Design and cost evaluation of a deep water support structure for a wind turbine in central Mediterranean waters

Abstract

This paper describes an evaluation of the technical and economic issues related to the setting up of an offshore wind farm at 70 metres depth In the Central Mediterranean near Malta. A literature review and preUmlnary conceptual analysis are first conducted to determine the most suitable support structure type for the site considered. Conclusions from this review and analysis show that the jacket is the most suitable type of fixed bottom support structure for the conditions in the Central Mediterranean region. Other design stages are then conducted to design the Jacket support structure using the state of the art wind turbine software Bladed (1 J and relevant standards. The jacket design Is carried out tor the central Mediterranean conditions as well as for another site in Scotland where two offshore wind turbines have already been constructed on jacket substructures (the Beatrice wmd farm at Moray Firth). The design for the Scottish site served as a benchmark for comparing the results obtained with those for the Mediterranean site. This was done both for the design and for the later cost analysis stage of the wind farm. To conclude the study a cost model was Implemented to investigate the economic feasibility of a wind farm at the two sites considered. From the results, it can be concluded that the more benign environmental conditions in the Mediterranean and the better seabed bearing capacity result in lower support structure costs even though the sea water Is deeper. On. the other hand the poorer Mediterranean wind resource still makes electricity cost conslderably higher than at Moray Firth.