Passing cars to generate energy for new UK supermarket

KW is already a measure of power, so why does it have another time component?

Good point. Maybe they meant 30 kJ?

Where is this energy goign to come from if not from the cars engine?

Where is this energy goign to come from if not from the cars engine?

good point - that basically means more fuel consumption => more CO2 => more environmental damage

Maybe the plates drop slightly creating the kinetic energy, converting some of the forward-momentum of the car into rotational energy.. thus slowing the car a small amount?

Wow energy for nothing? Are they having a laugh? So if you reverse over it do you get some back?

cars weigh over a ton. they are using the weight of the vehicles.

30 kW/h = 30 000 watts generated per hour.

This will inevitably slow the cars down. I suppose if the cars are going to slow down anyway, for example if there's a bend then it's better to put the energy into the store than just waste it by heating up the brakes.

It's quite a lot of power though- it's an average of 40 horsepower.

Maybe the plates drop slightly creating the kinetic energy, converting some of the forward-momentum of the car into rotational energy.. thus slowing the car a small amount?

cars weigh over a ton. they are using the weight of the vehicles.

30 kW/h = 30 000 watts generated per hour.

Paulo and moj85 are both correct. The energy harvested is pretty high, but it isn't free, of course. The plates are either set a little higher than the surrounding pavement, forcing the driver to give a touch more gas to climb the small incline, or they're level when the car begins to pass over them, and they sink a little, forcing the driver to give a little gas to climb out of the 'depression'. Either way, they're converting the chemical energy of the gas into mechanical energy to drive a linear or axial generator. It is a novel idea, but there are no free rides. And overall, the conversion efficiency would be equal to that of the car itself, (say, 25% tops) minus the generator and transmission losses. There are lots of other ways to produce so-called 'green' energy that have much higher efficiencies, but upfront costs might be higher.
Also, contrary to the statements in the article, it would indeed affect the vehicle's fuel efficiency, but averaged over a tank full of gas, it would be negligible. (Unless all the driver did was go back and forth over the plates all day).

In a way, it's as if the store installed a conventional gasoline generator to run part of the facility, but then forced every carload of shoppers to pay some small amount to fuel and maintain it. That would probably be a cheaper alternative, since efficiencies would be higher, but of course you would have to disclose it to the drivers--this way nobody knows...

Oh please people. You act like this device makes you burn a bunch of gas to get over it. You act like this is going to take a lot of money out of the customers pocket. Give me a break. If you look the picture, that plate is no more that 1/2 inch off the ground. Heck, I've driven over cracks in the pavement worse than that. The momentum of the vehicle can get a car over that easily. If people were truly concerned about gas and fuel efficiency, they'd try other methods that would save them a heck of a lot more money/gas such as driving the speed limit. I get 5-7 mpg more if I simply drive the speed limit.

I commend this business for at least trying and caring to be green. Not every answer is perfect but at least they care to actually do something.

Oh please people. You act like this device makes you burn a bunch of gas to get over it. You act like this is going to take a lot of money out of the customers pocket. Give me a break. If you look the picture, that plate is no more that 1/2 inch off the ground. Heck, I've driven over cracks in the pavement worse than that. The momentum of the vehicle can get a car over that easily. If people were truly concerned about gas and fuel efficiency, they'd try other methods that would save them a heck of a lot more money/gas such as driving the speed limit. I get 5-7 mpg more if I simply drive the speed limit.



I commend this business for at least trying and caring to be green. Not every answer is perfect but at least they care to actually do something.

It's great to see a post with some common sense.

This is basically either tax or theft. They make the car work harder and use the excess energy. The energy came directly from the driver's fuel tank.

Oh please people. You act like this device makes you burn a bunch of gas to get over it. You act like this is going to take a lot of money out of the customers pocket. Give me a break. If you look the picture, that plate is no more that 1/2 inch off the ground. Heck, I've driven over cracks in the pavement worse than that. The momentum of the vehicle can get a car over that easily. If people were truly concerned about gas and fuel efficiency, they'd try other methods that would save them a heck of a lot more money/gas such as driving the speed limit. I get 5-7 mpg more if I simply drive the speed limit.







I commend this business for at least trying and caring to be green. Not every answer is perfect but at least they care to actually do something.

It's great to see a post with some common sense.

Sorry. No common sense. I'm a physicist and this is a VERY inefficient petrol powered generator.

