Speed bumps to get new role as a source of green energy

[OKIsItJustMe]

http://www.guardian.co.uk/environment/2009/feb/08/alternative-energy-speed-bumps

Speed bumps to get new role as a source of green energy

Moving vehicles will generate electricity for street lights and road signs in a London trial

Rhodri Phillips
The Observer, Sunday 8 February 2009

"Green" speed bumps that will generate electricity as cars drive over them are to be introduced on Britain's roads. The hi-tech "sleeping policemen" will power street lights, traffic lights and road signs in a pilot scheme in London that could be rolled out nationwide.

Speed bumps have long been the bane of motorists' lives, but these will capture the kinetic energy of vehicles.

Peter Hughes, the designer behind the idea, said: "They are speed bumps, but they are not like conventional speed bumps. They don't damage your car or waste petrol when you drive over them - and they have the added advantage that they produce energy free of charge." An engineer who formerly advised the United Nations on renewable energy sources, Hughes added: "If it (the energy) wasn't harnessed by the speed bumps, it would go to waste."

The ramps - which cost between £20,000 and £55,000, depending on size - consist of a series of panels set in a pad virtually flush to the road. As the traffic passes over it, the panels go up and down, setting a cog in motion under the road. This then turns a motor, which produces mechanical energy. A steady stream of traffic passing over the bump can generate 10-36kW of power.

…

[CaliforniaPeggy]

1. That sounds very interesting.

Let's see how it plays out.

[mr clean]

3. Indeed interesting

Can you imagine if they put these in use full time? I know it cost a lot of money (at first) but I think after a while it would be worth it.

[drm604]

2. This doesn't make sense to me.

The energy isn't coming from nowhere. This is not free energy. If it captures some of a vehicle's kinetic energy then that vehicle has less energy and must burn more fuel to maintain speed.

If this is used only where vehicles are already slowing down, before a stop sign for example, then it might make some sense for most vehicles. Even then, in the case of hybrids, which are becoming more common, it's stealing the kinetic energy that would otherwise go from the brakes to the batteries.

[OKIsItJustMe]

4. If you already have a speed bump, why not use the energy that's currently being wasted?

Clearly, you can't just put in a tremendous amount of speed bumps to satisfy the world's energy needs.

However, if there's a location where a speed bump is needed, rather than invest energy deforming car suspensions, and a bit of pavement, why not use it to turn a generator?

[drm604]

5. But the quote from the article seems to assume otherwise.

"They are speed bumps, but they are not like conventional speed bumps. They don't damage your car or waste petrol when you drive over them - and they have the added advantage that they produce energy free of charge."

It seems to be saying that conventional speed bumps waste gasoline but these don't, and the energy produced is free. It could be very misleading to some people.

[OKIsItJustMe]

6. More information here

http://www.hughesresearch.co.uk/

[napoleon_in_rags]

7. No, really really good question. There is WAY more here than meets the eye.

So your post prompted me to do a little research. I think in a normal speed bump the kinetic energy is converted to thermal in the compression of air in the shocks, and thus lost. Of course it would also be lost thermally in the friction of braking before the speed bump. So the obvious thing here if you look at the physics is that for this to work, the driver is neither intended to brake, nor experience a bump. In an ideal version, it would be like the driver just hits a patch of peanut butter road, and speed is sucked from their vehicle like they hit a force field.

The truly interesting thing is that when you take off the veil of "free energy that would be wasted anyway", you see this as the fascinating landmark that it is: The advent of kinetic taxation, or direct energy taxation. The driver pays to run the lights not by a long convoluted process of taxes, but by the kinetic energy being sucked from his vehicle to power the lights. No currency, no income taxes, no banks, just direct energy.

There's something about this I can't put my finger on that seems really important with the banks making such a mess of things. Joules can't be created with the flick of a pen, or made up in fantasy land default energy swaps. They reflect actual, scientific reality. I guess I just wonder if the currency of the future might be something more like joules and less like dollars. Who knows.

Peace

[drm604]

9. Exactly.

Read the last paragraph in the OP.

