Using human motion to create produce usable energy

Now that's thinking outside the box:

Two graduate students at MIT's School of Architecture and Planning want to harvest the energy of human movement in urban settings, like commuters in a train station or fans at a concert.

The so-called "Crowd Farm," as envisioned by James Graham and Thaddeus Jusczyk, both M.Arch candidates, would turn the mechanical energy of people walking or jumping into a source of electricity. Their proposal took first place in the Japan-based Holcim Foundation's Sustainable Construction competition this year.

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.

The electric current generated by the Crowd Farm could then be used for educational purposes, such as lighting up a sign about energy. "We want people to understand the direct relationship between their movement and the energy produced," says Jusczyk.

The Crowd Farm is not intended for home use. According to Graham and Jusczyk, a single human step can only power two 60W light bulbs for one flickering second. But get a crowd in motion, multiply that single step by 28,527 steps, for example, and the result is enough energy to power a moving train for one second.

Given the relatively low amount of energy produced, I have concerns about whether this will be cost-effective; however, this is still a very cool idea.

What I want to know is when they are going to start hooking up gyms to electric generators. Because it would make me feel decidedly less gerbil-like if I knew that chugging away on the exercise bike had some useful purpose...

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Over 20 years ago I suggested creating Piezo electric sidewalks for New York City, where crowds are vast and constantly moving when the weather is warm. The physicist to whom I broched the idea laughed it off as wishful thinking.

By Howard Schamest (not verified) on 06 Aug 2007 #permalink

"According to the Japanese newspaper Chunichi Shimbun, the JR East program, assisted by researchers from Keio University, plans to embed piezo pads in the floor under the ticket gates. As people pass through, vibration and pressure on the pads is converted by piezo crystals into an electrical charge which can then be channeled to highly efficient power storage systems and provide clean, ecologically friendly power to parts of the station. Although the piezo current is apparently a small one, if enough passengers pass through (and bounce a bit as they do), quite respectable amounts of electricity can be accumulated." -

Never did hear much more about this...

By Spaulding (not verified) on 06 Aug 2007 #permalink

I have this vague memory the cost of Piezo electric crystals took a huge dive in the late 1990s, and has continued to fall since then. If this is the case, that could explain why using Piezo-electric crystals to turn crowd traffic into power was laughable 20 years ago, but practical (or nearly so) today.

Structural piezo elements would face worse cost and reliability problems than faces solar cells. And I doubt generators on gym equipment would cover the electricity bills for lights.

But IIRC people tests kinetic feed generator-and-battery packs in field equipment (you can by a back pack with it, I think) to enable carrying mobile equipment such as cell phones.

By Torbjörn Larsson, OM (not verified) on 06 Aug 2007 #permalink