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Power Earth Transportation Technology

Energy-Generating Floors To Power Subway Displays In Tokyo 98

Posted by timothy from the tap-your-foot-to-the-octopus-porn dept.
Jason Sahler writes "When the East Japan Railway Company (JR East) decided to invest in alternative energy sources, it only had to look to its users for the perfect source of energy. Recently the company decided to update their Tokyo Station with a revolutionary new piezoelectric energy generating floor. The system will harvest the kinetic energy generated by crowds to power ticket gates and display systems."
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Energy-Generating Floors To Power Subway Displays In Tokyo More

Energy-Generating Floors To Power Subway Displays In Tokyo

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  • Theft of services (Score:5, Funny)

    by Zerth ( 26112 ) on Thursday December 11, 2008 @02:23PM (#26079203)

    Will I be compensated with lower fares for the reduction of my kinetic & potential energies, or will they just take it as profit?

    • ALL THE STUPID ELECTRICTY JOKES GO HERE (Score:3, Funny)

      by Anonymous Coward

      You would be shocked by the potential of this technology. It has the capacity to replace large amounts of electrical expenses. Much like you, I'd be revolted if they did not make the best use of this technology!

      • Re: (Score:3, Funny)

        by Kagura ( 843695 )
        The crowds in Shinjuku are abuzz upon hearing this news, but it seems to have polarized Japan's greater populace.

      • My day is lightend by this experiment and electrified by the energy in the air.

    • Re: (Score:3, Funny)

      by bluefoxlucid ( 723572 )
      Being a Ninja will be punished by a stiff fine.

    • Re:Theft of services (Score:4, Interesting)

      by Anonymous Coward on Thursday December 11, 2008 @03:34PM (#26080495)

      I think this is a pretty cool idea. I can imagine a gym being a great place to do something like this: people go there to "waste" energy (tread-mills, various exercise machines). If they can set up their machines to basically be human powered generators, set resistance based on power output, etc, they might be able to convince people they are helping save the environment. Or at least cut down their electricity costs a bit.

      "You just burned 150 calories and generated X amount of electrical energy" OR "Please maintain a speed of above 5 miles per hour or the tv will lose power and shut off"

      • I don't think it would be any economic gain on this, installing generators, fixing with the electric system, et cetera. That's probably why cars which uses generators instead of brakes are so expensive. Amirite?
    • "Will I be compensated with lower fares for the reduction of my kinetic & potential energies, or will they just take it as profit?"

      considering the immense cost to implement this instead of just plugging into the grid I'd be surprised if the rates didn't increase instead. Think... powering your house with solar instead of electric, but solar when it was brand new and no one had it like "revolutionary new piezoelectric energy generating floors" are currently.

  • And what happens when the batteries drain? (Score:5, Funny)

    by CTalkobt ( 81900 ) on Thursday December 11, 2008 @02:26PM (#26079245) Homepage

    I can just imagine the batteries draining and the users not familair with the system getting off of a train to find there is no way to exit the gates.

    Of course, they'll then stomp their feet in anger - hopefully hard enough to blink the ticket gates functional again.

    Ah - innovation.

    • Re: (Score:1, Funny)

      by RemoWilliams84 ( 1348761 )

      If internet videos have taught me anything (as I'm certainthey have), it's that their are always going to be enough people humping on the subway to power the whole train if they wanted to.

  • What a waste (Score:3, Insightful)

    by snowraver1 ( 1052510 ) on Thursday December 11, 2008 @02:27PM (#26079273)
    I have a hard time believing that installing thousands of tiny peizoelectric generators in the floor to be either a) better for the environment or b)profitable.

    I would bet that the cost to the environment in producing these special devices, would be greater than the coal that would have been fed into a coal power plant to produce the same amount of power.

    • Re:What a waste (Score:5, Funny)

      by tsalmark ( 1265778 ) on Thursday December 11, 2008 @02:32PM (#26079343) Homepage
      SHHHH. The Green Movement is about feeling good, not consuming less.

