B3 - Moorings, anchors and foundations
B - Fluid-structure Seabed Interaction
Challenges/Opportunities
Foundation and station-keeping systems are a major fraction of ORE system costs and critical to system response.
Solution
Novel and higher performance mooring arrangements, lines, foundations and anchor systems will reduce the costs of support and station keeping, and optimise the dynamic response of wave devices
Context and Need
Importance
For all ORE systems, multiple devices and the connecting electrical infrastructure require support or station keeping. Station-keeping requires systems of mooring lines and anchor or foundation types for a range of bed conditions. Fixed devices require foundations that provide adequate strength and stiffness. Design methods have been developed for a range of water depths, aided by knowledge transfer from other offshore engineering sectors. However, typically, the mooring and foundation systems will comprise a significant fraction of the total system costs, particularly in deeper water. Reducing these infrastructure costs is important for overall cost reduction.
Breakthrough
Likely to require: new materials, better modelling approaches to capture the integrated behaviour of the mooring system with the floating structure, new foundation types particularly for high-energy environments.
Summary
New concepts and materials for moorings; design of coupled mooring and foundation systems and coupling mooring analysis and hydrodynamics for floating offshore wind and wave devices. Mooring systems for arrays including shared moorings and systems with multiple devices per foundation
Impact Potential
The mooring and foundation system can be a significant part of a fixed or floating structure, in shallow water, but as water depths increase these costs generally increase significantly. Deployment of wave and tidal systems is contingent on a suitable anchoring / foundation system. Self-installing systems or novel ideas may be needed to reduce costs.
Research Summary
There has been significant research completed worldwide on mooring and foundation systems for fixed and floating oil and gas structures. This research should be leveraged for ORE. Recent work on anchoring includes work on driven pile design (e.g. PISA, ALPACA) as well as on screwpile design (Supergen Wind funded project).