Environmental Engineering Reference
In-Depth Information
Figure 8.14
The Nysted offshore wind farm in the Baltic Sea off Denmark.
Source: http://uk.
nystedhavmoellepark.dk.
Construction of the wind farm.
Photo: Gunnar Britse.
wind turbines into high voltage to keep transmission losses to a minimum. Direct-
current transmission may also be necessary for installations that are far from shore,
as losses with alternating-current sea cables can be considerable. A special converter
converts the alternating voltage into direct voltage. On land it is converted back into
alternating current. Normal high-voltage lines then transport the electricity to the users.
Offshore, Onshore and Nearshore
The term
offshore
refers to wind turbines that are sited in the open seas. Use
of the terms
onshore
and
onshore wind farms
in respect of wind power is
relatively recent and only become popular in tandem with the growth of offshore wind
parks. Onshore means
on land
or
on the mainland.
In this sense onshore wind farms are
all wind farms that are not standing in water. These simply used to be called wind farms.
As part of a test of offshore wind farms, some wind turbines were recently erected in
the water just a few metres from the shore. Technically, these test facilities were really
onshore wind turbines with wet feet. The term
nearshore wind turbines
has also been
used to differentiate the turbines.
Numerous very large offshore wind farms have been erected in recent years.
Denmark has been one of the pioneers in this fi eld, followed by Britain. By contrast,
Germany has been rather slow in moving ahead in this fi eld. In part this is due to
the major technical requirements involved. German offshore wind farms are sup-
posed to be erected in comparatively deep waters of 20 to 50 m at a distance of 30
to 100 km from the coast (Figure 8.15). The biggest wind farms in Germany would
ideally consist of several hundred turbines with outputs of several gigawatts. The
investment cost would quickly add up to several billion euros.
