Optimisation of offshore wind floater from dynamic cable and mooring perspective

Abstract

Wind energy is one of the most promising energy sources, but it is currently limited to land and sea locations with a maximum depth of 50m. This leaves large areas of uninterrupted high seas unused, which can provide greater capacity than land-based and fixed offshore wind farms. Floating offshore wind farms (FOWF) can be deployed in deeper water depths away from the coast. Therefore, benefit from a greater volume and more consistent wind, resulting in a higher capacity factor, greater flexibility in the installation location, and no restrictions on the size of the wind turbine. One of the main challenges faced by FOWF is that dynamic power cables are exposed to severe load conditions during their design life. While traditional submarine cables are installed on the seabed, FOWF's cables remain in free span, having floating components that enable them to move with floating objects. Cables continue to be subjected to extreme dynamic loads during their whole design life; therefore, they may suffer mechanical damage in various parts. This thesis covers the preliminary study of the dynamic cables and their mechanical behaviour for the floating offshore platforms. The cable configuration has been designed considering extreme environmental conditions and then checked with normal sea state. In addition, the mooring system has been taken into account during the dynamic analysis: a preliminary design of the mooring line was considered and optimized for the project specific environmental condition. It also provides information about the challenges faced in developing and modelling designs, and finally, it defines future research for comprehensive design development.