Date of Award
Spring 5-4-2024
Level of Access Assigned by Author
Open-Access Thesis
Degree Name
Master of Science (MS)
Department
Mechanical Engineering
Advisor
Anthony Viselli
Second Committee Member
Andrew Goupee
Third Committee Member
Amrit Verma
Abstract
With the looming threat of irreversible effects of climate change on the near horizon, a green energy transition has never been more pertinent than it is today. Floating offshore wind is currently one of the most-explored renewable energy solutions for the United States, as a large portion of the wind energy available offshore is in deep waters requiring floating technologies, there are stronger and more consistent winds further offshore, and floating solutions have the potential to be minimally invasive in comparison to other technologies. While floating offshore wind has many positive attributes, a major current barrier is its cost in comparison to other, more established energy sources such as land-based wind and fixed-bottom offshore wind. In efforts to reduce the cost of floating offshore wind, new floating technology advancements, larger turbine capacities, and various optimization routines have been explored in recent work. Notably, there is a lack of comprehensive cost-optimization work on professionally produced floating offshore wind turbine (FOWT) substructure designs for a range of turbine sizes and wave environments. In this work, firstly, a review of current substructure cost optimization research is presented, highlighting the aspects of substructure cost optimization which require further development. Secondly, a methodology for rapid, mass-minimized FOWT substructure design for an arbitrary turbine power rating and set of site metocean conditions based on hydrostatics, frequency domain modeling, estimations of statistical extreme system responses, Froude scaling, and industry standard code constructability requirements is presented and applied to professionally-produced substructure designs. Finally, this tool is used to explore cost, design, and performance trends for the two FOWT substructures. Lastly, using this tool, it was found that the wave environment of the system significantly affects the mass efficiency of the hull, for example causing a 24% increase in the mass of a 10 MW hull as its designed wave environment changes from low to high severity. Additionally, it was found that as the rated capacity of the turbine increases from 10 to 30 MW, the mass efficiency of the hull increases with diminishing gains. These gains occur until design and constructability constraints are met, such as tow-out draft limitations.
Recommended Citation
Dagher, Joseph H., "Developing a Mass Optimization Tool for Floating Offshore Wind Turbine Foundations Based on Site Conditions, Turbine Size, and Constructability Requirements" (2024). Electronic Theses and Dissertations. 3940.
https://digitalcommons.library.umaine.edu/etd/3940