Operational Expenditure Modelling of the X-Rotor Offshore Wind turbine concept: Sensitivity of Key Modelling Assumptions

The focus of this paper is operational expenditure modelling of the novel X-Rotor offshore wind turbine concept. The X-Rotor presents significant opportunities for operational expenditure reduction. There are, however, numerous uncertainties associated with modelling of those costs. Namely; failure rates for a novel concept are difficult to quantify, and the design of the concept is still being refined. These uncertainties may be addressed via simple sensitivity analyses. Here, three such sensitivity analyses are presented: one focusing on the main bearing failure rate, one on the generator failure rate, and one exploring the provision of redundancy via the operational strategy of secondary rotors. The main bearing failure rate had a particularly significant impact on operations and maintenance costs, accounting for approximately 22% of costs under baseline assumptions. The generator was less impactful as a cost driver, accounting for approximately 10% of costs under baseline assumptions. Lastly, assuming the X-Rotor could operate at 50% capacity upon failure of one of the secondary rotors decreases the operational expenditure by 8% compared to full turbine unavailability.