Power produced from driving over water filled tubes....Discuss?

http://www.engadget.com/2010/07/16/powertread-turns-gridlock-into-electricity-with-a-series-of-tube/

Engadget said: Transportation Powertread turns gridlock into electricity with a series of tubes By Tim Stevens posted Jul 16th 2010 9:07AM Powertread turns gridlock into electricity with a series of tubes Getting stuck in traffic sucks, but thanks to a couple of Kiwis you might soon be feeling a little better about yourself while muttering about the brake-happy commuter ahead of you. An invention called Powertread by Justin Robertson and Brett Kemp looks to do something positive with the unending shuffling of queued cars. It's literally a series of tubes filled with water that, when run over, force their contents through a turbine to generate electricity. One car driving over one of the things generates 580 watts of electricity at 36 amps. That's not an awful lot power, but imagine a dozen of the things lined up at a busy off-ramp, run over by thousands of impatient drivers every day, and you can see the potential. The Singaporean government does too, providing grants to fund the project and two shopping malls there have already signed up to purchase the results. Who knows whether the things will follow our favorite folk duo over to North American shores, but until then you can at least get a similar feel at your local Burger King.

Feasible? I'm all for "free" energy etc and can't see this working well in the frost zones, but it's an interesting concept

Offramps and other braking zones could make sense, anywhere else and the road will be causing the cars to use more energy.

It's "free" power except to the people driving the cars. A car drives over the tube and compresses it. Now the car has to climb back up the same amount that it compressed the tube. Sure, it's not a lot of energy for the car to climb back up that 1/2 inch (1/2" is my wild guess), but the tube's also producing less energy than the car uses to climb up off the compressed tube. If they put these in an area where a vehicle had to stop every time, like in front of toll booths, then it would be worthwhile, as the tubes would help slow down the car so the driver wouldn't have to use the brakes as much.

It's the same idea as using a battery powered fan to turn a wind turbine. You're putting electricity back into the grid, but you're still wearing down the battery.

Bob

Maintenance will be a nightmare. Flexi tubes being pounded all day? Nah. Potential to damage cars? Power out put? More like Rube Goldberg, to me. Gimme some good solar cells, thank you. Want some REAL power? Figure out a way to harvest the Gulf Stream. Billions of tons of water moving at 4-5 knots, totally dependable. Might take a bit of creative engineering, though.

Yeah I doubt it would hold up. The concept could work for downhill areas though, it would save wear on the brakes (but increase wear on the suspension).

Another idea I saw was something like a Savonius turbine mounted across highways, they use the wash from traffic to generate power. That would really be capturing wasted energy.

Oh and there are some underwater turbines already in use, so capturing energy from the gulf stream could be done.

What happens when I use studded tires in the winter ?

In reply to mndsm:

The water leaks out of the tubes and freezes on the roadway. Then cars have a hard time slowing down on the slippery ice, so to combat that an easy solution is to put a buch of water filled tubes across the road.

Might make sense when used to replace speed bumps, other then that, its a crap idea.

First thing I thought of was the hoses used in gas stations that would ring a bell when a customer came in. Simple mechanism to turn compressed air into mechanical energy. The hoses needed replacing sometimes, but the theory is the same.

There are actually large units on the coast of Ireland that use the tidal force to generate power without getting wet (which causes all kinds of problems). They capture the air when tides come in, and the air compressed run turbines, which are also designed to spin when the tide recedes and creates a vacuum. Seems like a pretty sound design.

is this something Ted Stevens dreamed up from jail? a series of tubes? really?

The tubes will be filled with Methyl Ethyl Bad E36 M3 which does not freeze.

I wonder if they ran them lengthwise instead of widthwise if that would make them suck less.

They can't make asphalt or concrete to hold up to the pounding of traffic. What makes them think some tubes will make it through the day.

It's also being superseded by regenerative braking. You'd essentially end up taking the power people recovered and putting it onto the grid, probably less efficiently than the onboard regenerative systems could scavenge it.

I just followed the link and saw that they're just laying these on top of the road. I assume that's just for testing right? I mean, they can't seriously be planning on just laying them on top of the road? I assumed the road would be "floating" on top of them and as the car passed over the road deflected slightly which pushed the water through the turbine.

What if we gave up on cement/ashpalt and made the entire road out of piezoelectric material?

Schmidlap wrote: It's "free" power except to the people driving the cars. A car drives over the tube and compresses it. Now the car has to climb back up the same amount that it compressed the tube. Sure, it's not a lot of energy for the car to climb back up that 1/2 inch (1/2" is my wild guess), but the tube's also producing less energy than the car uses to climb up off the compressed tube. If they put these in an area where a vehicle had to stop every time, like in front of toll booths, then it would be worthwhile, as the tubes would help slow down the car so the driver wouldn't have to use the brakes as much. It's the same idea as using a battery powered fan to turn a wind turbine. You're putting electricity back into the grid, but you're still wearing down the battery. Bob

Yep, there is no free lunch. The energy to compress the tubes has to come from somewhere, and it comes from the far-less-efficient-than-a-stationary-generator internal combustion engine in your car.

They need to use these things as flooring for kindergarten classrooms.

Salanis wrote: They need to use these things as flooring for kindergarten classrooms.

True....I'm amazed by the expendable energy my children put out