Evaluation of a multi-turbine floating platform concept considering wake effect

Floating offshore wind currently implements a one-turbine-one-platform strategy. A nominal offshore wind farm with 1GW capacity will require more than 60 floating platforms, 200 mooring lines and complex distributed power take-off infrastructure, leading to costly inspection and maintenance. Hence, upscaling the one-turbine-one-platform strategy to GW-scale floating offshore wind array represents a major challenge. A multi-turbine shared platform approach has the potential to reduce this complexity and cost. However, to space the turbines effectively and prevent turbine interference on power production due to wake effect, these structures need to be of unconventional size, i.e., Very Large Floating Structures (VLFS). The unprecedented size of VLFS imposes techno-economic challenges such as demanding structural integrity requirement and significant increase of material cost. In view of this, this paper evaluates the trade-off between the mitigation of wake effect and the cost-effectiveness of platform’s structural design. Constrained by structural integrity considerations, a multi-objective optimisation is completed in which the Pareto front of maximum power output and minimum total cost is evaluated. A Jensen’s single wake model is employed to assess the impact of turbine interference. Comparison with a previously developed reference design with 600 metres’ total length indicates the potential to extend the length by 200 metres, enhancing the power output without compromising cost-effectiveness.