Prototype piezoelectric road could generate power by simply sitting there
By Darren Murph 
posted Dec 13th 2008 1:20PM
posted Dec 13th 2008 1:20PM
By sitting there and getting ran over by motorcars, that is. In an effort to best other power-generating highway options that involve solar panels and enlarged blender arms, Britain's Environmental Transport Association is looking to test a prototype highway that's embedded with piezoelectric crystals. Essentially, the process would work much like the power-generating Tokyo station floors we saw earlier this week; each car that squishes a crystal would contribute a tiny bit of energy, and the collective effect could be enormous. In fact, it's estimated that a single kilometer of roadway could generate 400-kilowatts of energy, or enough to power around eight small cars. And we're no rocket scientists (nor physicists), but we're assuming these whiz kids already made sure these magic crystals weren't friction-generating, too. Right?
Regardless of friction, any surface that harnesses energy from cars is going to require more energy from those cars. With a piezoelectric system like this, the energy comes from "squishing" the crystals-- essentially making the road a little softer. softer surfaces require more energy to traverse.
This idea makes much more sense with pedestrians and bikes, because at least then the root energy source isn't burning fossil fuels.
your talking about a tiny, tiny amount of "squish"
the amount of additional energy consumed would be far less then what you would lose from having your tires a few PSI low.
But would it squish more than it normally would? Asphalt does have a little give to it anyway, so it might not be a problem. It gives me an idea though, why not piezoelectric tires? That way you'd generate power without needing a special road. It'd probably work even better in those honey comb tires, more material to bend and flex.
Maybe if you drive on concrete roads... Sadly enough, most roads are pebble bed, sand, asphalt, sometimes they even replace the sand with dirt (maybe not sometimes, more like always in the places i live). If they don't already have enough rolling resistance, i don't know what does. In fact, most piezos don't change shape that much, and when they are already less than a millimeter thick, it results in negligible dimension loss. Yes, road surface changes efficiency, but as pointed out above, the biggest source of energy loss due to rolling friction is in the tires being under inflated.
you. It's still stolen energy from me. It's not right.
basroil:
My tires are not underflated. I have an air compressor just for that purpose.
And besides, even if they were, it still wouldn't be right to steal energy from me. It'd be like saying a gas station rigged their pumps to give out 0.9 gallon of gas per gallon charged because "people are driving gas guzzlers anyway".
Unbelievable...
ROADS ARE GETTING "SQUISHED" ANYWAY!
Robert Abramson is right, this does just take energy from the cars due to rolling fricton. Sure there already is rolling friction, but this ADDS to that friction. It's simple conservation of energy.
Conservation of energy means that you will never get back as much energy as you lose from the extra squish.
Thank you moose, and everybody else that understand the conservation of energy and the loss that accompanies transfer of energy from one form to another. I tried mightily to defend the laws of nature and economics in the last piezoelectric topic [ http://www.engadget.com/2008/12/11/piezoelectrics-installed-in-tokyo-railway-station-floors-generat/ ], but my argument still wound up being "rebutted" by someone calling me a fool.
Robert, pedestrians and bikes are still powered by the human body, which is ultimately powered by food. Increase human energy output requires an increase in food intake. You can't get energy for nothing. It's simply more efficient to go from Sun->Solar Panel->Electricity than from Sun->Plant->Human->Bike/Foot->Electricity.
I'm going to charge them for using my cars fuel.
There's no such thing as free energy...
Guys,
All I'm getting at is that using this for serious power generation would be silly-- it would be far more efficient to run a gasoline generator.This technology could be useful for running extremely low-power appliances like traffic signals where the energy required from each passing car is negligible, but anything more would be extremely wasteful; and since the root power source is gas anyway, it's not particularly green.
Tobias,
I understand that human beings ultimately draw their power from the sun-- that was exactly my point. A sidewalk using this technology is essentially a way to harness some solar energy, while the same thing on a road would be harnessing fossil fuel. I also understand that solar panels are more efficient than this; I was just making a point about the "green-ness" of this particular proposition. But that said, this would work in situations without any sun, and seems like it might be cheaper.
