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Underwater ‘kite’ captures tidal energy

A small "kite" that's flown under water is boldly going where no tidal turbine has gone before.
Image: Artist's conception, Deep Green
Deep Green, which looks like a kite, has a nearly 40-foot wingspan and can operate at greater ocean depths, where currents are
/ Source: Discovery Channel

A small "kite" that's flown under water is boldly going where no tidal turbine has gone before.

“Deep Green” looks like someone’s flying kites from the sea floor. With its 39-foot wingspan and 328-foot cable tethering it to the ocean floor, all it’s missing is a colorful tail.

Though a nearly 40-foot wingspan may seem big, the kites are small compared to other tidal energy designs. That’s one of the big advantages to Deep Green: it can operate at greater depths, where currents are slower.

When anchored, Deep Green can be steered into a figure eight like a sport kite, its turbine capturing tidal energy at 10 times the speed of the actual stream velocity, according to Minesto, the Swedish developers of Deep Green. One Deep Green sea kite is expected to generate 500 kilowatts of power, enough to power a modern refrigerator for a year.

But hold on to your Pop Tarts. It will be a few years before sea kites power your toaster. Testing is scheduled to start in Northern Ireland in 2011. Minesto hopes to have a commercial model of Deep Green out in four years.

As fossil fuels dwindle, the need for renewable energy sources becomes clear; scientists have even drawn up plans to power the planet with purely renewable energy.

More and more companies are working with solar, wind and tidal power. Tidal turbines’ main drawback is their cost, but the predictability of the tides makes up for it.

When wind farms and solar panels get skunked on calm, cloudy days, the tides still come in like clockwork.