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Israeli Scientists Claim To Have Made Road That Generates Electricity From Traffic
Posted: 18 July 2011 01:37 PM   [ Ignore ]
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Making his dream come true are hundreds of rugged metallic crystals. When put under pressure they generate electricity.

So lined up in special pads buried under the tarmac, they create power. It is called ‘piezo’ electricity. It has been around a while, but never used like this before.

One truck can generate 2,000 volts, but to create useful electricity you need a lot of amps too and that requires many pads over hundreds of metres and a high percentage of traffic, preferably moving quickly.

The team is pioneering the idea on a 30 metre strip of highway near Tel Aviv.

It could be used to power traffic lights or street lamps already, but with sufficient progress the technology may one day generate enough electricity to send power to the national grid.

Now that’s a novel idea.  I wonder if this will pan out.

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Posted: 18 July 2011 04:04 PM   [ Ignore ]   [ # 1 ]
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I wonder where that energy would go otherwise. Heat?

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“What people do is they confuse cynicism with skepticism. Cynicism is ‘you can’t change anything, everything sucks, there’s no point to anything.’ Skepticism is, ‘well, I’m not so sure.’” -Bill Nye

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Posted: 18 July 2011 08:50 PM   [ Ignore ]   [ # 2 ]
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Whatever happened to the idea of placing small windmills along interstate freeways ? ? ?
to be driven by the wind caused by 18 wheelers flying along.

As someone who, in younger decades spent a few adventures hitchhiking along western interstates,
I can tell you bro, an eighteen wheeler going full throttle can knock a person off their feet, so I’ll bet it could turn a row of windmills.

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Posted: 19 July 2011 05:12 AM   [ Ignore ]   [ # 3 ]
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And elevators! What about all that wasted kinetic energy as they fall.  smile

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Posted: 19 July 2011 07:19 AM   [ Ignore ]   [ # 4 ]
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In my everlasting role as Official Puritanical Sourpuss, I’ll happily rain on the Israeli piezoelectric road. Yes, compressing and decompressing piezos generates electricity. Yes, it can generate high voltages. But the currents coming out of those crystals are extremely small. You’d need gazillions of those things to get any significant amount of power, and they aren’t cheap. Worse, dere’s dat ol’ debbil “Conservation of Energy”, which says “There are no free lunches” or, more prosaically, “the energy you get out comes from some other source of energy.” So, if we were to pull a megawatt of power out of freeway traffic, it would have to generate an extra megawatt of power in order to maintain its speed. In essence, this boils down to an extremely expensive and inefficient way to convert gasoline energy into electrical energy.

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Posted: 19 July 2011 07:31 AM   [ Ignore ]   [ # 5 ]
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Other question is how much energy it would take to fabricate all those piezoelectric crystals, and how often they’d need to be replaced. I can see this developing into something that ends up burning more energy than it creates. IIRC corn ethanol and hydrogen cars are like that. (Though for different reasons).

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Posted: 19 July 2011 08:39 AM   [ Ignore ]   [ # 6 ]
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The researchers did say that it would only work in high speed, high traffic areas.  But I thought about the maintenance issue myself.  It’s already immensely expensive to build and maintain a mile of regular highway.  I can’t imagine how much this little idea would increase those costs.  Still, it’s an interesting idea.

EDIT
Fixed a typo.

[ Edited: 19 July 2011 08:26 PM by Dead Monky ]
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Posted: 19 July 2011 05:12 PM   [ Ignore ]   [ # 7 ]
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Chris is right about the conservation of energy.  If the crystals are slightly compressed when the tire drives over them, it means that the tire has to go up-hill (even if only a tiny bit) as it leaves each crystal.  So, the vehicle would really be driving up a hill constantly, and that means slightly lower fuel mileage.  It would probably be more efficient and no more environmentally damaging to just use a diesel powered generator, and make the electricity directly.

Occam

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Posted: 19 July 2011 08:53 PM   [ Ignore ]   [ # 8 ]
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Dead Monky - 19 July 2011 08:39 AM

The researchers did say that it would only work in high speed, high traffic areas.  But I thought about the maintenance issue myself.  It’s already immensely expensive to build and maintain a mile of regular highway.  I can’t imagine how much this little idea would increase those costs.  Still, it’s an interesting idea.

Yea, how does one fix a piezoelectric crystal fabricate pot-hole?

But, windmills are cool   smile

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Posted: 19 July 2011 09:36 PM   [ Ignore ]   [ # 9 ]
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citizenschallenge.pm - 19 July 2011 08:53 PM

Yea, how does one fix a piezoelectric crystal fabricate pot-hole?

Duct tape.

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Posted: 27 July 2011 04:44 PM   [ Ignore ]   [ # 10 ]
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picture_of_forces_on_wheel.JPG style=float : right; border : inset 5px #ba0033; background : #002277; margin : 1em 1em 1em 2em; padding : 3px;

“Innowattech has developed a new technology, which enables harvesting and conversion of mechanical energy of the passing vehicles, wasted throughout movement, into electrical energy.”

“It does not change the MPG of the vehicle.”

