The lease agreements concluded between RWE npower renewables and the Cammell Laird shipyard are to run for a term of three years. The leased port area covers around 14 hectares and includes a nearby quay of 230 meters on the western bank of the mouth of the River Mersey. It is from here that over the coming months the foundations for a total of 160 wind turbines of the 3.6 megawatt class will be preassembled, loaded and shipped to the wind farm site in Liverpool Bay around 18 kilometres off the Welsh coast.
RWE Innogy will build the Gwynt y Môr wind farm using its own offshore installation vessel called "Friedrich Ernestine". The Gwynt y Môr wind farm is currently one of the largest offshore wind energy projects in the world. The wind power plant with an installed capacity of 576 megawatts (MW) is scheduled to come on stream in 2014. RWE Innogy has a stake of 60 percent in the Gwynt y Môr offshore wind farm, the municipal utility of Munich and Siemens hold shares of 30 percent and 10 percent respectively.
"The space required to store and preassemble the large-scale components is enormous. With the port area in Birkenhead we have now found an ideal construction site to cope with the complex logistics involved. It will take our offshore installation vessel about six hours to cover the 48 km distance to the construction site out at sea. This fits in excellently with our logistics concepts", says Prof. Martin Skiba, Head of Offshore Wind Power at RWE Innogy.
To build the Gwynt y Môr wind farm, the offshore installation vessel will transport up to three so-called monopile foundations plus transition pieces at a time and install them at a water depth of between 12 and 28 metres. Each of these foundations is between 50 and 70 metres long and weighs up to 700 tonnes. Subsequently, the actual wind power systems will be installed, including tower components, nacelle and rotor star. The installation vessel can transport and install up to six complete sets of turbines of the 3.6 megawatt class at the same time.
RWE Innogy uses a so-called mono-vessel concept in the construction of its offshore wind power plants. According to this concept, the Seabreeze offshore installation vessel is loaded with the individual components at the base port. It then leaves the base port for the construction site at sea where it installs the foundations and wind turbines on site. While the installation vessel is at sea, further components are preassembled at the base port and prepared for shipping. This concept helps to avoid expensive waiting times for the installation vessel at port. Moreover, the number of jack-up operations for large components at sea is limited to a minimum in contrast to other concepts which work with a platform firmly installed at sea and a ship shuttle service between base port and jack-up rig.
The port of Mostyn on the north coast of Wales will become the operating base for the Gwynt y Môr offshore wind power plant from 2014. A corresponding lease contract has been concluded with the local port operator. The two existing RWE offshore wind farms in the Irish Sea, North Hoyle and Rhyl Flats, are already operated from this port.
Through its logistics subsidiary, RWE OLC GmbH, RWE Innogy operates two of the world’s largest installation vessels for building its offshore wind farms. These vessels are satellite-controlled and can be secured in position with inch-perfect precision for construction work at sea and at water depths of more than 40 metres. While the "Friedrich Ernestine" vessel will start on the construction of Gwynt y Môr, the identical sister ship "Victoria Mathias" will build the Nordsee Ost wind farm about 30 kilometres off the island of Helgoland. This wind power plant which comprises 48 wind turbines of the 6-MW class is scheduled to be fully operational in 2013.
At the present time, RWE Innogy is building offshore wind power plants in Europe with an installed capacity of 1,000 MW on its own or together with partners. The company aims to obtain permits for additional offshore wind projects of a total of 5,000 MW by 2014.
