Floating Offshore Wind Subsea Cables

Abstract Subsea cables for floating offshore wind are complex composite structures designed on a bespoke project by project basis into various system configurations. The objective of this paper is to outline the key areas for attention for developers to work with subsea cable suppliers in order to optimize the subsea cable systems to minimize cost, whilst maintaining acceptably low risk of failure in the field. Various methods are presented addressing cost saving optimization opportunities in various areas including; in the designs of the dynamic cables themselves, optimization of the accessories that make up the dynamic cable system, and specification of the dynamic analysis requirements. The above methods are then overlaid against the potential challenges for dynamic subsea cables for large scale floating offshore wind farms and the differing cost saving options are discussed considering how potential volume cost saving optimizations can be benefitted from. Specific figures are presented comparing the effectiveness of each approach using representative examples to provide an idea of the scale of possible savings or the impact of the design requirement. The complexity of the cable system dynamic analysis process is presented along with the inputs required and a description of the iterative process. This then feeds into opportunities for optimization of the analysis philosophy and how this may differ in considerations from site to site depending on the water depth and other environmental conditions. A large proportion of the expense for a dynamic cable system is in the dynamic system accessories such as buoyancy modules and any accessories that may be required to provide stability at the cable touchdown point. An overview is provided for how these costs may be optimized including specific examples. Some of these cost saving opportunities need to be investigated at an early stage in the project before the floater specification is finalized. This paper is intended to support developers in working with cable suppliers to find and utilize these potential cost saving opportunities at the right stage.