Comparison of Power and Thrust Performance for a Fixed and Floating Offshore Wind Turbine

ABSTRACT Floating offshore wind turbines have been identified as a critical technology for sustainable electricity generation. Wind resource assessment is used to determine optimal locations for floating wind farms. However, current methodologies do not account for performance differences between fixed and floating turbines due to wind‐ and wave‐induced motion. Furthermore, there has been no study which systematically investigates the influence of environmental conditions on turbine performance. We compare average and fluctuating power and thrust between a floating and fixed offshore wind turbine using a numeric, in‐house blade element momentum model coupled with potential flow‐based solver. We investigate these performance indicators, first in regular waves and then at four case study locations at water depths near the transition between fixed and floating technologies. We find that, at below‐rated wind speeds, floating turbines experience an increase in power capture due to motion‐induced wind on the turbine, while at near‐rated wind speeds power capture is decreased. This trend is consistent across both regular and irregular wave conditions for all case study locations. Consequently, we find that floating turbines can outperform the annual energy production of a fixed‐bottom turbine by 2%–5% under representative operational wind and wave conditions. However, this increase in power is accompanied by higher fluctuating loads. The 10th–90th percentile range of thrust for a floating turbine is increased by 50% relative to a static turbine. We also show that wind–wave misalignment can decrease floating turbine annual energy production and increase thrust fluctuation. The methodology presented can be used to improve site selection for floating turbines, because our results suggest that currently power capture is underpredicted by not adjusting for platform motion. Furthermore, the results may inform the design and optimization of turbines, platforms, and controllers, to further advance floating wind technologies.