Commuters' stamping harnessed for power

They're not stamping! They're just walking, or perhaps treading. Granted, some of them might be having a hissy fit, but on the whole, people don't stamp around in train stations. BTW, the system is piezoelectric.

Got to set one of these in every marathon path or race track.

Well, one person may generate 1W. At the same time on the panels, there might be 10 persons. So, could be that 10 W is generated. Now, one simple neon light nearby will take more than this 10 W. The system needs service and a control computer. Also such control might take more than the estimated 10W. The missing number here, is the expected power, the passenger on the platform will generate. There are plans for such power generation for personal mobile use (including military). Still the power per person is limited to a value in the range from 1 Watt to 5 Watt.

Looks not like a realistic energy saving. As comparison, solar panels start to make sense, when you have an installed power of 1kW or more. Then a loss of 10% (let's say 100W) in the control of these solar panels can be accepted.

Here is a more precise number: http://www.japanfs.org/en/pages/027023.html

It says the power generated is 100W for 80 minutes per day. Or in average 100 divided by 18 = 5.5 Watt if the power is assumed to be continous. So the assumption of 10W I gave before was even to optimistic.

And from JR

http://techon.nikkeibp.co.jp/english/NEWS_EN/20061017/122345/

On the first day of the test, the total output generated from early morning to 14:00 reached approximately 1 Wh. "The output is small and it will take some more time to finish verification on durability and other factors before the actual debut," says a source from JR East.

For 1W*hour over 8 hours, this means 0.125 W average power. Less than 1 mobile needs.

Then, more recent: http://techon.nikkeibp.co.jp/english/NEWS_EN/20081204/162357/

JR East expects a generating capacity of total 1,400kW/sec per day.

This means in average 388 W. Comparable to the power of one Personal Computer with Monitor. Big effort. Marginal savings.

I'm just sitting here watching the wheels go round and round I really love to watch them roll.

J.L

theres a bar in london which has this and the dancefloor lights up when people dance on it

If they can get this to work its great. One thing Tokyo isnt short of is people. Agreat peice of lateral thinking.

electric2004,

JR East expects a generating capacity of total 1,400kW/sec per day.

This means in average 388 W.

This is where you get it wrong, dude. Just like a lot of not-so-technical people, you confuse the concepts of power and energy. Power is actually the amount of energy used (or generated) during a specific time interval, generally one hour. So if a light bulb has the power of 100 W it means that during one hour it will use 100 Wh, or 0.1 kWh of energy (notice that it's watts times h, not watts per h). Similarly, a power plant with an installed capacity of 1 MW will generate 1 MWh of energy every hour. We define the capacity of a device in power units because the energy it will consume (or generate) depends on the amount of time it works. You probably get the idea by now...

As such, 1,400 kWsec (energy) means about 388 Wh, or 0.39 kWh. If this energy is generated per day then the installed capacity of these piezoelectric panels is roughly 5.83 W. Which is really small!

But I guess the idea behind this experiment is not to light up Tokyo, but merely to prove that the technology exists and works, and of course it can be further perfected. 5 watts is still better than 0 watts, in my opinion.

do you get more watts for fatties? if so this experiment should have been run in the states.

Bill

JavaChip:

It is not my fault that the web-site wrote 1,400kW/sec per day. Like you pointed out, it should be an Energy of 1400kW * sec = 1.4MJoule. And this energy is generated during one day. Then this is 388Wh (as you wrote). Exactly as you mention I forgot to divide by 24 (hours per day). This is my mistake.

Finally, this means an average power of 16.2 W

Somehow a factor 2.8 different from your number 5.83W.

we must harness the power of the Lemmings: Next step is hamster cages (rotating type)

Or small turbines in rain water pipes.

Hey, I've got a great idea! Lets make an economic system where everyone is herded and funneled like cattle across a threshold that generates power! If we can just enslave enough of these dupes we can save the planet from global warming! Wow... I'm brilliant! Now if we could just stop all the cattle from farting... Hey, I've got ANOTHER great idea!...

Good idea anyway; proof of concept.

how about those heavy doors for entrances or exits? Or revolving doors? wouldn't you make more energy from moving turnstiles and doors connected to generators rather than minor piezoelectrics? then they wouldn't waste all that electricity for control systems. Instead, use a water pump, and as they walk through, water is pumped vertically into a container. Then the water downwards can make a consistent electricity like a waterwheel. Again probably not much, but not zero either.

this is all mechanical-age stuff, clocks, gears, potential energy etc. digital age can't compete as it always takes electricity for itself first. Basic use of Thermal is always easier (and cheaper) than swanky solar panels and gadgets.

heck, why not put a bowling ball on the arm of the gate, then move it back and forth all day long? Bigger mass, make it lightly magnetic and it'll make way more energy. It'll be perfectly weird for Japan too

just one last idea....;) why not generate energy from the trains as they enter the station? you're never going to get perpetual motion no matter which idea is used, so these are all exersizes in saving from declines. ie: regenerative braking etc. but reclaiming some efficiencies instead would do a whole lot more. Otherwise it's like throwing out bicycles while recycling yogurt cups.

if you really want to save energy, just get rid of the trains and have people walk along the train lines.

so in order to comb at global warming Japan is spending huge amounts of energy making near useless devices like this. next thing will be making everyone buy an "ecoback" to save the environment. you can't make an omelet without killing the chicken.

you can't make an omelet without killing the chicken.

