typodupeerror

## English Market Produces Energy With Kinetic Plates404

Johnathan Martinez writes "Sainsbury's market in England has installed 'kinetic energy' plates in the parking lot of its store in Gloucester. The plates are an experiment with a newer energy producing technology. The plates create as much as 30 kWh of energy as cars drive over them. The weight of the cars puts pressure on the plates creating kinetic energy to run a generator. The current is used to power the store and will lower the energy consumption of the market."
This discussion has been archived. No new comments can be posted.

## English Market Produces Energy With Kinetic Plates

• #### useful energy is not free (Score:5, Insightful)

on Thursday June 18, 2009 @01:53AM (#28370311) Homepage

This is just an gas powered electric generator, the likes of which rube goldberg would be proud of. You'd be better off siphoning a thimble of fuel from each car, selling it, and using the proceeds to buy electricity from the utility.

• #### Re:useful energy is not free (Score:5, Interesting)

on Thursday June 18, 2009 @02:01AM (#28370351) Homepage
Not to mention that's a crap ton of energy per car:

The plates create as much as 30 kWh of energy as cars drive over them.

30 kWh is 108 MJ. Say your car weighs 2 tons, well that's 18.1 kN of force it exerts on the ground. So your car would have to push one of these plates down a total of 5.9 kilometers to generate that much energy. Assuming that the plate only moves an inch, that's 238 thousand car/plate crossings to generate the quoted energy.

• #### Re: (Score:2, Insightful)

The numbers are bullshit, but so are all these suggestions that the plates are magically causing MORE gas/battery power to be wasted than would happen otherwise.

• #### Re:useful energy is not free (Score:5, Interesting)

on Thursday June 18, 2009 @02:58AM (#28370721) Homepage

If you put the plates on a downhill ramp, then the car need to move vertically anyway.
So instead of having to use the brakes to convert energy into waste heat, they can convert it into electricity.

A Parking house with multiple levels would be perfect if there are different lanes up and down. Or other descending roads.

We have e=m*v^2 - So the faster the plate can be pressed down, the more enery we will get, but there will also be some impact force. So the number can be much lower.

• #### Re:useful energy is not free (Score:5, Informative)

on Thursday June 18, 2009 @04:53AM (#28371463)

If you put the plates on a downhill ramp, then the car need to move vertically anyway. So instead of having to use the brakes to convert energy into waste heat, they can convert it into electricity.

Then it would be more efficient to build a conveyor belt or a lift for descending cars only... But still more efficient is to cut of fuel - all modern cars do that - AND use some regeneration - some more expensive/advanced cars do that already.

BTW, e=m*v^2 has nothing to do with it, that's just the kinetic energy stored in a moving body, it can be converted to potential energy and back, as in a pendulum. What you are looking for is force x distance: F*s (or mass x gravitational constant x vertical distance: m*g*h)

The original idea is silly from a thermodynamic point of view, but bright from ecological theatre point of view, I think.

• #### Re: (Score:3, Funny)

So instead of having to use the brakes to convert energy into waste heat, they can convert it into electricity.

So if I drive a hybrid, they're stealing my energy? Those bastards!

• #### Re: (Score:3, Informative)

Kinetic energy is actually half m * v^2 - but it has nothing to do with this. You don't need to strike the plates quickly; the motion downward can in principle be arbitrarily slow, just as if you wind a crank you don't necessarily have to wind quickly.

The energy that can be generated (or I should say captured) by the plate is limited by the energy lost by the car. The car loses potential energy, which as dna_(c)(tm)(r) says is m*g*h.

The only reason kinetic energy would play a role is if we consider the forc

• #### Re:useful energy is not free (Score:5, Informative)

on Thursday June 18, 2009 @04:05AM (#28371187)
There is no magic there - energy comes from somewhere. Unless this whole exercise is done when vehicles break (speed bumpers?) then it is just a tax on those driving there. It may be small but it does not mean it is not there.
• #### Re: (Score:3)

Unless this whole exercise is done when vehicles break (speed bumpers?) then it is just a tax on those driving there.

Wow, that's one hell of a speed bump if it breaks cars. I'd sue if a speed bump broke my car!

