Inshore mooring solutions for floating wind

In floating wind projects, efficient and reliable inshore moorings and wet storage solutions are crucial. Here is how a typical scenario plays out: an EPC (Engineering, Procurement, and Construction) company constructs hulls on the quayside. Once completed, these hulls are launched into the water, where they await favourable weather conditions for tower integration. During this interim period, Intermoor, Acteon’s Moorings and Anchors business line, is the perfect contractor to provide a temporary inshore mooring solution.

Lessons learned from oil and gas

The approach is akin to practices in the oil and gas sector when drilling rigs are not in use. Matthew Heyman, Business Development Specialist, Intermoor, explains:

“We identify a suitable location with appropriate water depth, favourable weather conditions, and compatible seabed types. 

To moor drilling rigs, we conduct a comprehensive mooring analysis and design. We then procure the necessary mooring equipment, pre-lay it, and secure the drilling rig when it is not being used. When the rig is ready to resume operations, we tow her to her next job site and dismantle the temporary mooring. 

This methodology is perfectly adaptable to floating offshore wind projects, supporting inshore marine operations. We provide tugs or towage operations on standby and move the hulls to the quayside. During optimal weather windows, the towers and turbines are installed. The hulls are then moved slightly further along the quayside for a few days of testing and commissioning before they are ready for installation. 

Typically, this is where the Transport & Installation (T&I) Contractor role begins. They take over the finished product and proceed with the permanent installation.” 

Challenges of inshore moorings 

Mooring floating wind turbines inshore present unique challenges, including:  

• Installing hulls in shallow inshore water
• Working with un-surveyed, inshore seabed conditions
• Understanding tidal and wave actions
• Accommodating various types of floating hulls and connection points
• Calculating the required number of mooring locations 

A full-package solution 

Our anchoring solution includes a rental model for the mooring equipment as well as mooring design, pre-lay of the mooring lines, and hook-up. Read how Intermoor Norway provided the mooring equipment for the inshore mooring of the Hywind Tampen turbines.  

Our team of mooring specialists develops multiple scenario options tailored to the project’s specific needs. These options include taut or catenary moorings. By detailing these alternatives in an anchoring and mooring feasibility study, we help developers build a robust concept model.  

Our scenario feasibility studies progress in small, phased steps, identifying potential anchor types, mooring designs, and associated costs. From there, we then create an installation timeline and procedures, including vessel requirements. This timeline enables us to formulate a plan for the stage-by-stage installation, incorporating port selection and logistics. 

The primary objective of this method is to ensure that developers have the essential information to develop more accurate planning, consenting and budgeting, as well as technical details for compliance and risk reduction. Additionally, the concept model can later be adapted and serve as a benchmark to assess the viability of new projects in different regions.