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."
The plates create as much as 30 kWh of energy as cars drive over them.
30 kWh is 108 MJ. Say your car weighs 2 tons, well that's 18.1 kN of force it exerts on the ground. So your car would have to push one of these plates down a total of 5.9 kilometers to generate that much energy. Assuming that the plate only moves an inch, that's 238 thousand car/plate crossings to generate the quoted energy.
Rampant carbon sequestration destroyed the Dinosaurs' tropical paradise. I'm here to help repair the damage.
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...
rationalized leeching is still leeching. Perhaps you own a hybrid with regenerative brakes?
~.~
I'm a peripheral visionary.
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.
They can get energy from the downward motion of the plate on the speedbump as the car drives over the top of it. The car is now a little lower, so that's energy it can't reclaim. This energy would be offset a little by the springs required to push the plate back up again.
They might also be able to gain energy by absorbing some of the forward motion of the car when it hits the speedbump. That would be more in keeping with the usual purpose of speedbumps. Now all we'd need is a speedbump that could smoothly absorb & convert most of the excess forward velocity of the car (in excess of the speed limit, that is), then we could install them in residential suburbs everywhere and power all the streetlights with them.
Why would anyone engrave "Elbereth"?
If you put the plates on a downhill ramp, then the car need to move vertically anyway.
So instead of having to use the brakes to convert energy into waste heat, they can convert it into electricity.
A Parking house with multiple levels would be perfect if there are different lanes up and down. Or other descending roads.
We have e=m*v^2 - So the faster the plate can be pressed down, the more enery we will get, but there will also be some impact force. So the number can be much lower.
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.