In recent decades, the global push for sustainable energy has grown, with offshore wind turbines emerging as a successful solution. This has led to the rapid growth of the offshore wind farm industry. As more wind farms are built, the demand for offshore installation vessels has increased significantly. It’s crucial for contractors to complete wind turbine installations safely, reliably, and fast. As turbines continue to increase in size, they require higher lifts of larger blades, complicating the installation process due to component movement.

One of the most critical stages in turbine installation is aligning the rotor blade with the hub. Blades can be attached to the hub from various sides. The most used method involves horizontal blade installation, but also diagonal and vertical installation has been done. To achieve alignment with the hub, the blades are lifted using yokes and their position is controlled using taglines. Taglines connected to the crane boom, slewing platform, or both are used. Taglines can operate in constant tension or speed-dependent tension modes. The question arises, how do different blade installation methodologies perform and compare.

The objective of this research was to model and quantitatively compare the performance of various blade installation configurations. Performance is measured by how well the blade root stays within a 0.2 meter envelope under different wind conditions to allow the final mating of blade and hub. The first step was to study the parameters affecting turbine blade alignment simulation, focusing on wind as the main environmental factor causing blade movement. This led to a detailed examination of the essential parameters to accurately model turbine blades.
A 6 degrees-of-freedom dynamic simulation model of a 15 MW wind turbine blade suspended from an installation crane was developed, focusing on the blade’s dynamic behavior during alignment with the hub. The model simulates the aerodynamic forces on the blade and its motions under different scenarios, considering environmental factors like wind velocity and turbulence intensity, but excluding movement of the jack-up vessel, vessel crane, and hub. The model allows for simulating many combinations of blade position, tagline configuration, and tagline operation mode, comparing the performance of different installation techniques during various wind conditions.

From the results, it is most likely that the way of attacking the hub by the turbine blade (side or bottom) is of high importance. From the results it appears that horizontal installation is most reliable. The model indicates that a tagline system that adjusts the pull force based on the speed of the blade’s movement as the most effective and the tagline configuration was of less importance. The results demonstrated that a higher steepness of the slope (ratio between tagline force and pay- out speed) of the damping tugger improves the damping of the blade and is most favourable for offshore turbine blade installation. The model indicated that the horizontal-horizontal installation method was the most effective. The results showed that it was most feasible to install the blades at wind speeds up to 8 m/s. For higher wind speeds, installations could still proceed if there was lower turbulence intensity.

It is recommended to extend the model to include vessel, crane, and hub motions. Another recommendation is to validate the simplified blade model with detailed (confidential) blade data. Finally, using a more detailed model to explore tools and control strategies to minimize blade root motions is recommended to improve workability.