Apr 23 2009

The Piezoelectric Race

Posted by: Jonathan Marshall

Is America in danger of falling behind the rest of the world in harnessing the piezoelectric effect, the property of certain materials, including quartz crystals and some ceramics, to produce an electrical charge when squeezed or stressed?

This effect, first demonstrated by French scientists in the 1880s, has been since been put to use in phonograph cartridges, ultrasonic submarine detectors, and even cigarette lighters.

In a passionate new essay, Kimberley Diamond, vice chair of the carbon and energy trading and finance committee of the American Bar Association, warns that "the U.S. is currently running at the back of the pack of global leaders in this space."

Insisting that "this needs to change," Diamond continues:

Revolutionary developments in piezoelectric technology now permit the kinetic energy generated from people walking and dancing, as well as from moving vehicles, to be converted into clean power. Innovative devices employing piezoelectricity offer vast public benefits and potential business opportunities in both the long and short terms. Increased piezoelectricity usage could be a trend that plays a significant role in shaping tomorrow's world in the alternative energy sector as well as in financial markets. Consequently, new scientific and technological advances in piezoelectric inventions merit endorsement and should be raised to the forefront of U.S. domestic public consciousness and discourse.

What are these revolutionary advances? NEXT100 covered one of them in January  -- a proposal by an Israeli engineer to embed piezoelectric crystals in road beds to generate electricity from passing cars. His company, Innowattech, claims that electricity can be generated this way at less than 10 cents per kilowatt hour, but the company's web site is notably silent about the results of a pilot test that was supposed to take place in February.

Another application is in dance floors at two European nightclubs, Club Surya in London and Wvatt in Rotterdam, where as Diamond explains:

The clubs' "bouncing" dance floors are engineered with springs and series of crystal and ceramic blocks. When patrons at each club dance, the pressure they exert on these blocks causes the dance floor to depress slightly and the blocks to rub against each other. The result is the generation of a small electric current. This process effectively captures the dancers' kinetic energy, and feeds it into nearby batteries. In Club Surya, for instance, batteries power the club's lights and air conditioning, and supply up to approximately 60 percent of the club's energy needs. As long as clubbers dance, the floor's movement constantly recharges the batteries. The more dancing, the more power produced. Each person can produce between five and 20 watts, depending on their activity level.

(Here's a diagram of how it all works.)

A more pedestrian application in Ann Arbor uses piezoelectric sidewalk tiles to power colorful LED lights, an example of a concept the inventor calls "Project POWERLeap."

Diamond sees "mind-boggling" potential for expansion of the use of piezoelectricity, but offers no perspective on the cost. But in a suggestion that borders on parody, Diamond offers another alleged benefit:

From an investment banking perspective, if a certain threshold of increased demand is reached over the next decade or two for secured borrowing for large-scale piezoelectric projects, then there is the potential that a new esoteric asset class involving piezoelectric loans or bonds could be formed. The creation of such securities, backed by infrastructure-related or commercial real estate-related debt, could herald additional transaction structuring and trading opportunities in the capital markets. For instance, asset-backed securities in the form of piezoelectric infrastructure or commercial real estate loans could be used in the future as collateral for structured finance transactions such as collateralized loan obligations (CLOs), or other structured investment vehicles.

For myself, if we're looking for ways people can harness their own energy, I vote for turning every health club in America into a mini-power plant by adding dynamos to all of their treadmills. Said the president of California Fitness (a Hong Kong company, go figure):

One person has the ability of producing 50 watts of electricity per hour when exercising at a moderate pace....If a person spends one hour per day running on the machine, he/she could generate 18.2 kilowatts of electricity and prevent 4,380 liters of CO2 released per year.

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