• #### Re:useful energy is not free (Score:5, Insightful)

<Peet42 AT Netscape DOT net> on Thursday June 18, 2009 @06:21AM (#28371897)

The numbers are bullshit, but so are all these suggestions that the plates are magically causing MORE gas/battery power to be wasted than would happen otherwise.

Add together the energy required to lift the weight of the car up onto each plate, then back up from the level of the plate to street level after the plate has sunk down - you'll find it's more than the car would have used traveling the same distance on the level. They're effectively making each customer pay a levy to use their checkouts, yet making themselves look "greener" by shrouding it in misdirection.

• #### Re:useful energy is not free (Score:5, Informative)

on Thursday June 18, 2009 @02:23AM (#28370525) Homepage Journal

Perhaps they only install these at the entrances to the car park, where you expect everybody to be slowing down - the excess kinetic energy might as well be siphoned off somewhere useful rather than being wasted as heat in the brakes.

However, I agree with your analysis that the numbers, as presented, make no sense (and the picture with illustrates the article is only a few mm thick, so 238,000 crossings is probably a rather conservative estimate). Another article [guardian.co.uk] on the topic says "The kinetic road plates are expected to produce 30 kWh of green energy every hour" (so that would just be 30kW, then) but I can guarantee you that a supermarket is not going to get a quarter of a million visitors in an hour (or to put that another way, more than 60 every second).

It's all just meaningless posturing, and it takes attention away from anything which might actually be useful. Any journalist reporting this as a green initiative ought to be ashamed of themselves.

• #### Re: (Score:2)

Maybe it's piezo-electric.

• #### Re:useful energy is not free (Score:5, Funny)

on Thursday June 18, 2009 @05:57AM (#28371779)

Say your car weighs 2 tons

Say that as loud as you want sunshine but the average car weight over here (Europe) is 1175 Kg, compared to 2000 Kg in the US. Of course this only adds weight to your argument . . .

Sometimes I even crack myself up.

• #### Re: (Score:3, Informative)

Just to be informative, the average curb weight of US cars is 3,239 lbs, or 1,469 kilograms. So not quite two short tons (although you might make it with four average mid-westerners and their groceries on board), and definitely nowhere near two metric tons.

• #### Re:useful energy is not free (Score:4, Funny)

on Thursday June 18, 2009 @09:52AM (#28374081) Journal
Hail to the imperial and other non-metric systems. Ideal for low mars flyovers.
• #### Re:useful energy is not free (Score:5, Informative)

on Thursday June 18, 2009 @08:14AM (#28372801)
The company that makes this system has some videos [hughesresearch.co.uk] that explain how it works.

From their FAQ:

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.

Seems to me like it probably works if it's deployed in the right place. So the idea seems OK.

But what about the numbers? The website claims it can generate 5-10kW. Looks like at least one of the plates moves about three inches (7.5cm). So, lets use their numbers:

10kWh = 36MJ. Taking your 18.1kN force from your 2 ton car, that requires a distance of about 2km. 2km / 7.5cm = 26700 crossings in that hour. Thats 7 per second. No, still doesn't add up.

Best you could reasonably hope for is a car every two seconds. That would give a distance of 7.5cm * 1800 = 135m in an hour. Your 2-tonne car falling 135m would generate 2.4MJ in an hour, so that's about 670W average. And that's assuming 100% efficiency. Likely this thing can power a streetlight or two.

But is it cost effective? Lets say it operates at that rate for 10 hours a day (pretty optimistic for a car park, but maybe on a busy road). 670W gives 6.7kWh per day, or 2400kWh per year. Electricity costs maybe 7p/kWh, so that's GBP171 (or \$270). No, this doesn't seem cost effective anywhere where you can get mains electricity.

• #### Re: (Score:2)

What if they could hook a device up to your engine block, and siphon off all the stored heat residing inside and use it to heat thier water? Its useful free energy (not withstanding the energy required to build such a system). And it would provide a valueable service.
• #### Re:useful energy is not free (Score:5, Insightful)

on Thursday June 18, 2009 @02:13AM (#28370437) Homepage Journal

This is just an gas powered electric generator, the likes of which rube goldberg would be proud of. You'd be better off siphoning a thimble of fuel from each car, selling it, and using the proceeds to buy electricity from the utility.

