Last Updated: Tuesday, 03 July 2007, 04:20 GMT

Slow-moving traffic will be used to generate electricity for a UK supermarket chain.

Lorries will drive over metal plates set into the road just outside a Sainsbury's depot.
Pressure from the vehicles triggers a series of pumps which are linked to an electricity generator

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If you can't take a joke you should never have joined.

Last Updated: Tuesday, 03 July 2007, 04:20 GMT

Slow-moving traffic will be used to generate electricity for a UK supermarket chain.

Lorries will drive over metal plates set into the road just outside a Sainsbury's depot.
Pressure from the vehicles triggers a series of pumps which are linked to an electricity generator

bizzare, whats the link to that story?

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Last Updated: Tuesday, 03 July 2007, 04:20 GMT

Slow-moving traffic will be used to generate electricity for a UK supermarket chain.

Lorries will drive over metal plates set into the road just outside a Sainsbury's depot.
Pressure from the vehicles triggers a series of pumps which are linked to an electricity generator

bizarre, whats the link to that story?

That's all there was it was on AOL News I'll try to find a link probably on Sainsbury's web site.

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If you can't take a joke you should never have joined.

http://news.bbc.co.uk/2/hi/uk_news/england/northamptonshire/6262134.stm

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Rosetta Moderator: Mod.Sense

http://news.bbc.co.uk/2/hi/uk_news/england/northamptonshire/6262134.stm

Thanks Mod Sense the article gives a 'bit' more detail but not much at least it say's where it is being trialed unlike Channel4 or the PA.

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If you can't take a joke you should never have joined.

other than the article on bbc website i can't find anything further, not even on the sainsbury's website.

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You don't get something for nothing. If the trucks are pushing a plate down, then they will be using more fuel to get up again. Stands to reason, you are extracting gravitational potential energy, if the truck is to end up at the same level it started at, it will need to supply that back. Being mechanical devices, both the generator and the trucks are inefficient, so trying to extract power from such a system is going to use more energy then it produces.

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Could a private citizen put these plates in a busy road [hoping that noone notices]?

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your theory while somewhat correct cannot be completely validated.
we don't know how far the plate sinks down or if it is raised or how big it is.
we don't know at what speed the truck is going when it comes to this plate.
if we knew these variables then we could tell if the truck is losing any energy when it passes over these plates. If they were used as speed bumps then the energy of the truck passing over them while slowing down would not be lost any more than a conventional speed bump and it would be going to a good purpose rather than being lost.

You don't get something for nothing. If the trucks are pushing a plate down, then they will be using more fuel to get up again. Stands to reason, you are extracting gravitational potential energy, if the truck is to end up at the same level it started at, it will need to supply that back. Being mechanical devices, both the generator and the trucks are inefficient, so trying to extract power from such a system is going to use more energy then it produces.

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The system is only expected to supply 2percent of the store's energy usage!! Is the expense worthwhile?

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depends on the cost of commercial energy vs the cost of installing this system. being a large corporation and also that some company in the US is willing to test this there must be some savings that was predicted for long term when you compare the two costs. heck, corporations look at .5% savings or even 1% savings if they can find a way to do it, usually by cutting personnel costs. if you look at their annual or quarterly electric bill (which is probally thousands of pounds) and then drop off 2% of that total vs the one time cost of installing the system plus maintance, i think the system wins.

The system is only expected to supply 2percent of the store's energy usage!! Is the expense worthwhile?

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Still sounds dodgy to me. If the plate sinks at all, then that "sink" has got to be gained again. If the plate is raised, then the vehicle needs to get up there before it can go down again. If there is a case to be made here, it is that the owner of the ramp is moving some of their energy costs onto the owner of the vehicle, and since the process is inevitably inefficient, the net cost to the vehicle is greater then the energy derived from the system.

Consider also, that using fuel in road transport is inherently more damaging to the environment then centralised power generation where emissions can be more economically controlled.

I wonder also about the increased wear to tyres and the vehicles in general negotiating these bumps/plates.

From a total system perspective it sounds like a bad idea.

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Wave upon wave of demented avengers march cheerfully out of obscurity into the dream.

If the plate is under the loading dock, then a truck full of goods parks on the plate. The plate is depressed while the truck is unloaded. When the empty truck drives away, it doesn't have as much weight to pull up what is presumably a 1 or 2 inch gap, as existed when it was parked there. So, it is possible that the energy to bring the empty truck back to the level of the roadway is less then the energy captured by the plate sinking.

But yes, you are still capturing energy from the truck. Nothing comes for free.

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we can all assume lots of things, but until a clear story or paper comes out about where and how this system works, its all speculation. Also, if the plate is in the roadway on the approach to the loading dock, its not just one truck that is depressing this plate. also, it is not known how deep the plate depresses or how high it is above the ground to be depressed. but this much i do know, a speed bump produces more wear and tear on the tires and causes greater fuel consumption (momentarily while the truck and trailer go over it) than this plate will ever consume. but as i said in the beginning we are all speculating over something we have no concrete information about.

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But yes, you are still capturing energy from the truck. Nothing comes for free.

Recovering some of the energy that was used to load the truck initially? Uneconomic, but possibly true.

but as i said in the beginning we are all speculating over something we have no concrete information about.

You are quite right.

Elaborate a theory whereby a system such as this could work, purely hypothetically.

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Wave upon wave of demented avengers march cheerfully out of obscurity into the dream.