People power

People power

New energy-harvesting device generates power one step at a time
January 21, 2009
While the modern world embraces greener technologies to produce cleaner energy from the wind, sun and plants, a Vancouver-based scientist has invented a device that harvests what is arguably the cleanest energy around—our own. Max Donelan, a biomedical physiologist at Simon Fraser University, wants to win back energy we lose each day through the simple act of walking.
 

Clean energy from walking? Could this be the breakthrough the warming world has been waiting for? Not exactly, says Donelan.

“It’s misleading billing this as having a direct effect on climate change,” he says. “It will decrease the number of disposable batteries that end up in the landfill, perhaps. But the bigger effect is more of a psychological one. People will understand what it takes to make 10 watts of energy.”

Assistant Professor Max Donelan observes a
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Assistant Professor Max Donelan observes a subject wearing the Harvester
Image © Science

The Bionic Power Energy Harvester, a machine that fits around the human knee much like an orthopaedic knee brace, adopts the same “regenerative braking” principle used in hybrid cars. Just as a hybrid brakes using a generator and sends the recovered energy to an electric motor via a battery, the Harvester recovers the energy absorbed by our hamstrings as they slow down our knees just before our feet hit the ground—the “braking” phase, as it were, of our walk—and can use this electrical energy to power an electronic device. One minute of walking could generate about 10 watts, enough energy to power a cellphone for about a half-hour. 

A recent forum in downtown Vancouver brought together Donelan, kinesiologist Scott Lear and park and recreation specialist Wolfgang Haider to discuss the possible links between obesity, exercise, diet, global warming and government policy. Both Lear and Haider claim that Donelan’s Harvester offers exciting possibilities for some of our modern concerns.

“The bike is the most ingenious invention. It’s three to four times as fast as a human,” says Haider. “Bionics [the Harvester] is just as efficient.”

Illustration of the Bionic Power Energy Harvester
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Illustration of the Bionic Power Energy Harvester
Image © Science

“All our instincts go against recreational activity,” adds Lear, an expert in obesity. “This works against us with climate change and obesity.”

Despite the excitement, says Donelan, the Harvester can’t be held up as a tool for helping solve the world’s energy crisis. Factoring in the amount of energy it would take to produce the food we’d need to create the energy we would harvest, along with the energy required to build the energy-harvesting machine, the equation is not necessarily carbon-neutral. “There are more efficient ways of producing electricity,” he insists.

But the invention does have some other practical, even essential, uses. 

The Bionic Power Energy Harvester close up
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The Bionic Power Energy Harvester close up
Image © Science

Yad Garcha, CEO of Bionic Power Inc., a privately held company developing the Harvester, believes there are several markets in which the device could become indispensable. “It’s for those whose lives depend on portable power,” he says.

In June, the company plans to field test the Harvester with the military. The device could lighten the load for soldiers who commonly carry up to 14 kilograms  of disposable batteries on missions far from any electrical grid. First responders working in disaster zones where electrical power is down or non-existent and people who rely on power for artificial limbs could also make use of the Harvester.

So what about the everyday consumer who cares about global warming? Couldn’t we add a little bit of clean energy to the planet one stride at a time? Perhaps one day, but for now, Donelan suggests, we can do more with less.

“What’s most important is that people understand the magnitude of power,” says Donelan, “and not become an energy source, but reduce their own use of energy.”