Design, Validation, and Certification of a Synthetic Mooring Line System for a 15+ MW Floating Wind Turbine in the Humboldt Bay Wind Energy Area

University of Maine System acting through the University of Maine

Recipient

Recipient Location

beenhere

$308,908

Amount Spent

refresh

Active

Project Status

Project Update

To date a basis of design (BOD) that outlines all of the assumptions required to develop 25% and 50% Front-End Engineering Designs (FEED) of FOWT deepwater moorings for the California environment has been drafted. Chapters of the BOD include coordinate reference systems, design assumptions (corrosion, marine growth, factors of safety, etc) for mooring design, metocean conditions including wind, wave, and currents for both operational and extreme conditions, seismic conditions, dynamic cable assumptions, and design load cases for both FEED levels.

A 22 MW version of the University of Maine VolturnUS-S platform topology has been designed to accommodate the next generations of turbines that will likely be deployed in the CA environment. The basin design team at UMaine has also begun to scope out the basin test with the novel mooring system and upsized hull.

The Issue

California’s goals of 5,000 megawatts (MW) of offshore wind by 2030 will require approximately 1,000 km total length of mooring lines, while 25,000 MW of offshore wind by 2045 will require upwards of 4,500 km total length of mooring lines. The current worldwide supply of mooring chain cannot meet such demand, and therefore the adoption of synthetic rope mooring systems will be necessary to accelerate the deployment of Floating Offshore Wind Turbine (FOWT) mooring systems. The current state of the art of synthetic mooring systems is limited to oil and gas installations and shallow to intermediate FOWT deployments. Deepwater taut-synthetic mooring systems deployed in California WEAs will need to be optimized to reduce hardware and connections while also increasing ease of installation due to significant weather window constraints present in the California offshore environment. In addition, any mooring system in a California WEA must withstand site-specific and technology-specific conditions, including length due to water depths between 550 and 1,300 meters, handling, and installation of the moorings with commercially available vessels, weight of the platforms, forces due to wind speed and storms, and seismicity.

Project Innovation

The University of Maine and its subcontractors will develop a novel mooring system design to tackle the unique challenges of floating offshore wind energy sites off the coast of California, including deep water, seismicity, and utility scale life cycle and supply chain constraints. Collaboration with synthetic rope suppliers and industry leading permanent mooring installers and suppliers will allow for detailed representation of synthetic rope properties in early design loops to achieve realistic life-cycle performance of the system. Project objectives include design of a deep-water synthetic mooring system to 50% Front-End Engineering Design level, validation of mooring system through scale modeling in a state-of-the-art wind wave basin facility, de-risking mooring systems through life cycle assessments, including mooring integrity management (MIM) and risk managements, increasing technology readiness level (TRL) from 3 to 4, verified by Approval in Principle letter from certification agency, development of cost estimates to allow comparison to contemporary deep-water mooring systems, and assessment of environmental impacts relative to the proposed mooring system.

Project Goals

25% and 50% FEED of deepwater mooring
HAZID workshop/installation storeyboard
1:70th scale basin test to verify design

Project Benefits

Benefits of this project include the approval of the Basis of Design by a 3rd party certification agency (ABS) to demonstrate appropriate use by future commercial developments. Novel mooring design will apply a cradle-to-grave design approach that takes into consideration constructability, installation, decommissioning, and environmental impact during the design phase. A 1:70 scale model basin test of the mooring system will verify performance of numerical models to capture appropriate mooring behavior, and an Approval in Principle designation from ABS will prove commercial feasibility for future development.

Key Project Members

Spencer Hallowell

Spencer Hallowell

Research Envineer
University of Mainer
Project Member

Jacob Ward

Research Engineer
University of Maine
Project Member

Anthony Viselli

Chief Engineer, Ocean Renewables
University of Maine

Subrecipients

Rocket

American Bureau of Shipping

Rocket

Delmar Systems, Inc.

Rocket

Bridon Bekaert - The Ropes Group

Rocket

Match Partners

Rocket

University of Maine System acting through the University of Maine

Rocket

American Bureau of Shipping

Rocket

Delmar Systems, Inc.

Rocket

Bridon Bekaert - The Ropes Group

Rocket

Contact the Team

*Required