Wind energy developments offshore focus on larger turbines to keep the relative cost of the foundation per MW of installed capacity low. Hence typical wind turbine hub-heights are extending to 100 m and potentially beyond. However, measurements to these heights are not usually available, requiring extrapolation from lower measurements. With humid conditions and low mechanical turbulence offshor...

The size of wind turbines has been growing fast in recent years with the largest now exceeding 7MW. Furthermore, this trend is expected to continue for the offshore sector. However, this increase in size is accompanied by an increase in the dynamic loading on the structure, in particular, unbalanced loads on the blade and hub. Apart from making wind turbine components more load tolerant, e.g. t...

In the design of land-based or offshore wind turbines for ultimate limit states, long-term loads associated with return periods on the order of the service life (20 years, usually) must be estimated. This requires statistical extrapolation from turbine load data that may be obtained by simulation or by field tests. The present study illustrates such extrapolation that uses field data from the B...

The wind power industry has experienced a large growth the past years. The growth mainly focus on a growing market, better economical conditions for wind power because of political decisions and the development of large wind turbines and offshore farms. A goal is to increase reliability for turbines. The topic is even more important for offshore farms where service is difficult and expensive. T...

An experimental study was conducted to investigate the effects of relative rotation direction on the wake interferences among two tandemwind turbines models. While the oncoming flow conditions were kept in constant during the experiments, turbine power outputs, wind loads acting on the turbines, and wake characteristics behind the turbines were compared quantitatively with turbine models in eit...

In this study, large-eddy simulations (LESs) were performed to investigate the effects of changing wind direction on the turbine wakes and associated power losses in the Horns Rev offshore wind farm. In the LES framework, the turbulent subgrid-scale stresses are parameterized using a tuning-free Lagrangian scale-dependent dynamic model, and the turbine-induced forces are computed using a dynami...

In new energy development, wind power has boomed. It is due to the proliferation of wind parks and their operation in supplying the national electric grid with low cost and clean resources. Hence, there is an increased need to establish a proactive maintenance for wind turbine machines based on remote control and monitoring. That is necessary with a real-time wireless connection in offshore or ...

The use of offshore wind farms has been growing in recent years, as steadier and higher wind speeds can be generally found over water compared to land. Moreover, as human activities tend to complicate the construction of land wind farms, offshore locations, which can be found more easily near densely populated areas, can be seen as an attractive choice. However, the cost of an offshore wind far...

The construction, operation, and removal of offshore wind power facilities have the potential to increase the levels of noise in the surrounding waters. Increased shipping noise can be associated with all phases of the life cycle of wind farms. Pile driving during platform construction can be short-lived but can introduce very high intensity pulses into the ocean. Operational noise, while at a ...

Offshore wind farms with high installed capacities and located further from the shore are starting to be built by northern European countries. Furthermore, it is expected that by 2020, several dozens of large offshore wind farms will be built in the Baltic, Irish and North seas. These wind farms will be constituted of a considerable number of turbines packed together. Due to shadowing effects b...