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Power Technology

Ramp Creates Power As Cars Pass 426

Ant wrote to mention a BBC News report on a ramp that generates power via passing cars. From the article: "Dorset inventor Peter Hughes' Electro-Kinetic Road Ramp creates around 10kW of power each time a car drives over its metal plates. More than 200 local authorities had expressed an interest in ordering the £25,000 ramps to power their traffic lights and road signs, Mr Hughes said."
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Ramp Creates Power As Cars Pass

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  • Great idea! (Score:5, Insightful)

    by confusion ( 14388 ) on Saturday December 17, 2005 @10:53PM (#14282527) Homepage
    Takes generating electricity to a new level of inefficiency...

    I suppose it might work on a ramp going down, but level or up, and the "free" energy is coming from the gas tanks of the drivers.

    Jerry []
    • Re:Great idea! (Score:5, Insightful)

      by Anonymous Coward on Saturday December 17, 2005 @10:57PM (#14282550)
      If used on straight road, silly. But if on an off ramp where the car has to slow down anyway, then it is a form of regnerative braking for the car.

      But it won't be good for the efficiency of hybrid cars.
    • Re:Great idea! (Score:5, Interesting)

      by MemoryAid ( 675811 ) on Saturday December 17, 2005 @11:01PM (#14282578)
      It looks like a speed bump, so presumably it is to be placed somewhere cars are encouraged to slow down. It would make sense to convert some of that energy into electricity instead of heat.

      The article said that "Depending on the weight of the vehicle passing overhead, between five and 50kW can be generated." I wonder if that is only while the car is passing, or an average figure for some reasonable level of traffic. I imagine the duty cycle of a speed bump is low.

      • Re:Great idea! (Score:3, Insightful)

        by Rangsk ( 681047 )
        You're most likely correct in that it's an aggregate under ideal traffic conditions. It would probably act similarly to generators powered by wind, or to a bike, where a turbine continues to spin after you've stopped pedalling.

        So, a car rolls over the ramp, causing the turbine to start spinning, and then it slowly winds down, generating power as it slows. When the next car rolls over it, it spins up some more. The faster it is spinning, the more power is generated.

        The power could easily fluctuate between
    • Creator's Website (Score:2, Informative)

      by nursegirl ( 914509 )
      Here's the inventor's website: []

      There's some videos on the site, but the "Technical" section is laughably vague.
    • It looks to me that they are planning on using the ramps in place of speed humps. In that case the car would have been slowing down and speeding back up anyway so it isn't going to cost anything extra for the driver.

      Naturally this is leaving aside the question of whether speed humps are worthwhile or not.
    • What about a buncha coils of wire in the roads and some magnets on the wheels/body of cars.. As cars roll by, they generate a small amount of electricity.. While it's tiny, I would think in very high traffic areas, NY,LA, etc.. It might be worthwhile..
      • Re:What about.. (Score:3, Insightful)

        by dougmc ( 70836 )

        It might be worthwhile..

        No, not really. First, you're right -- the amount of power generated would be tiny, unless the magnets and such were huge. Second, people won't want the magnets on their car -- and why would they? They're dead weight, don't help the car at all, and will probably pick up (magnetic) trash and stuff from the ground.

        That, and every bit of power generated by anything like this will be power removed from your car, so ultimately you'll pay for it at the gas pump.

        Ultimately, th

    • The really frightening part is that the vast majority of the public will not grasp this concept in the slightest. They'll think of it as free energy and applaud it as it is implemented.

      I wonder, why go to such extreme measures when the same money could be invested in A) a solar panel, and B) LED stoplights; a solution that would actually harness new energy from the sun rather than another system that would waste energy infused into fossil fuels by the sun over the course of many, many years.
      • by billstewart ( 78916 ) on Sunday December 18, 2005 @01:36AM (#14283167) Journal
        There are parts of the British Isles where solar panels might work. There are other parts, especially in Scotland, where using solar panels would require seeing the sun, and therefore are obviously out of the questions. The typical local description of the weather runs to "If you can see across the bay, it'll rain within 24 hours; if you can't see across the bay, it's already raining."
        Sure, some parts of the year it's sunny and beautiful, but you need the streetlights to work all year around, *especially* when it's foggy, raining, and dark. So you might need some pretty big panels.

        On the other hand, these ramps probably cost a big enough pile of money that it's still cheaper to use mains power than "free" power siphoned off passing cars.

