A Floating Wind Tower Is Launched in Maine

Source: Mathew Wald, NYT • Posted: Monday, June 3, 2013

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The test wind tower will be anchored in the Gulf of Maine. Its 20 kilowatts in capacity could be used up by a handful of big homes. Jeff Kirlin

One reason that offshore wind has not caught on in the United States is the steep cost of erecting a tower in the water, but researchers at the University of Maine tried another approach on Friday by launching a floating wind machine. It is the first offshore wind installation in United States waters, according to the Energy Department, which helped pay for it.

The tower, launched in Brewer, Me., sits on three hollow concrete tubes and will be anchored in the Gulf of Maine. It is a mere 20 kilowatts in capacity, an amount of power that could be soaked up by a handful of big suburban houses on a hot summer day. But it is one-eighth the dimensions of the one the researchers hope to deploy in the next few years, a gigantic 6-megawatt model, with each blade as long as the wingspan of a Boeing 747.

Because of its location, it will have two big advantages over machines on land, according to Habib J. Dagher, a professor of civil engineering at the university. Onshore wind machines produce most of their energy at night, when it is least valuable to utilities buying the power, but this one will catch the predictable, strong breezes that come up every sunny summer afternoon, he said, when the sun heats the land more than the sea, creating an onshore breeze.

Over a year, onshore machines in the Eastern United States produce only about a third as much electricity as would result if they ran at full tilt every hour of the year, but this one will produce 40 percent to 50 percent as much, he said, because winds offshore are stronger.

The engineering, though, is tricky; for one thing, the tip of the tower will swing on the waves. But the platform is designed to rock at a slower rate than the waves to lessen their impact.

The project is one of seven sponsored by the Energy Department under a $168 million program. Three are floating, four are fixed, and this is the first to be put into use, according to Jose Zayas, director of the department’s Wind and Water Power Technologies office.

The Friday project is small but “it’s important to recognize it is at a relevant scale,” he said. “It does represent the behaviors and dynamics of a large machine.”

Among the issues is durability; Mr. Dagher said the concrete would not corrode and should last 60 years, just as the Hoover Dam had proven durable over many decades. The offshore wind resource is equivalent to thousands of Hoover Dams, he said.

“The beauty of the floating technology is it doesn’t care what the water depths are,” Mr. Dagher said. The platform bears some resemblance to the ones the oil industry uses to drill from.

Water is shallow off most of the East Coast but not off Maine, and not off much of California’s coast, experts say. Peter Mandelstam, a wind developer and longtime chairman of the American Wind Energy Association’s offshore group, said, “We and other developers want this technology developed on both coasts.”