@Tobias:
it could mean an increase in food intake or hopefully just less fat people
@Dr. Funky
Right now heat is being produced on our roads as the tires run over it. If we used this technology instead, less heat would be produced and a little electricity. This could result from the exact same amount of fuel. There is no fundamental theoretical problem here.
There is no break of the laws of nature. Might be of economics, but that doesn't interest me as much.
It seems to me that everyone has missed the point. Roads already "squish", but that energy is wasted. On this road, you actually yield electricity from the squishing of the road. My gosh, what you're saying is like telling people that gas mileage can't be increased, because of the laws of thermodynamics. Here's a hint, the laws of thermodynamics only prevents efficiency from reaching 100%, but you can still increase efficiency on an inefficient design.
@ Tobias.
This is silly, "Sun->Plant->Human->Bike/Foot->Electricity". Human/automobile energy being calculated here is power that is being generated by the normal actives of people, capturing that energy is what's efficient. The real question is how much these piezoelectric panels costs, this is the same reason why solar energy is still an insignificant part of out energy supply, because the cost and energy that is going into it is more then what you get out in a reasonable amount of time.
Using your logic for petroleum:
""Sun->Plant->Animal->(millions-of-years-underground)->Drilled->Processed->Transported-to-market->combusted in engine"
Point being, its not about absolute efficiencies that are important its whats available and accessible; petroleum is probably the most inefficient, but its readily available and cheap. "Conservation of energy" is a high-school level concept that isn't relevant everywhere, people cars move around in this world; if that energy can be captured in a cost effective manner then its worth investigating.
First off, physicists: The laws of thermodynamics only apply to closed systems. There is no closed system known to man. A road most certainly isn't.
I'd be sceptical about these piezo elements - the inventors would need to show that the energy created does not require the cars to burn more fuel. There are arguments for and against above, many of them valid, but it seems like this would be something to be determined empirically rather easily. Just measure it. I can't imagine it wouldn't require more fuel to be burned but why not provide some cold, hard numbers. If it does require more fuel the question is how much, and the efficiency of generating energy this way could be determined from that. I am sceptical - it probably won't add up.
Dr. Funke: Cycling requires more food intake? You must not be living in America! Though I'd suggest that wiring up the fitness centers would be more efficient... put those treadmills and other machines to good use and make them generate electricity.
In regards to friction. The surface will likely be asphalt and there should be absolutely no increase in rolling resistance, the piezoelectric plates will likely be underneath the surface. The material is usually combined with the piezoelectric crystal, the expansion and contraction is done on a microscopic scale, there is negligible 'softness', and shouldn't effect the efficiency of the vehicle traveling over it.
The real questions is cost. The installation and maintenance of these plates would be expensive. The real question is how cheaply can make and deploy them. Many natural sources, like sugar crystals, have been shown to show piezoelectric effect, so there is hope for cheap piezoelectric materials. As with all technology you have to start somewhere.
Robert Abramson:
You are entirely correct, essentially this road is absorbing energy from the vehicles that traverse it; in turn, the vehicles will need to generate more energy to travel the same distance.
The offshoot of this is twofold:
A) The energy is harnessed from gasoline and diesel powered vehicles, therefore there will be more emissions.
B) More fuel used means that the energy gathered in this manner comes at the expense of those traversing these roads.
This seems like a poor way to make money off of roads and a terribly inefficient way to generate power. At best this can be seen as an alternative to tolls.
We need to see the cost of the piezo-electric road compared to the current cost of laying current road material. If the cost of the Piezo roads are higher, Big Oil is going to KILL THIS DEAD.
More along the like of if this product is too expensive compared to generating electricity the old fashioned way, common sense will kill it dead.
Having said this, I'm glad products like this are being researched. Even if this one costs too much to justify it, soon enough there will be cheaper ones.
