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This work examines the aerodynamic response of a floating wind turbine due to platform pitch motion and active turbine control. This is done with a wind tunnel experiment and numerical simulations. A procedure is developed for scaling a reference controller and using it in the experiment. It is found the turbine aerodynamic response is predicted by the numerical model with different accuracy depending on the turbine control regime and the greatest differences are observed in above rated wind.

Vortex generators are evaluated on a 2 MW wind turbine rotor blade by computational fluid dynamic methods. Those devices delay flow separation on the airfoils and thus increase their efficiency. On the wind turbine blade, rotational phenomena (e.g. rotational augmentation) appear and interact with the vortices from the vortex generators. The understanding of those interactions is crucial in order to optimise the placement of the vortex generators and evaluate their real efficiency on the blade.

Wake steering is a promising strategy to increase the power output of modern wind farms by mitigating the negative effects of aerodynamic interaction among turbines. As farm layouts grow in size to meet renewable targets, the complexity of wake steering optimisation increases too. With the objective of enabling robust and predictable wake steering solutions, this study investigates the sensitivity of wake steering optimisation for three different farm layouts with increasing complexity levels.

Wind turbines are designed to withstand any wind conditions they might encounter. This includes high turbulence flow fields found within wind farms due to the presence of the wind turbines themselves. The international standard allows for two ways to account for wind farm turbulence in the design process. We compared both ways and found large differences between. To avoid overdesigning components and enable site-specific design, we suggest definitively moving being the more simplified method.

This paper assesses lidar-assisted collective pitch feedforward (LACPF) and multi-variable feedback (MVFB) controls for the IEA 15.0 MW reference turbine. The main contributions of this work include (a) optimization of a four-beam pulsed lidar for a large turbine, (b) optimal tuning of speed regulation gains and platform feedback gains for the MVFB and LACPF controllers, (c) assessing the benefits of the two control strategies using realistic offshore turbulence spectral characteristics.

Simulations of different fidelity made by the participants of the OC6 project Phase III are compared to wind tunnel wake measurements on a floating wind turbine. Results in the near wake confirm that simulations and experiments tend to diverge from the expected linearized quasi-steady behavior when the reduced frequency exceeds 0.5. In the far wake, the impact of platform motion is overestimated by simulations and seems to be even oriented to the generation of a wake less prone to dissipation.

Wake steering is a wind farm control technology in which turbines are misaligned with the wind to deflect their wakes away from downstream turbines, increasing total power production. In this paper, we use a wind farm control model and historical electricity prices to assess the potential increase in market value from wake steering for 15 U.S. wind plants. For all plants, we find that the relative increase in market value from wake steering exceeds the relative increase in energy production.

Modelling the aerodynamic wake of airborne wind energy systems is crucial to properly estimate the power production and to design such systems. The velocities induced at the AWES from its own wake are studied with a model for the near wake and one for the far wake. The model is validated with the lifting line free vortex wake method implemented in QBlade.

Wind energy is one of the pillars to accomplish the future objectives stablished by the governments with regard to the reduction of emissions of CO2 expected by 2050. Wind energy usage increase will be only possible if more efficient and durable wind turbines are designed. In addition, such increase in wind energy installation worldwide will be only achieved if floating wind turbines design is mature enough. With this purpose a new tool to design and optimize floating wind turbines is presented.

We present recent research on dynamically modelling wind farm wakes, and integrating these enhancements into the wind farm simulator, HAWC2Farm. The simulation methodology is showcased by recreating dynamic scenarios observed in the Lillgrund offshore wind farm. We successfully recreate scenarios with turning winds, turbine shut down events, and wake deflection events. The research provides opportunities to better identify wake interactions in wind farms, allowing for more reliable designs.

This paper presents an upscaling methodology for floating offshore wind turbine platforms using two case studies. The offshore wind turbine industry is trending towards fewer, larger offshore wind turbines within a farm, which is motivated by the per unit cost of a wind farm (including installation, interconnection, and maintenance costs). The results show the platform steel mass to be favorable with upscaling.

High-fidelity MDO enables more effective system design than conventional approaches. MDO can shorten the wind turbine design cycle and reduce the cost of energy. We present a first-of-its-kind high-fidelity aerostructural optimization study of a turbine rotor using a coupled CFD-CSM solver. We simultaneously improve the rotor aerodynamic efficiency and reduce the mass of a rotor of a 10 MW wind turbine using 100+ design variables. We discuss the results with unprecedented detail.

This paper reviews and implements several techniques that can be used for condition monitoring and failure prediction on wind turbines using SCADA data. The focus lies on techniques that answer to requirements of the industry, e.g. robustness, transparency, computationally efficiency, and maintainability. The end result of this research is a pipeline that can accurately detect three types of failures, i.e. generator bearing failures, generator fan failures, and generator stator failures.

Wind energy developers frequently have to face some spatial restrictions at the time of designing a new wind farm due to different reasons such as: existing of natural protected areas around the wind farm location, fishing routes, presence of buildings, etc. Wind farm design has to account for these restricted areas, but sometimes this is not straightforward to achieve. We have developed a methodology that allows for different inclusion and exclusion areas in the optimization framework.