True but if you are going to build speed humps and waste energy that way, this may make sense.

• #### Re: (Score:2)

The only energy they can reclaim is that from going up the speed bump and that may be regained when the car goes down the other side of the speed bump (ie: car goes faster as it's downhill). It depends on the normal driving patterns of people (do they hit the brakes at the top of a speedbump?) and the efficiency of that downward energy reclamation.

• #### Re:useful energy is not free (Score:4, Interesting)

on Thursday June 18, 2009 @02:51AM (#28370671) Homepage

They can get energy from the downward motion of the plate on the speedbump as the car drives over the top of it. The car is now a little lower, so that's energy it can't reclaim. This energy would be offset a little by the springs required to push the plate back up again.

They might also be able to gain energy by absorbing some of the forward motion of the car when it hits the speedbump. That would be more in keeping with the usual purpose of speedbumps. Now all we'd need is a speedbump that could smoothly absorb & convert most of the excess forward velocity of the car (in excess of the speed limit, that is), then we could install them in residential suburbs everywhere and power all the streetlights with them.

• #### Hmmm (Score:2)

Traffic signals use active induction loops to detect ferrous objects above them. If you move a magnet through a magnetic field so that it crosses field lines energy can be recovered from the motion. Thats how generators work of course. But then you may as well use trains with linear motors instead of cars.
• #### Re: (Score:3, Funny)

You'd be better off siphoning a thimble of fuel from each car, selling it, and using the proceeds to buy electricity from the utility.

Where the hell would you get all those thimbles?

• #### Re:useful energy is not free (Score:4, Funny)

on Thursday June 18, 2009 @06:30AM (#28371951)
Sainsburys Market sells them in packs of ten.
• #### Re: (Score:2)

Of course the kinetic energy isn't free, but you're forgetting about how that energy goes to waste when non-hybrid cars brake. In a parking lot, chances are the car is braking and slowing down quite frequently. Also, many parking lots have speed bumps to control speed anyway. Unless every car there is a hybrid that uses regenerative braking to recharge a battery, my bet is that they're harnessing some kinetic energy that would otherwise be completely wasted via braking/slowing for the speed bumps.
• #### Re: (Score:2)

You'd be better off siphoning a thimble of fuel from each car, selling it, and using the proceeds to buy electricity from the utility.

Plenty of supermarkets ask customers to drive at a low speed in their car parks, and use speed bumps to encourage this.

How is this any different?

If you were going to slow the car down anyway, what does it matter if you get some additional use out of the kinetic energy the car loses?

• #### Re: (Score:2, Informative)

Nobody seems to have pointed out yet that Sainsbury's also sell fuel, so it's a win for them all round. The execs must have been pissing themselves laughing, "Hey, we've got this idea that we can pass off as 'Green Energy', and will mean our customers will be buying more petrol from our stores! Muaahahaha! Stick another swan on the fire!"

• #### Great (Score:2, Flamebait)

So when you drive in, it drains your battery to power their market. How the fuck is this 'green'?

• #### If I had an electric car (Score:5, Funny)

on Thursday June 18, 2009 @01:54AM (#28370321) Homepage Journal
...I could put these in my driveway, use it to charge the car and never have to buy energy again!
• #### lame? vampiring other people oil? (Score:2, Insightful)

is that energy extracted from the cars? then is not magically created, but just a inefficient way to suck energy from other people use of oil.

• #### Re: (Score:2)

Are those plates causing more oil to be consumed than would happen otherwise? Then it is not being magically wasted, but just a reasonable way of getting more energy out of the same use of oil.

• #### Re: (Score:2)

is that energy extracted from the cars? then is not magically created, but just a inefficient way to suck energy from other people use of oil.

It sounds to me (IANAPhysicist) like the energy is already being wasted, this is just using it. It harvests energy by pressing down on the plates, wouldn't the car driving over a strip of pavement use the same energy, except it wouldn't be reharvested at all?

