• Image about Tom Krupenkin
Illustration by Katy LeMay

Could COPPER TOPS become extinct?

Batteries. They cost money, they’re heavy and bulky, they can leak inside (and ruin) expensive electronics, you never have the right size — and losing or leaving behind whatever various charger is necessary for the battery on your phone and/or other gadgets has become the new American pastime. Plus, your gadgets’ batteries always die at the wrong moment, a moment that arrives earlier and earlier in the day as faster networks, fancier applications and brighter screens gobble up ever-increasing swarms of electrons. But batteries’ power over us may be ending, thanks to innovative ideas about where else to go for energy on the go.

Walk It Off
One of the most intriguing approaches is to capture the energy that humans use when moving around and then turn it into electricity that can be used to operate or charge portable electronics such as phones, music players and the like. The human body generates about 100 watts of power while sleeping and more than a kilowatt in an all-out sprint, says Tom Krupenkin, an engineering professor at the University of Wisconsin-Madison and president of InStep NanoPower in Madison, Wis.

Krupenkin’s approach places fluid-filled sacks in the heels of footwear. As a person walks, the pressure of heel strikes forces the fluid to flow back and forth, generating electricity. The total that Krupenkin hopes to generate when wearable laboratory prototypes are ready in about two years is only half a watt per leg, but that’s enough to make a cellphone call. And it would mean a walker wearing energy-capturing shoes would be able to talk for as long as he or she could walk. The wattage would also be free, and Krupenkin says charging your phone as you walk wouldn’t noticeably slow you down. “This power is lost, anyway,” he explains. “We dissipate this power as heat as we walk around.”

While gadgets that tap humans for power have existed for decades (take self-winding watches, for example), there are also other potential battery replacements, or extenders, that require truly new technology. One is portable fuel cells. Long used in larger formats to power satellites and other high-value electricity consumers, they are now beginning to find their way into consumer electronics.