Could ocean wind be an energy bonanza?

UC IRVINE (US)—Stable air and cold water make U.S. coastal regions prime spots to tap wind energy, say researchers from the University of California at Irvine.

The study by Charlie Zender, earth system sciences associate professor, and graduate student Scott Capps is the first to calculate potential wind energy at 80 meters above the ocean—the typical wind turbine height, where 50 percent more power is available. Previous wind estimates were made at 10 meters, the height important to the shipping industry.

“In the midlatitudes, you find these stable environments where air really takes off and accelerates rapidly as you move away from the ocean’s surface,” says Zender.

With global calculations made twice a day between 2000 and 2006, the researchers estimate the average global ocean wind power at 841 watts for every square meter swept by turbine rotors. A single ocean turbine produces about 1 million watts of power, enough to continuously supply about 1,000 houses.

“When you put our research together with existing studies over land, you get—for the first time—a global estimate of wind power reserves,” says Zender. “There’s a lot of power in the wind. The more we compare it to other energy sources, the more I’m impressed.”

Unlike other energy sources, such as coal-powered plants, ocean wind energy is clean and renewable and doesn’t use land-based real estate.

Also, ocean turbines, typically placed in water up to 40 meters deep, can be closer to population centers than power plants, reducing leakage and cost of transmission lines. And networks of ocean wind farms are as reliable as coal plants at producing consistent levels of power, Zender says.

While ocean wind power has its perks, it also has restrictions, Zender notes.

Offshore wind turbine towers must be anchored to the ocean floor—restricting their distance from the coast—and they cost about 50 percent more than land models, partly because upkeep is more difficult.

“There are issues with every energy resource,” Zender says, “but wind has relatively few compared to coal, ethanol, or nuclear power.”

The National Science Foundation and NASA supported the study, which was published in the journal Geophysical Research Letters.

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