The construction diary for Hohe See

Fully commissioned: At 11:10 a.m. on 5 January 2020, the first of 16 turbines at the Albatros wind farm was commissioned and began feeding electricity into the grid. Four days later, after the 71 EnBW Hohe See wind turbines, all 16 EnBW Albatros turbines were also connected to the grid. The commissioning has thus been successfully completed: Currently, all 87 turbines of the offshore wind farms "Hohe See" and "Albatros" are feeding in electricity. They have a total output of 609 megawatts.

Christmas 2019: Work continues at the wind farms Hohe See and Albatros even during the holidays. Marcel Seidt, service technician for the wind farms, was on duty there until 25 December: "On the Bibby Horizon, we were on the construction site over Christmas as a team of about 20 men, and actually the celebration there is a day like any other: We accompanied the commissioning of the Transition Pieces, i.e. various inspections of the commissioning. Commissioning work is also underway on the OSS and there are various maintenance and service intervals. Only the Christmas decorations with a small Christmas tree in the canteen made it clear that it really is Christmas. Unfortunately I missed a Christmas dinner: Since the Bibby is flying an English flag, Christmas dinner was not served until the 25th night when I was already off.

From the inspection and approval of the ships allowed to navigate in the wind farm area to the coordination of ship movements on the construction site: During the entire installation phase of the Hohe See/Albatros project, Marine Coordination in the EnBW office in Hamburg ensured the smooth operation of all activities at sea on a 24/7 basis. In the picture: Heiko Tetzner and Michael Vandersee (from left).

The first kilowatt hour of electricity was generated and fed into the grid by the first wind turbine at the “Hohe See” wind farm on 15 July. Eight turbines had generated electricity by the end of July and completed a 10 day test period. More turbines will be switched on in August. Our photo: The “Brave Tern” installation ship is situated next to a wind turbine, while the “Seajacks Kraken” lies alongside the offshore substation on the right of the photo. This ship is used as an accommodation platform at the construction field.

Halfway point reached on 24/06/2019: The 44th turbine for the neighbouring wind farms “Hohe See” and “Albatros” in the North Sea has been erected. More than half of the turbines have now been installed. The “Brave Tern” and “Blue Tern” installation ships each load the parts for four wind turbines at the port of Esbjerg in Denmark and install them at sea onto the foundations anchored into the seabed.

The substation for the EnBW Albatros offshore wind farm has been installed. The “Pacific Osprey” collected the substation in Rotterdam and then the “Innovation” lifted it into place on the already installed foundations.

The construction of the EnBW Hohe See and EnBW Albatros offshore wind farms is continuing with two new special ships: the jack-up vessel Innovation has been on the construction site since mid-February and is installing the rest of the total of 87 monopiles. The ship Sea Installer is also set to begin work in the near future. It will transport the transition pieces for the later towers of the wind turbines from Rotterdam to the construction site and position them on the monopiles. Both new ships are being used after the Pacific Osprey used in 2018 was no longer operational following crane damage.

All the major components for the OTM have been installed on the platform since the end of 2018. Before the planned load-out in March 2019, the systems are due to be commissioned on the platform.

The first steel plates were cut to mark the start of construction of the ALBATROS OTM (Offshore Transformer Module) in Zwijndrecht, the Netherlands, in February this year. After 5 months of steel construction and coating work, the two decks that had been constructed separately were ready to be joined together. The main deck was positioned and aligned on top of the cable deck. It will still take some time until the work to join the two decks has been completed.

The cable installation ship “Spirit” has transported its first load of cables to the construction field from England. It is being supported by the supply ship “Stril Server”. This ship houses the personnel required for installing the cables at the foundation sites. The first cable was already laid across the seabed between two of the foundation sites and installed on 13 August.

The cables being produced in Lochem (the Netherlands) and Hartlepool (Great Britain) for the array cabling are almost finished. The first sea cables were loaded onto the cable installation ship “Stemat Spirit” in Velsen, near Amsterdam. From there it sailed to England to collect the remaining cables. A total of 130 km of sea cables for the array cabling will be installed for the EnBW Hohe See / Albatros project.

The four mud mats are being constructed. They are the bottom sections of the jacket foundation. The jacket itself sits on the seabed. A jacket can be used as the base for erecting e.g. a standard wind power plant or, in this case, the transformer platform.

The jackets for the foundations are also already in production. Since January 2017, the basic pipes have been produced in Germany. Once they are ready, the individual pipe segments are transported to Belgium. There they are then coated and fitted with anodes to guarantee protection against corrosion underwater.

The transformer station of the EnBW Hohe See wind farm has been in production since October 2016. Electricity will flow via this station to reach land. The prefabrication of the individual steel components is taking place in Poland, Bulgaria and Belgium. The photograph shows a section of the main deck in April 2017 being moved on a floating pontoon to the coating hall in Balen, Belgium.