  • Ramp up (Score:2, Funny)

    by dotslashdot ( 694478 )
    Ramp up production, but make sure you have an exit strategy.
  • Obviously the energy for the ramp is coming from the forward motion of the car pushing up the ramp, slowing the car, causing it to use more fuel.

    So, basically, they are making people pay in gas incrementally for passing over that section of the road. A toll ramp of sorts...

    I don;t know if I'm cool with that, although the idea is very cool.
    • Well seeing as the electricity goes to power things like traffic lights and such, things that the drivers use while on the road, I guess this is more of a pay-to-use type tax.

      I guess the tax paying bloke down the street who rides a bike to work will be glad he no longer has to pay for it.

      • I guess the tax paying bloke down the street who rides a bike to work will be glad he no longer has to pay for it.

        I'm sure he'll be thrilled that the exact same amount he will pay in taxes will now be used to buy a slightly better stapler, despite the cheap one being good enough, for a government pencil pusher. Either that, or go towards the salary of the guys that maintain the road's new moving parts.
    • On the other hand, if it's installed before traffic lights or on highway off-ramps, cars will be slowing down anyway. If the energy would otherwise go into the brakes, it's not going to increase gas consumption. The only people who would have a reason to complain would be hybrid drivers with regenerative braking.
    • by interiot ( 50685 ) on Saturday December 17, 2005 @11:30PM (#14282703) Homepage []

      Basically, put these things in places people would always slow down anyway (eg. off-ramps), and it's a win-win. Free energy production for the city, and reduced wear on brake pads for the citizens.

      • It's not a win-win for people driving cares that already have regenerative braking.
  • How much power? (Score:4, Interesting)

    by rob_squared ( 821479 ) <rob@rob-square d . com> on Saturday December 17, 2005 @10:57PM (#14282546)
    Does a tractor trailer give it? Or would that break it?
  • by tkdog ( 889567 ) on Saturday December 17, 2005 @10:57PM (#14282549) Journal
    That's not even the bad part. Those damn government bastards have installed "friction" all over the place and it is WARMING THE PLANET. It's a plot I tell you, a plot.
  • by johndierks ( 784521 ) on Saturday December 17, 2005 @10:57PM (#14282554)
    I wonder how long it takes to pay off a 25,000 pound piece of equipment plus installation and maintenance with savings in electricity for street and traffic lights? I'm guessing a really long time.
    Is it even worth it?
    • by An Onerous Coward ( 222037 ) on Saturday December 17, 2005 @11:12PM (#14282621) Homepage
      Even worse, most modern traffic lights use energy efficient LEDs, and therefore don't use nearly as much electricity as they used to.

      I don't know how many light installations one of these is supposed to power, but the only easy way to power more than one would be to hook it directly into the grid. So basically they're taking the amount of energy being produced by these things and subtracting it off the city-wide electricity bill.

      If Salt Lake ever starts looking at these, I'll be looking over the city charter, trying to figure out where it requires the city to generate electricity at all, much less in the most inefficient and annoying way possible.

      Maybe if you only installed them on downhill slopes....
      • 10kW per car is pretty good. Most households us 2-3kW on average.
        • That would be a peak flow, when the car is actually crossing it. Unless cars are crossing it every instant (which is impossible) the average wattage would be much lower.
      • I'm not sure they'd even keep up with the maintenance costs.

        Or the energy conversion costs since you're burining fuel to power them instead of whatever the grid sources from.

        Or.. wait a minute, "10kW" that's not even sensical is it? I'm not an electrical engineer but that seems fishy as well.

        The new monorail?
    • by Anonymous Coward
      Based on my local cost of electricity ($0.06/KwHr), and assuming a ramp generates 10Kw continuously, each ramp generates $0.60 worth of electricity per hour. Neglecting installation costs and maintenance and using Friday's currency exchange rate, each ramp would have to operate 8.4 years to recoup the initial $44300 cost. Looks to me like they are far from being cost effective.
    • by blibbler ( 15793 ) on Sunday December 18, 2005 @12:10AM (#14282869)
      If it was designed well, the maintenance should be negligible. There might also be a benefit in that the lights would stay on in a power outage.
      As far as electricity usage goes, I would guess that each bulb might be 200 Watts. Depending on the design of an intersection, there would probably be between 8 and 16 of these lights on constantly. According to [] the cost per month would be about £130/month, or a bit more than £1500/year. Assuming there is no interest (or increase in the price of electricity) it would take almost 16 years before these savings make up for the cost of the equipment. Many governments make investments on this time-scale anyway. Additionally, if it could be used to power more than one traffic light, it might only take 7 or 8 years to pay for itself.
  • by quakemeister ( 190139 ) on Saturday December 17, 2005 @10:57PM (#14282555)
    when there is a red light ahead. so instead of wasting peoples gas, these things would save consumers brake pads?

    so you could have a field of them that pop up some distance before each light to absorb all the wasted energy that goes into brake heat.
  • Although the cost would be astronomical, it would be nice to implement this on highways/roads to keep them heated during the colder seasons (ie, Northern Ontario). Snow only stays on the ground because the ground temperature is below freezing. So, keeping the roads at 1 Degree Celsius would keep snow and ice off the roads.