    • Re: (Score:2, Funny)

      by Anonymous Coward

      but you are overlooking the smug factor

      Think of how much smug this will release into the atmosphere! The thick, massive smug clouds will certainly cool the Earth by a degree or two.

      • Re: (Score:1, Flamebait)

        by Randall311 ( 866824 )
        I think there are already enough Apple stores generating enough massive smug clouds to last a long time. Our grandchildren will never have to worry about a shortness of smug, thanks to Steve Mobbs and Mapple. Think differently.

    • Re:What a good idea! (Score:5, Funny)

      by Anonymous Coward on Thursday December 11, 2008 @02:39PM (#26079477)

      You're wrong, and to prove it, I'll make a supposition with no factual basis whatsoever: I would bet that the cost to the environment in producing these special devices will be far less than the coal that would have to be fed into a coal power plant to produce the same amount of power.

      • Re: (Score:3, Interesting)

        by Tisha_AH ( 600987 )

        Just stewing this over in my brain I was astonished by the possibilities.

        Human activity follows a semi-diurnal cycle and in something like a subway station your peak generating capacity would be when masses of people are using the stations, let's say from 6 am to 9 am, 4 pm to 6 pm. Wherever this technology is applied you would need a certain level of foot traffic to make it cost effective.

        Imagine this on the floors of airline terminals, sports stadiums, very busy downtown areas (sidewalks in the New York b

    • In all seriousness... how do they expect to generate energy with this? I mean 99% of a subway ride is either you sitting there, or standing room only. Either way, you're not walking around and thus not generating any power unless you are boarding or exiting. I didn't RTFA, are they talking about putting these peizoelectric generators on the floor of the station or the subway car itself? It would probably make more sense to line the damn subway tracks with something like this so that they can "recycle" s

      • Re: (Score:2)

        by leenks ( 906881 )

        Did you not read the summary either?

        "Recently the company decided to update their Tokyo Station with a revolutionary new piezoelectric energy generating floor. The system will harvest the kinetic energy generated by crowds to power ticket gates and display systems."

  • Not Just Theft of Services, Theft of Calories (Score:3, Insightful)

    by gblackwo ( 1087063 ) on Thursday December 11, 2008 @02:34PM (#26079387) Homepage
    It may be a joke that they are stealing PE and KE, but they really are making it slightly harder to walk around. Thus the user will be doing more work- ie- burning more calories.

    • Re: (Score:1, Funny)

      by Anonymous Coward

      They should install this at Wal-Mart.

    • Re: (Score:2)

      by SQLGuru ( 980662 )

      I wonder how much could be generated from the bouncing that the passengers do as they RIDE the trains/subways. They aren't walking much, so the impact to them should be negligible.

      Layne

    • Gravity is doing the work that generates the energy, the "user" is only providing a mass for gravity to work with. You still have to pick your feet up, but it is no more difficult to put it back down than on any other type of walking surface.

      • In order to generate the power, the surface has to give way a small amount.

        Now, take a walk down the sidewalk for 100 meters, then walk through soft sand for 100 meters and tell me which burned more energy. Yes, this example is on the extreme side, but it does illustrate the issue.

        TANSTAAFL

        • Normally the floor has to absorb the energy of a foot falling anyway. This could be just taking advantage of that - A bit like regenerative braking uses the energy using energy that would normally be spent as heat.

          Or it may not. I have no idea about the maths behind it. Just pointing out that sometimes there is free-ish energy.

    • Is that necessarily true? It obviously would be if you assumed there is no energy lost during normal walking, but clearly that is not true. If it's just recovering some of the energy lost as we throw our feet into the ground so we can turn around their momentum, it might not be any harder.

      If I had to guess, I might think this might actually make it slightly easier to walk, if it's like walking on springy ground. For instance, thinking about it now in my head, I think it's less tiring to walk wearing a pa

  • Deja Vu, circa 2002? (Score:3, Funny)

    by Ancient_Hacker ( 751168 ) on Thursday December 11, 2008 @02:35PM (#26079407)

    Is this a totally independent outbreak of imbecility, or is it related to the SD article from ~2002?

    This piezoelectric idea is never going to recover the initial cost of construction and installation.