The wind slows down as it approaches a wind plant, this phenomenon is called blockage. As a result, the turbines in the wind plant produce less power than initially anticipated. We investigate wind plant blockage for two atmospheric conditions. Blockage is larger for a wind plant compared to a stand-alone turbine. Also, blockage increases with atmospheric stability. Wind farm blockage is amplified by the vertical transport of momentum as the wind approaches the front-row turbines in the array.

Wind turbines are an important electric power source. Usually, they are organized in wind farms. Thereby, each wind turbine causes a so-called wake with a reduced wind speed. This can influence following wind turbines and is an opportunity to optimize the operation of each wind turbine. A wind gust usually makes the tower oscillate. We control a wind turbine in a way such that the following turbine significantly less oscillates. Thereby, we also paid attention to the power of the wind turbines.

NREL has published updated maps of the wind resource along all US coasts. Given the upcoming offshore wind development, it is essential to quantify the uncertainty that comes with the modeled wind resource dataset. The paper proposes a novel approach to quantify this numerical uncertainty by leveraging available observations along the US East Coast.

Wind energy is crucial for dealing with the climatic change challenge. Society needs more efficient wind turbines reducing the costs and the operation and maintenance works. In addition, uncertainties should be also reduced. One of the biggest uncertainties in the wind energy field, is the wind turbine performance with regard to the blade status. Blades are living components and their surface changes with the wind turbine life evolution: they become dirty and or they suffer from erosion.

Inflow wind field measurements from nacelle based lidar systems offer great potential for different applications including turbine control, load validation and power performance measurements. On floating wind turbines nacelle based lidar measurements are affected by the dynamic behaviour of the floating foundations. Therefore, effects on lidar wind speed measurements induced by floater dynamics must be well understood. A new model for quantification of these effects is introduced in our work.

In the present study, for the first time, the SWUF-3D fleet of multirotor is deployed for field measurements on an operating 2~MW wind turbine (WT) in complex terrain. The fleet of multirotor has the potential to fill the meteorological gap of observations in the near wake of WT with high temporal and spatial resolution wind vector measurements plus temperature, humidity and pressure. The flow up- and downstream of the WT is measured simultaneously at multiple spatial position.

In order to provide early warnings of faults in the main bearing, a fault detection system is developed in this work by applying an anomaly detector based on principal component analysis. Without the need to obtain the fault history or install additional equipment or sensors that would require a larger investment, this model is constructed using only healthy SCADA data. The results obtained enable failure detection even months before the fatal breakdown takes place.

We study how climate change will impact extreme winds and choice of turbine class. We use data from 18 CMIP6 members from a historic and a future period to access the change in the extreme winds. The analysis shows an overall increase in the extreme winds in the North Sea and the southern Baltic Sea, but a decrease over the Scandinavian Peninsula and most of the Baltic Sea. The analysis is inconclusive to whether higher or lower classes of turbines will be installed in the future.

Benefits of orientating a 3-legged offshore wind jacket relative to the metocean conditions for pile design are assessed; considering the IEA 15MW reference turbine and a reference site off the coast of Massachusetts. Results, based on the considered conditions, show that the pile design can be optimized by orientating the jacket relative to the dominant wave direction. This design optimization can be used on offshore wind projects to provide cost and risk reductions.

Floating offshore wind turbines move due to not having a rigid foundation. Hence, as the blades rotate they go through more complex aerodynamics than standard onshore wind turbines. In this paper, we show computational simulations of a wind turbine rotor moving in various ways and quantify the difference this motion makes in the forces acting on the blades. We show that these forces behave in nonlinear ways when the motion of the turbine is increased.

Wind turbines placed in farms interact with their wake lowering the power production of the wind farm. This can be mitigated using so-called wake mixing techniques. This work investigates the coupling between the Pulse wake mixing technique and the motion of floating wind turbines using the Pulse. Frequency response experiments and time-domain simulations show that extra movement is undesired and the 'optimal' excitation frequency is heavily platform-dependent.

The optimal misalignment angles for wake steering are determined using wake models. Although mostly analytical, data-driven models have recently shown promising results. This study validates a previously proposed data-driven model with results from a field experiment using lidar measurements. In a comparison with a state-of-the-art analytical model, it shows systematically more accurate estimates of the available power. Also when using only commonly available data, it provides good results.

The turning of the wind with height, which is known as veer, can affect wind turbine performance. Thus far meteorology has only given idealized descriptions of veer, which has not yet been related in a way readily usable for wind energy. Here we derive equations for veer in terms of meteorological quantities, and provide practically usable forms in terms of measurable shear (change in wind speed with height). Flow simulations and measurements at turbine heights support these developments.

Better wind farms can be built by simultaneously optimizing turbine locations and control, which is currently impossible or extremely challenging because of the size of the problem. The authors present a method to determine optimal wind farm control as function of the turbine locations, which enables turbine layout and control to be optimized together by drastically reducing the size of the problem. In an example, a wind farm's performance improves by 0.8 % when optimized with the new method.

We further enhanced a knowledge base for choosing the most optimal wind resource assessment tool. For this, we compared different simulation tools for the Perdigão site in Portugal, in terms of accuracy and costs. In total five different simulation tools were compared. We found that with a high degree of automatisation and a high experience level of the modeller a cost effective and accurate prediction based on RANS could be achieved. LES simulations are still mainly reserved for academia.