals, plastic and ceramics are excellent materials for generating the piezoelectric effect.

The prototype design from Redmond and Katz consists of a ceramic piezoelectric compound sandwiched between the top of the rigid flooring and the substrate. While neither will talk publicly about their architecture in any detail during the patent-approval process, they do say it's designed to be modular so flooring can be fitted in pieces and if one portion goes down, it won't take the entire flooring network with it.

Right now, they're targeting $100 to $200 per square foot. By comparison, laminate flooring costs $1 to $6 per square foot, while hardwood floors can run $5 to $15 per square foot. Of course, that flooring doesn't generate electricity.

PowerLeap is currently working with an unnamed "green" dance club in San Francisco to install its piezo flooring there as a test bed.

"Some of our initial calculations that we've come up with in the lab is that standard pedestrian foot traffic will generate 1 watt-hour per square foot, while a dance floor will generate 10 watt-hours per square foot," Redmond said in an interview.

There's no word when the flooring will be ready for party time or whether Baylis will be invited to show up and put his dancing shoes on.

Brian Fuller is a freelancer writer and social-media consultant. He has more than 25 years worth of journalism and new-media experience, including 15 years at EE Times – the last six as editor-in-chief – and nearly two years running social media strategy for Blanc & Otus in San Francisco. He writes about industry issues and evolving communications strategies and tools on his blog, Greeley's Ghost.