Improving wind farm accessibility for operation & maintenance through a co-located wave farm: Influence of layout and wave climate

• The shadow effect of co-located wave energy converters is analysed.
• Four case studies are considered in a comparative study.
• High-resolution numerical modelling and real sea conditions are used.
• The wave height reduction and the accessibility to the wind turbines are quantified.
• Conclusions about the influence of water depth, sea climate and layout are drawn.

One of the challenges of offshore wind energy farms lies in their reduced availability relative to onshore facilities. In effect, with wave heights over 1.5 m impeding workboats access, sea conditions often cause delays to operation & maintenance tasks, and thereby impact on the availability for power production of the farm. The most immediate consequence is larger non-operational periods, which could translate into lower power production and, therefore, a reduction of their economic viability. By deploying wave energy converters along the periphery of the wind farm, wave height within the park can be reduced, and the accessibility for operation & maintenance tasks improved. The aim of this work is to analyse this synergy between wave and wind energy through the comparison of four case studies, and more specifically, to investigate how this synergy can be materialised under different conditions in terms of: (i) location (depth and distance from the coast), (ii) sea climate, and (iii) wind farm layout. It was found that the combination of wave and offshore wind energy results in enhanced accessibility for operation & maintenance tasks in all the cases considered, with accessibility values of up to 82%.