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Energy-Generating Floors To Power Subway Displays In Tokyo
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."
"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
There is truth in humor.
They do.
http://techon.nikkeibp.co.jp/english/NEWS_EN/20081204/162357/
The article talks about a 25 square meter area producing 1400 kW per day.
Meep.
You lose.
Watts are not an energy unit.
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 houses.
For the computer-savvy^Wobsessed /. crowd, that's about 200 medium size servers.
Say what?! Japan has only one commercial maglev line in the whole country, which runs in Aichi-ken. It's only about 6 or 7 miles long IIRC, and has a top speed of about 65 - 70 MPH. It went into service n 2005. JR has some on their test track, though, and they are really fast. But it was just last year that JR announced they plan to start commercial maglev shinkansen service in 2025. They don't have it now because, well, the maglev rail lines haven't even been built yet. China has a maglev line running between Shanghai and somewhere; Korea also has a single maglev line, and AFAIK those are the only commercial service maglevs in Asia. Everything else is on a test track.
Also, electric != emissions-free. All passenger rail in Tokyo is electric, but that doesn't make it emissions-free. That electricity still has to be generated, and not all of it comes from nuclear plants (although much of it does; Japan probably has the highest percentage of nuclear power in the world). The emissions from an electric train are produced at the point of power generation, but they're still produced. Is that better than diesel engines on the train? Probably, but it's not emissions-free. This goes for electric cars as well. Many people mistakenly state that electric vehicles are non-polluting, but they are just non-polluting at the place where they are being driven.
Finally, maglev trains do consume quite a bit of power; it's not like making it maglev will suddenly make it an energy sipper. Sure, you gain some efficiencies from doing away with rolling friction, but you add electromagnetic resistance, and because maglev trains in development are aimed at being faster than existing rolling stock (the trains at JR's test track in Yamanashi-ken are way faster than any shinkansen currently in service), there will be increased air resistance. Expect maglev to be somewhat more power efficient than wheeled trains, but it's not going to be a power panacea.
it's Japan, not New York
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