Commuters' stamping harnessed for power

Friday 12th December, 05:31 AM JST

TOKYO —

Japan has found a way to harness clean energy from thousands of stamping feet that pass through one of its busiest train stations every day.

Panels that generate energy from vibrations have been laid by ticket gates through which up to 80,000 passengers pass every day at Tokyo station.

In theory, the system consisting of slates, rubber sheets and ceramics can generate enough energy to power automatic ticket gates or electric billboards at the station.

“This experiment is one of our ideas to help the environment,” said a spokesman for the joint venture between Japan East Railway and a government-backed group that began testing the system this week.

Japan has tried to project itself as a leader in the fight against global warming, but it is far behind in meeting its obligations under the Kyoto Protocol—a landmark environmental treaty negotiated in Japan’s ancient capital that mandates cuts in the gases blamed for global warming.

Wire reports

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Latest 15 of 28 Total Comments Show All

30061015 at 01:51 AM JST - 13th December

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!...
sf2k at 07:55 AM JST - 13th December

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.
sf2k at 07:59 AM JST - 13th December

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
sf2k at 08:15 AM JST - 13th December

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.
PepinGalarga at 07:41 PM JST - 13th December

if you really want to save energy, just get rid of the trains and have people walk along the train lines.
kitakirisuzume at 08:42 PM JST - 13th December

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.
likeitis at 09:06 PM JST - 13th December

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.
electric2004 at 10:02 PM JST - 13th December

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.
UnagiDon at 10:08 PM JST - 13th December

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.
electric2004 at 10:10 PM JST - 13th December

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.
sf2k at 04:12 AM JST - 14th December

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.
Nessie at 09:59 AM JST - 14th December

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.
Latenights at 03:12 PM JST - 14th December

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?
sf2k at 04:11 PM JST - 14th December

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
sf2k at 04:16 PM JST - 14th December

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.