Maybe not vampiring so much as collecting dropped change?

Maybe there's more friction moving over these plates though. In which case I'd say most of the drivers probably waste more energy driving around looking for parking spaces than they've lost to t

Greenwash

• #### it reminds me (Score:4, Interesting)

on Thursday June 18, 2009 @02:10AM (#28370413)
of the anecdote about Franklin and his entrance door. When a friend complained about how difficult was to push that door, Franklin explained that the door was connected to a ground pump and every time someone opened the door, 2 gallons of water were extracted as well...
• #### Supermarket, doofus (Score:4, Funny)

<jginspace@Nospam.yahoo.com> on Thursday June 18, 2009 @02:12AM (#28370423) Homepage Journal

England market produces green energy ... Sainsburyâ(TM)s market of England has installed âkinetic energyâ(TM) plates in the parking lot of itâ(TM)s store in Gloucester.

What atrocious writing. Sainsbury's [wikipedia.org] is a supermarket.

• #### Re:Supermarket, doofus (Score:5, Funny)

on Thursday June 18, 2009 @02:59AM (#28370731)
Quiet true. And it also doesn't have a parking lot either, it has a car park.
• #### This is so stupid it hurts (Score:3, Insightful)

on Thursday June 18, 2009 @02:14AM (#28370447) Homepage
As many other commented, the energy comes off course from the petrol engine of the cars. 1. The efficiency of this system from petrol to electricity must be really low 2. It creates pollution right where you don't want it, in the city: Exhaust fumes plus tire wear
• #### it's not green (Score:3, Insightful)

on Thursday June 18, 2009 @02:19AM (#28370489)

TFA calls it a "green energy project". The type of people who think this is green energy are the complete f-ing morons that side track the rest of us from real viable energy advancements.

Further more, the TFA claims this will "lower the energy consumption of the market". At the inefficiency of this (which is already limited to being no more efficient than a car is itself), it will actually increase the energy consumption of the market.

• #### Re: (Score:2)

it will actually increase the energy consumption of the market.

But it will lower their electricity bill. And isn't that the most important thing?

Mmm?

• #### Not energy generation, but still fine (Score:2)

Since people usually slow down anyway when they enter a parking lot, it makes more sense to convert the kinetic energy into something useful than have everybody just brake and convert it into heat.

• #### Re: (Score:2)

If you put it like this then it makes sense. But if anything, converting energy from braking/slowing down should be done in the cars themselves.
• #### Let's pave a road with that! (Score:2)

Hey if you pave a stretch of road with that, make the energy harvested available from a rail along the road and connect the engines of electric cars to that rail, do you get cars that can travel forever without spending any energy? OMG GREEN HOLY GRAIL!!

Also, pre-emptive 'whoosh' sound for anyone who wouldn't get it.

• #### Re: (Score:2)

I have read suggestions that pipes could be buried under roads to recover energy in the form of sound waves. Of course the energy you get that way is very low quality so using it to power (say) public lighting might not be straightforward.
• #### Isn't this just theft? (Score:2)

The car is climbing over the plate before it drops (or out of a slight dip after it does). This requires a little extra gas and therefore it's coming out of the customer's pocket.

I mean if this is "free" energy, why not pave the streets with them?
• #### Energy isn't free (Score:2)

Basically to generate 30KWH of power requires about 41HP. In this case, the power would come from the car pressing down on the plate, but the car must then use additional power to climb off of the plate. Cars are far less efficient at generating power than a dedicated power plant (ICE is at best around 24% efficient not counting losses due to the drive train, a power plant is typically over 40% efficient).

• #### Re: (Score:2)

Careful there, you're mixing energy (kWh) and power (hp).
30kWh is approximately 40.2hp *during an hour*

Granted, TFA and TFS didn't realize either that mentioning an energy without a time span is basically useless.
A nuke can produce 30kWh (in 50ms), so can my bicycle (in a month).

As mentioned in other posts, to produce 30kWh with 10% efficiency, they "just" need to steal 30l of oil during an unspecified amount of time.

Stupid technology + stupid submitters = Welcome to Slashdot!

