Energy futureNew source of energy: People-powered "crowd farms"

Published 3 August 2007

These boots are made for walking: Two MIT students propose harvesting the energy of human movement in urban settings

Two MIT M.Arch candidates have an idea: “Crowd farms” which 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. The two students, James Graham and Thaddeus Jusczyk, have already designed a crowd farm for Boston’s South Station railway terminal would. Here is how it would work: A responsive subflooring system made up of blocks which depress slightly under the force of human steps would be installed beneath the station’s main lobby. The slippage and movement 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.

The crowd farm is not intended for home use. According to Graham and Jusczy, a single human step can only power two 60W light bulbs for one flickering second. If we get a crowd in motion, however, we can multiply that single step by 28,527 steps, for example, and the result is enough energy to power a moving train for one second. The farm is an urban vision, but the dynamo-floor principle can also be applied to capturing energy at places like rock concerts, too. The principle may also be applied on farms, were herds of cows or sheep may be made to walk back and forth, in the process generating energy. The students’ test case, displayed at the Venice Biennale and in a train station in Torino, Italy, was a prototype stool which exploits the passive act of sitting to generate power. The weight of the body on the seat causes a flywheel to spin, which powers a dynamo that, in turn, lights four LEDs. As we have written recently, piezo-electric (mechanical-to-electrical) surfaces have been built in the past, but the crowd farm has the potential to redefine urban space by adding a sense of fluidity and encouraging people to activate spaces with their movement. “Our intention was to think of it not as a high-tech mat that would be laid down somewhere, but to really integrate it into a new sort of building system,” Graham says.

The crowd farm’s floor is composed of standard parts that are easily replicated but it is expensive to produce at this stage, the two students said. The two were inspired as well by an “ingenious little device by Thomas Edison. When visitors came to his house, they passed through a turnstile that pumped water into his holding tank,” says Graham. In addition, they were guided by their advisor, Associate Professor J. Meejin Yoon, who helped them take their proposal from the power-stool to the Crowd Farm.