You may have read about the backpack or combat boot that generates power from its wearer’s walking. These are small-scale examples of “power harvesting” from human motion. They work by clever use of devices and/or materials that convert motion to power. The power generated is small but potentially enough for a mobile phone or other personal electronics. And if we get a little futuristic, the power could be used for wearable computers or smart clothing.
For me, these technologies invite the question of scaling-up. For example, can a highway overpass be instrumented to harvest the vibrational motion from thousands of heavy, fast-moving cars and trucks? Can the overpass’s surface be adapted to harvest power directly from contact with those cars and trucks’ motion?
How would this work? A core technique of small-scale power harvesting is the use of piezoelectric materials. When these materials bend or stretch, they create power. Instead of having a small wafer of piezoelectric material in a shoe, how about thousands of wafers arrayed throughout an overpass? What if they were connected to the surface so that they bent and stretched with the forces of multi-ton vehicles constantly zipping by?
This isn’t my area of expertise, so I don’t know the answers. But the questions illustrate the more general opportunity of thinking bigger about harvesting (some might say recycling) energy that humans are already expending. From a societal point of view, it would be a welcome area for innovation.