Boat sailing in front of wind mills
With a detailed analysis in the early phase of the project, the developer can save large amounts of steel.

Concept design for offshore wind turbines at Borssele

Competitive wind energy

Two new wind farms – Borssele 3 and 4 – are to be built in the North Sea off the Dutch coast. Steel can be saved by using the latest knowledge about offshore technology.

Engineers are famous for wanting to be on the safe side – and preferably a little bit extra as well. Conservative estimates and precautionary principles are good practice when calculations must be made. However, sometimes it pays to challenge the general precautionary principles.

When NIRAS had to make a so-called concept design, that is to say an early, comprehensive design for the foundations of two new wind farms in the North Sea off the Dutch coast, the customer stressed that the design needed to be competitive.

NIRAS proceeded to examine how the best design for the price could be developed, and the method was to use the latest knowledge about offshore technology precisely tailored to optimise the design for the Borssele 3 and 4 wind farms.

Established CFD wave models

Knowledge about the technology behind offshore wind energy is constantly in development. Instead of sticking to the usual models, NIRAS made detailed analyses already in the early phase of the project, for example, of voltage concentrations for the purpose of calculating steel durability, when the weather and wind wear on the materials over time – the so-called fatigue calculation. The engineers also developed an advanced model of wave conditions called CFD, Computational Fluid Dynamics. Based on the simulated waves, the surge pressure could be calculated with high precision. In this way, the engineers built upon standard practice for the design of offshore wind turbines with the latest methods. By going to the limit with detailed analyses as a basis, NIRAS could deliver a concept design, where a significant proportion of the steel was cut out.