American Offshore Energy (Aston, Pa., USA) takes a page from the Americas Cup sailboat design technology to build a high-tech, low cost, floating Vertical Axis Wind Turbine (VAWT). The aerodynamic section of this VAWT is built with a combination of sailboat mast and bicycle wheel technology. The tension and compression design principles allow for stiff lightweight structures that can scale to huge size. The low center of gravity and broad support base makes for a stable floating wind turbine design.
With kinematic support bearings and generation at the perimeter, there is no central shaft. Each bearing point is directly above one of three floats which are tied together structurally and each secured to an anchor screw in the sea floor located to provide anti-rotation.
The VAWT would be assembled onshore and could be towed though shallow water out to deep water moorings. Sail type air foils are the lowest cost per square foot compared to conventional blades and the lightest weight air foils possible. They can be automatically reefed to fit conditions or completely furled for hurricanes. A turbine 100 miles off shore could be towed back for major repairs in a day. This reduction in risk reduces the cost of money and insurance on the project.
Floating turbines allow for placing wind farms more than 25 miles off shore, putting them out of migratory bird patterns, NIMBY issues and state jurisdictions. The daytime thermal issues that require high towers on land are eliminated far out at sea as wind aloft reattaches to the surface providing high capacity factors. Capital costs for the large castings, gears and roller bearings in the conventional turbine supply chain are not necessary with this design, and manufacturing could scale quickly using common steel fabrication and fiber glass technologies. A franchise model could put wind turbine factories and jobs in our old ship building, Navy Yards or cargo transfer ports across our coasts and Great Lakes allowing us to leapfrog foreign turbine builders with a technology that suits America’s resources, says the company.