FOOS

GeFOrceerde OScillaties

Offshore wind turbines are exposed to strong dynamic loads from both wind and waves. If these loads are not properly managed, the resulting oscillatory forces can negatively affect the lifetime of the foundation. The project investigates the causes and impacts of power oscillations from offshore wind farms on grid stability, with attention to risks for safe operation, potential system-wide consequences, and measures to mitigate these effects.

Context

When wind turbines are in operation, fore–aft oscillations benefit from strong aerodynamic damping, while lateral oscillations have little passive damping. For this reason, turbine manufacturers implement active damping solutions. However, wind turbines still cause fluctuations in generated power, which in turn can have a destabilising effect on the electricity grid. There is an urgent need for better insight into and improved estimation of power oscillations, which are becoming increasingly important for transmission system operators and wind farm operators to make accurate assessments for new concessions, such as those in the Princess Elisabeth Zone.

The project ‘cSBO FOOS – Forced Oscillations’ focuses on power oscillations caused by offshore wind farms in the North Sea and aims to mitigate them in order to ensure grid stability. Updated models will predict the impact and magnitude of this phenomenon for future (larger) wind turbine generations and their interaction with the European electricity grid. The project will identify, investigate, and evaluate mitigation solutions for their effectiveness in damping power oscillations and for their overall efficiency, both in existing wind farms and in scenarios considered for future concessions in the Princess Elisabeth Zone.

Mitigation measures may be applied at different levels: the individual wind turbine, the wind farm, or the entire electricity grid. The project aims to develop solutions that are beneficial for both offshore wind farm operators and grid operators, taking into account factors such as safety and cost. Promising technologies will be further analysed through performance comparisons and sensitivity analyses.

Insights into the phenomena that may affect the stability of the energy system are not only important for Belgium, but also for the EU’s energy transition strategy, as offshore wind energy plays a crucial role in achieving ambitious targets, including 70 GW by 2030.

Objectives & Results

FOOS adopts a comprehensive approach to improving grid stability in the context of offshore wind integration. The project focuses on several core domains:

Foundation monitoring and integrated wind turbine model development, crucial for achieving a qualitative and quantitative understanding of offshore wind turbine power oscillations and their load interactions with the foundation.
Assessment of grid impact and stability through data-driven characterisation using existing offshore wind farm data. This enables a comprehensive understanding of power oscillations and the structural parameters associated with them, at different levels (turbine, wind farm, and zone). This includes adapting grid requirements to the evolving dynamics of energy generation and distribution.
Quantitative analysis and advanced modelling techniques (scaled models) to study the sensitivities of power oscillations under various conditions. This will improve understanding and quantification of their impact on the broader electricity grid and analyse interactions between wind farms and the grid.
Evaluation and comparison of electrical and structural solutions and strategies to mitigate the impact of power oscillations at different levels, from individual turbines to the full network system. The impact of mitigation solutions on the Levelised Cost of Electricity (LCOE) will be calculated, assessing cost implications at both wind turbine and grid level, with a specific focus on the Princess Elisabeth Zone case.

An industrial advisory board is involved in the FOOS project. The project aims to create synergy between research and practical solutions, making a significant contribution to renewable energy, particularly for the safe and efficient integration of offshore wind energy into the electricity grid. The approach addresses both immediate challenges and the long-term sustainability of renewable energy sources within electricity systems. Findings will be published in open-access reports and peer-reviewed publications and disseminated through workshops and a final event focusing on potential mitigation measures and their impact on the Princess Elisabeth Zone.