"Crowd Farm" to Collect Energy?

Cain writes to mention that a couple of MIT students would like to harness the mechanical power of large groups of people. "A Crowd Farm in Boston's South Station railway terminal would work like this: A responsive sub-flooring system made up of blocks that depress slightly under the force of human steps would be installed beneath the station's main lobby. The slippage of the blocks against one another as people walked would generate power through the principle of the dynamo, a device that converts the energy of motion into that of an electric current."

Re:one problem left?

[EtoilePB]

Now the only technical problem is getting americans out of their cars...

If you've ever been in Boston's South Station or New York's Grand Central or any of a dozen other major urban transit hubs at rush hour... there are plenty of people there not using cars.

Re:School Science

[Anonymous Coward]

Don't *you* mean MPG? Last time *I* checked, British road signs were in Imperial, not Metric measurements......

Re:house music all night long

[dextromulous]

And why not gyms? Tap into "spinning" bicycles and treadmills directly.

Because it is prohibitively expensive. [wsj.com]

If all the exercise machines were in use 10 hours a day for a year, the gym could generate roughly $183 worth of electricity. At that rate, it would take about 82 years to pay off the initial $15,000 investment.

Re:A better idea

[techiemikey]

Because Boston no longer has turnstiles for their subways. They have little "High tech"doors which open when you swipe a Charlie Ticket.

MIT plagiarism

[rubycodez]

the japanese already have such a system http://www.japanfs.org/db/1667-e [japanfs.org]

Re:One possible drawback

[Mattintosh]

Actually, it will probably be more comfortable to walk on. You already step down onto a hard floor, and that causes the "shock" (suddenly stopped kinetic energy) to reverberate up your skeletal system, making your joints hurt. That energy would be absorbed by this flooring system, so the joint shock would be lessened.

Re:depression distance

[Anonymous Coward]

One step powering 2x60W bulbs for one sec = 120J
Assume a human of ~120kg on average (it's the US after all)
Work done by depressing the plate is ~120kgx10m/s^2xheight=120J (+losses, but let's neglect that for now, after all, we're in a generous mood)
Plate must move approximately 10cm.

Wow! Brilliant! ... wait, I mean rather dim.

note that the 'MIT geniuses' are from the School of Architecture. You'd have thought they teach basic Mechanics to architects-in-the-making at MIT, but maybe these to items skipped that particular class. Perhaps consult someone in Engineering next time?

Re:house music all night long

[dextromulous]

$15,000 investment / $183 per month savings = about 82 months = about 7 years payback period

You missed one thing, that was $183 per year, not per month.