Oh, and I just started designing this in my head, thinking about it. Wouldn't it be something like a slab of concrete over something like springs? And when the car moves over it, the weight pushes it down, and then when it moves off the springs push it up? And that movement would generate the electricity. I've not looked into it, but that is how I'd design it.
And if you get _just_ the right combination of cars of exactly the right weight and wheelbase moving at exactly the right speed and spaced apart by the precisely correct amount, your roadway ends up flipping cars over each other like leapfrog. Fun times!
Run buddy, Big Oil is going to get you, and he's BIG
Jinto, congratulations; you've just described the basics of piezoelectricity.
I can't help but notice the number of "experts" in the laws of thermodynamics in these comments. Honestly, people, these are researchers, not a single man wearing a tinfoil hat. I think they know a little more about physics than you do, so let them do their jobs, alright?
Actually big oil would LOVE this sort of thing. The energy is STILL being produced by fossil fuel .. the car would obviously have to burn up extra fuel as it contributes energy to the "crystal crushinG" .. which would result in slightly more fuel being burned per car than if it were a solid road. This is actually a very inefficient way of generating electricity, so actually more fossil fuel will be burnt because of this. Government likes it because they dont have to tell anyone they're raising taxes (though actually the effect is the same). Big Oil would love it because the energy is being produced from oil .. inefficiently at that!
@ Johna S,
Thank you! I made a similar comment about how ridiculous this process is on the Tokyo subway thing.
PEOPLE! Energy doesn't come from nowhere! It cannot be created, and it cannot be destroyed; only transferred (and nearly always without 100% efficiency).
Cars use gas to move. Running over these crystals will only make it harder for the car to move, which will make it use more gas. Plus, a good portion of the extra gas that is used is immediately converted to heat-energy (coming off the engine), thus being wasted, as is a lot of the friction energy that the crystals absorb.
If you want to store and use otherwise wasted energy, you basically need to trap heat. Most of our wasted energy is in the form of heat. Whether it's the rays from the sun that we aren't catching, or the refrigerator blowing hot air into your air-conditioned house in the middle of the summer. Or even the wind power that we aren't using. What makes wind? HEAT! (or more specifically, the MOVEMENT of heat).
@dg
"Energy doesn't come from nowhere! It cannot be created, and it cannot be destroyed; only transferred (and nearly always without 100% efficiency)."
Err... you've just contradicted yourself! If energy cannot be destroyed, and it's rarely transferred 100%, then it has to go somewhere. It *is* transferred perfectly, always - look up the law of conservation of energy - it's just not always transferred where you want it, which makes something inefficient.
Read what Zach said. This is using wasted energy. Not turning roads into balloons.
Next one of you guys will make a lolpiezo that says "Im in ur roadz, reducin ur cars eficiency"
Just put these on the downhill slopes when the cars would be braking anyway. Helps braking and generates power. Fixed it for you.
Just like public transportation!
Better yet, let's have a generator dyno on every highway, and before you can get on, you have to sit on a dyno for 5 minutes on full throttle.
seriously. If counties or countries or whoever builds these insists on getting energy from the cars that travel over their roads, id rather pay a toll equivalent to what id lose in gas mileage driving over a "magic road;" it could then go to purchase energy much more efficiently than 30% ice * whatever losses from generation and transmission. Bonehead politicians do shit like this just so they can get most of the voting populous to think they're being green. like they give a shit.
Or install this in the beds of Nympho couples... Should generate a good 1.21 Giggawatts every night!
You mean...
Giggidy-giggidy-giggidy watts?
Ummm... this sounds like the most inefficient way of generating electricity ever proposed.
I LOVE your line there HITSTHINGS.... hilarious....
This will cost tax payers dearly; then they charge excessive tolls for "maintenance." Sounds like a scam.
Ever been on the IL toll roads? They needed a way to pay for its construction. The booths were supposed to be temporary...
Free energy for everyone!