"The system is expected to produce about 30 kW of energy per hour"

I find this interesting. I remember reading or seeing something about this idea being used for a sidewalk or something like that, but that each person in a city of millions over their entire lifetime would generate only enough electricity to light a decent wattage light bulb for like 1 second. I know the weight and speed increases from driving over these panels in a vehicle would obviously generate more power using this method, however, it seems like a huge jump to generate that much more power than the last capabilities I heard of. If its true, bravo, great strides were made in this, and where can I get these panels to do my house and garage flooring in for cheap :)


corban-its a measure of the tiem it takes to produce 30KW of power potentially. You are thinking of kwh (kilowatt hours) I think....which is absolutely fine since you are giht I think, and they are using the phrase "30KW per hour" in place of the proper way of waying it as 30kwh...from my limited electrical non expertise...


lord jag-i hear that kind of statement alot...and this is my response to your particular statement...it does not matter where the energy comes from because it is free energy no matter which way you slice it or dice it. Yes, in one frame of mind you can say the energy comes from the engine because the engine drives the car that is going over the panels, right, I agree, in that mindset. However, if you really look at it, and this is the point I can never seem to get across to anyone correctly, so I try yet again...
the engine is already driving the car, you are already using its power for another use..if you were on the road and not in this stores parking lot, then you would still be using your engine right...so, if these panels were not in the parking lot here, you would still have to use your engine to drive onto the parking lot to park and get your smokes (or fags if your english..lol) right, so if those panels are there, they are collecting power from an action that your engine would be performing whether or not they were there. In my thinking, this therefore equates to the engine utilization being null and void, and the panels are collecting absolutely, positively free power by making use of what is in todays day and age, a natural event. No different than using the wind or sun for power. In fact solar power is a DAMN good example here to use too...the sun gives off what, 9 fkn trillion hiroshima bombs per second of energy in the form of light...under your thinking, if i understood your thinking right that is, that would mean that solar power is not free because the sun has to exert energy for us to collect it.
To me, this isnt a cause and effect thing, this is an effect and effect thing. Using the solar example, the cause is the sun burns its fuel, the effect is energy in the form of heat and light, and the effect of that is we can gather that energy using solar panels to generate electricity at no cost for power generation.
My thinking on the parking lot panels here is the same...the cause is that you needed to go to the store for diapers, cigarettes, beer, and a porno magazine right, the effect of which is you have to drive to the store (and through their parking lot), the effect of which, with the panels in place, is that electrical energy is gathered via kinetic means...another effect and effect, which equals free to me :)
Ok...shit...I think I confused myself now....


alex-electric or hydrogen powered vehicles, which will be here in full force sooner rather than later....there is no output from those as you describe...

Moj-why does the car need to be slowed? power doesnt need to be withdrawn from the engine necessarily...a simple magnet and coil design could do this without withdrawing power form the engine providing enough pressure is exerted to move the magnet through or over the wire coils...aka, it seems like its been possible for a century...




Hell to make it shorter than it wouldve been, and sweeter, yes, of course you need an input ot get an ouput, BUT, if it is something that is going to be done anyways (such as the fact the sun IS going to shine on a clear day), that effectively makes it free energy.

30 kW/h is nonsense.

30 kW/h = 30 000 watts generated per hour.

This is sad reflection of the state of our educational system.

Watts are already a derivative of energy with respect to time. If you are generating one watt of power you're generating 1 joule of energy every second.

The only way to make sense of 30 kW/h is as an accelerating energy production, for each hour that passes your power generation increases by 30 kW. If you start at 0 watt you're expecting to generate as much power as a 1 GW nuclear reactor in just 3 years and 10 months.

This would be theft of energy except for the fact that you presumably need to slow down as you enter the store's parking lot, so as to avoid running over people and to get parked and all.

An interesting idea which points out as well as anything I've seen lately that the devil is in the details.

Properly done, this basically amounts to regenerative braking, just an external version rather than on-board like on a hybrid vehicle.

***

It's nice to see I'm not alone in the dismay over many writers showing no ability to grasp the whole power = KW and energy = KW-hr thing. Even physorg, sigh.

...that you presumably need to slow down as you enter the store's parking lot, so as to avoid running over people and to get parked and all.

Based on what I've seen going in and out of the parking lots in my area, I wouldn't necessarily make this assumption! ;)

Soylent, I don't know how to respond to that - your statement makes no sense at all. I'll try to put it simply so you might understand....

kW h, or Kilowatt hours is the product of power in kilowatts and time in hours.

The electricity company where I live charges 18 cents per kW h, meaning they charge 18 cents for every hour you use 1 kW of electricity (a kilowatt is 1000 watts, btw) - if you have a 1000 watt heater running for 1 hour it will cost you 18 cents. Understand? This is how they measure electricity usage. Kilowatt hour, or kW h. It is equal to 3.6 megajoules.

Why don't you have a look at your electricity bill.

And have a look at this while you're at it...

http://en.wikiped...att-hour

Soylent, I don't know how to respond to that - your statement makes no sense at all. I'll try to put it simply so you might understand....

Then don't respond. You're clearly too incompetent.

kW h, or Kilowatt hours is the product of power in kilowatts and time in hours.

What does this have to do with ANYTHING? We're talking about kilowatts PER hour.

As anyone can see you yourself said: "30 kW/h = 30 000 watts generated per hour."

Either your reading comprehension is lacking or you're so embarrassed to admit that you said kW/h that you have to resort to lying.