    Also, because the ice couldn't melt then freeze and expand, this would be an excellent cost savings measure over the long term: no more cracking or pot holes (which are mainly caused by
    • You'd need the warmers, because you'd have to do something to keep these things from getting snow/ice on them ... speedbumps and snowplows don't mix.

      A little freezing rain, and these things might become rather expensive speed bumps, with the sole use of catching passing snowplows and causing accidents as cars lose traction coming over them.
  • by synaptik ( 125 ) on Saturday December 17, 2005 @11:00PM (#14282565) Homepage
    ...or perhaps I should say, taxing gasoline *more*. After all, the power is coming from somewhere... you know, conservation of energy, and all that jive?

    So, instead of tearing up the road, installing this infrastructure, and then paying to maintain it, why not just add 1 cent more of taxes to a gallon of gas, and earmark that money for the purpose of paying the electric bill? Seems a lot simpler. Besides, the taxes levied really ought to accurately reflect the full cost of utilizing the municipality's infrastructure... if this cost is something the bean-counters have overlooked in the past, just add it to the tax bill.
    • Valid point there about the conservation of energy, but this is not quite the equivalent of taxing gas. For example, you could install these devices on a downhill section of road, where motorists should be looking a deccelerating, so in addition to slowing them down you would get some power in the process. Another suitable location is before intersections on cross-streets. Many cross-streets here that come on to a major road have their light red until a car arrives, and then it turns green after some time.
    • "...why not just add 1 cent more of taxes to a gallon of gas, and earmark that money for the purpose of paying the electric bill?"

      Why should the people who never use these ramps pay for it? Why should those with more efficient cars pay less than those who don't have the money to buy a hybrid? Why not make high traffic areas a little more self sufficient?

      Before you hit reply: I'm not answering these questions to shut you up or anything like that. I bring them up because those are exactly the sort of ques
    • Because. They're politicians. As such, they LOVE to launder money through inefficient programs to make them selves look good.

      I agree with you on how it should be done. But the answer to your question is found in human psychology and not in its engineering application.
  • creates around 10kW of power

    Um, OK, for how long? Because the more relevant quantity that we'd actually care about is energy.

    Not to be pedantic, but for something like this it actually matters (as opposed to the typical /. grammar-nazi asshattery).

    • Well...because the watt itself is already a unit of energy and time (joules dissapated each second), it doesnt really matter what timeframe it takes for the car to generate the power as it would simply work out to be less joules over more time or more joules over less time and end up with an average of 10kW per car.
      • If the wattage were sustained, then yeah, the timeframe doesn't matter. But the term "10kW per car" implies that the wattage isn't sustained.
      • it doesnt really matter what timeframe it takes for the car to generate the power as it would simply work out to be less joules over more time or more joules over less time and end up with an average of 10kW per car. You have this completely back to front. What is important is how much energy (joules) are transferred to the device by each car.

        The time during which this happens is not so important.

        I assume that the 10kW is only for a short time (it's far to high to be a sustainted average over a long tim

  • Well, the users of the road pay for the electricity.

    If it is placed low enough on the ramp it will be more "free" energy because the cars would need to be slowing anyway, so a small hit there would not be noticed at all by a driver. If anything, if it was at the bottom of the ramp, it would help save the driver some brakepad.
  • Instead of using a mechanical device, why not use the passing car to induce a current in an underground coil and generate electricity.

    These could be placed in high vehicle traffic areas (not just near traffic lights). No moving parts means little maintenance.

    • Because most cars are not magnets.
  • by craXORjack ( 726120 ) on Saturday December 17, 2005 @11:09PM (#14282610)
    You'll have to drive your car on a giant hamster wheel attached to a generator for two minutes.
  • OK - 5-50KW for 1/10 second isn't much - but it would light a ton of LED signs for a looonnnng time.

