Article

2009-03-11 Science & Technology

Israeli company to generate electricity from under highway generators

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Posted by mhw 2009-03-11 00:00|| || Front Page|| [11136 views ] Top

#1 Now, that's very unGreen approach.

Posted by g(r)omgoru 2009-03-11 03:54|| 2009-03-11 03:54|| Front Page Top

#2 It's called "Induction" and markedly slows the cars (Or whatever) Passes, that's gonna be reeel popular. (S)

Posted by Redneck Jim">Redneck Jim 2009-03-11 06:24|| 2009-03-11 06:24|| Front Page Top

#3 The correct link is this

btw, it converts mechanical energy into electricity so it shouldn't slow the cars.

Posted by mhw 2009-03-11 08:05|| 2009-03-11 08:05|| Front Page Top

#4 It can't create energy from nothing. The cars compress the piezoelectric material -- that's what generates the electricity. So the cars sink into it a minuscule amount and then require a minuscule bit of extra energy to move off it. That's why it says "harvest enough energy from passing vehicles". The amounts of energy have to be small, but perhaps they can do something useful like illuminate some LED traffic control devices.

This is NOT renewable energy.

Posted by Darrell 2009-03-11 10:14|| 2009-03-11 10:14|| Front Page Top

#5 100 kW will not power 40 typical American houses. That's 2.5 kW per house or 2,500 watts per house. You'll have to turn off everything else to turn on either the electric clothes dryer or the electric water heater or the electric stove.

Posted by Darrell 2009-03-11 10:26|| 2009-03-11 10:26|| Front Page Top

#6 1. The road compresses every time it gets a compressive load. Assuming the piezos compress similarly as does pavement, there is no loss to the cars.

2. A typical Israeli home corresponds to a 2 or 3 bedroom American apartment. Many of them do not have in home washer/dryers.

Posted by mhw 2009-03-11 10:48|| 2009-03-11 10:48|| Front Page Top

#7 Bad assumption, mhw. The piezos do nothing to strengthen the ribbon of pavement, so they are an extra layer of compression requiring extra energy to traverse. You don't get energy out of nowhere. There has to be a loss to the cars and even the article says it is harvested from the cars.

Why would we want to power homes with cars at all, let alone through this highly expensive method? Cars are far less efficient than any type of commercial power plant.

If it works at all, this will be a novelty item that is only good for powering some remote traffic devices for which running power lines is prohibitive. Even then, it will have to stand up to solar which is renewable and doesn't require embedding in the road.

Posted by Darrell 2009-03-11 11:52|| 2009-03-11 11:52|| Front Page Top

#8 maybe I'm being dumb.. but I'm just not following you Darrell...
Cars use energy to move forwards or backwards. They do not use energy to press downward.

At what point does burning the gas in the tank become responsible for the effects of gravity?
(I think you are confusing your energy sources)

Posted by Dcreeper 2009-03-11 13:38|| 2009-03-11 13:38|| Front Page Top

#9 Why is your car less efficient with partially-deflated tires?

Think of riding over the piezoelectric as riding over a rubber mat. Riding over a rubber mat is like riding with partially-deflated tires: you lose energy by using it up in the flexing of the rubber.

It's called "rolling resistance" and can be due to the deformation of the tires, the deformation of road surface, or both.

Posted by Darrell 2009-03-11 14:03|| 2009-03-11 14:03|| Front Page Top

#10 BTW, if there were not deformation issues, they could just put two layers under there and power 80 homes instead of 40, right? Or 20 layers? Or 200 layers?

Posted by Darrell 2009-03-11 14:11|| 2009-03-11 14:11|| Front Page Top

#11 they could just put two layers under there and power 80 homes instead of 40, right? Or 20 layers? Or 200 layers?

Wait till Japanese get hold of that.

Posted by g(r)omgoru 2009-03-11 14:23|| 2009-03-11 14:23|| Front Page Top

#12 Oh, and this guy's talking $6,500 per kilowatt for an intermittent power source. Nuclear plant capacity goes for $2,000 to $3,000 per kilowatt and it's output is continuous.

Posted by Darrell 2009-03-11 14:23|| 2009-03-11 14:23|| Front Page Top

#13 This is gonna make solar seem downright affordable. File under Rube Goldberg.

Posted by ed 2009-03-11 14:45|| 2009-03-11 14:45|| Front Page Top

#14 The 'produced' energy has to come from somewhere. I think its called the law of conservation. In this case the energy is coming from less efficiency (or additional drag) of the cars traveling over the road.

Isn't this kind of like walking or rolling on a giant mattress. You are always having to exert extra energy for each step (or roll in this case) to 'push' down the matress with each step (to compress the piezos). In effect you are always going 'uphill' - adding kenetic energy - (over the uncompressed stuff) even if its a minute amount - this energy is used to compress the matter which this device collects.

This is just converting the energy your car uses to 'climb' the side of the compression into electricity. Probably at a high cost of loss of energy in heat (of the surface) etc....

It may produce energy - but the cars will use more more additional energy then this will ever produce.

Posted by CrazyFool 2009-03-11 15:11|| 2009-03-11 15:11|| Front Page Top

#15 "they could just put two ~~layers~~ lawyers under there "

There, fixed

Posted by Herb Unetch6843 2009-03-11 15:19|| 2009-03-11 15:19|| Front Page Top

#16 Better 200, Herb.

Posted by Darrell 2009-03-11 15:20|| 2009-03-11 15:20|| Front Page Top

#17 Just to simplify things. The energy loss isn't from the car moving downward so much as when the car has to fight gravity to come back up.

Posted by Mike N. 2009-03-11 20:44|| 2009-03-11 20:44|| Front Page Top

#18 What he said :)

Posted by CrazyFool 2009-03-11 23:25|| 2009-03-11 23:25|| Front Page Top

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