Slashdot Mirror

← Back to Stories (view on slashdot.org)

Ramp Creates Power As Cars Pass

Posted by Zonk on from the rolling-rolling-rolling dept.

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."

14 of 426 comments (clear)

  1. Great idea! by confusion · · Score: 5, Insightful

    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
    http://www.cyvin.org/

    1. Re:Great idea! by Anonymous Coward · · Score: 5, Insightful

      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.

    2. Re:Great idea! by confusion · · Score: 4, Insightful

      It has nothing to do with the drivetrain, that's true, but it has everything to do with sapping the inertia from a moving car. I don't but for a second that it "harnesses the vehicle pressing down on the road". The plate is an elevated ramp, which my car pushes down on as it goes over. My car will take more enery to go over a road of those things than a normal, flat road.

      And yes, I did RTFA
      Jerry
      http://www.cyvin.org/

    3. Re:Great idea! by DrXym · · Score: 4, Insightful

      The thing is, that councils in Britain put in speed bumps / ramps all over urban areas to slow (calm) traffic and to stop joyriders. If they're putting in the ramps anyway, why not make a bit of power from it at the same time?

    4. Re:Great idea! by Rangsk · · Score: 3, Insightful

      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 0kW and 50kW depending on traffic, but unfortunately I don't think the weight of the car has anything to do with it, so a 2 door coupe would generate as much power as an 18-wheeler (well, I guess an 18 wheeler would roll over it more times and so would generate more power that way).

      The only soluton to this I can think of is if they created some kind of weight sensor (before the vehicle rolls over the bump) and had a quick gear system, they could get more energy from heavier vehicles. With an efficient system, they might get a good percentage of the potential energy stored in the vehicle. However, I doubt such a system is plausible. It's most likely a constant amount of energy no matter the weight of the vehicle, and the rest is simply lost.

      --
      "Don't believe anything you read on the net. Except this. Well, including this, I suppose." --Douglas Adams
  2. Cost vs. benefit... by johndierks · · Score: 5, Insightful

    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?

    1. Re:Cost vs. benefit... by An+Onerous+Coward · · Score: 3, Insightful

      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....

      --

      You want the truthiness? You can't handle the truthiness!

  3. how about if they only pop up by quakemeister · · Score: 5, Insightful

    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.

    1. Re:how about if they only pop up by Temporal · · Score: 4, Insightful

      But those of us with hybrid cars are already reclaiming that energy...

  4. This is equivalent to taxing gasoline... by synaptik · · Score: 4, Insightful

    ...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.

    --
    HSJ$$*&#^!#+++ATH0
    NO CARRIER
  5. Are you sure it's just wasted energy? by Eric+Damron · · Score: 4, Insightful

    What do you base your belief that this is "wasted energy" being used?

    It's only wasted if the driver would have applied his brakes turning the forward motion of his automobile into heat. This would make sense on off ramps or downhill slopes. On a flat road, however, this will convert some of his forward motion into energy that this mechanism will leach.

    --
    The race isn't always to the swift... but that's the way to bet!
  6. 10kW of power? For what time span? by Temporal · · Score: 4, Insightful

    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.

  7. Re:Power vs. Energy by Melfina · · Score: 3, Insightful
    I'm sure it's not going to generate enough electricity to make too much of a difference unless you're in a heavy traffic area. But consider this; How many times have you seen the power go out and the traffic lights are down? That's a real pain in the neck because not only are the local authorities delaing with a storm, but traffic control and accidents now. For street lights and traffic lights this could be an awesome idea.

    As for the amount of gas it's going to use... A little bump like that should be nothing in comparison to some of the pot-hole filled roads I've driven through. It's no larger than a speed bump, and this sinks into the ground when you hit it.

    --
    :3 rawr.
  8. Kilowatts mean nothing, it's Kwh we need to know.. by Quebec · · Score: 5, Insightful

    They talk about kilowatts, but for how long?... 1 second? 1/2 second? 1/100?

    if it's 1/40th of a second as I would estimate each passing car would generate 0.069444 KWh and it would take about 50 cars to produce the equivalent of a fully charged AA rechargeable (if we take a 2500mAh battery). But I guess their marketing department wouldn't want us to learn those number first...