Sainsbury's nicking petrol off customers?

bonzer

Sainsbury's are apparently installing a series of plates in the car park in their new Gloucester store that you drive over which powers a generator. This then supplies power to the store.

http://www.guardian.co.uk/environment/2009/jun/15/sainsburys-kinetic-plates-speed-bumps

The claim is this doesn't affect car efficiency. So where's the energy ultimately come from that powers this? So you drive over a raised plate which must very slightly slow your car down, then your engine has to work slightly harder to pick up speed again as a result (i.e. you must use slightly more petrol because it's putting a slight hill in your way).

So isn't this effectively nicking petrol out of your tank to power their store? Isn't this also a really inefficient method of generating electricity?

mattymoo

Is this thread for real?

From the article you linked to

The kinetic road plates are expected to produce 30 kWh of green energy every hour — more than enough energy to power the store's checkouts. The system, pioneered for Sainsbury's by Peter Hughes of Highway Energy Systems, does not affect the car or fuel efficiency, and drivers feel no disturbance as they drive over the plates.

Having seen the picture of the Kinetic Plate I would suggest you waste as much fuel driving over a cats eye, i.e. none.

Find another battle and move on

1984ReturnsForReal_2

mattymoo wrote: »

Is this thread for real?

From the article you linked to


Having seen the picture of the Kinetic Plate I would suggest you waste as much fuel driving over a cats eye, i.e. none.

Find another battle and move on

Stealing ones kinetic energy is a serious offense & should not be trivialised.

Lemonade_Pockets

I think there are better things to worry about to be honest.

I can kind of see your point but judging by the photo the effect would be negligible at best. Certainly less than the fuel used slowing down for speed bumps or pot holes, trolleys, pedestrians.

Kinetic energy is probably misleading, i don't know the science but it seems gravity is providing the energy for this!

Bongedone

Looks like it uses the weight of the car and gravity to me. This means it will be taking energy from the Earth.

Bongedone

Lemonade_Pockets wrote: »

I think there are better things to worry about to be honest.

I can kind of see your point but judging by the photo the effect would be negligible at best. Certainly less than the fuel used slowing down for speed bumps or pot holes, trolleys, pedestrians.

Kinetic energy is probably misleading, i don't know the science but it seems gravity is providing the energy for this!

Great minds think alike!

bonzer

Bongedone wrote: »

Looks like it uses the weight of the car and gravity to me. This means it will be taking energy from the Earth.

Er no. All the energy is coming from your car petrol tank. When you come down a hill you're under gravity. What gets you up a hill in the first place? - petrol. When you go down into a dip (gravity). Come out of the dip (petrol).

There's no magical free energy. It's electricity generated from a petrol engine by a convoluted method.

Sainsbury's say this is "green" electricity. What's green about generating electricity from petrol?

Bongedone

How is gravity and weight a "magical free energy" ?

Anyhow, if it is taking the power from the cars momentum you should really be slowing down at the point in the picture anyway.

Think of it as Sainsbury's saving wear and tear on your break pads.

cte1111

I think the energy would otherwise be used up in friction, i.e. heat.

BubbleFrogette

There is no such thing as free energy - so it would be petrol being used to generate it. Myself and ppl at work were discussing this today funnily enough.

Bongedone

From the manufactures website it is meant to replace breaking. As another poster said above. It replaces heat that would be generated by using the breaks.

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.


Website: http://www.hughesresearch.co.uk/index.php?option=com_content&view=category&layout=blog&id=28&Itemid=41