    These guys really need to give their collective heads a shake - ~&25,000 will purchase a hell of a lot of LED lights, a battery/capacitor bank and Solar Array (OK - Britain doesn't get as much sun as some places - but its possible, OK?)

    Put this one up there with the ones who think there is a perpetual motion machine.
  • Energy doesn't just get created. If ur taking(stealing) energy from my car, I'd want to be compensated.
    What, next they'll discover powering traffic lights by tapping into the neighboring house's electrical outlet?
  • by Anonymous Coward on Saturday December 17, 2005 @11:28PM (#14282692)
    Here's a diagram [] of how it works. Be sure to wipe your mind after you're done looking at it though, it's labeled "STRICTLY CONFIDENTIAL".

    Home Page: [] with other photographs and some short & long video clips.
  • Perceived obstacle? (Score:3, Interesting)

    by Dan East ( 318230 ) on Saturday December 17, 2005 @11:35PM (#14282726) Journal
    From the pictures, that ramp appears to stick up at least 3 inches above the road surface. I don't know about you, but if I saw anything remotely that large sticking up, I'd be hitting the breaks or changing lanes to avoid it. That could be a real danger unless 100% of the drivers were already familiar with it. I would be very surprised if they tried to use it on roads with speed limits greater than 35 MPH or so.

    Dan East
  • I think the people who've assumed the purpose of this device is to "save" electricity are missing the actual use of this device. The article never mentions it, but I have to believe the use of this invention is to power traffic lights or anything else that uses electric power in remote areas where electric power hasn't been strung. It would of course be rather pointless to try to offset the tiny amounts of power that a traffic light uses with this (relatively) expensive machine. On the other hand if the
  • by Temporal ( 96070 ) on Saturday December 17, 2005 @11:47PM (#14282768) Journal
    They say it generates, on average, 10kW of power each time a car crosses. OK, great, but a watt is a measure of energy over time. So, for how long does it generate 10kW of power? Is it 10kW for a half second? 10 seconds? An hour? A millisecond?

    If I have a 100W light bulb, how long can I power it off of the energy generated by one car crossing this ramp? With the information given, I have no way to calculate this. The "10kW" number is completely meaningless.

    Energy is measured in joules, dammit. A watt is one joule per second.
  • by zerosignal ( 222614 ) on Saturday December 17, 2005 @11:49PM (#14282777) Homepage Journal
    So, this ramp generates 10kW when 'active'. Let's say you have a continual stream of cars so that it is active 50% of the time (since there must be gaps between the cars). This mean it's generates 5kWh of energy per hour.

    Assume that the standard cost for elecricity is US$0.10 per kWh. So this thing can generate US$0.50 of electricity per hour. Over the course of a year it will generate about USD4000 worth. So after about ten years it /might/ just pay for itself.

    And that's not even considering maintaining the thing. Road wear out, and they're just simple concrete. This is a mechanical device, which will have /millions/ of cars passing over it.

    The whole things stinks of INVESTOR SCAM.
    • My first gut, wet finger in the wind estimate as a thinking human with a technical eduaction is that this thing is total snake oil.

      Two issues with your approach:

      1. You're forgetting the numbers are from a crazy optimist inventor who believes his own propoganda, is given to quoting unscientific data, and is trying like hell to sell his crap :-)

      2. I suspect your 50% duty cycle is way, way overestimated. My gut is that the 10kW is a theoretical peak for the fraction of a second an axle is actually passing over
  • power != energy (Score:3, Informative)

    by Per Bothner ( 19354 ) <> on Saturday December 17, 2005 @11:54PM (#14282798) Homepage
    This article (like all-too-many others) confuses energy and power (i.e. energy per unit of time). It's nonsense to talk about generating "10kW of power" "each time" something happens.
  • This is not a new idea, I've seen this exact idea in (IIRC) Popular Science maybe 30 years ago. The blurb talked about the same issues covered by many /.'ers such as taking energy from the passing cars.

    I always thought, again like many here, that the mechanism seemed too complex for it's job and couldn't pay for itself.

    If you want to invent something interesting devise a way to take energy from cars going over a certain speed. That is, if the speed limit is 55 MPH and you go 65 have the system extract ene
  • The next great Hype (Score:2, Interesting)

    by Robbyboy ( 802040 )
    Let me chime in from the other side of the Nay-Sayers for Electro-Kinetic Road Ramps. How rugged are these things? What kind of road debris will it take for these to jam up? What will it take for someone to try to stop their cars, and lock the wheels on the ramp. What if the ramp ices over? With our litigous society, how long of a wait will it be before the inevitable occurs...
  • My electrically-assisted car depends on the energy of braking to return energy to acceleration.