It's likely that this won't show up as lost fuel economy for the individual. They will just show the total that it has produced and everyone will be amazed. Average Joe is going to see it as free energy even if it would waste more energy in form of fuel burned by the wasteful car engines.
...getting RUN over... Grammar is your friend!
The key technology questions are, how hard are they to dig up, can it be done on a dark night, and what's the resale value?
Pick axe, yes if you don't mind risking a toe, and with very little market, negligible.
What do the squiggly lines in the road stand for (in the picture)?
Indicates the area of a pedestrian crossing.
You mean it isn't just me this time?
of course energy can't be had for free, or come from no where.
This would be stealing slight amounts of energy from the cars driving over it.
Essentially this would be petroleum powered electricity.
The roads already steal slight amounts of energy from the car when the pavement flexes. This is more akin to regenerative braking, in that it's harnessing wasted energy.
Regenerative braking is teriffic because you are conserving the energy that would be wasted while the car is slowing down anyway. It's not desirable to add any more drag to cars that are cruising down the road.
Now adding this to off-ramps and places where cars are always decelerating anyway, that is where this technology should be used if anywhere.
Sounds like creating a "perpetual motion machine" to me (since the cars generate the same energy they'll use) -and since we all know that wouldn't work, at least that'd make the whole transportation process much more energy efficient. Why not inventing solar floors? or solar paints for that matter?, that way it'd be much easier to have just about anything generating electrical power =).
Careful there. Using sunlight to generate electricity means that sunlight will generate less heat. Of course, all the electricity will eventually be converted back to heat, but depending on the nature of the work it's used to do, the release of that energy could be delayed for years. Converting too much sunlight in an area into electricity could lower the average temperature enough to have a significant effect on that area's weather patterns, especially if the electricity is consumed outside of the area.
Why is this becoming the new rage I have seen three or four stories on piezo's lately not a new technology and not a good source of energy. They have been used forever to determine pressure differences in scales and such because depending on the pressure changes the small and I mean Tiny amount of voltage that they produce these are not useful for generating electricity anymore than hooking up a generator to every hamster wheel sold from now on. (Wait can I claim that idea it might just sell these days)
1 piezo = little voltage
Lots of piezo = big(ger) voltage
Piezotastic
Would it be petroleum powered, or gravity powered? Gravity is what would be acting on the car to compress the road/p-electric crystals, right?
Use it to power street lights and such.
Well you can't power anything from gravity, you have to raise something away from the source of gravity then let it fall to get energy, it is impossible to get back more energy from harnessing the energy from the fall than the amount you put into raising it. If the car was not moving the road would not generate any energy.
Now the reason I don't say this idea is completely stupid is that I know that just about all road surfaces compress when cars travel over it. If the compression of this road surface is IDENTICAL or less than that of what would normally be used then I think it is a great idea because cars would use no more energy than normal to travel the road, and the energy that would normally go into generating heat and sound/seismic waves would be converted into electricity.
And if they do compress more but generate lots of electricity while it may not be very efficient sale of the electricity could help pay for the road, IE driving on the road and using more fuel/energy to do it you are sort of paying a toll, then no one has to run toll booths.
Also if it has more compression than a normal road then it could be quieter.
-Edward from http://blog.freesoftwareforkaren.com
Well, sure you can power things with gravity :
http://en.wikipedia.org/wiki/Water_wheel
But you are right, without the forward motion, then it's rather pointless.
I guess I was just thinking- the forward motion of the car isn't in the same direction as the compression.
CTMike: That's not energy coming from Gravity. It was the potential energy the water "had" in having been raised upward against Gravity. Gravity is just a force, not a source of energy.
Finally! An excuse for speeding!
"Honestly, officer! I was just trying to do my part to generate more electricity!"
I wonder how much power they could generate by sticking these in the home of the average morbidly obese person?
Very little considering the morbidly obese are fat lazy fuckers who would rather shit themselves than go to the nearest toilet.
Being morbidly obese is pretty average here.
