Piezoelectricity: Would Highway Power Be Stealing From Drivers?

01/17/2009 05:12 am ET | Updated May 25, 2011
  • Yoni Levinson EcoGeek and Treehugger

Israeli company Innowattech is currently developing technology to harness some of the most bountiful manmade kinetic energy out there - the movement of cars, trains and planes over roads, rails and runways. The idea is simple - stick a piezoelectric generator under the road. Innowattech claims that 1 km of piezoelectric highway could generate 500 kilowatts (that's .8 MW per mile, for those of you keeping score at home).

A recent article by Treehugger, however, blasts the idea, stingingly (albeit cleverly) calling it "highway robbery". The author argues that piezoelectric roadways would increase the drag felt by the moving vehicle which, in turn, would cause the driver to burn extra gas to get over the road. Thus, all the electricity generated by such a system would in fact be stealing money from the drivers:

Energy theft is in the news again, in the guise of turnstiles in Tokyo, revolving doors in the Netherlands, and now piezoelectric generators for road, rail and runway from an Israeli company, Innowattech.

Perhaps a case can be made for revolving doors and turnstiles as most people could use a little more exercise, so a little extra energy expended won't hurt the able-bodied, although the elderly and the disabled might notice the difference and have trouble with them. But roads and rails? It is literally highway robbery, and inefficient at that.

They claim that with the Innowattech Piezo Electric Generator (IPEG), "1km of roadway or runway can produce up to 0.5mW (500kW) of electricity per hour." [sic. please no comments on their energy terminology] IPEGs can "harvest energy from weight, motion, vibration and temperature changes."

But there is a certain law called conservation of energy, and what they are doing is converting the energy from gasoline, paid for by the driver and inefficiently converted into forward motion, into electricity by increasing drag. You can't make energy from nothing; better they should put their money into solar cells, where at least the source of the power is free, and is not ultimately expensive fossil fuels.

It's an interesting ethical question, and it depends a lot on details.

Read the full story here.