Scour protection

In offshore wind farms, scour protection around monopiles or jacket structures is a critical element of the foundation design.

Monopiles are large steel tubes that are driven into the seabed to support wind turbines in offshore environments.

Jacket structures are one of several types of foundations used in offshore wind farms, with others including gravity-based structures and suction buckets. The choice of foundation type depends on factors such as water depth, seabed conditions and project economics. Jacket structures are particularly well-suited for deeper waters and in areas with more challenging seabed conditions.

The scour around the monopile or jacket structure can cause erosion of the seabed, potentially leading to instability of the foundation, wind turbine and power cables.

Scour protection measures for offshore wind turbines typically involve the installation of an additional layer of material around the base of the structure to prevent sediment erosion. This layer can be made of various materials, including rock, concrete or a specially designed geotextile fabric. The layer is placed on the seabed around the structure to dissipate the energy of the fluid flow and reduce the rate of erosion.

The choice of scour protection depends on several factors including water depths, sediment characteristics and expected flow velocities. In some cases, scour protection may not be necessary if the seabed is stable but in areas with high flow velocities or unstable sediment a robust scour protection system is essential to ensure the stability and longevity of the structure foundation and associated cables.

Balmoral HexDefence is a unique scour protection system that provides seabed protection, effectively lowering operational costs and mitigating the risk of cable failure.

Balmoral HexDefence is a scour protection system manufactured from lightweight concrete panels that interlock and are externally profiled for rigidity and connection. The panels are custom-sized to fit foundation diameters and feature integrated lifting and access points.

The below sequence shows CFD work conducted on jacket foundations, simulating wave and current flows to evaluate shear bed stress and turbulent kinetic energy.

Balmoral HexDefence scour protection system offers several key benefits, including the elimination of excessive rock operations and a non-invasive approach to the foundation structure.

HexDefence requires a smaller footprint compared to traditional methods, enabling cables to be buried closer to the structure. This enhances stability and reduces associated risks. By facilitating closer burial of cables to the structure, HexDefence reduces exposed cable sections by up to two-thirds, thus minimising fatigue and increasing cable lifespan.

Offered as individual segments, HexDefence can be installed as full assemblies or retrofitted as half rings, significantly reducing installation time and costs.

Concrete segments feature forklift pockets for easy handling and maneuvering, while bespoke tooling aids storage, lifting and installation.

Leveraging existing vessels and handling equipment, HexDefence streamlines installation, minimising additional costs and environmental impact.

Additionally, the system is capable of use with antifouling and does not require special equipment for end-of-life recovery.