There's nowt from nowt.

This will extract energy from the kinetic energy of the vehicle - making the engine work harder and increasing fuel consumption & CO2 emissions.

And because of the low efficiency of these kinds of devices, the fuel use will be some number of times the value of the energy generated.

They should be made to test the fuel consumption of the vehicles using this road.

You know what? This is a perpetual motion machine. It violates the 2nd law of thermodynamics. Think about it. How does the traffic squeeze the crystals? It takes MORE ENERGY to drive on a more mushy road with the compressible crystals. The extra energy expended by traffic equals the amount of electricity produced, minus the inefficiencies. It has to be less than 100% or the energy is coming from somewhere else. It is much more efficient to generate electricity by burning fuel at a central plant than in cars and trucks

Yeah at first it definately seemed to me like you are creating a problem here because the vehicles end up working harder. However, the system actually derives its energy (partially) from the vibrations in the road. Since these vibrations are present even without the crystals your car should not have to work harder than before. Also, the amount of deflection in the roadway should be the nearly the same w/ the crystals as w/out them so you won't have much mushyness.

"Normal" roads already flex and compress when driven on. They would be harvesting the energy that is already lost as heat. 50% efficiency is better than 0%. The amount the crystals would need to be compressed is miniscule. Think of the crystal in your watch that "moves" to keep time. It is actually a vibration. Instead of providing power to vibrate the crystal the opposite is used.

Bert, your average power station (coal & conventional gas) works at only 30%-50% thermal efficiency &-if overly centralized-can lose a further 7%-15% of its generated energy in Transmission & Distribution losses. Indeed, by having the source of electricity close to the area of demand, you can significantly reduce total energy losses attributed to central power stations. Using \"waste\" energy to generate electricity makes perfect sense to me!

imagine if they could harvest enough energy from the roads to power entirely maglev cars. if only there werent so many people keeping us out of the future!

I know this is extremely late, but for those who know nothing of this: These crystals when compressed by mere nanometers (which roads will do anyway) will produce electric charge.
The Curie\'s were responsible for finding these crystals, thanks to their access to X-rays. It is not perpetual motion, it runs on the same idea as solar panels - the energy is being put out ANYWAY, and it is simple to get it.
How efficient is it? Well, let\'s look. Solar panels, in recent weeks, were exposed for not lasting the 20 years they were supposed to. They are extremely expensive and need to be manufactured PERFECTLY to get any efficiency in bright sunlight. The energy put into producing them is still not recovered over the lifetime of the panels - they die too quickly.
With Piezoelectric crystals, you are using consistent driving as your mechanism - not really dependent on the weather, and minimal (albeit, more expensive) maintenance compared to a normal road. Your biggest problem is the cost for the material, and determining how much you want. Obviously, it is expensive to produce this stuff, and some of the materials (like small amounts of Lead in most cases) will be toxic, or hard to come by.
Even if it doesn\'t work on a massive scale, think about it - your driveway can harvest energy for (emergency) lighting in the garage. Major highways and truck routes may opt for this. Parking lots.

I would be curious to know whether this type of parasitic energy harvesting could ever become any fractional contributor (even to the extent of say, 0.01%) of baseload power generation in a grid? Especially for countries with very long distances of road infrastructure and heavy freight haulage routes, or even for high frequency domestic vehicle usage? Perhaps not, if such piezoelectric vibrational energy harvesting is only sufficient to generate wattages capable of powering traffic signage boards, traffic lights, highway/ freeway lighting, etc?
On a scaled down related note: footpath piezoelectrics powering any kind of (low power) devices from pedestrian foot traffic? If they can do it for nightclub dance floors.....

I think it is viable. The roads arent necessarily any more mushy than others. Concrete roads ride different than asphalt. The point is they are riding the roads anyway. and if it can generate energy doing something they are going to do anyway I see it as a benefit And with the new developments with lower cost (see advanced article on this) it is much more viable.

They are making this too hard. It does not have to be this hard or expensive. They might as well just put those panels on a frame and let the rise and fall of the ocean tides squeeze those as they are jigged from pressure to pressure, depth to depth.