The ramps - which cost between £20,000 and £55,000, depending on size - consist of a series of panels set in a pad virtually flush to the road. As the traffic passes over it, the panels go up and down, setting a cog in motion under the road. This then turns a motor, which produces mechanical energy. A steady stream of traffic passing over the bump can generate 10-36kW of power.

This does not sound like a typical speed bump to me. This is flush to the road and therefore does not serve the purpose of a typical speed bump. A typical speed bump deters speeding because it's a visible bump in the road which causes the driver to slow down to avoid damaging his vehicle. This doesn't sound like that at all. This description sounds like something placed in the middle of a busy highway in order to steal energy.

Even if it is placed somewhere where vehicles do need to be slowed down, what about law abiding citizens who slow down to the required speed on their own? This thing would slow them down even more causing energy to be wasted in getting back up to speed.

This strikes me as something that works (in the sense of using energy that would otherwise be wasted) only when people disobey the law. You could argue that lawbreakers should be penalized in this manner, but the problem is that law abiding citizens receive a similar penalty.

If the point is that no one should slow down on their own ("slow" signs and such are removed) so that the kinetic energy goes into the "bumps" rather than the vehicles' breaks then it seems to start to make more sense. I say "seems" because of hybrids, which are likely to become more and more common. In the case of hybrids, using the "bumps" rather than the brakes steals the energy that otherwise would have gone into the cars batteries.

[OKIsItJustMe]

10. Check the link I provided above

(Among other things) you will find video and animations that explain the system.

I think your concerns mostly come from a poorly written article.

[drm604]

12. I looked at your link.

You linked to the front page rather than pointing to something that specifically answers my concerns so I had to search around. I did find this on the FAQ page.
http://www.hughesresearch.co.uk/index.php?option=com_content&view=category&layout=blog&id=28&Itemid=41

Q1. Doesn’t the ramp just steal pennies from our petrol tanks?
A1. The ramp is designed to be situated in parts of the roadway where vehicles are having to slow down, for example on downhill gradients, when approaching traffic lights or roundabouts as well as replacing sleeping policemen and traditional traffic calming measures.
In the these situations, the kinetic energy of the car is being dissipated into heat (i.e. through the braking system) anyway; the ramp at this point scavenges a degree of kinetic energy as the car passes over it, but this is far less than is lost through other mechanisms.

This is what basically what I admitted in my previous post, that it makes some sense if it's placed where vehicles are already slowing down. The problem, as I said, is with hybrids, which are probably going to become more and more common. Hybrids use their brakes to recover their kinetic energy by transferring it to the vehicle's battery. These "speed bumps", even when used where vehicles are already slowing down, will steal this energy from hybrids.

If these bumps become a common part of infrastructure, and hybrids also become common, then we will be stuck with a situation where they do in fact "steal pennies from our petrol tanks".

This type of system is attractive to politicians because it's a way of paying for needed services without visibly taxing their constituents, but as we move toward more energy efficient vehicles which attempt to recover their own kinetic energy it will end up working against those vehicle's recovery systems.

[Robb]

11. Fascinating, isn't it?

I lived in a small town that was the "speed trap" between two larger towns, and there was discussion of something like this as a way to "get something" out of the traffic that didn't stop much to frequent the businesses in town.

Interesting discussions came out of that as well.

[excess_3]

8. another tax on the poor .n/t

[Howzit]

13. At £20,000 to £55,000 per "bump", it sounds like a way to make the manufacturer rich.

Speed bumps stick up to warn drivers into slowing down. If this invention drops down as you drive over it the visual warning is lost and the risk of bottoming out your car at the other end remains. If the "bump" doesn't move down much it won't generate much power.

As for the energy being free, it can only work if it takes energy from your car, that you paid for.

By the way, the fact that the projected cost range is so wide is further evidence of a snow job for personal gain.

[eppur_se_muova]

14. This is not "free" energy, it's a tax on moving vehicles.

This idea has been around for a long, long, time, and gets slain by the Law of Conservation of Energy on a regular basis.