June 16, 2009: Kinetic Plates

[xoxoxoBruce]

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.



It all helps and they expect a 2 year payback.


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[AdamTheMechE]

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.

[Eclipse]

Originally Posted by AdamTheMechE

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.

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.

[DanaC]

Originally Posted by AdamTheMechE

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.

Oh I completely agree with this. Totally cheeky lol.

Nice to meetcha Adam, welcome to The cellar

[ajaccio]

Originally Posted by AdamTheMechE

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....

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!

[Degrees]

I'm not sure that electricity is all that green. A lot of electricity energy is lost as heat during transmission through the land line. Sure, an automobile engine may only get 30% conversion of fuel to motion, but fuel burning electrical plants have the same problem. Somewhat higher efficiency - but nowhere near 60%. And gasoline doesn't lose energy as it sloshes around in the tank. Electricity loses power every meter it moves.

[Diaphone Jim]

It is amazing how much comment, and how quickly, some threads generate.
It is obvious that stores need to install "kinetic plates" in the aisles to capture the energy from all those shopping trolleys.

[spudcon]

Originally Posted by Diaphone Jim

It is amazing how much comment, and how quickly, some threads generate.
It is obvious that stores need to install "kinetic plates" in the aisles to capture the energy from all those shopping trolleys.

Great idea! The fatter the shoppers, the more electricity generated, and calories burned. Everybody wins!

[SPUCK]

Originally Posted by Degrees

Somewhat higher efficiency - but nowhere near 60%.

Um, yes, actually they do get better than 60%.

[glatt]

We have speed bumps all around my neighborhood. It would be awesome to put these things in instead. (Assuming the snowplows don't destroy them.) In fact, I'd like to put one in front of my house and plug it in to our electrical system (on our side of the meter.) Slow the damn cars down as they speed by, and power my house at the same time.

[ZenGum]

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 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.

[SPUCK]

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.

[spudcon]

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.

[capnhowdy]

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.

[todd_brannigan]

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".