ABS has completed a design review for the University of Maine-developed VolturnUS foundation for floating offshore wind turbines.
The patented VolturnUS, developed by the Advanced Structures and Composites Center at the University of Maine (UMaine), is based on a concrete four-column semi-submersible.
In 2013, the UMaine team successfully tested the feasibility of the concept by developing a 1:8 scale model and deploying it offshore Maine. The current pilot project consists of two full-scale semi-submersibles, each with a 6 megawatt (MW) turbine. Both units will be connected to the Maine power grid by subsea cables.
Plans are in place for the semi-submersibles to be used for the New England Aqua Ventus I project, a 12 MW facility offshore Maine funded by the US Department of Energy. This is a pilot project to demonstrate that the innovative design of the VolturnUS is a viable and economical alternative for offshore wind developments in water depths greater than 50 m.
“UMaine is pleased that its innovative design became the first floating wind turbine concrete semi-submersible hull to be reviewed by ABS, and found to meet the ABS requirements,” says UMaine director and principal investigator Dr Habib Dagher.
“After 10 years of development, this is a major milestone for our programme, and we expect the VolturnUS hull concept to continue to attract private investment from the US and around the world. Nearly 70% of the US offshore wind resources can be captured using the UMaine VolturnUS technology, and we are looking forward to working with offshore wind developers across the country.”
ABS completed a design review of the semisubmersible, verifying compliance with its Guide for Building and Classing Floating Offshore Wind Turbine Installations. The process consisted of an independent review of the hull/tower structure, coupled aeroelastic/hydrodynamic loads, safety, stability, electrical systems, equipment, piping and hydrodynamic and station-keeping design. ABS determined that FEED design, as presented, met the requirements of the relevant ABS Rules and regulatory standards.