New Jersey Turnpike As a Power Source?

New Jersites writes "New Jersey, home of the eponymous Jersey barrier, is considering wind turbines powered by the breeze generated from traffic on the Jersey Turnpike. The wind turbines won't be built on the side of the highway. They will be built inside — what else? — the Jersey barriers. By replacing sections of solid concrete with Darius turbines, they might be able to harvest enough energy to power a light-rail line."

Drag?

[Graham MacRobie (1082093)]

I'm not a physicist, but won't the turbines cause a drag effect on the cars, resulting in the cars burning more fuel? Is so, aren't they just moving the problem from one place to another? There's no such thing as free energy, right?

Truly curious - I'd love an explanation if someone knows why this isn't the case.

Re:

[TheSexican (796334)]

Yes you would be correct. This is a terrible idea.

Re:Drag?

[WrongSizeGlass (838941)]

A better idea would be to try to harness the anger and frustration of those of us who drive the NJ Turnpike. You could really support the power grid with all that wasted energy.

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[hab136 (30884)]

A better idea would be to try to harness the anger and frustration of those of us who drive the NJ Turnpike. You could really support the power grid with all that wasted energy.

Ghostbusters II: New Jersey Edition?

Re:Drag?

[name*censored* (884880)]

>>A better idea would be to try to harness the anger and frustration of those of us who drive the NJ Turnpike. You could really >>support the power grid with all that wasted energy.

>>but won't the turbines cause a drag effect on the cars, resulting in the cars burning more fuel? Is so, aren't they just >>moving the problem from one place to another? There's no such thing as free energy, right?

Putting two and two together.. wouldn't harnessing the anger make people ANGRIER? There's no such thing as free anger!

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[yahooadam (1068736)]

>I'm not a physicist, but won't the turbines cause a drag effect on the cars, resulting in the cars burning more fuel? Is so, aren't they just moving the problem from one place to
>another? There's no such thing as free energy, right?

No it wouldn't cause drag on the cars

the cars are already pushing a wall of air, ATM that wall of air just dissipates after a while, the barrier would take that wall of air and convert it to some power

So in fact, its actually making the cars more efficient, as the wasted e

Re:Drag?

[Rei (128717)]

Yeah. Without the extra drag from the turbines, that "breeze" would be reducing drag on the cars. They're basically using cars as generators. Brilliant strategy there, given how inefficient ICEs are.
 

Re:Drag?

[dbIII (701233)]

Yes, insightful for a given value of insight - however moving the turbines a short distance away from the things instead of doing something stupid will give you both the wind to spin the turbines and no extra drag on the vehicles. Ducting is also possible to get a lot of wind to the turbines if they are far away without reflecting much back on to the vehicles.

I know it's not exactly high school stuff but if you think of it as simple 2D water flow it still is not difficult - the ripples from an obstruction only travel a finite distance upstream.

Re:Drag?

[Rei (128717)]

Any boost that the turbines are getting is resisting an equivalent amount of airflow induced by the cars, which the cars will need to reaccelerate. The further you move them away, the less work the cars you need to do, but you get correspondingly less power.

It's a really stupid idea.

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[Gilmoure (18428)]

Isn't the wind from the cars currently impacting on the plain barriers now, exerting a force on them? Granted, that force isn't enough to move the barriers or even heat them appreciatively (friction) but if the wind is already there and just be deflected upwards/out towards the cars, why not harness it. It's like harnessing the wake in a channel. The boat's going to make the wake regardless of what it impacts on. Is doubtful current highway is designed for the wind wake to bounce back and power the cars goi

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[san (6716)]

> It's like harnessing the wake in a channel. The boat's going to make the wake regardless of what it impacts on.

That would be true if there were only one car (or boat). If there is a flow of cars, those cars are going to consume less fuel if there is less drag due to an airflow.

Exactly how that flow behaves at the edge of a freeway is fairly important for the efficiency gains: a smooth wall may actually have a beneficial effect, while turbines would do exactly the opposite.

Big Dig problem solved

[BitterAndDrunk (799378)]

There was that one problem, where mob bosses were thinking "hey what can we do to make more money" . . . that problem was solved pretty well I think.

Re:Drag?

[arivanov (12034)]

Absolutely. This is not a free energy at all. What I find more interesting is that the system uses the same turbine design as Quiet Revolution turbines. AFAIK this design is still under a couple of patents so they will have to shell out a very sizeable license fee. Pity Quiet Revolution is not public, this would have been a good time to play with its shares.

Re:Drag?

[Alioth (221270)]

Not quite.

