Ocean waves could become a constant source of renewable energy. M

Monday, July 14, 2008

Energy from Waves
New technology could provide a way to harness wave energy.


By Prachi Patel-Predd

The ocean's waves have enough energy to provide two trillion watts of electricity, according to the Department of Energy's office of Energy Efficiency and Renewable Energy. Extracting that enormous resource of power, however, has proved to be a herculean challenge.

A new device being developed by U.K.-based Checkmate SeaEnergy could help tap a portion of this wave power. The device, aptly named the Anaconda, is a long, water-filled rubber tube closed at both ends. It currently exists as a small laboratory-scale model, but it could eventually be 200 meters long and seven meters in diameter. At such a size, it will be capable of generating one megawatt of power at about 12 cents a kilowatt-hour, which is competitive with electricity costs from other wave-power technologies.

The one-megawatt Anaconda, which will use about 110 tons of rubber, should be lighter and cheaper than other wave-exploiting designs, says John Chaplin, a civil-engineering professor at the University of Southampton, in the United Kingdom, who is testing the lab-scale device. It is also simpler, with fewer moving parts and hinges, which means less maintenance. Since it is a pliant rubber tube, it should be able to survive severe weather conditions. "We don't really know how Anaconda works in big waves yet, but intuitively, it seems likely that it's going to be able to survive big waves," Chaplin says.

The Anaconda will face plenty of competition from other wave-power devices that have already reached commercial-scale deployment. Scotland-based Pelamis Wave Power's snakelike device was the first to provide power to the grid when it was installed off the coast of Orkney, Scotland, in 2004. In October 2007, Pelamis deployed three of its 750-kilowatt devices--770-ton, 120-meter-long chains of metal cylinders--off the coast of Portugal. Other companies, such as Finavera Renewables of Vancouver, AWS Ocean Energy of Scotland, and Ocean Power Technologies of Pennington, NJ, are testing bobbing buoy-type devices. In addition, others are developing technology to exploit tidal energy.

The Anaconda floats horizontally just below the ocean's surface, tethered to the ocean floor at one end, facing oncoming swells, with a turbine attached, at the other. A wave hitting the tube creates a bulge in the water inside. The bulge travels down the tube with a speed that depends on the diameter of the tube, wall thickness, and elasticity of the material, Chaplin says. The tube is designed so that the speed of the bulge is the same as the speed of the wave. The wave travels outside the tube alongside the bulge, making the bulge bigger and bigger, so that it drives the turbine with maximum power.

Technology Review: Energy from Waves

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National Debt =

Well, if the running water of rivers can be harnessed for electricity, why not ocean waves?

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A panda walks into a cafe. He orders a sandwich, eats it, then draws a gun and fires two shots in the air.

"Why?" asks the confused waiter, as the panda makes toward the exit. The panda produces a badly punctuated wildlife manual and tosses it over his shoulder.

"I'm a panda," he says at the door. "Look it up."

The waiter turns to the relevant entry and, sure enough, finds an explanation.

"Panda. Large black-and-white bear-like mammal, native to China. Eats, shoots and leaves."

I'm all for it! If this sort of thing works, and doesn't really disrupt fish and whatnot, I'd love to see this country go all-electric energy.

I could see this thing clubbing the hell out of some passing dolphin, though. But, I'll trade the occasional stunned dolphin for energy dependence......

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An employee gets trampled to death by a frenzied, greedy mob at a Walmart sale, and customers actually complained when the store closed. Yet, I'm the bad guy for suggesting policies that assume people act like retarded herd animals that need government nannying and control....

Then maybe the dolphins will learn not to get near the things.

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A panda walks into a cafe. He orders a sandwich, eats it, then draws a gun and fires two shots in the air.

"Why?" asks the confused waiter, as the panda makes toward the exit. The panda produces a badly punctuated wildlife manual and tosses it over his shoulder.

"I'm a panda," he says at the door. "Look it up."

The waiter turns to the relevant entry and, sure enough, finds an explanation.

"Panda. Large black-and-white bear-like mammal, native to China. Eats, shoots and leaves."

And I would see Dolphins getting curious about this and then using it like a playground device. Remember, they have bigger brains than we do.

When I first say this, it didn't look like a big deal until you think of how many of these you could use and the alternative being those gargantuan wind towers anchored in the ocean. This method seems to be less invasive to the environment.

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National Debt =

The environmentalists will fight it: shipping hazard.

Apparently, dolphins aren't so smart as to have figured out the tuna net = death equation.

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An employee gets trampled to death by a frenzied, greedy mob at a Walmart sale, and customers actually complained when the store closed. Yet, I'm the bad guy for suggesting policies that assume people act like retarded herd animals that need government nannying and control....

Environmentalists caring about shipping hazards?

The oceans/coasts are pretty big, and even if we ended up doing this large-scale, I'm sure ships will be able to use them thar newfangled navigational devices to steer clear. Unless Joseph Hazelwood is driving, of course....

Even if one broke off, and was floating around as a 200 meter long rubber tube, it's no different than the already continent-sized island of trash out there.

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An employee gets trampled to death by a frenzied, greedy mob at a Walmart sale, and customers actually complained when the store closed. Yet, I'm the bad guy for suggesting policies that assume people act like retarded herd animals that need government nannying and control....

No- that would merely be their excuse for fighting it. Their true agenda must remain hidden.

It will never be built, at least not in my lifetime. The NIMBY and BANANA nuts will kill it, along with the greenies.

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Jarlaxle
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I know that I will never be politically correct
And I don't give a damn about my lack of ettiquette
--Jim Steinman