Wind Energy Science 

In this study, we propose a new method to detect sea breeze events from the WRF simulation. Our results suggest that the proposed detection method can identify the three different types of sea breezes in the model simulation. In addition, the coastal impact, seasonal distribution and offshore wind potential associated with each type of sea breeze differ significantly. This highlights the importance of identifying the correct type of sea breeze in numerical weather/wind energy forecasting.

In wind plants, turbines can be yawed to steer their wakes away from downstream turbines and achieve an increase in plant power. The yaw angles become expensive to solve for in large farms. This paper presents a new method to solve for the optimal turbine yaw angles in a wind plant. The yaw angles are defined as Boolean variables – each turbine is either yawed or nonyawed. With this formulation, most of the gains from wake steering can be reached with a large reduction in computational expense.

The power performance of a wind turbine is often tested with the turbine standing in a row of several wind turbines, as it is assumed that the performance is not affected by the neighboring turbines. We test this assumption with both simulations and measurements, and we show that the power performance can be either enhanced or lowered by the neighboring wind turbines. Consequently, we also show how power performance testing might be biased when performed on a row of several wind turbines.

Wind turbines extract kinetic energy from the flow to create electricity. This induces a wake of reduced wind speed downstream of a turbine and consequently downstream of a wind farm. Different types of numerical models have been developed to calculate this effect. In this study, we compare models of different complexity, together with measurements over two wind farms. We find that higher fidelity models perform better and the considered rapid models cannot fully capture the wake effect.

To get more insights into the influence of the urban terrain flow on the performance of the rooftop mounted two-bladed Darrieus vertical axis wind turbine, scale resolving simulations are performed for a generic wind turbine in realistic terrain under turbulent conditions. It is found that the turbulence and skewed nature of the flow near rooftop locations has a positive impact on the performance of the wind turbine.