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Offshore Wind May Power The Future

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Posted by pautrey2 on November 17, 2008, 9:09 am
 
October 20, 2008

Offshore Wind May Power the Future

Not only are offshore winds stronger but landlubbers have fewer
objections to turbines almost invisible from the coast
By Emily Waltz

The waters of the Jersey Shore may soon become home to the nation's
first deepwater wind turbines. New Jersey officials recently announced
the state would help fund an initiative by Garden State Offshore
Energy to build a 350-megawatt wind farm 16 miles (26 kilometers)
offshore. The state wants by 2020 many more of these parks, at least
3,000 megawatts worth, or about 13 percent of the state's total
electricity needs.

"This is probably the first of many ambitious goals to be set by
states," says Greg Watson, a senior advisor on clean energy technology
to the governor of Massachusetts. "Three thousand megawatts is
significant. With that you're able to offset or even prevent fossil
fuel plants from being built."

The federal government is about to open up to wind energy development
vast swaths of deep ocean waters, and states and wind park developers
are vying to be the first to seize the new frontier. Wind parks in
these waters can generate more energy than nearshore and onshore
sites, they don't ruin seascape views, and they don't interfere as
much with other ocean activities.

New Jersey's plan was prompted, in part, by new federal rules that
will greatly expand the territory in which developers can build
offshore wind parks. Until now, such projects were only allowed in
shallow state watersthose within 3.5 miles (5.6 kilometers) of shore.
The new rules would allow them in federal waters, known as the outer
continental shelf, which extend to the edge of U.S. territory about
230 miles (200 nautical miles, or 370 kilometers) out. These are the
same waters where the hotly debated oil and gas drilling has been
proposed, but the sites are unlikely to overlap, say wind developers.

The U.S. Department of the Interior's Minerals Management Service, the
federal agency with jurisdiction, plans to finalize the rules by the
end of the year. The agency says it will lease plots of the shelf to
developers of wind parks and other renewable energy projects, such as
ocean current and wave-harvesting technologies. States are chipping in
on wind park development projects in the hope that the energy from
these complexes will feed into state grids and help meet renewable
energy requirements.

Some groups say the rules leave too many barriers for developers to
overcome. "Are these waters really open?" asks Sean O'Neill, founder
of the Ocean Renewable Energy Coalition. O'Neill says the leases may
be prohibitively expensive and the environmental review process too
extensive.

Which way the wind blows
But opening up the shelf may be the only way a viable offshore wind
industry can develop in this country. Wind projects in state waters
are visible from shore and can interfere with shipping routes and
recreation. Turbines often have to be smaller and fewer to minimize
these impacts, leading to less profitable projects. And prior to the
new federal rules, no one knew who was in charge.

These obstacles have delayed, and in some cases nixed, many projects
and so far, not a single offshore wind turbine is operating in the
U.S. Organizers of Cape Wind, an offshore wind park to be built more
than five miles (eight kilometers) from Cape Cod, Mass., have been
battling public opposition and regulatory hurdles for more than seven
years.

Leasing the outer continental shelf may solve some of these problems
and open a tremendous energy resource. Researchers at the National
Renewable Energy Laboratory (NREL) in Golden, Colo., estimate that the
wind in this territory could generate nearly 1000 gigawattsa little
more than the current U.S. electrical capacity.

The figure is enticing because nearly 80 percent of the population
lives in coastal states. In some of the most densely populated areas,
particularly in the Northeast, there is not enough space for large
onshore wind farms. Offshore wind parks can get much closer to some of
these coastal cities without having to run long transmission lines
over rocky terrain and through urban areas. "I think a lot of people
would like to bring the energy from wind farms in the Midwest to the
cities in the east, but those links aren't easy to make," says Walter
Musial, an engineer at NREL.

Europe has far surpassed the U.S. in offshore wind with more than two
dozen wind parks in its waters. But nearly all are built within nine
miles (14 kilometers) from coastlinesa distance still visible from
shoreand in depths less than 60 feet (18 meters). Researchers must
tackle some turbine design challenges before wind parks can move into
deeper waters.

Building for depth
A common design for shallow depths is a simple pole driven into the
seafloor, called a monopile. The deeper the water, however, the longer
and more wobbly the pole. Beyond 65possibly 100feet (20 to 30
meters) deep, monopiles are no longer suitable. "At some depth you
have to switch technologies," Musial says.

Researchers are experimenting with new designs such as underwater
tripods and lattice structures called jackets, which provide extra
support. Engineers for the Beatrice Wind Farm in the North Sea near
Scotland are leading the way with two turbines in water 138 feet (42
meters) deep and more than 15 miles (24 kilometers) from shore. German
developer Alpha Ventus plans to build in the next few months a dozen
turbines with both tripod and jacket technologies.

Engineers say these designs could hold up in depths of as much as 200
feet (60 meters). To go any deeper, the best option is likely a
floating structure similar to that used by the oil industry. Wires
would anchor the platforms to the seabed. But unlike an oil platform,
the floating wind turbine would have to better restrain the sea's
pitch, roll and heaving motions. Commercial development of these
structures is likely a decade away, says Musial, although some private
developers in Europe say they are working on prototypes.

The depths of the U.S. outer continental shelf vary: Off of
California's coast, for example, it gets deep fairly quickly compared
with the east coast shelf. To get to a point where turbines are barely
visible, wind parks must be built at least 14 or so miles (22.5
kilometers) from shore, says George Hagerman, a marine renewable
energy researcher at Virginia Polytechnic Institute.

Offshore costs can be prohibitive, particularly without tax credits
and incentives. Turbines and transmission lines are more expensive.
Boats have to make long trips to and from the wind park. And some of
the equipment to build in deep waters doesn't yet exist. In Europe, an
offshore wind park costs nearly twice as much per megawatt as an
onshore wind park, according to the European Wind Energy Association
in Brussels. The question, says Paolo Berrino at the association, is
whether greater wind generation efficiency offshore will outweigh the
additional costs.

"Going into deeper water is not something we're comfortable doing
yet," says Jim Lanard a spokesperson for Bluewater Wind, a company
that has proposed a wind park 13.2 miles (21.2 kilometers) from the
Delaware shore that will employ monopiles to depths of about 75 feet
(23 meters). "The first offshore wind parks cannot fail because it
will send a signal to the industry and the government that [the] U.S.
offshore wind industry is not ready for prime time. So we are taking a
conservative approach with technologies proven in Europe."

http://www.sciam.com/article.cfm?id=offshore-wind-may-power-the-future

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