    If the local government is STEALING power from me, then I will have to burn more gasoline.
  • by RoffleTheWaffle ( 916980 ) on Sunday December 18, 2005 @12:00AM (#14282820) Journal
    ... And for what?

    Okay, okay. I get the idea, this is essentially a means by which electricty can be derived from the same energy that drives your vehicle. However... isn't this energy that would just be wasted, anyway? This thing doesn't exactly slow down your car. It's not like it's sucking power right out of your engine. This is kinetic energy combined with the force of gravity and the weight of your car, energies that would just be wasted and poured into the ground otherwise. Ten kilowatts, depending on your perspective, may or may not in fact be 'drops in the barrel' energy wise, but it's more than enough to power devices like stop lights and road signs, granted it's stored efficiently and the devices attached to it are similarly efficient.

    On a well traveled road, energy that is essentially being wasted can be recaptured and used to power lights and signs for several intersections without placing any load on the local power grid. Sure, these things are pricey, but as their price decreases with time and their efficiency and output both climb, doesn't it make sense that these things just might pay for themselves? That reduces the cost of maintaining roads in the long run by cutting out virtually all energy expenses in areas that are frequently traveled - and if the system becomes efficient enough, it could cut out the energy costs for an entire community's roadways and intersections.

    This isn't 'another gas tax'. This is one less reason to have gas taxes. On a highway like ol' I-69 here in Indy, a couple handfuls of these ramps could power every lighted roadside sign and traffic signal within the city of Indianapolis, with energy to spare. Higher traffic translates directly into greater energy gains. If these things are durable enough to take the punishment, they'd pay for themselves within a matter of weeks. Now let's think about even more heavily traveled roadways, like those in New York City or LA. 10 kilowatts per panel times a few thousand automobiles a day, that's megawatts and megawatts of power being generated every day. The excess could be put into the city electrical grid, however small an amount it may be by then, and used to power other things. Street lights, low-demand municipal facilities, etc... All of this from WASTE. This is an excellent idea, and I hope to see technology like this move forward.

    And before anyone replies to this, no, this is not 'just another way for the government to control our cars'. I won't be concerned about that until they start installing spike strips in these things. (And with or without ramps, that could be done at every intersection anyway....) This is hardly ripping off the taxpayer, either, if a comparatively small expense saves a ton more money. Sure, right now that expense isn't small, but it'll get smaller if enough communities buy into this stuff - perhaps even going from a few thousand dollars to just a few hundred. Money in the bank, and back in our pockets, folks... No problems here.
  • Sounds like a bizarre gasoline tax where the government spends a pound to collect a penny.

    Flush the idea down in the nearest penny house []

  • Simpsons (Score:2, Funny)

    by John Frink ( 919768 )
    In this house we obey the laws of THERMODYNAMICS!!!
  • by birge ( 866103 ) on Sunday December 18, 2005 @12:17AM (#14282897) Homepage
    You need power for the lights, which need electricity, which costs money, so: you take electricity it from cars, which have kinetic energy, which they get from chemical energy (with losses) which their drivers get from money. If only there were a way for the government to get money directly from it's citizens...
  • by Animats ( 122034 ) on Sunday December 18, 2005 @02:37AM (#14283360) Homepage
    This is a very poor design. Take a look at the mechanism []. When a vehicle drives over it, the full impact lands on the hinges and the drive mechanism for the generator. This thing has to resist huge impacts, especially when a heavy truck comes along. It also has electrical components and moving parts below road level, where they'll flood and corrode.

    How does he get 10KW out of this? That looks like an automotive alternator in the picture. Automotive alternators range from 300W to about 1.5KW, and that looks like one of the smaller ones.

    A more reasonable mechanism would be to make a heavy duty rubber mat, like the ones used on railroad crossings, but with internal chambers, like a tire. When a vehicle drives over it, you'd get some compressed air. Put in a check valve, an air tank, and a small air motor driving a generator, and you'd have a rugged little power source. A hydraulic version of the system might produce more power output than a pneumatic one. The bump felt by the vehicle should be easier than that at a railroad crossing. And no big, expensive machined parts that get beaten up by traffic.

    Realistically, get a solar panel, like CALTRANS uses to power much of their roadside infrastructure.

Thus spake the master programmer: "Time for you to leave." -- Geoffrey James, "The Tao of Programming"