Slashdot Mirror
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."
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.
...I could put these in my driveway, use it to charge the car and never have to buy energy again!
http://michaelsmith.id.au
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...
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 is a supermarket.
It's not leeching. The cars are slowed down at the point at which the cars should be slowing down anyway - they're coming into the car park. The 'kinetic energy' device helps where the vehicle's brakes would normally be doing all the work. Bin the TFA, see this insightful article from yesterday's Guardian.
Wait, so the plate drops down and it makes some power, how does your car get out of the now slight pot-hole? Why it has to drive forward, which (considering you are driveing up a very brief and very small hill) uses a tiny amount more fuel.
There is never, and WILL never be a free ride, all power comes from somewhere.
...
rationalized leeching is still leeching. Perhaps you own a hybrid with regenerative brakes?
~.~
I'm a peripheral visionary.
Technically, you're right. Practically, cars waste such vast amounts of energy that the energy drain for this thing (about equivalent to driving over a small bump) probably couldn't even be measured.
People don't understand just how much energy cars use, because car engines are typically measured in horsepower rather than in kilowatts. But it's the same quantity --- they're dimensionally equivalent. It's instructive to play with Google's units converter a bit: the Tata Nano, the world's cheapest car, has a crappy little engine producing 33 horsepower. That's 25 kilowatts, which is slightly more than the entire electrical supply to my house. A typical racecar produces about 400 kilowatts. A medium model wind turbine (with a 50m tower) produces about 600 kilowatts.
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 !
Anyone quoted by a reporter knows how little they understand
Don't believe what you read is the truth.
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.
I once measured my cars efficiency (an old Renault 5).
I drove 100 kph (28m/s) on a flat freeway, with no wind, and set the gears in neutral. It took the car about 30 seconds to slow down to 90kph (25m/s). The car weighs about 900kg.
So we have E0=0.5*m*v*v = 353kJ and E1=281kJ. The car lost 717kJ in 30 seconds or 2.4kW
So it takes just 2.4kW to keep a small car cruising at 100kph on a freeway. The stated gas consumption of that car is about 1 liter/18 km at 90 kph so 1.3 ml/second of gasoline. Gasoline has ca 32MJ/l energy content, so 1.3ml/s is equivalent to 44kW.
The system efficiency of a car cruising on a flat freeway is about 5%!
Do the experiment yourself and see what numbers you come up with. It's also a really good highschool experiment.
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.