Offshore wind farm
North Sea, Germany
EON Climate & Renewables
Amrumbank West is a 288MW offshore wind farm located in the North Sea, Germany. It is situated 35km north of Helgoland and 37km west of Amrum.
The €1bn ($1.3bn) project was developed by EON Climate & Renewables. It is the company’s first commercial wind project in Germany and will produce 720GWh of clean energy a year, which will be sufficient to power approximately 300,000 homes.
Construction of the wind farm began in January 2014 and commissioning was completed in October 2015. The project is expected to offset 740,000t of carbon emissions a year.
Amrumbank West wind farm details
The wind farm includes 80 Siemens SWT-3.6-120 wind turbines, rated at 3.6MW each. The turbines are installed over an area of 32km² in water depths ranging between 20m and 25m.
They are supported by 800t steel monopole foundations with a diameter of 6m and height of 70m.
The turbines have a rotor diameter of 120m and hub height of 90m. They are interconnected by 33kV infield cables over a total length of 86km.
The onshore facilities of the wind farm include a 1,800m² operations and maintenance building on Helgoland Island. The construction of this building was completed in April 2015.
The turbine installation was performed using a jack-up rig named MPI Discovery.
Grid network for the German North Sea wind farm
Electricity generated by the wind farm is transferred to the 690MW HelWin2 offshore converter station through 8km of cables. The 10,000t converter station is 27m high and includes 98m x 42m steel topsides.
It was supplied by Siemens and uses the company’s HVDC PLUS technology to transform the electricity generated into high-voltage, low-loss direct current.
The converter station was built by grid operator TenneT to serve as a hub for future wind farms in the German North Sea. It is one of the ten hub projects undertaken by TenneT to transport offshore wind power to the German grid network.
Construction of the Helwin2 converter station started in October 2012. The station was built on an 18m-high separate platform and was commissioned in June 2015.
An 85km export cable transfers the electricity from the Helwin2 to a landing point near Bussum. From there, a 45km spur line transfers the electricity to the onshore coastal converter substation at Buttel. The substation converts the direct current into alternating current and transfers the electricity to the grid network.
Contractors involved in Amrumbank West project
Siemens delivered, installed and commissioned the wind turbines. It is also responsible for the maintenance of the turbines for the first five years.
Heerema Fabrication Group and Siemens jointly built the HelWin2 converter station, under an engineering, procurement, construction and installation (EPCI) contract from TenneT. Siemens also supplied the coastal converter station.
A consortium of Prysmian and Siemens was responsible for supplying, installing and commissioning the HelWin2 converter station. The €600m contract was awarded by TenneT.
Nkt Cables was awarded a €20m contract to manufacture submarine cables for the wind farm at its Cologne production facility.
Siem Offshore Contractors (SOC) was awarded a $60m contract for the installation of the inner grid cables. It also provided associated services, such as cable route survey, route clearance operation and testing.
SOC subcontracted marine survey company MMT to perform a geophysical cable route survey for the offshore wind farm. MMT used its IceBeam survey vessel to conduct the survey.
A joint venture comprising HOCHTIEF Construction, WeserWind and IAG Industrie-Anlagen-Bau Georgsmarienhütte installed a met mast for the project.