English Market Produces Energy With Kinetic Plates 404
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."
Re:useful energy is not free (Score:5, Interesting)
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.
What kind of journalism is this? (Score:1, Interesting)
"The kinetic plates are only one of many green energy projects that Sainsburyâ(TM)s hopes to incorporate in its stores". Yeah, because generating electricity from combustion engines operating in a very inefficient regime is fantastically green...
If this had been the average journalist I'd have given credit for ignorance, but this guys bio says that he's an "energy technology examiner", a "student in robotics" "working on a new process for harnessing wind energy" who hopes to make "a huge impact one day in the field of science."
I think he has a little way to go...
it reminds me (Score:4, Interesting)
Re:leeching energy from cars (Score:4, Interesting)
rationalized leeching is still leeching. Perhaps you own a hybrid with regenerative brakes?
Put plates at the bottom of an exit ramp (Score:5, Interesting)
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 !
Re:useful energy is not free (Score:3, Interesting)
Although I agree with you and all posters above, from what I get from the article this is just (an expensive ?) way to /create/ energy in an extremely inefficient way.
That said, I do wonder if it wouldn't be possible to somehow harvest some "free" energy from such a system, assuming the car-park is BELOW GROUND.
=> assuming the car-park is located below ground, the car will need to drive down a ramp anyway
=> if we replace that ramp with a series of 'steps' that are "pushed up" by an internal spring-system, when in 'neutral', each next step is 10 cm lower than the previous one.
=> the car will arrive at ground level (0), drive on the fist step and the step will "sink" say 10 cm.
=> as a result, the step is now level with the second step, and the car simply drives on it "horizontally"
=> again, step 2 will sink about 10 cm due to the weight of the car, while step 1 veers back up because of the internal springs
rinse & repeat...
I guess it'd probably be 'more efficient' to have 1 giant step that goes down the full 3m or so, but it would make the process more cumbersome (drive on, wait, drive off, wait for platform to rise again etc..), while the 'steps' in fact can simultaneously function as a speed-lowering device (if you drive down to fast, the steps will not have time to be pushed in completely and you're in for a 'shocking' ride).
Off course this still 'steals' away some of the car's fuel as you now need to "drive the whole way down horizontally" instead of just coasting down, but then again at least some of the braking power would be converted to useful energy instead of heat.
just my 2 cents...
Re:useful energy is not free (Score:4, Interesting)
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.
Re:useful energy is not free (Score:5, Interesting)
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.
Re:Put plates at the bottom of an exit ramp (Score:3, Interesting)
Agreed. Sainburys seems to care about looking green, rather than being green. At their Kingston store the large Sainsburys sign has a smallish wind turbine and a solar panel attached to it. Trouble is the wind turbine is positioned between buildings, so it never gets a clear airflow, and the solar panel is positioned facing East. East? What were they thinking?
Cars waste 95% of gasoline energy when cruising (Score:5, Interesting)
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.
Re:useful energy is not free (Score:1, Interesting)
Our most efficient cars are just as efficient in generating "useless" heat energy as they are turning our tires. So yes extracting heat from the engine (just not too much) and putting it useful work is an excellent idea.
On the other hand sapping energy from moving vechicles is a selfish endeavour that does not positivly contribute to society. People can justify being selfish till they turn blue in face but it doesn't change the fact that they are still selfish.
I always believed that with the advent of hybrids it would be practical to build gas engines out of ceramics and raise the internal temperature since they were no longer directly connected to the drive it should be practical to manufacture?
Re:useful energy is not free (Score:3, Interesting)
...which can be used to do work. Otherwise you better hurry up and let the people over at the hover dam know their master plan isn't working.
This scheme is obviously sapping energy from your car, but if it could be done in a place where you want to remove energy from your car (i.e. when you're braking) it could be a net positive. That said - I don't think this is ever going to pan out.
On a somewhat related note, a while ago there was some work being done on placing a piezo insert into soldiers boots, and having the impact of marching to charge their batteries. It turns out, that walking on a piezo is a lot like walking on sand, and the soldiers performance suffered, and the whole idea was scrapped.
Re:useful energy is not free (Score:2, Interesting)
It's not driving that's a problem.
It's true that most parks have speed bumps - but the point is that I suspect many people find these annoying too. They simply accept them as a necessary evil, for those who might drive fast and cause an accident.
But installing bumps for the purpose of stealing energy? That'd be much more unpopular. The fact that Sainsbury hide this fact, and instead claim that it's "green energy", and falsely state that the car doesn't lose any inefficiency from the systems, suggest that they are well aware what customer reaction would be if they knew the truth.
Either that, or they also are just plain ignorant of basic scientific facts.
Imagine someone going into the store and picking up a grape everytime they went in. It's only one grape right, they won't miss it, and there's always grapes that go missing or rotten or dropped at the end. So surely they can't disapprove, and isn't this a revolutionary system to create grapes that would otherwise be wasted?
No, you'd be done for shoplifting. In fact, I remember when I worked there years ago, they explicitly warned us that even eating a single grape would be treated as theft.