The electricity company where I live charges 18 cents per kW h, meaning they charge 18 cents for every hour you use 1 kW of electricity (a kilowatt is 1000 watts, btw) - if you have a 1000 watt heater running for 1 hour it will cost you 18 cents. Understand? This is how they measure electricity usage. Kilowatt hour, or kW h. It is equal to 3.6 megajoules.

That's nice dear, but would you mind calling them up and asking what the take for a kilowatt PER hour?

If you go to Sainsbury's Gloucester store website

http://opening-ti...oucester

you will see that they are not a 24 hour branch so PERHAPS they are saying that sufficient energy is accumulated to power their check-outs with 30 kW over the 11 hour shopping day. There again PERHAPS the writer doesn't have her Physics "O" level.

Too true, Soylent. a "watt per hour" (watt/hr) is meaningless, unless it has to do with a change of power over time. A Watt-hour is the energy equivalent of running a 1 watt bulb over the course of one hour. Poor article writers :/

It's great to see a post with some common sense.

Not really.

In a normal shop the energy needed for running it is funded by the customer by adding a little on top of the price of the products.

In this shop, they get the this by borrowing a little energy from the cars of the customers by using this system.
So the customer can buy the products e bit cheaper but pays more for running the car.

But now the system has to be bought, installed and maintained and that has to be funded by ... indeed, the customer.

So now the customer pays 2 times for the energy and the electricity is now produced by inefficient engine in stead of an efficient powerplant.

So both the customer and the environment are worse off by using this system.

Micro theft is the wave of the future. If your car had regenerative breaking then you just got bitten by an energy mosquito.

You want energy from cars driving into your lot?

Well, just imagine this scenario: locate the parking lot on a decline. The cars come in on a movable long ramp initially held up by springs - the weight of the car would cause the ramp to descend and run a generator. Being a long ramp, the car would not have to stop and would continue and would not have to brake as much because the decline is not as severe as without the moveable ramp.

Practical problems aside - and yes there are many for this to be workable - if a plate raised by 1/2" generates as much energy as the article indicates, with a sufficient slope, this baby should make enough to power the market and sell back to the grid :-)





Are you stealing energy?

Not really, because the cars would have to use brakes to keep from speeding down the slope.

Don't parking lots have speed bumps anyway?

soil lint, my bad, but there is no need to shout, or insult your fellow man.

I did indeed put a slash where there should be no slash.

So you can walk away with your head held high knowing that you have won this online argument. You are indeed the chest-beating male monkey of far superior intellect, and I, the submissive monkey, will crawl away to the other side of the pen to eat my fleas, and watch you have intercourse with your harem of females, and bash all other male monkeys into submission.

As a positive side-effect of our little tete a tete I have learned something.... and I'm sure that it will give you a warm inner glow to know that you have saved me from the ignominy of ignorance as regards the Kilowatt hour.

Thank you, my friend, I have learned the error of my ways. My infinite gratitude goes out to you.

Much love, Paolo.

The only way this could avoid impacting cars' efficiency is if it's on a downhill slope or if the car is braking when it hits the plate anyway (and the car is not a hybrid.) Otherwise, it is false to call this system "green", and it is also taking a (trivial) amount of money out of the customer's pocket. Of course, speed bumps take a much larger (but still trivial) amount of money out of the customer's pocket. The whole article is much ado about pennies anyway.

So they're ripping you off before you even enter the store!

Technically, yes. :)

That kilowatt-hours convention ALWAYS bugged me. I guess it makes sense for the power companies to bill me in terms of their rate of production... but couldn't you just tell me how many joules I used in the month?! And charge me based on that? Or maybe eVs, just for shits and giggles? :)

One way to explain it to people is that electricity is like water coming out of a hose. The system needs to provide the stuff at the rate it is demanded, so the focus is often on generating capacity. But when it comes time to send customers the bill, you need to charge for the number of buckets they used. It is very awkward to talk about the flow rate and how often it flowed, but quite easy to count the total number of buckets over a month and simply charge by the bucket.

water : electricity
gallons : kilowatt-hours
gallons per minute : kilowatts

From which one can you see that the term 'hours' shows up in the opposite case, which is very much counter-intuitive for most everyone.

[Way to go paulo, nice post - I've seen a LOT of well-qualified engineers make the same mistake. I once had a Mech Engr'g professor spend an entire hour on this subject and end up confusing almost everyone by the time he finished. :-) ]

That portion of industry which deals with kilowatts is focused on amps and volts. Joules and J/s are rarely used as units.

electricity is generally measured in kWH. The cars are slowing down as they enter the parking lot, so the energy stolen would have been used to heat up the brake rotors.

There was an article some months back exploring this idea on street pavements and another on sidewalks(heat absorption. Whether they succeed or not, BRAVO! for trying to inspire something creative and clever (instead of twiddling their thumbs at a safe distance with negative condemnations).