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12.17.08

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Phaedra
Courtesy SRI International
GREAT GRID GETAWAY: A model of the wave-powered generator farm tested by SRI International.

Current Events

New technology finds electricity a mile offshore

By Jessica Lussenhop


I hope I don't get seasick," says a Japanese translator as she and several visitors from the Tokyo-based company Hyper Drive prepare to board Velocity, a 60-foot Stagnaro whale-watching boat. They're here to see the newest model of the company's ocean-wave-powered generator, which is at this very moment bouncing around in the waves about a mile off the central coast, creating small amounts of electricity.

Hyper Drive's president and CEO, Shuji Yonemura, is explaining with some difficulty through his translator how the device actually works. "Within 10 years, we can bring it to land," says the translator. "Powering a city. A whole city."

Chief technology officer Mikio Waki chimes in, reporting that the trial model that is working today is producing about 20 joules of energy each time it bobs in the water. That's enough to power a dim light bulb.

Roy Kornbluh, the principal research engineer from the venerable research firm SRI International, politely asks the translator if he may clarify. "We are only making small amounts of energy today," he says. "The focus is on the way we are making energy, using artificial-muscle technology."

Hyper Drive is a start-up company that partnered with SRI's scientists looking to commercialize the device's energy-gathering capabilities. This demonstration is the generator's second run; the first was in August 2007 in St. Petersburg, Fla., when a buoy was tested in relatively placid Atlantic waters to determine if it could operate in a marine environment. This time the investors at Hyper Drive and the scientists from SRI International were looking for more active waters to determine whether or not their invention, a rubberlike material called electroactive polymer artificial muscle (EPAM), could use the heaving motion of the waves to generate power. Philip von Guggenberg, the director of business development at SRI, figured the Central Coast's early-winter chop was a convenient solution.

"We're hoping there's not a hurricane," he says. "But we are certainly looking for bigger waves."

To the Japanese translator's chagrin, after a rather placid morning, the afternoon waves picked up. A quick trip takes the Velocityout to where the canary-yellow buoy is jostling about in the ocean, connected by a length of thick rope to the Shana Rae, a smaller boat equipped with computer equipment taking a reading 10 times every second. A legion of life-vest-clad scientists cluster on its deck, including the main inventor of the artificial muscle, Ron Pelrine, identifiable by his bushy beard.

The Velocity pulls up alongside the buoy to allow its passengers to watch, entering into the same rocking dance.

Mounted on top of the buoy are two long cylindrical tubes, and inside, what looks like the black bellows of an elongated accordion is pumping jerkily up and down in response to the waves. The black material is the artificial muscle, a polymer coated in an electricity-conducing material. As the material expands and contracts, a small amount of mechanical energy is changed to electric energy, collected and detected on the Shana Rae. Two jaunty white arms protruding from the base of the buoy serve to amplify the pitching motion, producing even more work inside the tubes.

It seems wonderfully simple, almost too simple to have dragged five Japanese business-people, three U.S. Department of Energy representatives, one PG&E representative and a half-dozen of SRI's brightest minds out into the ocean. But simplicity is the whole point.

"Power-generating buoys exist, but they work on conventional approaches. The waves pump a cylinder, that spins a turbine, that drives a rotary," says Kornbluh. "This is very simple. We like to say it's just a souped-up rubber band."

Everything has to start somewhere.

As the frantic search for energy alternatives brings all sorts of solutions out into the open, it's easy to look at them skeptically, with their far-off promises for real solutions. SRI International's solution is intriguing not just because of the uniqueness of its EPAM model, but also because of the enterprise's track record.

On Dec. 9, 1968, SRI scientist Doug Engelbart showed how to use the first computer mouse. Grainy black-and-white videos show Engelbart, his hair scrupulously combed, explaining how to type, cut and paste, save a file, as well as use teleconference, multiple windows and hypertext linking. The '60s also brought Shakey the Robot, the first mobile robot able to reason its surroundings. And on Oct. 29, 1969, at 10:30pm, a scientist at UCLA used an interface message processor, or "node," to talk to another node at SRI. It was the first host-to-host peep the Internet made. In 1977, SRI sent an inter-network transmission from a van in Menlo Park, through London, and back to USC.

From those beginnings in robotics, fast forward to the '90s, when Roy Kornbluh wrote the paper that would jumpstart EPAM, a treatise on the need for a polymer that would bend and move like a muscle, as opposed to the static joints that named Shakey.

"We started with a clean sheet of paper and thought, what can we come up with to simulate a muscle," Pelrine remembers. "We decided one of the best approaches would be to put a polymer between two electrodes."

A current through the polymer caused expansion and contraction, which could create musclelike movement—more fluid, more durable. And Pelrine also saw that the opposite was possible.

If the polymer were stretched and then allowed to relax, this would create energy, usable if captured by a material that can conduct electricity.

Using polymers from commercial silicon and rubber, one branch of the project used EPAM to create a line of spidery little robots, while work began in earnest on the wave-powered generator as well.

"There's nothing necessarily magic about the material itself, but how it's used," Pelrine says.

On the Velocity, things are progressing well. Someone has his head hanging over the edge on one side, but that's good news for Pelrine and Kornbluh, who are getting lots of data thanks to the raucous sea.

"This is really good," says Pelrine from the Shana Rae. "We're really psyched."

"Every technician loves to see their creativity turned into reality," Kornbluh says.

Of course, it's the next step that is truly important. Hyper Drive hopes to use SRI's technology to create larger units within two years that will generate about 100 watts of power. While too small to power a grid, this would be useful in producing self-sustaining navigational buoys that currently run on expensive lithium batteries that need replacing. In five to 10 years, von Guggenberg says, the company hopes to be able to produce kilowatts for large-scale industrial uses, for example, seaside industries like canneries. Then someday, of course, the groups hope to feed a power grid, perhaps with long strings of buoys rolling up and down in the seashore, side by side, sending the power landward.

"Put this at a seawall or breakwater," Kornbluh says. "Why not make it work for you?"

   

They are still toying with the ways of capturing that energy. Ideas include an actual line that runs from the buoys to land, a pipeline for hydrogen broken down by the buoy's electrical power, or rechargeable battery cells that could be harvested from the buoy.

Suddenly, a seal leaps high into the air. He jumps over and over, circling the Velocity, the buoy and the Shana Rae again and again, to the delight of the visitors.

Von Guggenberg sighs. "Most of the time we work in the lab," he says. "We love it when our customers ask us to take their experiment out. This is a lot more fun."


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