    To generate real amounts of power at near zero cost, just let the people walk up the escalator and harness the power of the steps going backwards.

    • Because you can only have true alternate energy sources when they cost less money than conventional energy sources?

      It couldn't be that they are the alternate energy sources because they are less efficient monetarily than "conventional" sources, could it? So what if it doesn't recover the monetary investment? Things would be a lot better off it PROFIT! wasn't the sole motivation behind any decision.

      • Re: (Score:3, Interesting)

        by Ancient_Hacker ( 751168 )

        > So what if it doesn't recover the monetary investment? Things would be a lot better off it PROFIT! wasn't the sole motivation behind any decision.

        How? It took energy to make those floor devices. If they don't ever generate as much energy as it took to make them, we've wasted energy. How are we better off wasting energy?

        Moreover if the things are really inefficient, then it means you're turning the people's food energy to nothing. It took a lot of energy and $$$ to feed those folks. Again, we're was

        • So how about we all just return to the state of lowest energy and call it a day then? Anything other than that would just be wasting energy.
        • I believe the energy from food was already going to be "wasted". This is like a simpler version of generating electricity through exercise equipment. The people were doing it anyways, so why not get something back?

          And if you've ever seen these things, they basically look like a mat on the ground that gets stepped on a million times per day. I can't imagine there's a complex, expensive mechanical system going on in there that cost a ton of money to create.

          • Ah, no, you don't get something for nothing. The mat must be receiving work, i.e. force times distance, so the walker must be supplying it. And how much work is that? Assume 130 pounds and one tenth of an inch for one second, that's 1/40th of a horsepower, or about 20 watts. If someone is stepping on it every second, that's 2 watts average. Piezoelectrics are not too efficient, say 5%, so we have 0.1 watts electric. If electricity costs 10 cents a kilowatt-hour, the mat is generating about nine cents

            • Would doubling your "tenth of an inch" double the output? 1/10th of an inch seems rather conservative. Based on experience, I'd say it's closer to 1/4 or 1/2 an inch. And since they're running their machines off this, I have to question your math in its entirety.

              • If you look at their display, it's showing about 3600 watt-seconds. And they don't have any more digits on the display, so they can only go up to 9999 watt-seconds.

                Now do a teensy bit of unit math, and reckon there are 3.6 million watt-seconds in a kilowatt hour.

                Now if electricity costs ten cents a kilowatt-hour, a watt-second is worth 1/280000 of a cent.
                So that horn-blowing display is telling us they've generated a whole 1/100 of a cent. If my math is right.

                • To quote the article: "The total amount of floor-space will add up to around 25 square meters, and they expect to obtain over 1,400kw per day - more than enough to power their systems."

                  The pictures say they are "jikenchuu", which means "in the middle of the experiment". And the article states they are improving their results.

                  I just don't see how it could be a waste if they were really able to power their ticket-taking systems without outside electricity, especially if they can make the system durabl

                  • The clue is in the phrase "1400kw per day". That is meaningless. Totally meaningless. "kw" if it means kilowatts, is a unit of how much work is being done per unit time. For instance one watt is one joule of work being done each second. Or as mechanical equivalent, two kilograms moved one meter in one second. So saying "1400kw per day" is equivalent of saying "1.4 million joules per second per day", which is physically meaningless.

                    The numbers on the display jibe with my interpretation-- there is pitif

        • The recovered energy would partly come from the wasted energy of people slapping their feet against the floor. Currently, there is a lot of energy being dissipated in shoe soles and the lower leg. The widespread use of padded shoe soles (i.e. running shoes) demonstrates that there is some extra energy that needs to be dissipated somewhere, for the comfort of the pedestrian.

        • There is another point to be made here. Let's say the cost of this "mat" is $2000 USD and it produces 1mw per footstep (purely examples to illustrate a point, I don't know the cost or the energy-generating potential per impact).

          If I were to install this in my entryway and I estimate about 50 footsteps on this mat on average (probably high but makes the math easy), at $0.032 USD per KWh it would take 197,129 years to pay for that $2000 mat.

