Abstract: Sears Island Floating Offshore Wind (FOSW) port, situated on the eastern side of Sears Island in Maine, aims to bolster the offshore wind (OSW) industry along the eastern seaboard. Currently, all existing and planned future large-scale offshore wind projects along the east coast, excluding the Gulf of Maine, utilize fixed-bottom foundations for turbine support. These foundations are suitable for water depths up to approximately 200 feet (+/- 60 meters) and are well-suited for the shallow continental shelf characteristic of the eastern U.S. seaboard. However, in waters deeper than 200 feet, such as those found in the Gulf of Maine, installing fixed-bottom foundations becomes economically unfeasible, leading to the emergence of floating OSW turbines as a solution. The advancement of floating OSW technology necessitates the development of new offshore wind port facilities capable of staging and integrating (S&I) components, fabricating foundations, and loading assembled wind turbines onto floating foundations. The Sears Island FOSW port facility will primarily receive offshore wind turbine components via barge or delivery vessels and will function as a pre-assembly and storage area for these components. Raw materials for the floating foundation units will be transported to the site via barge or land, where the floating foundations will be fabricated and then moved to the waterway using submersible barges or ring cranes. The foundation units will be floated to a sinking basin, transferred, and moored to the berth for wind turbine assembly. The port facility, therefore, must accommodate large, open flat space; heavy lift platforms; deep draft at berth; and well-maintained deep and wide approach channel. The Maine Department of Transportation (MaineDOT) retained Moffatt & Nichol (M&N) to assess the feasibility of constructing a port in the Searsport region to support the Floating Offshore Wind (FOSW) industry. The project requires the assessment of the port characteristics in phases. Phase 1 will be designed to accommodate a demonstration project of approximately 150 MW to 200 MW while Phase 2 will be capable of supporting a full-scale commercial wind farm installation (over 1000 MW). M&N, leveraging its expertise from various major ports across the U.S. serving fixed-bottom offshore wind foundations and floating offshore wind projects in Europe, established criteria for FOSW ports. Following an analysis and comparison of potential port sites in the Searsport region against these criteria, along with conducting thorough alternative analyses and in collaboration with MaineDOT, M&N recommended the Sears Island location for the facility. M&N continues its collaboration with MaineDOT to further advance the project to the detail design and planning phase. This presentation will provide an overview of the conducted study, the developed FOSW criteria, the characteristics of Sears Island Port, and lessons learned in the process of establishing one of the first floating offshore wind ports in the U.S.
How does this project / topic contribute to the advancement of the industry and profession?: Floating Offshore Wind Ports must meet specific criteria to serve offshore wind turbine installation farms. M&N has conducted extensive studies to develop a set of criteria and its application in the Sears Island port, which will be shared through this presentation.
Does the project / topic implement new and innovative techniques, materials, technologies, and delivery methods?: Floating offshore wind technology is still in its infancy, with very few installed projects worldwide and none on a commercial scale. Similarly, FOSW ports are a novelty in the U.S., and a facility of this scale serving FOSW has yet to be constructed anywhere in the world. This presentation will delve into various findings and experiences related to these developments.
What was the most challenging aspect of your project / topic and how did you handle it to ensure success?: Multiple floating foundation technologies are being developed concurrently, each varying in size, shape, and material, necessitating individual accommodation. Simultaneously, wind turbine technology is evolving, and the specific turbine size for installation at the site has not yet been determined. In the interim, port design criteria must be developed for an undisclosed foundation supporting an undetermined turbine, requiring ports to be designed and constructed in a timely manner to efficiently serve the installation of the wind farm.
Who is the target audience for this paper?: Port planers and engineers, marine structural engineers, marine geotechnical engineer offshore wind developers, policy and decision makers in both private and state level could benefit from and understanding of both technical and planning criteria for a FOSW port and lessons learned during planning phase of the project.
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