Piezoelectric is the word to remember

The weight of a footstep is packed with energy – if only this energy could be harnessed.

In fact, there is electric potential within 20 varieties of naturally occurring crystals when force is applied. Piezoelectricity is the word used to describe this process of matching force with a crystal to gain electricity. The electric potential is proportionate to the force exerted upon it.

Today the concept is not just imaginative, but already powering Dutch dance clubs via dancers, Japanese train stations via commuters, and soon, French street lamps via pedestrians.  As futuristic as piezoelectricity sounds, it is the same principle that enables a scanning electric microscope, or ignites a cigarette lighter.

A Netherlands-based company called Sustainable Dance Club offers the world’s first dance floor which converts mechanical energy (the force of dancers’ footsteps) into electricity (though the company website does not name this process piezoelectric capacity.) Sustainable Dance Club’s flagship project is called Watt, a dance club and bar in Rotterdam, Netherlands. The average dancer generates between 5 and 20 Watts – admittedly not enough to stop climate change – but a gesture in the right direction. The floor lights up interactively as club-goers dance. According to the New York Times, the 270 ft2 floor cost $257,000 – an investment that will not be recovered in saved electricity costs. Since this is a first generation prototype, club owner Aryan Tieleman predicts that costs would reduce once further development of the concept occurs.

In 2009, the Miami Science Museum installed Sustainable Dance Club floor in its permanent collection. Sustainable Dance Club recently installed their floor panels in the sidewalk in Toulouse, France. The modest pilot project there produced energy sufficient to power one street light.

German auto manufacturer, Audi, is testing methods to deploy piezoelectric devices capable of capturing vibration and converting it into energy to run onboard electronics, according to GreenTech Media.

In Japan, the company Soundpower Corp., ran a pilot project in several train stations including Shibuya Station in Tokyo. In December 2008, commuters’ footfalls ran the Christmas lights decorating the station. Likewise, at another pilot site, the electric arrival/departure board was run via passengers footsteps.

Soundpower Corp has an history with a familiar ring: Hayamizu Kohei left graduate school to found his company. Within two years, the startup launched its Power Generating Floor™. The floor is composed of 20 in2 rubber tiles with a piezoelectric element inside. The average person weighing 125 pounds will generate 0.1 Watt in the 2 seconds it takes to cross the rubber tiles of the Power Generating Floor™.

Since electricity turns into sound through speakers, could sounds not be turned into electricity? Soundpower founder Hayamizu Kohei is investigating further innovation to leverage this principle. Proposed applications include a cell phone that can be recharged through conversations, or sound insulating walls that generate electricity from the noise of passing vehicles.

Piezoelectricity was first understood in the late 1800s.  German physicist Woldemar Voigt published his Textbook on Crystal Physics (Lehrbuch der Kristallphysik) in 1910.

It’s appropriate to remember another German physicist, Albert Einstein, who urged using the imagination, believing that creative thoughts might lend more to the advance of progress than academic knowledge alone.