In a joint venture with Danish LIC Engineering, NIRAS has secured the contract to design a large offshore wind farm project, 40 km off the coast of Belgium. The project, which poses great challenges, will promote NIRAS to the premier league of wind turbine consultants.
A mobile seabed and an extremely tight time schedule are just two of the challenges that NIRAS and LIC Engineering will face when they embark on the design of a completely new offshore wind farm 40 km from Zeebrugge in Belgium.
The Belgian project development consortium Northwind NV selected the two Danish consultancy companies to design the foundations for 72 offshore wind turbines as well as the foundation for the transformer station in water depths of up to 28 metres.
The offshore wind farm is scheduled for completion early 2013 and, with a capacity of 216 MW, it will be able to supply 120,000 households, which is equivalent to a reduction of 240,000 tonnes of CO2 per year.
Tight schedule
Before the contractor can install the first mono pile into the seabed, NIRAS and LIC must submit the finished design and there is a race against the clock to deliver by the beginning of 2012.
"Preparing a detailed design for an offshore wind farm within such a short time frame is an immense challenge. However, the timing was actually an important factor when competing for the contract,” says Claus Gormsen, market and project director at NIRAS, and he continues:
"The tight schedule was one of the reasons why we teamed up with LIC, with whom we have cooperated for many years now. LIC has vast expertise in the extremely specific calculations required for the project and NIRAS would not be able to complete these within the deadline if we worked alone."
Unstable seabed
Another great challenge is the nature of the seabed.
“The seabed is characterised by ‘sandwaves’, which make it mobile. In order to avoid foundation stability problems, it is important to stabilise the seabed by securing it with stone erosion protection," says Claus Gormsen.
Innovation required
The final great challenge is the task of ensuring a stable connection between the foundation and the transition piece that links it to the turbine tower.
"It turns out that, in many offshore wind farms, the joint between the monopile and the transition piece doesn’t hold, which causes the turbine and the transition piece to slide slowly down over the foundation. This means expensive repairs at sea. Therefore, it is our job to construct a durable joint and to develop a plan B to be implemented if it should fail."
NIRAS moves up to the wind energy premier league
This new project promotes NIRAS to the premier league of wind turbine consultants, several of which are Danish.
“The project for Northwind is the largest wind energy project in which we have participated to date. We are involved in the whole process, from the early planning stages to the actual installation of the foundations. The contract gives us a solid reference and places us among the top five wind energy consultants.”
Northwind NV has given NIRAS an option to supervise both the manufacture and installation of the foundations and the opportunity to design the Belwind 2 offshore wind farm, which will be located five kilometres from the Northwind project.
Fact: Over 20 years of experience in offshore wind energy
NIRAS has participated in offshore wind turbine projects since 1989, the largest being two offshore projects in the Irish Sea - the Barrow Offshore Wind Farm (90 MW) and the Walney Offshore Windfarm (367 MW) - and Lillgrund Offshore Wind Power Plant (110 MW) in Oresund near Malmø.