A versatile Floating Offshore Wind Turbine platform concept for Central Mediterranean Conditions (MedFOWT)

Abstract

The project is to provide a preliminary design for versatile self-aligning single point moored floating offshore wind turbine platform for the central Mediterranean conditions

Existing floating platforms reaching commercialisation have been primarily adopted from the oil/gas sector and are classified into three concepts: Spar, semi-submersible and tension leg platforms. In all concepts, the platform is securely anchored through a multi-point mooring system, demanding a yaw mechanism to align the turbine continuously with the wind, as in the case of land-based/shallow water turbines. Emerging concepts involving only Single Point Mooring systems should be a cheaper alternative as this enables the entire structure to align with the wind. Yet these designs have limited deck area and their geometry is not optimised for Mediterranean conditions.

The wind resources in the Central Mediterranean are enormous. MedFOWT will build on the University’s expertise in offshore renewables and maritime engineering. It will develop a new floating wind turbine concept optimised to address specific requirements of the region: (1) the need to accelerate cost reduction given lower wind (2) overcome logistical challenges associated with existing local port facilities and (3) the need to integrate additional infrastructural on board (e.g. energy storage to facilitate connection to weaker grids (e.g. islands)).

The concept design platform combines important attributes into a novel design that improves viability of offshore wind in Maltese waters and surrounding region:

• Lower cost: single point mooring (allowing entire floater to align with the wind, eliminating need for the expensive yaw mechanism in turbine nacelle); replace the conventional cylindrical tower by a lighter space-frame to support the turbine

• Adaptation for Mediterranean ports/docks: reduced width and low draught, allowing manufacturing/maintenance in existing ports

• Inclusion of a deck area: for integration of additional infrastructure (e.g. energy storage units to stabilise intermittent power output and increase revenue in peak energy demand)

• Hydrodynamic efficient hull: reduce towing drag, reducing fuel consumed by tug boats; dynamic ballast to enhance stability in rough weather.

• The proposed design will lead to a solution that is technically optimised for the Mediterranean region, allowing for lower generation costs by improved designs and avoiding need to construct new ports.