Jack-Up Barge to Provide Home at Sea for Nordsee Ost OWF’s Workers
RWE Innogy has awarded Dutch company Jack-Up Barge B.V. the contract to provide an accommodation platform at the construction site of the Nordsee Ost Offshore Wind Farm.
The jack-up vessel “JB 114” will temporarily accommodate up to 40 employees to carry out commissioning works at the wind farm’s internal transformer station from mid-July.
“With this platform we are providing a comfortable home for our employees during the transformer station’s commissioning phase of about two months and safe access to their place of work. The jack-up legs will lift the platform out of the water right beside our substation. As a result, the vessel will be in an elevated position and therefore won’t be exposed to the waves.
A gangway connecting the accommodation unit with our substation will be placed almost 25 meters above the water surface”, explains Marcel Sunier, Project Director for the Nordsee Ost wind farm at RWE Innogy.
Maarten Hardon, Commercial Director of Jack-Up Barge B.V., adds: “After the successful completion of the Gwynt y Môr project, Jack-Up Barge is once again looking forward to working with one of the leading companies in the offshore wind sector. This contract reaffirms the proven capabilities of the JB 114 in the offshore wind industry.”
The vessel has a deck of approximately 1,000 square meters, and a main crane with a lifting capacity of 300 tonnes. The existing helicopter landing platform allows flexible crew turnover. This is essential because up to 40 technical staff will stay offshore for the total period of the commissioning works.
The internal transformer station is the nerve centre of the wind farm. It transforms the electricity generated by the wind power systems at 33 kilovolt, to a transmission voltage of 155 kilovolt so that it can be transmitted by submarine high-voltage cable to the coast.
The transformer station of the Nordsee Ost wind farm is about 15 meters high and weighs around 2,000 tonnes. Like the wind turbines, it is anchored to the seabed on a steel jacket foundation and stands some 35 meters above sea level once fully assembled.
The 700 tonnes steel foundation for the transformer station was installed in July 2013. Welding work is initially carried out during the commissioning phase to connect the transformer platform (topside) with the foundation, which is referred to as “wedding”. The overall system is then electrically put into service and the wind farm’s internal cabling as well as the external cables of the grid operator (Tennet) are connected.
The erection of the wind turbines is due to start in May 2014. Once the wind farm is completed, estimated to be in Spring 2015, Nordsee Ost Offshore Wind Farm will have an installed capacity of some 295 megawatts (MW) and be capable of producing enough electricity to supply the equivalent of some 300,000 residential households per year.
RWE Innogy, April 30, 2014