Heavylift / Breakbulk

  • An Esvagt SOV testing an Ampelmann boom.

14.09.2015 By: Clemens Finkbeiner-Dege

Artikel Nummer: 11458

Siemens: SOVs instead of SUVs

Omnipresent sport utility vehicles (SUVs) have a new look, at least in some coastal areas. Siemens, a multinational corporation from Germany and a major player in the offshore wind turbine industry, is revolutionising the options for offshore wind farm maintenance. The pioneering technology is breaking new ground – in the middle of the ocean.

Siemens customers operate hundreds of wind turbines, with many power farms located far off the North Sea and Baltic Sea coasts. The largest turbines stand up to 200 m high at their rotor tips and are embedded 30 m deep in the seabed.


These «giant asparagus» have to withstand extremely adverse weather conditions to provide a reliable supply of electricity. The need for maintenance and spare parts is concomitantly high, but now Siemens has come up with innovative new techno­logy for the field. The industry is young, so engineers could not draw on previous experience. Almost everything had to be specially developed and tested, including the ships from which the maintenance is carried out. Siemens’ wind division tied up with the Danish shipping expert Esvagt and together they developed a completely new type of maintenance ship – named service operation vessels, or SOVs – to carry out such jobs.


Hamburg – a key wind city

The first two of these unusual looking 84 m units were named in Rostock and Hamburg in June. They were taken out on test runs in spring, after a two year construction phase in Turkey and Norway. The Esvagt Froude operates in the Baltic Sea and her sister vessel, the Esvagt Faraday, is deployed in the North Sea. Basing the second vessel in Hamburg was the ­obvious choice: Siemens has been running its entire global wind power business from the German port for the last four years. Since the two service ships were commissioned, they have been in operation for the Siemens’ customers EnBW and WDP, providing improved maintenance services for offshore wind farms. Each SOV is home to a 40 person service team and a 430 sqm spare parts storage area. The ships can remain at anchor next to a wind farm for weeks on end.


Earlier, it used to take a maintenance teams an hour just to get to the site; the journey time to and from the wind turbines has now been reduced to a fraction of that. Technicians at the wind farms operate up to 50% more effectively now. René Wigmans, the head of maritime and aviation solutions in the entity Siemens Service Wind Power, which puts him in charge of offshore services too, says that «our technicians can walk to work, as these vessels can be based at a wind farm for several weeks at a time. This will reduce downtimes caused by bad weather, and increase efficiency. Getting technicians to the turbines will also become safer and more convenient. At the same time, we can use the ships for storage too, right in the middle of a wind farm.»


Walking to work at high sea is meant literally: one of the ships’ features a 25 m gangway, built by the Dutch company Ampel­mann, which uses high-tech hydraulics to assure access to wind turbines even during rough seas and 2.5 m waves.


An eye-catcher on the high seas

The special eye-catching form of these two bright red SOVs, with their prominent windowless inverted bows, allows the ships to remain steady even in rough seas, without sacrificing speed. The ships’ diesel engines are equipped with Siemens blue drive systems that allow them to run at low speed, which saves fuel and carbon dioxide emissions – an important consideration as the vessels remain anchored in wind farms for long periods.


The Esvagt Froude, which is named ­after the English shipwright William Froude (1810–1879), operates in the Baltic 2 wind farm from her home port of Rostock (see also page 59). Her sister ship the Esvagt Fara­day is named after an old Siemens vessel from 1874 that was deployed to lay subsea cables and was called the Faraday. Her successor operates in the North Sea’s Buten­diek wind farm and is currently based in the Danish port of Esbjerg.


Overall, Siemens maintains 1,400 offshore wind turbines worldwide, with a total capacity of 4,800 MW, or four times the capacity of the largest Swiss nuclear power plant in Leibstadt in the canton of Aargau.


The market is continuing to grow. Two other service vessels of the Ulstein successor design have now been ordered. In the North and Baltic Seas off Germany a total of 5,346 MW of wind generation has already been installed or was under construction in the first half of 2015. The government’s target for 2020 – a mere five years from now – is 6,500 MW.


With the current rate of expansion the goal should be in easy reach, but there is a simultaneous increase in demand for maritime transportation, installation and maintenance services. In contrast to new installations, which may tail off, demand for service and maintenance will stabilise at the level of the total installed capacity at the very least in the coming five years – making it a promising field for the service vessel fleet to do business in.


After years of slump in the industry Siemens has apparently taken a liking to the north. In mid-August the corporation announced that it was building a factory for wind turbines on a 170 ha site in the maritime port of Cuxhaven. It is the multi­national’s first German production facility for offshore wind turbines, it said. EUR 200 million has been put aside for the investment, with construction due to start in a few weeks and production expected to commence in 2017. And how else are turbine nacelles weighing many tonnes expected to reach their wind masts at sea other than on transport and installation vessels?  




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