The air moved around by the cars is being absorbed and dissipated anyway by the objects surrounding the road. All the turbines will do is instead of the airflow from the cars going to swish the surrounding grass, trees and bushes - it'll spin a turbine. The energy is already being absorbed by the surrounds of the road.

It's like putting a turbine over a kettle - you won't cause the kettle to use more energy to boil the water by allowing the steam coming from it to pass through a turbine - you'll just extract some of the energy that otherwise would have been used up by the environment of the kettle.

If it's designed correctly, it won't increase drag.

Re:Drag?

[deek (22697)]

I'm not a physicist, but won't the turbines cause a drag effect on the cars, resulting in the cars burning more fuel?

You've got it right. The turbines would take energy from the air being pushed around by the cars, leading to the breeze around the car slowing down, and therefore exerting more drag on the car.

At the same time, this is a rather ingenious way of creating a virtual toll for roads. If the power gathered is then invested into a public transport system, then you'll end up having drivers subsidise public transport. The fuel savings with public transport may well offset the extra fuel burnt through the turbine induced drag.

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[ookabooka (731013)]

If the power gathered is then invested into a public transport system, then you'll end up having drivers subsidise public transport. The fuel savings with public transport may well offset the extra fuel burnt through the turbine induced drag.

Uh, is it me or does this just seem like a bad idea. Using cars (that use combustion engines about 30% efficient) to move air and then use turbines to convert part of that to energy. . .If it was entirely passive and just collected "wasted" energy I'd be all for it. O

Re:

[smenor (905244)]

At the same time, this is a rather ingenious way of creating a virtual toll for roads. If the power gathered is then invested into a public transport system, then you'll end up having drivers subsidise public transport.

That's a great point I never would have thought of.

The fuel savings with public transport may well offset the extra fuel burnt through the turbine induced drag.

I'd be shocked if the energy extracted from burning extra fuel in cars on a freeway would come close to what you'd get by burning the same fuel in a properly designed power plant (and I'm quite confident that the emissions would be worse).

Re:Drag?

[Myself (57572)]

The wind blowing on that unit isn't caused by the cars, and that wind doesn't always benefit the cars.

The wind in the (been-shot-down-before) turnpike story is a draft caused by the cars' motion, and benefits their efficiency because it acts like a slight tailwind for each vehicle. Eliminating that tailwind would have a large energy cost, compared to the minor harvest from the turbines.

Drag's not the full story.

[EmbeddedJanitor (597831)]

The energy must come from somewhere, so it must be ultimately coming from the gas powered car. However, if it is being taken in the right way it is energy that would otherwise be converted into waste heat/sound.

In other words, if the car drag is causing a wind of sorts, that wind would normally dissipate its energy as friction against the surfaces it blows along - causing the energy top be lost as heat. Now we're just providing an alternative energy soak that extracts the useful enrgy.

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[Mateito (746185)]

You are spot on. You get nothing for nothing. That doesn't necessarily mean that the idea is without merit

The turbines will increase drag on the cars, which will increase the amount of fuel consumed, which will result in higher emissions from the vehicles in the area immediately local to the generators. Anybody who's ever felt the car speed up when a tail-gater leaves your slipstream to overtake is familiar with the effect.

The question is whether the additional pollution due to the turbines is more or less

Re:Drag?

[smenor (905244)]

I am a physicist and had the same thought.

Without a doubt, the turbines will interfere with laminar flow, increase turbulence, and increase drag.

I have no idea if the increase in drag will dominate over the increase in efficiency by reclaiming lost energy, but it's definitely something that should be studied before implementing this kind of system on a large scale.

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[Capsaicin (412918)]

There's no such thing as free energy, right?

Indeed! There is, however, such a thing as wasted energy.

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[dheera (1003686)]

This is an unfathomably silly idea that shows how much energy is being wasted in commuting. The solution is instead to reduce the amount of driving and replace the insane amount of driving in this country with a decent train and bus network that actually gets people where they want to go. New Jersey has extremely poor public transportation for its density compared to other similar-density parts of the world outside the USA. The amount of energy that could be saved (in joules provided by gasoline) by reducin

Re:

[tobias.sargeant (741709)]

The wind isn't mechanically attached to the turbines either, but it still acts upon them.

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[tobias.sargeant (741709)]

I agree with you. Turbines do generate turbulence, however, and turbulence will impede the progress of cars to some small extent. It is possible for this to be a net win, contrary to the assumption of the originator of the thread. It's also reasonable to assume that it will cause a non zero increase in energy expenditure by cars. Whether it's negligible or not is something best left to engineers and fluid dynamics simulations.

