Nordsee Ost Offshore Wind Farm, Helgoland, Germany
Nordsee Ost offshore wind farm is a 295MW renewable power project being built approximately 19 miles north-east of Helgoland, a German archipelago found in the North Sea. Construction on the project is poised to commence in summer 2012 and the wind farm is set to be fully operational in 2014.
Upon its completion, the wind farm will generate about 1.1 terawatt-hours of climate-friendly electricity per annum, which is sufficient to power 310,000 households. It is estimated to avoid the production of approximately 850,000t of carbon dioxide each year, when compared to a modern gas-fired power plant.
The project is owned and will be operated by RWE Innogy. The company is investing around $1.13bn in the development and construction of the wind farm. It the company's maiden offshore wind farm in Germany.
European Union (EU) has sanctioned a loan of approximately $63m for the project, through the European Energy Programme for Recovery (EEPR).
The recently commissioned Victoria Mathias offshore installation vessel will be used to install the wind turbines. She was deployed at the construction site in late June 2012.
Origins of the German wind farm development
Plans for the construction and operation of the wind farm were originally developed by Winkra Offshore Nordsee Planungs - und Betriebsgesellschaft in 2000. Two years later, the project was acquired by Essent, the largest Dutch energy company.
In October 2009, Essent itself was acquired by the German electric utilities company RWE. Nordsee-Ost was consequently transferred to RWE's renewable energy subsidiary, RWE Innogy.
The project was approved in 2004 by the Federal Office for Shipping and Hydrography. In 2005, a metering mast was installed at Amrumbank to monitor the behaviour of the wind, wave and current. The recorded data is used as the basis for the development and operation of the Nordsee-Ost wind power station.
One year later, a five megawatt REpower turbine was commissioned at Cuxhaven for testing the performance, durability and reliability of the turbine. In 2007, the project was given the necessary approvals required for the installation of offshore cables.
Details of the Nordsee Ost offshore energy project
The site of the Nordsee-Ost wind farm is located well outside the main shipping routes, military training areas and marine bird conservation zones. The power station is designed for an operational life of 20 years.
A total of 48 REpower 6M type wind turbines are planned to be installed across an area of about ten square miles. These turbines will be secured on 100m high towers. Each turbine will have a rotor diameter of 126m and rated capacity of 6.15MW. The rotor blades are made of glass-fibre reinforced plastics (GRP) and measure 61.5m in length.
The turbine towers will be fitted on four-legged jacket foundations which will stand in water depths averaging 25m. Exagrout Masterflow 950, a cement based grout developed by BASF, will be used to fasten the foundations to the seabed.
Each foundation will weigh about 550t and measure 50m in length. The foundation base will have an area of approximately 400 square metres.
Wind turbine connections and offshore substation
All the wind turbines will be connected to one another via inter-array cables, which in turn will be connected to an offshore substation. More than 35 miles of cabling is estimated be required.
An offshore substation will be built to convert the 33kV electricity produced by the wind turbines to a transmission voltage of 155kV. The stepped-up power will be transmitted to the grid connection point at Brunsbüttel using high-voltage subsea cables.
Suppliers for RWE Innogy's German wind farm
Baltic 1 Offshore Wind Farm is Germany's first commercial offshore power project located in the Baltic Sea.
REpower Systems was given a contract in February 2010 to supply 48 offshore wind turbines of the 6M make, for the Nordsee-Ost project. In May 2010, RWE Innogy signed a two-year lease contract with Eurogate Container Terminal Bremerhaven for the use of Bremerhaven container port as a base port for the development activities of the wind farm.
Aker Solutions was given an engineering, procurement and construction (EPC) contract worth approximately $144.6m for the delivery of 48 steel jackets and piles for the wind farm. ABB is supplying around 40 miles of offshore sea cables. This supply contract is valued at $12.5m.
Siemens Energy is responsible for the construction, supply and installation of the offshore substation. The contract, valued approximately $724m, was signed in August 2010. Foundation grouting will be undertaken by FoundOcean.
TÜV Rheinland was commissioned in April 2011 to inspect and supervise the production of the wind turbines.