A device records the voltage produced as Assistant Professor Xudong Wang presses his hand on an electricity-producing floor prototype.
Wang (right) and Research Assistant Chunhua Yao in their laboratory at the University of Wisconsin.
Solar power, wind power … floor power? A recent invention is successfully harvesting usable energy from the simple action of walking across a floor. "It's a good way to reduce your electricity use from the grid," says Associate Professor Xudong Wang from the University of Wisconsin-Madison, who developed the method. Here's how it works: Two layers of wood pulp are put inside an engineered flooring product. One layer is treated with a chemical that makes it attract electrons, while the other is not treated and repels electrons. A person steps on the floor and causes a compression that, however minuscule, pushes the two layers together. When the person's foot comes up, the layers separate, and that action creates an electrical charge. The charge is channeled out of the floor through embedded wires and can power lights or charge batteries. The technology is still in prototype stage, but the prototypes are getting bigger. What started as a single plank has now turned into a working, 96-square-foot electricity floor walked on by thousands daily at a student union on campus. And Wang eventually sees the technology making waves at larger venues, where the footfall would be in the millions and the electricity produced could make a real impact. "If you put it in a stadium or in a shopping mall, then we're talking about a whole different level of input," he says. "Then we're talking kilowatts."—A.A.
See Professor Wang demonstrate how the electric floors work:
