The offshore access problem and turbine availability: probabilistic modelling of expected delays to repairs

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Difficulty of access due to adverse sea-state can cause significant delays to operation and maintenance on offshore wind farms, resulting in lost energy production and increased cost of energy. This paper presents a method of expressing such delays in closed form, in terms of a probabilistic event tree and Weibull parameters of the ‘storm’ and ‘calm’ duration distributions.
Coupled with turbine subsystem reliability statistics and threshold sea states for access, annual expected delays and turbine availability can be estimated using a simple spreadsheet, without lengthy Monte Carlo simulations, as well as their sensitivities to site, turbine and access parameters.
Original languageEnglish
Publication statusPublished - Sep 2009
EventEuropean Offshore Wind Conference 2009 - Stockholm, Sweden
Duration: 14 Sep 200916 Sep 2009


ConferenceEuropean Offshore Wind Conference 2009


  • offshore maintenance
  • access delay
  • sea state

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