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Rubber snakes designed to act like electric eels

July 7, 2008 |  7:00 am


British scientists and engineers are betting that a giant snake-like tube may hold the key to producing cheap and clean energy from ocean waves. It's just one of many alternative-energy devices in the works to harness power of waves, but this one is simpler and less expensive to maintain, its designers say.

The Anaconda, named after the giant South American swimming snake, consists of a long tube filled with water and closed at both ends that would be anchored just below the sea surface. As a wave rolls through, it squeezes the tube, causing a "bulge wave" to form inside and run through the tube like the proverbial pig in the python, only faster. When the bulge waves reaches the end, it turns a turbine and produces power fed to shore via a cable.

"The Anaconda could make a valuable contribution to environmental protection by encouraging the use of wave power," said John Chaplin, a University of Southampton professor leading the effort funded by the Engineering and Physical Sciences Research Council.

Because it's made of rubber, the Anaconda is much lighter than other wave energy devices that are often tethered to the sea floor and bob like buoys or pump like pistons. So far, only small versions of the sea snake have only been tested in the lab. But engineers envision energy farms that would have 20 Anaconda devices, each tube about 20 feet in diameter and extending 600 feet long. The devices would produce enough electricity to power 2,000 homes -- at a cost of about twice that of coal-burning plant, but with none of the carbon-dioxide emissions.

An animated clip of the device shows how it would work in an offshore environment, where waves are rolling through the water as opposed to crashing on shore. Still, the challenge with all of these oceanic devices is to withstand the corrosive nature of seawater, the relentless pounding of the sea and avoid becoming so much marine debris.

"The ocean is a very hostile environment," Chaplin said. "The structure has got to be there and still working after the largest storms."

-- Kenneth R. Weiss

Illustration provided by Engineering and Physical Sciences Research Council