O.
A cheaper, more efficient, more environmentally friendly, more honest option:
Just tax the people who drive on the roads. They save on petrol, and you buy electricity from more efficient, even renewable sources.
In America, that already happens through vehicle Taxes, yearly tag registration, and fuel taxes.
The amounts are used for transportation administration use for road funding.
Dan, we incur pretty small fees to drive on highways (or just to drive in general) compared with the rest of the world.
How comes that nobody ever thought of harnessing the precious energy and the valuable combustible natural gases that get wasted everyday by over 6 billion people farting loose in the atmosphere (which moreover contributes to greenhouse effect) ???
Just a little accumulator stored in your panties could charge your cell phone/pda at the end of a day, and all the little accumulators of the nation could power a medium sized city for a month.
Let's be frank here, you are an idiot.
@ Samboini: idiots is what Einstein, Touring, Kantor and Tezla where called by pathetic moron that like you lacked the mental openeness and the intelligence to realize that thing could be different if approached in a different way.
Let's be frank Samboini: You're a pathetic & useless turd.
Well when you prove me wrong I will rescind my comment, until then stop coming out with comments so idiotic even iEye would cringe. There is a difference between open, alternative thinking and sheer idiocy.
I also LOL at you (albeit tentatively) comparing yourself to Einstein et al. If it is any consolation this 'pathetic moron' has just helped save his client ~£1m/month in money via taking an alternative approach to their fee structure.
"Touring, Kantor and Tezla", "alternative approach to their fee structure". Face it, you, and all the other engadget commenters are all nerds.
End nerd on nerd violence!
My, what a big epeen you have, Samboini.
Um. People have known about piezoelectrics for ages. It's how we came to develop electronics of all kinds. These ideas of integrating with streets and places of high density for people to walk over and generate electricity were conceived long before these articles. And by long before, I mean at least 40 years ago. You can't just implement piezoelectrics into any material. The compression forces that apply a stress to the crystral lattice structure change the charge distribution which needs to be connect to some sort of circuit. That's why a tire isn't going to work.
Think about the possibilities! If you can get these efficient enough, and combine this with MIT's wireless electricity charger, you can have cars powered by their own weight!
Yeah, that sounds like just about the most efficient energy transfer ever...
The technology isn't the question IMO, the question is can I electrocute the racoons and squirrels before or after I run over them on this road, and will the piezoroads clean up the roadkill, or simply cook it for 3 hours at 300 degrees untill theres no pink in the middle?
With nanomachines, the road will "carry" it directly to your door when it's done and all the parasites are dead. Kinda like the way those waves in Marble Madness pushed you along, and off the cliff...repeatedly.
I understand people saying it's stealing petroleum powered energy; however this would be a completely different road surface. Let's say the road is able to have the same amount of "squish" of you will, as a standard road. Using that same level of squish that is normally there, we could harness some of the energy that the road was "stealing" anyways. I'd rather have wasted energy go to the grid than go to deteriorating the asphalt.
And as electric cars become more prominent, it's really energy reclamation anyways. This is a good step to be taking in research; why are there so many naysayers?
Is'nt this harnessing energy that would be wasted anyway? It doesn't necessarily have to 'take' an extra energy from the passing cars, just utilise the energy that is normally wasted as vibration and friction. Solar power does'nt cause the sun to burn more fuel, it simply recovers some lost energy as useful power. Think of it as increasing the overall % efficiency of motoring, rather than robbing the motorist, or conversely, 'free energy'.
This is pretty easy to prove or disprove and that has probably already happened. It just that most articles on the subject assume that readers would be bored by those details. If an ordinary road compresses, there will be waste heat that can be measured. If a piezio-road can recover some of that energy then it is not stealing it from the cars.
