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Offshore Wind Power


Offshore wind farm BARD. Photo: BARD Group
Offshore wind farm BARD. Photo: BARD Group

Construction of alpha ventus, the first wind farm in German marine areas, began in 2009. The current state of development and planning in the North Sea and Baltic Sea is shown here Northsea and Baltic Sea.

So people can use the power generated by offshore wind farms, transformer and converter stations and submarine cables are needed to connect the wind farms to the onshore grid. Further information on power cables and connecting wind farms to the grid is provided under Submarine Cables and Grid Connection (only in German).

Offshore wind farms are huge

With hub heights of nearly 100 metres, rotor blades 60 metres long, overall heights upwards of 150 metres and a total weight of around 250 tonnes each, offshore wind turbines are gigantic. To stand up to the forces of wind, waves and currents, wind turbines need special bases that are safely anchored to the sea floor. Most wind turbines in the North Sea and Baltic Sea have deep pile foundations. Either a single foundation pile (monopile), usually with a diameter of more than six metres, is driven up to 50 metres into the sea floor, or the turbine has a jacket foundation that is permanently anchored by several piles of slightly lesser diameter (three to four metres), likewise driven into the sea floor.

Most wind farms in the German North Sea and Baltic Sea EEZ consist of 80 turbines. The installed capacity depends on the size of the individual turbines and can be 400 megawatts (MW) or greater. Each wind farm covers a marine area of up to 80 km2.

The Federal Maritime and Hydrographic Agency (BSH) is responsible for the approval of wind farms in the German EEZ, while BfN is in charge of nature conservation assessments.


Converter platform in Trianel Wind Farm, Borkum. Photo: Trianel
Converter platform in Trianel Wind Farm, Borkum. Photo: Trianel

Appearance of a wind farm at a distance of approximately 6 km, as seen from beach.
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Appearance of a wind farm at a distance of approximately 6 km, as seen from beach.
Appearance of a wind farm at a distance of approximately 20 km, as seen from beach.
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Appearance of a wind farm at a distance of approximately 20 km, as seen from beach.
Appearance of a wind farm at a distance of approximately 40 km, as seen from beach.
Figures: BfN
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Appearance of a wind farm at a distance of approximately 40 km, as seen from beach.

Ongoing urgent need for research

In view of the huge extent of offshore wind power projects and their construction, the building of offshore wind farms will soon be one of the largest-scale human interventions in the German North Sea and Baltic Sea marine areas alongside shipping and fishing. This large-scale deployment of a relatively new technology will have impacts on the marine environment and ecosystems that still need further research – despite numerous studies so far, including many by BfN. There is also potential for conflict with designated marine protected areas. New projects are not permitted in marine protected areas, but pile driving noise in particular from outside such areas can affect the fauna within them.

The impacts of offshore wind farms on the marine natural environment are subject to intensive study, largely with funding from the Federal Environment Ministry. Preliminary findings from studies of ecological impacts of wind farm construction and operation are now available, among other things from the first German offshore wind farm, alpha ventus. Further research is still needed however, notably into the impacts of underwater noise from wind turbines on the marine natural environment together with potential noise mitigation measures, into seabird habitat loss as a result of wind turbines, into barrier effects and collision risk for migrating birds, and into the cumulative effects of wind farms. BfN is active here and has been involved for several years in funding a range of research projects that in the meantime have confirmed some of the early risk projections.

 

Map North Sea

Offshore Wind Farms, Grid Connections and Natura 2000 Sites in the German Exclusiv Economic Zone (EEZ) of the North Sea.

Offshore Wind Farms, Grid Connections and Natura 2000 Sites in the German Exclusiv Economic Zone (EEZ) of the North Sea. (As of 03.2015)

Map Baltic Sea

Offshore Wind Farms, Grid Connections and Natura 2000 Sites in the German Exclusiv Economic Zone (EEZ) of the Baltic Sea.

Offshore Wind Farms, Grid Connections and Natura 2000 Sites in the German Exclusiv Economic Zone (EEZ) of the Baltic Sea. (As of 03.2015)

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