Ramp Creates Power As Cars Pass

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."

Great idea!

[confusion]

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/ [cyvin.org]

Noooo way

[LiENUS]

No way I would avoid any roads with these, that energy the ramp "creates" it is really sapping from the vehicle. Heres an idea, since I was already taxed for purchasing the gas USE THAT MONEY TO POWER THE LIGHTS.

Great

[ScrewMaster]

Just great. Yet another gas tax.

Re:Great idea!

[Anonymous Coward]

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.

Cost vs. benefit...

[johndierks]

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?

how about if they only pop up

[quakemeister]

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.

This is equivalent to taxing gasoline...

[synaptik]

...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.

Re:Great idea!

[confusion]

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/ [cyvin.org]

Re:Cost vs. benefit...

[An Onerous Coward]

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....

Are you sure it's just wasted energy?

[Eric Damron]

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.

Re:Noooo way

[Sancho]

Fine--but is there any indication that these ramps would replace gasoline taxes? More likely they'd be in addition, as most Americans wouldn't understand that they're losing gas mileage.

Re:how about if they only pop up

[Temporal]

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

How much Energy per Car?

[Anonymous Coward]

Dorset inventor Peter Hughes' Electro-Kinetic Road Ramp creates around 10kW of power each time a car drives over its metal plates.

Perhaps I'm mistaken but this information doesn't seem particularily useful. Watts or kilo-Watts tells us the rate of energy transfer but how long is the car actually generating energy on one of these plates? If it's on a busy road and is practically constantly generating power then this is number if useful. If it only gets hit for a split second now and then its hard to tell how much energy is actually being generated.

50kW is a big impressive number and all, but doesn't seem very useful. How much Energy does this produce per car?

Re:Great idea!

[ceoyoyo]

I think you're right. Very little is lost in contact with the road, at least when you're driving on pavement. But if you start making the road soft, you lose extra energy. Of course, if you're not driving on pavement you might actually lose more energy to the ground than internally. In deep sand, for instance.

Re:This is equivalent to taxing gasoline...

[kisielk]

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. This means that motorists approaching the main road pretty much always have to stop. This would be a prime place to install such a device, which could likely also perform double duty as the sensor that detects approaching vehicles. I agree that putting these on a major road where traffic is moving most of the time and motorists have their foot on the gas is probably a bad idea, but it's not the only possibility.

The really frightening part

[bradleyland]

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.

10kW of power? For what time span?

[Temporal]

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.

A few calculations...

[zerosignal]

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.

Re:Creator's Website

[wealthychef]

It doesn't have to convince us. It just has to convince some Junior-college educated city councilmen somewhere and the inventors are millionaires!

Re:Cost vs. benefit...

[blibbler]

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.

Re:What about..

[dougmc]

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, the whole idea of car powered lights and such only makes sense if 1) it's in a rural location where power is hard to come by and/or 2) you want to slow the cars down anyways, like a speed bump (and others have already mentioned it.) Beyond that, implementing this sort of thing would not be cost effective.

Re:This doesn't generate power...

[AndroidCat]

From the look of the top picture in the FA, it won't do your tires or wheel-alignment much good either.

A few more calculations...

[RallyDriver]

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 the ramp.

Take a different approach - let's figure out n upper bound on how much energy per car this thing could yield from first principles (reminds me of the Physics Part 1A Tripos at Cambridge, the short "back of the envelope" questions):

Suppose each axle ramps up and falls 0.1m when passing over it, that's roughly equivalent to the whole mass of the car doing so.

An average car in the UK masses 1300kg.

Gravity is 9.81 m/s^2

Total available energy per car is thus 0.1 x 1300 x 9.81 = 1275J

Now, let's figure out how many cars can pass over it in a given unit of time ... to a rough approximation, this is constant regardless of speed, unless there is a traffic jam, because the inter-car gap is a roughly constant amount of *time* regardless of traffic speed - recall the mantra "Only a fool breaks the two second rule". Let's take that number....

1275J per car x 0.5 cars/sec = theoretical maximum output ceiling of .... drumroll .... 637W. For my fellow petrolheads, this is 0.85 horsepower :-)

Average over a 168 hour week is going to be less than 1/4 of this, due to variability in traffic -> 150W or so.

Regardless of what timebase the inventor is measuring his 10kW peak over, he admits he is at only 800W on his own scale, or less 8% of what he considers maximum possible efficiency.

Applying that 8% to the above calculated theoretical maximum, we are down to a net average of 12W yeild from this thing, which is less than the heat being given off by the idle kitten sitting on my lap as I type this.

Conclusion - as we expected at first gut, total snake oil :-)

Re:The obvious question is

[ucblockhead]

It's not a win-win for people driving cares that already have regenerative braking.

Re:Power vs. Energy

[Melfina]

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.

This is a really crappy design

[Animats]

This is a very poor design. Take a look at the mechanism [hughesresearch.co.uk]. 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.

Kilowatts mean nothing, it's Kwh we need to know..

[Quebec]

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...

Re:Great idea!

[DrXym]

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?

Re:Great idea!

[Rangsk]

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.

Negativity with a real reason

[Chas]

This is NOT energy that'd just be lost. And it's NOT waste.

If they put this out on open roads or uphill grades (ramps, etc), then it IS theft.

If they put this on downhill grades (also ramps, etc), it's STILL theft. On places where people need to stop, people using regenerative braking will lose some of their fuel savings (when they're already having problems recouping the price-premium of a hybrid). On straight downhill stretches where no stopping is needed, they're increasing the wear and tear on the suspension, tires and requiring the car to expend energy it would otherwise not spend (coasting) to traverse the same distance.

All this energy is coming directly from increased fuel consumption. So it's NOT good for the environment (increased emissions and all).

So no. It's NOT money in the bank. It's money out of our pockets FOR GOOD.

Unless you want to somehow claim this device violates the Second Law of Thermodynamics....

Re:Great idea!

[gronofer]

Every government in the world differs. Who do you think defines what "theft" means, legally?

Re:how about if they only pop up

[Gothmolly]

And wasting fuel to produce it in the first place. Hybrids don't use any less fuel than a well-maintained VW TDI, and with the TDI you have the added benefits of :

Not sitting inside a giant magnetic field
More power
Ability to burn 100% plant-derived fuel oil, aka BioDiesel
In general, not perceived as an insufferable prick

Re:Great idea!

[Anonymous Coward]

Ok, so the long and the short of it is that it's only ethical for them to use it on exit ramps where the car needs to slow down anyway.

Why is it otherwise unethical for car users to pay to power traffic lights?