Coupled loads analysis of a novel shared-mooring floating wind farm. (15th February 2023)

• Record Type: Journal Article
• Authors: Lozon, Ericka; Hall, Matthew
• Is Part Of: Applied energy. Volume 332(2023)
• Publication Date: 2023-02-15
• Subjects: Offshore wind -- Shared moorings -- Dynamic analysis -- Floating wind; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2022.120513
• Languages: English
• ISSNs: 0306-2619

Abstract

Abstract: Shared mooring lines are a method to reduce the stationkeeping cost of floating offshore wind farms; however, their impacts on floating array dynamics are not yet well understood. This article presents advancements to floating wind farm simulation capabilities that allow the dynamic modeling of shared-mooring floating wind arrays—specifically, platform coupling through shared lines and proper phasing of wave loads across the array. These capabilities are demonstrated on a 10-turbine shared-mooring array featuring two staggered rows of wind turbines. A baseline array design with individually moored turbines is used as a basis for comparison. Coupled analysis using FAST.Farm shows that the shared-mooring design has smaller fluctuations in surge when compared to the baseline design. The mean and maximum platform offsets are highest in normal operating conditions, but the maximum mooring line tensions are highest in 50-year storm conditions. Power spectral density analysis of platform surge and sway motions shows that the shared mooring configuration does not introduce any significant inter-platform resonances. The tower-base bending moment statistics and the line tension damage equivalent loads indicate no consequential differences in turbine loading or mooring fatigue life. Anchor load analysis shows that the total required anchor capacity for the shared-mooring array is decreased by approximately 25% when shared anchors are used. Dynamic simulations of the shared mooring system under line failures show that remaining line tensions stay within bounds and that offsets are significantly smaller when compared to the baseline design. Overall, the results show that shared moorings do not introduce any dynamic response concerns in this floating wind array design. Highlights: FAST.Farm can now be used to model the dynamics of a shared-mooring array. The shared mooring design shows smaller surge fluctuations than a baseline design. Shared moorings do not introduce any concerning dynamic behaviors in this design. In failure scenarios, the shared mooring design shows much smaller turbine offsets. The shared-mooring design reduces the relative line tension dynamics