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New field trials will see U.S. Army soldiers become their own power sources simply by walking, thanks to an idea conceived and developed in a Simon Fraser University lab.

An idea germinated in a biomedical lab at Simon Fraser University is being tested by the U.S. military in a research project meant to turn foot soldiers into their own power-generating stations.

Using a lightweight device that looks like the kind of knee brace a high-performance athlete might wear, soldiers can use the Canadian-designed PowerWalk Kinetic Energy Harvester to produce enough electricity to run their GPS units, night-vision goggles and radios. In the process, they can shed the 20 pounds of batteries they now have to carry into the field.

"They are really trying to take science fiction and turn it into something they can use," SFU's Max Donelan said of the field trials being done by the U.S. military under a $5-million (U.S.) contract with Vancouver-based Bionic Power Inc.

The field tests are part of a project known as the Joint Infantry Company Prototype, which is run by the U.S. Army and the Marine Corps. According to a Web posting by Captain Anthony Ripley of the Marine Corps Expeditionary Energy Office, the project "is aimed at lightening the load and reducing the size, weight, and power requirements" of foot soldiers.

He states that over the past decade, Marine Corps battalions have seen a 250-per-cent increase in the amount of power they need for radios and a 300-per-cent increase in the power needed for information technology, including computers.

"Consequently, for the individual Marine, the increased dependency on energy has meant an increase in overall weight carried, increased injury, and an increased dependence on resupply," Capt. Ripley writes. "If the weight of Marines is too heavy, they either function at a reduced capacity, or they break."

Dr. Donelan, a professor in SFU's biomedical physiology and kinesiology department, wasn't thinking of foot soldiers when, about 15 years ago, he first came up with the concept of generating power from walking.

At the time, he was contemplating the mechanics of the simple act of walking and wondering about the power potential.

"I was working in the course of my research on how people walked and how much energy they needed, how many calories they consumed. And it occurred to me that the walking was doing something inherently inefficient," he said in an interview on Wednesday.

Dr. Donelan said that when people walk down a hill, their muscles work as brakes, with the energy dissipating as heat.

"It occurred to me that that is in some ways silly because you could instead use a generator to help slow you down and the generator instead of turning it into [lost] heat would turn it into electricity," he said. "If it sounds like how regenerative braking works in hybrid cars, it's because it is – it's exactly the same."

But the challenge facing Dr. Donelan was how to take that concept and turn it into an actual working device.

"The trick in [harvesting energy from] walking is just to know when the muscles are pushing on the brake … and then rather than engage a conventional brake, which in the case of walking is muscles, … you engage a generator instead," he said.

Working with a team of researchers and engineers at SFU, funded by a grant from the Natural Sciences and Engineering Research Council of Canada, Dr. Donelan came up with a prototype of what would later evolve into the PowerWalk device. It can generate 10 to 12 watts of electricity – enough in an hour's walking to charge four smartphones.

"It was hard," he said of the development process. "That first proof of concept took us a good solid year to build. … It was this fairly clunky thing hanging off the side of the knee that convinced us we were on to something … but it was far from being something people could actually use. … It was too heavy, too bulky, too uncomfortable, too noisy, too expensive."

Bionic Power Inc., of which Dr. Donelan is a founding director, was created to push his idea further. Two years ago, the company signed a $3.8-million (U.S.) contract with the U.S. military, which was intrigued by the possibilities. That contract was recently extended for $1.25-million to allow field trials.

Dr. Donelan said that when soldiers first tested the device, they complained that it was bulky and uncomfortable, but it was improved through redesigns. Now, he said, they tell him, "It looks like something I would wear when I'm playing a video game like Halo."

"So it crossed from being an inconvenience to something that made them feel a little bit superhuman."

The device is not available commercially, but Dr. Donelan said that if it passes field trials and gets adopted by the U.S. military, it could pave the way for mass production.

"My hope is that eventually we get to the point where we could start to address the needs of the developing world," he said. "More than one billion people live without reliable access to electricity. … They rely on cellphones for so many things, but often don't have the infrastructure to charge those cellphones."

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