Custom Projects: Structural Monitoring for Offshore Wind Turbines
Offshore wind turbines, whether fixed directly to the seabed or floating on the open ocean, are exposed to some of the most extreme environmental conditions of any energy infrastructure. While fixed wind turbines rely on solid foundations embedded in the seabed, floating turbines offer greater flexibility by enabling deployment in deeper waters where wind speeds are typically higher and more consistent. However, both types of turbines face structural challenges at the waterline – the point where the structure meets the ocean surface – and floating turbines present an additional complexity due to the dynamic forces acting on their mooring systems.
Unlike fixed turbines, which experience relatively stable loading conditions, floating turbines are in constant motion due to waves, currents, and wind forces. This continuous movement amplifies fatigue loading at key structural points and places additional strain on mooring lines, which secure the turbines in position. The ability to monitor these stresses in real-time is critical to ensuring the structural integrity and long-term reliability of offshore wind infrastructure.
Waterline and mooring system structural challenges
The waterline is one of the most critical areas for structural monitoring, as it is subject to a range of environmental stressors that can impact turbine integrity. Constant exposure to wave action creates cyclic loading, leading to long-term material fatigue. This repetitive stress can weaken structural components, particularly at joints and connections, increasing the risk of failure. The accumulation of biofouling – marine organisms such as algae, barnacles, and mollusks – adds additional weight to the structure and alters its hydrodynamic profile, increasing drag and intensifying mechanical stress.
Corrosion is another major concern, as saltwater accelerates the oxidation of metals. Without effective monitoring and maintenance, corrosion can gradually compromise the structural integrity of critical components. Floating debris, including driftwood and other man-made objects, poses an additional threat. Collisions with debris, particularly in high-wave conditions, can lead to localized damage that, if undetected, could escalate into more serious structural issues.
For floating turbines, mooring systems introduce an additional layer of complexity. Mooring lines experience continuous dynamic loading from wind, waves, and currents, making them highly susceptible to fatigue and wear over time. If a mooring line fails, the turbine can drift out of position, posing risks to the structure itself, as well as to nearby turbines and marine infrastructure. Monitoring the strain on mooring lines is therefore as essential as monitoring the turbine structure itself.
Applying fibre optic sensors for offshore wind turbine monitoring
The SENSFIB system, developed by Light Structures, offers advanced structural health monitoring tailored to the unique challenges of offshore wind turbines. By integrating SENSFIB technology into turbine designs, operators can continuously track stress, strain, and fatigue across key structural points.
SENSFIB’s fiber optic sensors provide data about what is happening at the waterline, capturing the effects of wave-induced stresses before they lead to structural fatigue. This data and
subsequent insight allow for proactive maintenance, enabling operators to identify potential issues before they escalate into costly repairs. The system also helps detect and log stress events caused by debris collisions, providing valuable data for damage assessment and response planning. The non-mechanical nature of fibre optic sensors is also ideal for installation in a position often subjected to extreme impacts.
For floating turbines, SENSFIB monitoring capabilities can be extended to mooring systems. By equipping mooring lines with fiber optic sensors, operators can track tension and load distribution in real time, identifying areas of excessive strain that could indicate potential failures. This predictive capability helps prevent mooring line detachment incidents, ensuring that turbines remain securely positioned even in rough sea conditions.
Beyond individual turbines, the value of structural health monitoring can be scaled across an entire offshore wind farm. Rather than installing sensors on every turbine, a strategically selected subset of turbines can be instrumented to provide data that is extrapolated across the entire field. Given that turbines in the same farm experience similar environmental forces, insights gathered from a few key locations can be used to predict stress and fatigue patterns for all turbines, optimizing maintenance planning and reducing operational costs.
Ensuring Long-Term Reliability
Implementing SENSFIB not only enhances the safety and reliability of offshore wind turbines but also contributes to reducing the need of building new turbines. By transitioning from scheduled inspections to condition-based maintenance, operators can extend the lifespan of their assets while minimizing downtime and reducing unnecessary interventions. Whether monitoring the waterline of fixed turbines or ensuring the stability of floating platforms and mooring lines, SENSFIB provides the critical data needed to make informed operational decisions.
As offshore wind energy continues to expand into deeper waters, the challenges of maintaining turbine integrity will only grow. With advanced monitoring solutions like SENSFIB, operators can take a proactive approach to structural health management, ensuring that both fixed and floating turbines remain safe, efficient, and operationally viable for years to come.