Yes: Drag.

[Ungrounded Lightning (62228)]

But the cars are the wind generators, not the turbines. If a turbine generated any significant wind itself, then it wouldn't be a very effective generator, would it?

The stream of cars generates an air motion along their path. Like geese (though through a different mechanism) the leading cars reduce the amount of air drag experienced by following cars. This improves their fuel economy. (The phenomenon is even more pronounced with semi-trucks. "Drafting": following another truck closely to save even more fuel, is a common practice.

A smooth central barrier separating the two directions of traffic improves the situation by letting the two sides of the freeway have separate airstreams traveling in opposite directions. The barrier reduces energy lost to turbulence, improving the airflow.

Replacing the barrier with turbines will suck energy out of the air streams on both sides to generate electricity. The result will be to decelerate the airstreams that had been giving following vehicles an advantage.

While some of the power comes from captured crosswinds and some from capturing energy that would have been lost to turbulence anyhow, a large portion of it comes from increasing the drag on following vehicles by putting friction on the "following wind": Fuel economy for the trailing vehicles in a bunch is reduced to something near that of lone or leading vehicles.

But there's plenty of power to be had higher

[Ungrounded Lightning (62228)]

By the way:

There's PLENTY of power to be had WITHOUT disrupting the traffic airflow and canabalizing the fuel of the cars.

A freeway or toll road is a clear area and there will be plenty of winds ABOVE it that are essentially unrelated to the airflow near the ground. They're also faster - with energy going up with the CUBE of the airspeed.

By building a wind turbine that starts significantly above the ground the turbines can avoid disturbing the flow at traffic level while collecting plenty of energy.

Also: A Darrieus wants linear airflow THROUGH it. It would be great for salvaging power from crosswind, but rotten for snagging power from opposing winds on the two sides of its axes.

And they're a major hazard: Darrieus turbines fly at tip speeds of about 7 times the wind speed and their narrow blades experience drag loads about equivalent to a wind barrier with a cross-section the size of the swept area - reversing twice per rotation. This has tended to produce fatigue in their materials, sometimes ending with the mill coming apart in high winds some years after construction, with massive pieces flying around at a goodly fraction of the speed of sound.

A savonius-derived design (like the Sandia configuration) would be a better choice. Though it only collects about 2/3s as much power for a given swept area, it rotates at about an eighth the speed and has broad blades that can be much more solidly constructed.

Re:Yes: Drag.

[Bastard of Subhumani (827601)]

The phenomenon is even more pronounced with semi-trucks. "Drafting": following another truck closely to save even more fuel, is a common practice.

I assume this aerodynamic phenomenon miraculously turns into a cushion in the event that the truck in front has to stop real damn quick?

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[by Anonymous Coward]

The wind from the cars *is* loosely attached to the cars. It's called viscosity [wikipedia.org].

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[Fordiman (689627)]

Actually, the turbines wouldn't 'drag' on cars. The breeze caused by the cars, and which assists the cars' passage, would be siphoned off to the turbines. The net effect is similar to drag, in that the wind assist is now gone.

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[Nefarious Wheel (628136)]

The point is, the cars are going to be generating that wind whether it's used or not. Inside a plenum, you will get a lateral compression shock wave from pushing the car through that air. That compression results in drag. Where that compressive effect is diminished (by say, venting it through holes in the plenum walls --- oh, yes, let's stick some turbines there while we're at it --- you will get a net reduction in the amount of drag on the cars. They're still pushing air and making the shock waves, but

Re:

[njh (24312)]

Actually, it's nearly 60%:
http://en.wikipedia.org/wiki/Betz'_law [wikipedia.org]

50% ain't bad anyway. It beats many other common energy transformations. Your average automobile is probably only 10% efficient.

Finally...

[ZiakII (829432)]

Finally something I have to be proud about in NJ besides the Devils....

yawn

[User 956 (568564)]

y replacing sections of solid concrete with Darius turbines, they might be able to harvest enough energy to power a light-rail line.

That's boring. Wake me up when they can power a light rail gun.

Why's the train not running?

[rmadhuram (525803)]

Oh wait, there's a traffic jam!

The barriers are supposed to be solid.

[deopmix (965178)]

This might work until somebody decides to use the barriers for their original purpose(separating traffic). When the Powers That Be realize that the only thing separating two lanes of traffic moving at each other at 140 mph is a few turbines they may decide that this is a Bad Idea.

Re:The barriers are supposed to be solid.