Robert Abramson is totally correct. TANSTAAFL. Interesting idea for pedestrians, but doing it for roadways is just silly. The energy generated will actually be caused by the increased fuel consumption of the vehicles - meaning its just a way to generate power less efficiently. Cynically, the only reason that I can imagine the government/councils would be keen on it would be so they could then sell the power to line their budgets and it would in effect be yet another fuel tax on the road users - and one that would actually be worse for the environment compared to more efficient generation systems.
I wonder where people like you come from. You have absolutely no proof for your claim and yet you state it as fact.
It would be nice to see details on how this will produce a net gain in energy. It may produce a net gain in useful energy if, for example, the cars' pressure would ordinarily produce a tiny bit of heat that will now be captured as electricity instead.
But this obvious question remains unanswered by the article, so what we have is another journalistic failure.
Ain't no such thing as a free lunch when it comes to Physics.
Conservation of energy means that the car will continuously require more throttle as it will encounter more resistance from the road surface.
Nice try, but you'd be better off building a power station that ran on PETROL.
Wow, I heard about this technology like 2 years ago. Where you could simply walk on it and it would generate electricity. The idea was to replace mall floors and sidewalks (of say time square) with it so that the area could be self sufficient in energy. I agree with the flaws you guys mentioned about using cars to generate the energy
Nobody mentions other problems with piezoelectric crystals. I'm curious to know if they figured out how to prevent them from wearing out. From what I know about crystals used in gas lighters, they stop making electrical spark pretty soon, and don't work at all when system get's moisture in it.
400 Kilowatts of energy per? Hour? Week? Year? Come, now, get it together, boys!
One watt is one joule of energy per second. There is your time unit.
This thread is as bad as those plane-on-a-treadmill threads.
Here's a comment from TFA that explains why this works and doesn't "steal" energy from drivers:
"Piezoelectric crystals generate electricity from vibrations, not compression. This will have no effect on the gas mileage of cars as it will be using the waste energy that already exists as vibrations in the road from tires rolling across it. Normally this energy is wasted as it is absorbed and dissipated into the asphalt. The same amount of enery will be going into the road but now instead of just being wasted and absorbed by the asphalt it will vibrate the piezo crystals and generate electricity. Just as placing a PV panel on the roof of your house will take the normally wasted energy from the sun and trun it into usefull energy."
Well said. Here, have a cookie.
...Why not just put the piezos in the tires!?! That way you're always using them, and you dont have to carpet an entire road, where most of them wont be touched anyway...
Seems like a nice way to reduce your environmental guilt level when driving a gas guzzling vehicle.
apparently, no one read that 400kw of power is generated per kilometer of roadway. Assuming 16 hrs equivalent peak traffic per day @ $.10 per kilowatt-hour, this 1-Km section will generate $640 per day per kilometer, or $233,600 per year. I've read somewhere that a mile of road costs $1 million to build, so 1 kilometer would cost $625,000. So, this device would pay for itself in 3 years, with pure profit afterwards. And those who wrote that this increases friction/energy use for the cars are idiots, it's using WASTED energy.
amen scorpion. I've been reading through these comments and i'm disgusted with how many people think it's "stealing energy". Piezoelectrics require very little "flex," so little that it can be a vibration. This small vibration produces a small voltage spike. It's using wasted energy that would otherwise be absorbed by the asphalt.
Guys
Think bigger.. The cars are already running over the road and friction is variable because of the surface which changes anyway... what if the energy transferred in the road was used to power Led street lights then the saving is in the cable sunder ground, maintenance of them or even power local housing in some way.
The Power supplier chain starts at the Car production plant when the first nut and bolt are creating by power of heating metal.... the power supply chain grows as each component is completed, built together fuelled to run along the street and starts to lose the energy into the road through the power train and the friction (and lots of other areas) this idea is about capturing that lost power in to the road and making use of it.
IT IS NOT ABOUT perpetual energy, just a good idea about redirecting energy.
Steve
Piezo electric,
Free energy of the future? More than you will ever know.
It will replace ALL current forms of power production. Just wait and see!
There is something BIG in the works regarding Piezo electrics. When I say BIG, I really mean HUGE!!!!