The development of offshore wind farms has demonstrated significant value in harnessing renewable energy sources. However, the offshore wind energy sector faces increasing challenges, making the realization of new wind farms a greater financial risk. This has reached the point where several high-profile offshore wind projects have been halted. A key contributor to these struggles is the aerodynamic effect of wind farm wake losses. As wind turbine sizes increase, costs rise, but the wind farm concept limits energy yield. This is due to slow wake recovery behind turbines, causing downstream turbines to only be able to harvest energy from low-momentum flow. Based on the literature review conducted, the methods to improve wind farm efficiency by reducing wake losses, such as wind farm layout optimization and rotor yawing or tilting, only partially address the problem.

The concept of regenerative wind farming, proposed by Ferreira, seeks to provide a solution. This involves integrating lifting devices into wind energy harvesting systems that can redirect the wake vertically, enabling the flow from higher atmospheric layers to contribute more to the wake recovery process. Such interactions can dramatically enhance the energy that is replenished into the wind farm, offering a promising approach to overcoming these challenges.

This research aims to evaluate the potential of the novel wind farm concept, regenerative wind farm, through a scaled wind farm experiment. In the scaled wind farm, there are nine wind energy harvesting systems, which are aerodynamically modeled by using porous disks and wings. The study focuses on the far wake and the performance of downstream turbines. The experiment was conducted in the Open Jet Facility (OJF) at TU Delft. The flow field was measured using Particle Tracking Velocimetry (PTV) with Helium-Filled Soap Bubbles (HFSB), and load measurements were accompanied.

Load measurements revealed that thrust values for downstream turbines increased by more than three times when lifting devices were attached to the actuator surfaces. Also, flow field data showed significantly higher wake velocities, as potent vertical flows in the wake regions were induced by the tip-vortices of the wings, which enhanced vertical energy entrainment. This vertical motion actively entrains the flow above the wind farm, allowing high-momentum air to enter the wind farm layer, something that does not occur without the wings. Additionally, the lifting devices reduce turbulence intensity in the rotor projection area at the downstream end of the wind farm, helping to lower the fatigue loading of downstream systems. An investigation of a misaligned row confirmed that the concept remains effective even under such conditions.

This work demonstrates that the regenerative wind farm concept holds great potential to enhance wind farm power output while reducing the required wind farm area. With this concept, wind turbine wake losses are effectively mitigated by entraining high-momentum flow into the wind farm.