• #### Put plates at the bottom of an exit ramp (Score:5, Interesting)

on Thursday June 18, 2009 @02:35AM (#28370605) Homepage

For those who are rightly saying this energy isn't free...
If the plates are positioned at the bottom of a downhill exit ramp, they will aid drivers braking, prividing kinetic energy without "stealing" drivers fuel. Somehow, I doubt this is where they will be positioned though :-)

(Incidentally... a similar idea was to build tram / light-rail stations on the top of small hills. Thus gravity assists the train in braking and accelerating away from teh station)

Oh and Sainsburys is a British Supermarket, not an English Market..... Big difference !
• #### Re: (Score:3, Interesting)

If the plates are positioned at the bottom of a downhill exit ramp, they will aid drivers braking, prividing kinetic energy without "stealing" drivers fuel. Somehow, I doubt this is where they will be positioned though :-)

Agreed. Sainburys seems to care about looking green, rather than being green. At their Kingston store the large Sainsburys sign has a smallish wind turbine and a solar panel attached to it. Trouble is the wind turbine is positioned between buildings, so it never gets a clear airflow,

• #### Green if it's for parking (Score:2)

I suppose as long as they install it only in the parking spaces where the cars are coming to a stop anyway, then it wouldn't really be stealing from the drivers/cars. It'd also help them save on their brakes as well.

Then again, this is Slashdot, so someone's going to point out that people may not park right the first time, or that they may be driving across parking spaces to get to the other side instead of on the designated driving lanes, etc...I guess I'll shut up now.
• #### Not to bitch and moan but,... (Score:2)

Don't want to bitch or moan. But isn't that just stealing energy from cars?
There's no such thing as free energy. It probably will cost cars extra to drive over the plates. That is, the 30 kWh come from fossil fuel. Way to go!
• #### This reminds me a story used in Superman (Score:2)

This reminds me a story where the guy stole fractions of cents from each Bank Account. Nobody noticed !

Who is going to stop going to that market because of this highly imperceptible extra charge ? In this perspective it is ingenious. But can you imagine cities going this route in low speed limit zones ? Where will it stop ?

Energy saving wise, it is no good, gas motor would use that energy more efficiently, there is always a lost when you transfer one form of energy to another.

As for the guy who stole fracti

• #### Energy vs Power (Score:2)

30 kWh is something, but how long does it take to collect that? 30 kWh for each car hardly succeeds!
It could be calculated for each year, maybe..

Anyway kWh is a measure of amount of energy, not power. If the plates power would be 30 kW, it would take one hour to collect 30 kWh. But 30 kW is way more than the car normally uses.

• #### Just converting kinetic energy into electrical (Score:4, Insightful)

on Thursday June 18, 2009 @03:06AM (#28370783)

Probably 2/3 of the comments so far seem to think this is some kind of perpetual motion machine con. Those people should be embarrassed.

It's not. It's simple. It's just slowing cars by converting kinetic energy into electrical, instead of dissipating it as heat in the brakes or converting it to potential energy like a speed bump.

There was a discussion a while back, I think here on Slashdot, about a device that used a revolving door to generate energy. It prompted exactly the same comments. What these people didn't seem to realize is, revolving doors have brakes, and that device replaces the brakes. Same damn thing.

Do you really think the engineers who designed this device didn't think it through? This reminds me why it's never a good idea to discuss physics on Slashdot. I leave it to psychologists to explain why there are so many kneejerk contrarians.

• #### Better uses of a good idea (Stairs)? (Score:2)

Wouldn't it be more useful to integrate such plates (smaller versions of course) in the stairs of your nearest subway station? Or any other public building? In cities like London, Berlin, Tokio, Paris, New York etc., etc. literally millions of people are using the subway. If you shut down the escalators you could even improve customer health) and generate even more energy! (just kidding :-)) Seriously though: At the core of the "smart", bidirectional and decnetralized energy grid of the future lies the
• #### Shock Horror (Score:2)

Newsflash! Supermarket requires customers to pay for electricity that the supermarket uses!

Next you'll be telling me that shop assistant's wages are paid by a small portion of the money that we hand over at the till.

Writing software is more fun than working.

Working...