June 16, 2009: Kinetic Plates
 

Sainsbury's stores in the U.K., looking to cut costs, have built new stores with kinetic plates in the parking lot.
Cars driving over these plates cause them to deflect, and the deflection is transfered to electric generators
which produce an expected average of 30kW of energy an hour. That's enough power to run all the check outs.

http://cellar.org/2009/plates.jpg

It all helps and they expect a 2 year payback.


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This is NOT Green Energy
 

This is the opposite of green energy. Any energy collected from cars is only as green as the energy used to drive those cars, minus efficiency losses in the plate system. A car's engine is already much less efficient than any source of the electricity through the land line, and adding in another system reduces overall efficiency in a very non-green way.

What this system does do is rob customers of (granted, minute amounts of) fuel energy, so the overall cost of this system considering everybody involved is greater than before. Granted, the shop saves money after 2 years, which is sneaky, but not nearly as sneaky as touting this as a green improvement.

I don't agree
 

There's no doubt cars are anything but green, but these plates are simply collecting energy that would otherwise be lost anyway. It's the same concept as the backpack that charges your mp3 player or laptop from the bouncing of your motions.

Instead of powering the checkouts from a city generator, it's using the energy from the cars passing by. The compressions from the weight of the car shouldn't be very great, so driving across the plate should not sap any more energy than driving over uneven asphalt -- the same energy lost through everyday regular driving. Instead of losing that bit of energy to earth, some of that energy goes to drive a generator.

It may be true that now car drivers are paying for the energy to power the checkouts, but note that it's not one driver powering them. Tens, if not hundreds, of cars pass over the plates to refuel a day, so that each individual driver probably loses a few dollars of gas energy a year to compressing the plates with the weight of their cars. The loss is almost nil, and cars lose more energy driving over bumpy roads than a flat plate anyway.

This system recycles energy that would otherwise be lost, and is "Greener" in the sense that it uses that energy rather than energy from a municipal power plant.

It depends on whether that is a point cars were going to have to brake anyway. If it is used as a slowing device in place of speed humps, then it is grabbing energy that would otherwise be wasted, and so counts as green. If it is anywhere else, it isn't.

I'm more :eyebrow: about the 30kW. Thirty kilowatts? (what the hell is a gigawatt?) From cars rocking a metal plate? That is enough to run several houses. They must be expecting a whole lot of cars.

Welcome AdamTheMechE.

I totally agree. It is ripping off the drivers. There is no free energy. If those plates deflect then the cars have to drive up off of them. I have a really hard time believing 30kW anyway. That's like a 40HP engine running all the time.

Oh I completely agree with this. Totally cheeky lol.

Nice to meetcha Adam, welcome to The cellar :)

I suppose it's much greener for the gubermint to raise taxes on gas that costs each driver thousands each year. Now that's greed...er, green.

I'm glad they are at least making an effort to produce additional energy. Too many people are scratching their heads and ridiculing everybody else's attempts instead of getting off their ass and trying to come up with a solution themselves.
I think it's a good idea.

I like how these articles never mention the power required to design, prototype, produce, transport, install, maintain, repair, decommission, & dispose of these energy recovery systems - it's vastly more than they will ever "recover".

So let the cars run over a plate & collect a coupon for the store at the other side and keep everybody happy. Seriously, innovative technologies seem always to be ridiculous and inefficient to start. As an experiment that will be monitored and tweaked, I think this could be great. Next they should try out my idea of installing zillions of pinwheels between lanes on highways to collect the wind energy produced by passing vehicles. Hey, someday it will all seem normal.
Some day. ;)

i defend this practice. "green" is too nebulous, but i believe it is worthwhile.
this is the consumer face of innovation; a visible, profitable design. perhaps this isn't the best work, it might be stealing energy from the cars, or contributing to the false impression that driving can be healthy, but it demonstrates the technology and feeds money back to research.
would you like to see houses with exterior walls that power the lights? what about lumbar support in your computer chair that powers your computer? you'll get these things and many more if the technology is popular and profitable.
"the better is the enemy of the good." --voltaire

ps. welcome, adam.

Green? I see no claims that this is "green". Just recycling and I'm all for that.

And for those folks who bemoan the wear and tear of driving onto and off of one of those plates, in my neck 'o the woods, a plate like this would be an improvement in most parking lots! It would actually give me x number of smooth feet to drive across. :p

Welcome to the Cellar, Adam!

My Sainsbury's in Greenwich had solar panels and three wind turbines. I've no idea whether they did anything useful, but seeing them there made me at least think they are trying.

Used to make me even more mad when the person in front of me at the checkout loaded up a trolley full of shopping into disposable carrier bags...

Umm...I use disposable shoppng bags...but then again I reuse them ...as bin liners and as a place to store paperwork

I use a shopping trolley.
Yes, I have a granny shopper and I'm proud of it.
Dad likes it because when I go to Tesco they give me 5 green points on his Clubcard. Mingy old Sainsbury's only count it as one point on my Nectar Card.