boomer

See Shoppers' cars will soon be able to power supermarkets



This has to be a April Fool?

mb

Leslie

Marks have got a couple of great big propeller devices outside their store and they say it produces electricity for the shop!

Going by the way they go round without any discernable wind, I reckon they drive them with electric motors!

Les

FlightMan

Apart from being a possible recycled April Fool, what is the problem with this?

I don't understand the " green nutter " reference at all.

AndyC_772

iTrader: (2)

Basic physics is the problem. The energy to push the plates down comes from the car's engine, which does work in lifting the car up and onto the top of each plate before the weight of the car pushes it down again. The car is effectively climbing stairs.

What's frightening is that such an obviously flawed concept even got as far as a cartoon image. I despair at the fact that anyone tasked with thinking about ways to save energy should lack even the most basic understanding of engineering and mechanics, and should be prepared to embarrass him/herself in this way.

In fact, this might form the basis of quite a good exam question at school, namely:

"The following is a proposal for recovering energy from vehicles using a supermarket car park. Where does the energy come from? Is it more or less efficient than using energy from a coal or oil fired power station? Should it (a) be implemented as a matter of routine? or (b) used as an humiliating example of why people who know f**k-all about basic physics shouldn't be allowed anywhere near a job involving energy policy?"

CrisPDuk

As far as I can tell the basic principle is sound, whether they ca get it to work in practice is another thing entirely. So, considering the cars would be going onto the car park anyway, I don't see why it shouldn't be looked into

Plus, I can't see that it would require any more energy input from a car than that required to traverse a speed bump

Butty

iTrader: (2)

It would only make energy efficiency sense if the plates were leading up to a point where the car had to stop- e.g. barrier. Instead of braking, the car slows down by transferring energy to the plates.
I suspect the payback and overall environmental lifecycle for this is fairly horrendous though.

A better option for on site power and heat generation may be a small anaerobic digestion plant to process the out of date food.

FlightMan

[quote=Butty;8769117A better option for on site power and heat generation may be a small anaerobic digestion plant to process the out of date food.[/quote]

But wouldn't that deprive Lidl's and Aldi of their stock?

Butty

iTrader: (2)

darts_aint_sport

I think it's a very good idea, converting otherwise wasted energy of a speedbump into electricity. Not sure what there is to criticise there AndyC_772?

StickyMicky

Nissan have a windturbine outside the factory in Sunderland, and i am told that on a busy day, they resell the excess power to the local energy company as it makes far tooo much for the factory to use up!!

AndyC_772

iTrader: (2)

From a fuel consumption point of view, speed bumps are horrendous anyway. Even with these 'active' humps, most of the car's kinetic energy is still wasted as heat in the brakes, slowing down for such a hump, with further energy lost as heat when the car accelerates again afterwards.

That assumes that they're being installed in place of conventional speed humps, but they're not - the claim is that they generate 'free' energy, which is simply untrue, and that they're installed for that purpose alone.

What they're doing is converting mechanical work done by the engine into electricity. Imagine an electrical generator being directly strapped to the wheels, nobody would have any problem seeing where the energy was coming from and that it wasn't in any sense "free". But complicate the issue slightly with a system of wheels, levers and pistons and all of a sudden the idea of "free" energy suddenly seems more likely or plausible. That's what I find so alarming.

boomer

Thank you Andy for understanding and explaining the serious flaws in this whole concept - and i am amazed by the lack of a basic understanding of o-level physics by some people!

mb

boomer

...and as for the article itself...

Incorrect, the forward momentum/energy will (may) be converted into electricity to keep checkouts ringing. If it was the weight doing the job then the car would immediately get stuck in a "dip".

It is nothing whatsoever like KERS, and KERS does not convert kinetic energy into "speed" either!

For a start, you don't produce any amount of "kw" in an hour, as kW is the rate that energy is being produced (although you could produce 30kilowatt-hours in a hour!). It would also take an AWFUL lot of "kinetic plates" to produce 30kW in the first place - that is over 40hp assuming perfect energy conversion. Imagine a Ford Fiesta at full throttle just about keeping the tills running


No it doesn't, it demonstrates that the reporter hasn't got a clue what he is talking about!

WHAT??? So the compressors on the fridges have to work overtime to stop the food overheating, to cool staff who are also overheating due to "big windows"??

At least most of the Comments in the article have spotted the flaws, e.g.

Yup, the green nutters are working overtime these days

mb

Butty

iTrader: (2)

Shouldn't that read "Sainsburys media team issuing unsubstantiated bull$hit"??

I just can't get the Sainburys figures to add up - either its 0.5 kW (9 cars per hour ) which won't power many tills or its 30kW which is a hell of a lot of cars for a supermarket.

The plates come from: Highway Energy Sytems who promote them in situations where vehicles need to brake. It does make sense from an energy conservation point of view, so long as drivers get used the extra retardation they'll get going over these and not overbrake.

Unfortunately I can see them being misused in unsuitable locations like Andy points out.