Optimum CTV fleet selection for offshore wind farm O&M activities

Operation and Maintenance (O&M) contributes a significant share of the expenses during the lifetime of offshore wind farms. When compared to onshore wind, O&M costs are increased, due to the use of specialised vessels, shorter weather windows and challenging environmental conditions. Furthermore, increased frequency of failures, longer downtime and limited accessibility create uncertainties in the planning stage of the O&M tasks. In order to decrease the cost of power generation and increase the competitiveness of offshore wind industry against other alternative energy sectors, it is essential to keep the costs of the vessel fleet used for O&M tasks at minimum level while providing sufficient support to sustain power generation. In order to address these issues, the focus of this paper is to provide decision support for the selection of a Crew Transfer Vessel (CTV) fleet for the offshore wind farm maintenance operations. This is achieved through analyses of environmental conditions, investigation of failures, and assessment of vessel operations. The developed methodology and analysis enable operators to decide the specification of CTVs which will bring the optimum financial benefit, considering both the enhancement of the offshore wind farm power generation as well as the minimisation of the total O&M cost.