Sounds like a joke proverb George Carlin would have made up. Only, I don't think you were going for humor, which makes it so much more funny!

Anyway, interesting tech. I would like to use this to have cars going by power my hoard of vending machines...if I had a hoard of vending machines.

sf2k:

Regenerative braking exists for trains. I know it for the ICE train running in Germany, but I am not sure about the local trains in Japan. Regenerative braking increases the complexity of the inverters, which drive the motors in the train. So it depends on what the train company orders. 2 quadrant inverters for accelerating and breaking without putting energy back into the network (the braking energy goes into resistors as heat) or real 4 quadrant inverters, where braking energy goes back to the network. As good example, the Toyota Prius has such 4 quadrant inverters, but it is not a train.

This experiment

Very relevant point which many armchair experts have overlooked - let's see how it works first before rushing to judge it, though I doubt we'd expect to see such follow up on JT.

Thinking of energy savings ... recently the small chargers for mobile phones and games and so on have become less energy consuming and more efficient. Until recently, each of such chargers, if equipped with a standard 50 or 60 Hz transformer would take in 5W from the power grid. Unfortunately, small transformers are quite inefficient. Thinking of 100 Million users (actually it is much more), this is already 500 MW, which is half the capacity of a standard 1GW nuclear plant. Recent devices can be efficient in the order of 80 to 90%, which means almost only the power to charge the device is used, so in the order of 2W per device. A small number, but multiply it with the number of users of mobile phones, cameras and games and so on, and the number reaches the equivalent of one or 2 nuclear plants. Now this is happening in quiet (some companies like Panasonic show they are going eco by cutting standby losses) but it is still impressing.

thanks electric2004 for the info on ICE trains.

I was refreshing my memory on piezoelectricity on wikipedia, and an American university is working on using the piezo effect to charge a cellphone by just talking on it, which sounds promising. For micro electronics finding means of recharging seems to be getting easier. Seriously though if we just rode bikes more often the energy is there already.

For a city or a commuter that's quite a different matter. Maybe have gyms that put all that mechanical energy to use would be better than cattle calls? It really gets down to just recycling everything and increasing efficiencies rather than making more supply. What I like to call saving from declines.

when oil cuts off Japan in 3 years this will start getting serious instead of these nice toys. (My Peak Oil inferrence on the IEA report Paris November 2008). Given communities in Japan though that have hot springs and whose cities are generally well organized locally, Japan can fair quite well. It's really just about how to move around? Or more about having a purpose to the trip. If more people lived locally they wouldn't need the train as often.

an American university is working on using the piezo effect to charge a cellphone by just talking on it, which sounds promising.

Sounds like you'd have to talk pretty loud.

130 million Japanese screaming into their cellphones? I can hardly imagine.

I don't know if anyone is already doing this... The trains moving through the tunnels create strong winds, and the tunnels are fitted with fans to extract smoke in the event of a fire or other disaster. Bearing in mind I'm neither a physicist nor an engineer, would it be unreasonable to fit those extractor fans with bearings and connect them to generators, so that when they are not extracting smoke they could spin freely in the winds created by the movement of trains, generating electricity the whole time the trains are running?

latenights; yes, but easier to take the mass of the train, which is much larger, and put it through heavy magnets on the station tracks while it stops and generate much more direct electricity. Regenerative braking performs like this. It could possibly be both on the train and on the station. Trains only have it built in currently since it's cost effective to do so. Platform magnets would be more expensive but maybe less inverter problematic as electric2004 suggested.

the wind generation could be put just below the platform as the trains pass above the magnets, so yeah I could imagine that it would produce something, but I wonder if it would be worth the effort. Another experiment please! everything helps

Sounds like you'd have to talk pretty loud.

piezoelectricity works at small changes so it would work at a normal volume. I suppose the American models would last longer though haha. The problem is that is rewards long talkers, the most annoying aspect of calls. but even button pushing would produce electricy so it's not just voice that would do it. text'ing is far more common, so as long as the potential energy in pushing the button is more than the display it could work. we'll have to see what they do.