Offshore wind energy is a promising application of wind power, particularly in countries with high population density, and difficulties in finding suitable sites on land. Construction costs are higher at sea, but energy production is also higher.

The largest offshore wind farms in Denmark are Horns Rev by the west coast of Jutland and Nysted close to Lolland – 160 and 158 MW respectively. A tendering procedure for new offshore wind farms will be commenced in late 2003.

The Danish energy plan, Energi21, from 1996 set up a target for 4,000 MW offshore wind power in 2030. These 4,000 MW are expected to produce 13.5 TWh per year equivalent to 40% of the Danish electricity consumption.

You can read more about offshore wind turbines in Research in Offshore

The most recent large offshore farm is Nysted Offshore Wind Farm at Rødsand built in 2003. The wind farm is located app. 10 km south of the town of Nysted on Lolland and consists of 8 rows with 9 turbines each. The total power of the 72 wind turbines each of 2.3 MW thus reaches 165,5 MW. The annual electricity production of the wind farm is 600GWh, enough to supply 145,000 (Danish) households. The wind turbine towers are about 70 m tall, and the rotor blades 41 m long. The picture is from the initial phase of the installation.
Learn more at www.nystedwindfarm.com

The largest wind farm in Denmark is the offshore wind farm of Horns Rev, which was completed in 2002. It is situated in the North Sea, 14-20 km off the coast of Jutland. With its 80 Vestas 2MW turbines, the wind farm has a total capacity of 160 MW. That makes it the largest offshore wind farm in the world today (2003). The farm supplies the equivalent of 150,000 (Danish) households. The larger production compared to Nysted is due to better wind conditions.
Learn more at www.hornsrev.dk

The energy consumption of the small Danish island Samsø is more than 100% matched by local production of renewable energy. A major reason for this is remarkable fact is a locally owned offshore wind farm consisting of 10 Bonus 2,3 MW turbines.
See online production data at www.samsohavvind.dk/windfarm

Middelgrunden is located 2 km off shore east of Copenhagen. It consists of 20 Bonus 2 MW wind turbines arranged to form an arch. With a total power of 40 MW the wind farm can generate 90 TWh a year. That is equivalent to the annual electricity consumption of 20,000 (Danish) households or three per cent of the total electricity consumption of Copenhagen.
Learn more at www.middelgrunden.dk

The Tunø Knob offshore wind farm (36K, JPEG) in the Kattegat Sea off the Coast of Denmark was built in 1995 by the utility company Midtkraft. The picture shows the construction work with a floating crane.

The Wind farm consists of 10 Vestas 500 kW pitch controlled wind turbines.

The turbines were modified for the marine environment, each turbine being equipped with an electrical crane to be able to replace major parts such as generators without the need for a floating crane.

In addition, the gearboxes were modified to allow a 10 per cent higher rotational speed than on the onshore version of the turbine. This will give an additional electricity production of some 5 per cent. This modification could be carried out because noise emissions are not a concern with a wind park located 3 kilometres offshore from the island of Tunø, and 6 kilometres off the coast of the mainland Jutland peninsula.

The park has been performing extremely well, and production results have been substantially higher than expected, cf. the page on offshore wind conditions.

The Vindeby wind farm (32K, JPEG) in the Baltic Sea off the coast of Denmark was built in 1991 by the utility company SEAS.

The wind farm consists of 11 Bonus 450 kW stall controlled wind turbines, and is located between 1.5 and 3 kilometres North of the coast of the island of Lolland near the village of Vindeby.

The turbines were modified to allow room for high voltage transformers inside the turbine towers, and entrance doors are located at a higher level than normally. These same modifications were carried over to the subsequent Tunø Knob project.

Two anemometer masts were placed at the site to study wind conditions, and turbulence, in particular. A number of interesting results on offshore wind conditions have been obtained through these studies which were carried out by Risø National Laboratory.

The park has been performing flawlessly.

Electricity production is about 20 per cent higher than on comparable land sites, although production is somewhat diminished by the wind shade from the island of Lolland to the South.