[mrchaotica (681592)]

I wouldn't be worried about the turbines failing to separate the cars (assuming they were built solidly); I'd be worried about cost. Jersey barriers are surely much cheaper and more durable than turbines, and I think the cost of turbine repair or replacement after the inevitable accidents would be enough to make this proposal uneconomical.

River

[Jordan Catalano (915885)]

Why not just sink some turbines in the larger rivers near the turnpike and get the juice from there?

People can fly?

[ghoul (157158)]

If you put a light rail right in the middle of a high traffic freeway how do people get on or off? Fly?

An excuse for speeding...

[xrapidx (615195)]

...this will create a good excuse when pullled over for speeding . You were only trying to do your part to power the light-rail line.

EMR

[Essequemodeia (1030028)]

How outlandish would it be to embed efficient magnets within Interstate roadways while installing similar magnets within cars and trucks? This is just a late-night idea but couldn't that generate a sizable amount of electricity? Perhaps it could be realistically considered once cars are fitted with a workable system for auto-navigation, a system that might require the installation of specialized equipment in existing roadways and therefore offer a justifiable economic solution (as well as an opportunity);

"New" Jersey Barriers

[Akron (799321)]

Before everyone decides to start bashing good ole NJ. I would like to point out that the actual article says nothing about the NJ Turnpike. The current concrete barriers are called Jersey barriers, and all we have here is a new barrier with turbines...thus the name "NEW" Jersey Barrier.

Dumb idea - way too small

[Animats (122034)]

Wrong answer. Too many little turbines not generating enough energy each. Worse, gearing a number of turbines together when they don't get uniform wind pressure means some of them are just sources of drag.

Progress in wind turbines has been through scaling them up. The 50KW - 100 KW machines of the 1970s never paid for themselves. Somewhere above 500KW, the economics start to work, and farms of megawatt and up machines are quite profitable. Here's General Electric's 2.5 megawatt wind turbine, [gepower.com] which is typical of current large wind turbines. Total worldwide wind generation capacity is about 75 gigawatts. Wind power is now a serious energy source because, at last, the units are big enough to generate serious power.

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[dbIII (701233)]

Lots of little ducts can power one big turbine.

Wind power is taking off - China is set to double the worlds installed wind power units within a couple of years. It still has problems like a small unit size and a short maintainance shedule - although with the two problems together it can mean that if you have a big farm of the things you don't lose much of the total when a unit is down. The real saving is you can burn less coal while the wind is blowing. The really big advantage is you can have a lot of s

Why aren't we moving towards electric transport?

[copponex (13876)]

This is a serious question: since virtually all energy comes from the sun, and we have an extensive infrastructure for transporting electricity as well as extensive technology for storing electricity, why are we wasting time on road-side turbines and hydrogen fuel? Obviously, you make adjustments for average cloud cover, available real estate, etc. But it seems silly to me to research hydrogen or whatever scheme Shell and BP (who are completely unbiased research firms) propose rather than leverage existing technology until they provide a real solution.

Wouldn't it make sense to say that all parking lots should be covered at least partially by solar panels? This would not only add juice to the grid but help reduce the local heating problem with asphalt, reduce temperatures inside cars (thus reducing energy used to cool them), and provide a convenient place to plug them in.

Would it cause to much pollution to make that many panels? Are electric cars truly that much more expensive? Or are lobbyists once again trying to ruin our chances of survival so we are nearly forced to keep spending money at their gas/hydrogen/soybean oil stations?

Rediculus

[rizole (666389)]

As has been pointed out already this is a stupid idea. It would make much more sense to put the turbine on the train so it's forward motion can generate electricity. That way the train is self powering. Much greener.

A far better idea than sapping cars' energy

[ZaMoose (24734)]

Lewis Black recently suggested a novel approach on The Daily Show - power cars on cognitive dissonance [newsbusters.org]. Celebrities weren't using those brain cells anyway, so any extra drag you put on 'em won't slow their hypocrisy down one bit. A win-win solution for everyone, actually...

Newsflash!

[fury88 (905473)]

"Tonight at 11. Commuters leave roadways to ride new rail. Not enough power to run the rail."

television remote power source ..

[rs232 (849320)]

If they banned television remotes and wired everyones couch to the grid, then every time someone got up to change the channel they would generate power.

Have you seen that "systems analysis"?

[Bearpaw (13080)]

This same systems analysis makes a hummer look competitive with a prius in terms of total energy consumption during its lifetime.

Have you seen that particular "systems analysis"? I have. It's so blatantly flawed that the flaws are almost certainly intentional.