Dong Energy in Norddeich, Germany: Building the O&M base for the Borkum Riffgrund and Gode Wind projects

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It is always good when you can go to a pretty village on the coast on a bright summer’s day; just imagine how good this is when you do this every day for your work. DONG Energy were probably not too concerned about this aspect when they chose the small North German port of Norddeich as the base for operation and maintenance for all phases of the of the Borkum Riffgrund and the Gode Wind offshore wind farms. However this can only add to the job satisfaction of their work force based there.

Offshore WIND visited the present base office, which is currently housed in a temporary modular unit building, close to the quay side, and the building site where the building for the permanent office, work shop and storage rooms is under construction.

The Danish wind farm operator is well on the way to supplying first power later this year from the first phase of these wind farms, Borkum Riffgrund 1, and full commercial operation which is due in 2015. We spoke with Mathias Albrecht, Operation & Maintenance Manager of the Borkum Riffgrund 1 project, Stefan Hoonings and Palle Uhre Knudsen, who are both in the EPC & Construction Management of this wind farm. We were guided on our visit by Iris Franco Fratini, head of communication and PR at DONG Energy in Germany.

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The DONG Energy team described the operator’s targets in this energy sector and spoke of their drive towards cost reduction by standardisation and modularisation which will eventually return reductions of 35 to 40%, and the use of innovative engineering in the drive for noise mitigation while piling the foundations. In the latter case the IHC Noise Mitigation Screen that was described in the January 2013 edition of Offshore WIND has proven to be successful on the Borkum Riffgrund 1 project keeping within the strict German limits.

A central place throughout construction and operation

The new building will have a geo thermal heat exchange unit using the latent heat from deep underground. This is a well-known and often used source of energy to this Danish company. When the new building is completed next year it will not only be used for storage of materials and spare parts needed for operation and maintenance purposes but it will also house the control room for monitoring the generation of electricity at every stage.

There will be another control room that will monitor all the movements of men, vessels and helicopters. This control facility is already functioning from the Marine Co-ordination Room (MRC) situated in the present temporary premises. Currently manned by at least one man, 24/7, all the planning, control and documentation of the movements are carried out by a team during the day to ensure a safe and fast emergency response if required.

When all the construction projects have been completed and the base finally becomes responsible only for O&M work, it is envisaged that the monitoring centre will be manned during only the working hours. A fully automated card swipe system, linked through to the base and recorded in the MRC, will be used to monitor technicians leaving or boarding the vessel.

Both boats and helicopters are used to take the technicians working on the construction project to and from their place of work. From the start of construction operations on Borkum Riffgrund 1 DONG Energy have chosen to use helicopters as and when weather conditions require. This was one of the reasons for the selection of Norddeich for base operations. Less than 5 km from the new marine base is the Norddeich airfield, Flugplatz Norden-Norddeich, which is managed by the local ferry company operating the Frisian Islands boat service to the Frisian islands of Juist and Norderney.

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The team use 1.5 m significant wave height as the limit for boat transfers; above that limit helicopters are deployed. A helipad has been included on the offshore substation for this very purpose. Although there is no accommodation unit built on the platform, this landing facility allows technicians to transfer to the required, relatively close, wind turbine installation, using a boat with a minimum of discomfort. When weather conditions allow DONG Energy have 2 Crew Transfer Vessels on charter at Norddeich for the 2-2 Vz hour journey to the wind farm.

Local work force for more efficiency

A subject that has become associated with the planning of almost every new offshore wind farm project is the preference to recruit from the local work force. Norddeich and DONG Energy are no different in this policy.
Working with a flexible schedule is possible and many times more efficient if the work force is resident close at hand.

Mathias Albrecht is recruiting candidates living in the North Western part of Germany wherever possible to make up the 40 service technicians that will work from this base in the future. If necessary they will be trained in the specific requirements needed for this new technical industrial base. He told Offshore WIND that an extremely flexible work schedule is required that takes into consideration times when offshore work is not possible for whatever reason and other times when the work has to be carried out as soon as possible. Allowances in the salary, with bonuses being paid for offshore periods and for what some people would call ‘not easy working hours and conditions’, have already been agreed between all parties.

Materials for the construction work are coming from many ports such as the 77 foundations that have been stored at and shipped out from The Orange Blue Terminal in the Northern Dutch port of Eemshaven. They were manufactured in Aalborg, Denmark, with German steel from Dillinger. The topsides for the offshore substation was built in Poland and completed in Denmark. Other ports that other contractors are using include the port of Nordenham and the airport at Borkum in Germany, and the ports of Esbjerg and Aalborg in Denmark.

By the time you are reading this all the 77 monopiles will be placed, which leaves only one more to be placed. It is this last one which will be the centre of much interest. This is the suction bucket test project, which is supported by the Carbon Trust’s Offshore Wind Accelerator programme research into foundations. This foundation is designed by DONG Energy based on one by SPT that was a finalist in a global competition organised by the Carbon Trust to find lower cost foundation solutions.

The base will also be the centre for the construction of the Gode Wind projects and the remaining phases of the Borkum Riffgrund project. The plan is to keep the construction team together as much as possible for all these projects, even though Gode Wind 1 and 2 will be using the larger Siemens 6.OMW turbine with a 154m rotor. These 2 projects will have a total of 97 turbines with a capacity of 582MW, sufficient for the annual electricity consumption of about 600,000 German households.

This visit to Norddeich was not just a day trip to the coast on a summer’s day or a visit to look at a building site. Nor was it just a visit to hear about a 312MW offshore wind farm that will supply clean sustainable power to over 320,000 German homes annually. It was a look into the future at a view with a community working together with nature and technology for a long time to come.

Dick Hill