Offshore wind installation vessels – A comparative assessment for UK offshore rounds 1 and 2

Abstract

Marine operations play a pivotal role throughout all phases of a wind farm’s life cycle. In particular uncertainties associated with offshore installations can extend construction schedules and increase the capital expenditure (CAPEX) required for a given project. Installation costs typically account for about 1/3 of the overall project cost. Therefore, informed engineering decisions and uncertainty reductions in this area hold the potential for risk and cost reductions. One of the governing factors are uncertainties in weather downtime for installation vessels, which can incur significant cost fluctuations. This has driven the creation of a variety of software tools in the offshore wind sector to predict installation schedules, assess the bids from participating contractors, optimise planning and identify the subsequent financial allowance required to cover these associated costs. This paper considers the installation modelling for UK offshore Wind Rounds 1, 2 and 3. T Through detailed sensitivity studies of key windfarm characteristics such as distance to shore and the number of turbines, an assessment of vessel performance was completed for generic representative sites for each round by comparing the sensitivities of predicted durations. The results provide a quantification of installation vessel performance, approximated costs and the associated deviations. The derived sensitivities can be used as measure of installation risk to support the planning and management and efficient use of project resources.