That gets to the heart of the green energy revolution, extracting energy from those small dispersed movements and light that’s normally dismissed.  Regenerative braking does that sort of thing.  Its those little places where energy is wasted, or dispersed, these are where some more gasoline can be saved.  Isn’t that a good cause worth cheering for, I can’t guarantee they’ll all work out but it’s good to see people try.  smile  If it works, its an efficiency increase, that’s a good thing.  smile  If it works then everyone will think that it was obvious all along.  smile

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Posted: 27 July 2011 06:08 PM   [ Ignore ]   [ # 11 ]
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Mr Pit (may I call you “Jump”?), I hope that your post was sarcastic, but on the off chance that it isn’t, I’ll be happy to explain to you why that proposal is bunk. The reason why it can’t work is not obvious unless you have some training in physics or engineering.

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Posted: 27 July 2011 08:02 PM   [ Ignore ]   [ # 12 ]
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The way I see it: the car weighs, gravity pushing it down always whether parked or rolling, no gasoline required to maintain that force, the peizo underneath needs that force to be applied and released, gasoline provides that movement onto and off of the peizo regardless of whether the peizo is there or not, and so the same amount of gasoline is used either way.  Either press the pavement or press the peizo, which could be productive?  Lets wait to see how the tests turn out.  Right Chris, or not?  smile

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Posted: 27 July 2011 08:46 PM   [ Ignore ]   [ # 13 ]
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The piezo generates a tiny pulse of electricity from the energy used to compress it; in order to generate any more electricity, it must next be permitted to expand so that it can be compressed again. But compressing a substance requires work—energy. Try to compress air into a tire with a tire pump and you’ll see how much work it takes to compress a substance. Hence, the energy coming from the piezo is actually coming from the weight of the car compressing it. But if the car is compressing the piezo, then it must be compressing the road surface by an amount equal to the depth of the compression of the piezo. It creates an extremely shallow dimple in the road. It must then climb out of that dimple—like climbing a hill. The energy required to climb out of the dimple will always be greater than the energy generated by the piezo (Second Thermo). Hence, all the energy coming out of the piezo is stolen from the car. It would be more efficient to just hook the car’s alternator up to the power lines—and that’s a really inefficient way to generate electricity!

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Posted: 27 July 2011 11:19 PM   [ Ignore ]   [ # 14 ]
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Chris Crawford - 27 July 2011 08:46 PM

The piezo generates a tiny pulse ...

Tiny doesn’t matter, electrons are tiny, just integrate the pulse and what do you get?  Tiny is just a distraction.  Still the wave propagates.

Chris Crawford - 27 July 2011 08:46 PM

of electricity from the energy used to compress it; in order to generate any more electricity, it must next be permitted to expand so that it can be compressed again.

And the word for compression and expansion over and over again is… wave.  See the exaggerated wave in the picture above?  The wave propagates through the medium of the pavement, with the speed of the vehicle.  It isn’t stopped by the rolling resistance, the air resistance, the cruddy old engine, the clogged fuel injectors, nor the snow, nor the rain, nor the heat or cold, not even as it crests and troughs the pavement, not even as it propagates through the piezo.  Still the wave propagates.

Chris Crawford - 27 July 2011 08:46 PM

But compressing a substance requires work—energy.

True, but does propagating a wave?  Yes, and still waves do propagate.  The forces of weight and the force of the speed combine to supply the wave.

Chris Crawford - 27 July 2011 08:46 PM

Hence, the energy coming from the piezo is actually coming from the weight of the car compressing it… 

It creates an extremely shallow dimple in the road.

You are missing a force, the one that comes from the speed of the car, the two force model is more accurate than the one force model.  Dimples have the ups and downs.  The wave propagates there is a constant uninterrupted crest and trough, the wave model is more accurate than the hill model. 

Chris Crawford - 27 July 2011 08:46 PM

It must then climb out of that dimple—like climbing a hill. The energy required to climb out of the dimple will always be greater than the energy generated by the piezo (Second Thermo).

There is a rebound force from the expanding pavement/piezo that helps the tire up the hill, plus the energy gained while descending into the dimple, plus some gasoline, and I think that we can make it!  smile  Again, still the wave does propagate, so I’m not worried about all that because we know that the wave does propagate, therefore it overcomes all that, with or without a peizo.

Chris Crawford - 27 July 2011 08:46 PM

Hence, all the energy coming out of the piezo is stolen from the car.

Don’t you remember all that gravity talk at the beginning of your message, Chris?  You were solely focused on one force, weight, and now you’ve suddenly switched over to the force from the speed of the wave.  That switch from one force to the other wasn’t explained.

And still the wave propagates, through either pavement or piezo, by the combination of gravity and speed.  I know you skeptics want to stop the wave, but no-one has been able to do it yet.  You skeptics do not want to believe it, but the idea has merit.  Maybe in the future, pavement that recovers some wasted energy, some tall flaps beside the highway that the air waves from the cars flap out and in recovering waste energy… expensive but maybe.  smile

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Posted: 28 July 2011 07:02 AM   [ Ignore ]   [ # 15 ]
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You skeptics do not want to believe it

Which is in fact the definition of skepticism: we don’t believe anything that cannot be demonstrated with evidence and logic. Remember, there is no empirical evidence that this proposal actually works as described. It violates the law of conservation of energy, for which there is a ton of evidence.

If you choose to reject skepticism and embrace faith, then no amount of logic or evidence on my part can accomplish anything.

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