Small wind turbines could help to generate renewable energy but are often inefficient and expensive. This study tested a counter-rotating dual rotor design with both rotors connected through one generator, eliminating gearboxes. Wind tunnel tests achieved a 1 kilowatt output with 33 % efficiency. A computational model showed the turbine could theoretically reach 51 % efficiency with optimized blade angles and speeds. This compact design reduces mechanical complexity and suits urban applications.

Atmospheric large-eddy simulation is a technique that simulates weather conditions in high detail and is used to plan new wind farms. This research presents ways to estimate the long-term (10-year) power production of a wind farm without having to simulate 10 years of weather and instead simulating much less (1 year or less). The results show that the methods reduce the uncertainty in power production estimates by an order of magnitude and that wind observations can be included as well to add more insight.

This work studies the energy production and wake losses of large offshore wind farms with a large-eddy simulation model. Therefore, 1 year of actual weather has been simulated for a suite of hypothetical 4 GW wind farm scenarios. The results suggest that production numbers increase significantly when the rated power of the individual turbines is larger while keeping the total installed capacity the same. Also, a clear impact of atmospheric stability on the energy production is found.

Within the framework of the fourth phase of the International Energy Agency's (IEA) Wind Task 29, a large comparison exercise between measurements and aeroelastic simulations has been carried out. Results were obtained from more than 19 simulation tools of various fidelity, originating from 12 institutes and compared to state-of-the-art field measurements. The result is a unique insight into the current status and accuracy of rotor aerodynamic modeling.

Modern wind turbines are subject to complex wind conditions that are far from the hypothesis of steady uniform inflow at the core of blade element momentum methods (the current industry standard for wind turbine design). Various corrections have been proposed to model this complexity. The present work focuses on modelling the unsteady evolution of wind turbine wakes (dynamic inflow), comparing the different corrections available and highlighting their effects on design load predictions.