Preliminary design of a monopile for an offshore wind turbine in the North Sea

Wind energy has a long history in The Netherlands, where for centuries, windmills were one of the main energy sources if not the most important. Today the Netherlands is one of the leading countries in installing wind power capacity. In Europe, this country installed the most wind capacity in 2020, most of it offshore. Offshore, The Netherlands has 29 wind farms, 11 of which are currently operating: seven active wind farms in the North Sea, which ensure a combined total installed capacity of around 2450 MW in addition to four active wind farms in the inner waters of Ijsselmeer. From a geotechnical standpoint, offshore wind turbine foundations provide unique design challenges. Environmental loads are larger than onshore; therefore, it is important to ensure that the foundation can adequately support vertical and horizontal loads. Each turbine manufacturer has unique deflection and rotation criteria. Therefore, the foundation should perform within those tolerances, even under worst-case loading. This thesis which was carried out in collaboration with Hopper Engineering and Consultancy B.V in Amsterdam, The Netherlands, presents a preliminary design of a monopile foundation for offshore wind turbine in Ten Noorden van de Waddeneilanden Wind Farm located in the Dutch sector of the North Sea. Capacity, deflection, and rotation of a proposed monopile foundation are calculated by various methods to simulate the design procedure. The results show that very stiff foundations are required to keep pile head movements within design tolerances.