Giant wind turbines near Heligoland completed as He Dreiht heads for full operation

German energy group EnBW has completed Germany's largest offshore wind farm to date, around 110 kilometres west of the Heligoland archipelago in the North Sea. News agency DPA reported this today. The He Dreiht project (literally "he turns" in Low German), costing EUR 2.4 billion (CZK 58.1 billion), comprises 64 wind turbines with a total installed capacity of 960 megawatts (MW).

According to EnBW, once fully commissioned, which is expected by the end of summer, the complex is to supply electricity to around 1.1 million households.

The project is one of the first German offshore wind farms not to be subsidised through feed-in tariffs under the Renewable Energy Sources Act. EnBW has instead concluded long-term agreements with major customers, including Google, Bosch, German rail operator Deutsche Bahn (DB) and Frankfurt Airport operator Fraport.

The turbines have a hub height of 142 metres and a rotor diameter of 236 metres. The complex is connected to the electricity grid via an offshore converter station and two high-voltage cables. These run underwater for more than 120 kilometres and then continue for another 110 kilometres on land.

At the end of July, part of a turbine blade about 20 metres long broke off during construction and fell into the sea. Manufacturer Vestas is still investigating the cause.

The completion of the He Dreiht project comes as EnBW warns of rising costs for further development of offshore energy projects, known as offshore wind farms. A few weeks ago, the company's chief executive Georg Stamatelopoulos called on the German government to scale back plans to expand wind farms in the North Sea and Baltic Sea.

According to Stamatelopoulos, turbines, logistics and cables have become 30 to 40 percent more expensive over the past five years. Germany aims to increase offshore wind capacity to at least 30 gigawatts (GW) by 2030 and 70 GW by 2045. At the end of June this year, 1,764 offshore turbines with a total capacity of around 10.8 GW were operating in Germany.