Floating wind farms in sea basins with moderate wind speeds: a critical assessment of the potential of low-specific-power turbines in reducing the LCoE

Abstract

Expanding offshore wind energy in sea basins with moderate wind speeds and higher depths by means of floating offshore wind turbines (FOWTs) is indicated as a priority to meet the challenging goals about renewable energy generation set by many countries worldwide. Upon reviewing the literature, a clear trend emerges for these sites, which suggests prioritizing the development of a different turbine technology with lower specific power than that in use to date, which can be able to ensure suitable energy conversion factors also at lower wind speeds. However, the same review also shows that the potential of low-specific-power rotors has not been studied so far in a sufficiently comprehensive manner to ensure robust assessments. Therefore, the first objective of this study is to develop an original and comprehensive simulation framework for floating wind farms, which is able to account for different rotor designs, floaters, moorings, and farm layouts. The techno-economic data in the model have been synthesized from an extensive and critical review of scientific papers, technical reports, and industry-provided insights. The second objective is then to apply such simulation framework to a variety of sites in the Mediterranean Sea, characterized by different wind speed distributions that span over the range of moderate wind speeds currently under study for new FOWT installations. Results for four rotors, having specific power values ranging from 331 to 175 W/m 2 , show increases in annual energy production of low-specific-power turbines compared to reference designs that range between 13 % and 30 %, providing potential decreases in LCoE between 3 % and 13 % across the examined locations. Results of this critical perspective are unprecedented in this form and are thought to potentially represent a catalyst for more detailed industrial studies. • Critical review of current challenges in expanding floating wind beyond conventional sea basins. • Development of new data-driven correlations for turbine design. • Exploration of the potential of low-specific-power turbines in the Mediterranean Sea. • 15 MW FOWTs with specific power ranging from 331 to 175 W/m 2 . • Optimal design choices and prospects of the technology discussed by AEP and LCoE estimation.

Topics & Concepts