          However, if you consider a subway station would have millions of foo

  • I can hear it now... (Score:5, Funny)

    by eqreed ( 1108821 ) on Thursday December 11, 2008 @02:36PM (#26079423)

    "The ticket will cost 100 yen and 5 jumping jacks."

    • Re: (Score:2, Funny)

      by tsalmark ( 1265778 )
      I think for a hundred yen you also have to high jump the gates at both ends of the trip. Note always make sure the gate has properly read your ticket before running through. the Machine does NOT have your safety in mind as at swings that bat out to stop you dead. No it didn't happen to me, it happen to a, erm, friend.

  • Interesting (Score:2, Interesting)

    by Eg0Death ( 1282452 ) *
    There are forklifts driving back and forth on the production floor here at my place of work. If those 10,000 lb forklifts carrying 2,000 lb loads were driving over piezoelectric energy generating floors, how much energy could be harnessed? Certainly not enough to offset the cost in the short term, which is the only term my employer seems to comprehend.

    • Re: (Score:3, Interesting)

      by hansamurai ( 907719 )

      Just tell them about all the energy savings and cartoon birds will start flying around their heads as a giant smile grows on their face.

    • There is nothing free about this energy, what you are proposing is a very elaborate and inefficient way of converting (propane, diesel, electricity or whatever your forklifts run on) into electricity.

      Every time a forklift runs onto the tile, the tile depresses slightly which causes the work, however the forklift will then have to compensate by climbing off the depressed tile. Where else do you think this energy is coming from?

      • Re: (Score:2, Insightful)

        by Eg0Death ( 1282452 ) *
        The forklifts are driving hither and yon and burning fuel regardless of the presence of these tiles. Having the tiles in high traffic locations would generate some electricity.

        The limited amount of information I've read regarding these tiles has not mentioned the distance they must travel for electricity to be generated. However, since they have to operate without impeding foot traffic, I suspect the distance is minimal. Certainly no more than an inch. If the tile was 1 inch above the level of the
      • You make a good point. The issue is the amount of compression. If it's on the molecular scale, you like *do* get something resembling free energy.

        The extra 'work' you mention comes when the wheel rolls off of a compressed tile and 'up' onto the next non-compressed tile. If that height is negligible compared to the rolling resistance it would present, it would seem to give you energy with little in the way of 'cost'.

        Of course I don't know details about this technology (mostly because i didn't stay at

        • Re: (Score:2)

          by ceoyoyo ( 59147 )

          If you're extracting energy from it, it MUST require energy to be input.

          By using a low friction material for the tiles it might be possible to reduce friction to offset the energy stolen by the piezo devices, but in that case you might as well just replace your floor surface with the low friction material without the piezos for even better efficiency.

          There is no free energy.

          • agreed, but lets say that compressing a solid caused it to:

            a) generate electricty which in turn
            b) generates heat

            Vent the heat to the atmosphere and you've converted your mechanical into electrical using only the already existing forces. While it isn't 'free' by energy standards, it is 'free' in terms of the inputs of the closed system you're talking about.

            My brain wants to equate it with regenerative braking in hybrid cars. You have the extra 10% (total guess) weight of the regen system to lower

    • how much energy could be harnessed? Certainly not enough to offset the cost in the short term

      Or any term. Unless the forklift fuel is free.

      • Although I have no real data to back it up, I sincerely doubt that presence of these tiles would result in a significant increase in fuel consumption. See the reply to hansamurai above.

        • Although I have no real data to back it up, I sincerely doubt that presence of these tiles would result in a significant increase in fuel consumption. See the reply to hansamurai above.

          The point here is that the increase in fuel consumption is, at best, exactly equal to the amount of energy generated by the tiles. This is basic thermodynamics. Considering that this isn't an ideal system (energy loss due to heat), it's never going to generate close to what it consumes.

          Personally, if these devices were

  • The article talks about a 25 square meter area producing 1400 kW per day.

    This sounds highly unlikely.

