Page 437 - (DK) Ocean - The Definitive Visual Guide

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Wind-farming in the Baltic

Declining oil stocks, threats to fuel supplies, and the risks
OFFSHORE WIND FARMS
of climate change are increasingly focusing attention on
alternative sources of energy that do not generate
greenhouse gases. After hydroelectricity, wind-farming
is the most advanced source of renewable energy. It is
easiest to build wind farms on land, but many people do
not want turbines built near their homes. Wind farms
built at sea are less controversial, although costlier to
build and maintain. Since it is usually windier at sea and
there are no hills or trees to cause turbulence, offshore
turbines are more efficient than land-based ones.
The world’s first commercial offshore wind farm was
built in the Baltic (see below). Other large wind farms
are in place or under construction in the nearby MASSIVE BLADES
Wind-turbine blades are
Kattegat sea area; in British, German, Danish, Dutch, assembled on the dockside,
and Belgian areas of the North Sea; and off the coast of then carried to the tower on
a barge. The rotors reach
China. There are also wind farms in the Mediterranean 295 ft (95 m) in diameter.
and off Ireland, Japan, Norway, and Spain, while a large
farm is planned in South Korea. The US and Canada UNDER CONSTRUCTION FOUNDATIONS
also have various proposed offshore projects for the The concrete foundations of
a turbine are cast onshore
Pacific Coast, East Coast, and Great Lakes. in a dry dock. They are then
Because they burn no fossil fuels, wind farms can help floated out to sea and sunk
in shallow water on site.
reduce greenhouse gases. However, the overall benefits
may take some time to appear. It can take 1,000 tons
of concrete just to build the foundations of an offshore
turbine, and concrete production is one of the biggest
sources of greenhouse gases.

Baltic and Kattegat Wind Farms

The countries around the Baltic Sea and the neighboring
Kattegat sea area have played a central role in the development
of offshore wind energy. The world’s first commercial offshore
wind farm was commissioned in 1991 near the Danish fishing
port of Vindeby. The Baltic and Kattegat are ideal for wind-
farming because of their low average depths. The first wind farms POWER DISTRIBUTION
in this region were sited in water less than 33 ft (10 m) deep. SUBSTATION The electricity generated by offshore turbines has
to be transmitted to land. This substation collects power from 72
wind farms wind farms under construction turbines at the Nysted Offshore Wind Farm off southern Denmark,
and transforms it from 33,000 to 132,000 volts for transmission
ashore via 30 miles (48 km) of submarine cable.
RODSAND II Completed in 2010
NORWAY and costing 450 million Euros,
LARGEST BALTIC WIND FARM it has 90 turbines, arranged in
Denmark’s Rodsand II is the
Nor th SWEDEN largest wind farm in the Baltic
and also one of the world’s twelve
Sea largest offshore farms. An average
of 6 miles (9 km) from shore,
Kattegat
five arcs. Rodsand II has a peak
capacity of 207 megawatts
of around 700,000 tons
DENMARK Middelgrunden and is saving the emission
of CO per year.
2
Vindeby Baltic Sea
Rodsand ll WHITE-TAILED EAGLE Although wind energy
may bring about potentially huge benefits
CASUALTIES turbines do sometimes harm birds.
POLAND for wildlife by reducing climate change,
GERMANY found at an offshore Norwegian
Four dead white-tailed eagles were
wind farm in early 2006.