English Market Produces Energy With Kinetic Plates

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."

Comments

useful energy is not free

[seanadams.com]

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

[MichaelSmith]

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:useful energy is not free

[Kickboy12]

Another Point: You ever driven in a parking lot? Count the number of speed bumps you go over. I wonder how "fuel" the stores are "stealing" from you by making you drive slow over these bumps. Replace those with plates. Might actually get some energy while making people drive slower at the same time. What a concept!

Re:useful energy is not free

[Rakishi]

So it'd be the same as dropping a giant stone on the plate? Free perpetual energy? No? Then where is the energy coming from? Remember those pesky laws that keep perpetual motion machine from working?

The energy doesn't come from gravity but rather from the potential energy of the car via gravity. The car has to gain that energy from the kinetic energy of it's engine somehow since nothing is free.

Let's say the plate is 1cm above the ground with no car on it. The car's engine exert extra energy to raise the car onto that 1cm plate. The plate then falls and takes that energy from the car by dropping it back to it's previous height. Had the plate not been there the car would not have used the gas needed to generate the energy to raise it 1cm against gravity.

Sort of sad how little physics is taught in school nowadays that people actually believe energy can come from essentially nowhere.

Re:useful energy is not free

[fractoid]

OK, let's put the cars bumper to bumper at 15km/h (which is about usual for a car park) and assume they're 5m long and have a gap of 3m between them. Any given plate would then have a car moving over it every two seconds, or 1800 times an hour. They're going to have to have 132 plates to generate that amount of power per hour, and realistically they'll need at least twice that many.

Re:useful energy is not free

[MichaelSmith]

Well maybe they can integrate it into the bazillion speed humps then. The energy may not be "free" but I certainly think all the arguments I've read on this article are ridiculous. The energy "Stolen" from drivers would be negligible, most of the energy would be coming from that wonderful thing called gravity!

How can energy come from gravity, other than building a one way system when things up high (say asteroids) and moved to somewhere low (say Sydney) and the potential energy recovered in the process.

Re:useful energy is not free

[Viol8]

You're wasting your time trying to explain this I'm afraid. Some people are so utterly clueless when it comes to basic physics that it would be funny if it wasn't such a sad reminder of the state of schooling these days.

Re:useful energy is not free

[Peet42]

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.

Just converting kinetic energy into electrical

[theodicey]

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.

Re:No such thing as free lunch...

[BeardsmoreA]

No. But afterwards, if you didn't give the engine any gas during the process, it would be moving slower. As lots of people have tried to point out, this might be desirable (see speed bumps). If the driver is just going to accelerate back to speed however, you have gained nothing.