    Steve

    • Perhaps they mean 1400 KJ/day

      • Re: (Score:1, Informative)

        by Anonymous Coward

        They do.

        http://techon.nikkeibp.co.jp/english/NEWS_EN/20081204/162357/

    • Re: (Score:3, Informative)

      by fifirebel ( 137361 )

      The article talks about a 25 square meter area producing 1400 kW per day.

      Meep.

      You lose.

      Watts are not an energy unit.

      1. It could be 1.4 MWh per day, which is 5.04 GJ per day, which averages to 58.3 kW constant power.
      2. Or 1.4 MW averaged over a day (now that's ridiculous).
      3. Or 1.4 MJ per day, that averages to 16W constant power, what's ridiculously low.

      My bets are on #1 (58.3 kW averaged).

      To give an idea on how much power this is, it is 530 Amps under 110 V. A typical house has a 100 A circuit. So it's generating about the maximum allowed power usage for a little bit over 5 ho

    • Not to mention 1400 kW is a rate of energy, not an amount. When will journalists at least realize that units are kind of important to understanding what they are talking about? I assume that means 1400 kWh, but it could just as well mean they generate 1400 kW on average throughout the day (which would be a pretty impressive chunk of money).

      Even assuming 1400 kWh, I can't imagine that number is correct. That's actually a lot of power, and, if true, this system might actually make sense in certain high tra

  • Summary Error (Score:3, Informative)

    by hobotron ( 891379 ) on Thursday December 11, 2008 @02:52PM (#26079699)
    "The system will harvest the kinetic energy generated by crowds..."

    No, it will harness the POTENTIAL energy change in the compression of the floor plates by a distance D with force F. The energy lost by the person and gained by the floor (neglecting efficiency losses) would then be F * D.

    Bad summary, Bad

    • Re: (Score:2)

      by thegnu ( 557446 )

      I only read your post because I thought you were abbreviating the F-word.

      Good point, though.

  • Godzilla (Score:4, Insightful)

    by OglinTatas ( 710589 ) on Thursday December 11, 2008 @03:38PM (#26080545)

    just imagine how much energy can be harvested this way the next time Godzilla rampages! Energy independence, AND the project will pay for itself in about a 40 minute feature film. Of course, then you have to rebuild it and wait for the next rampage for the new project to pay off...

  • At first, you won't notice the extra iota of compression made by your feet against the piezo-floor-plate. But next year there will be budget cuts, and some bureaucrat will crank up the device to make the floor plates just a little bit squishier to extract just a little bit more kinetic energy... a couple of budget cycles later, it'll be like Grand Central Station, covered in mud.

  • They've had these things at the gates of Tokyo Station for years now. What's the news part of this? I don't even notice them when I walk across them anymore.

  • If JR East really wants to generate some power, they should redo the floors in Shinjuku Station -- the place is bloody huge, and is a combined station for five different rail companies (JR East, Odakyu, and Keio railways, and Toei and Tokyo subways). Average daily foot traffic for fiscal 2007 (only people walking through ticket stiles -- not counting people just passing through on the trains, or other foot traffic like walkthroughs or same-company line transfers) came to 2,666,598 for the whole station, an

  • How much more tiring will it be to walk on a squishy floor rather than on a rigid or resilient one?

  • Sounds awfully familiar when something is turning people into a "battery" for energy.

    I might as well open up a gym and hook up electric generators to the machines so it'll keep the place lit.

     

  • Of course, this way of generating energy will only have a very tiny effect.

    In essence, these systems are stealing a bit of energy from the walking crowd.

    Let's assume the following: The system relies only on difference in potential energy. Say the engineers were smart and constructed an elevator that converts the potential energy of the passengers into electricity with close to 100% efficiency. For every 70kg passenger this would generate slightly under 2 watt-hours, assuming that the elevator covers a dista

  • I didn't see it in the article, but I would really like to know who makes a piezo generator that produces the kilowatts of power they are claiming. With the commercially-available piezo energy harvesters I develop for, a playing-card sized wafer ($50) generates not much more than 10mW under ideal conditions [slashdot.org] (continuous sinusoidal vibration from a lab shaker). Wouldn't I like to get me a few of theirs! (Goodbye epaper, hello giant LED matrix...)

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