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A floating wind turbine, reaching into the wind with a lightweight structure, based on America's Cup sailing tech, keeping the heavier bearings and generator near sea level, American Offshore Energy side steps logistical problems with floating HAWT. ©AOE

USA - American Offshore Energy Launches Novel Floating Wind Turbine Design

American Offshore Energy (AOE) has this week announced novel patents in the floating wind turbine industry including a vertical axis wind turbine which, the company says, can be deployed quickly, and even submerged in the wake of a hurricane.

AOE said said: "The AOE VAWT design, the "American Turbine", is the first wind turbine that has no center shaft, the bearings and electrical generation move to the perimeter where there are high surface speeds even at low RPMs, eliminating the need for rolling bearings, gearboxes, and oil.

"Maybe more importantly, the team at AOE used clever design principles to completely avoid moment forces being transmitted to the floating base; this means the floats may be made from fiberglass, saving thousands of tons of steel,"

The company said that it "took a page from Americas Cup Sailboat Racing to build a lightweight but powerful aerodynamic rotor that may be "trimmed" to conditions."

"The big idea is that to make a floating wind turbine, it makes more sense to reach up into the wind with a lightweight structure, like a cross between sailboat masts and bicycle wheels, keeping the heavier bearings and generator near sea level. Turbines that have been successful on land are being put on floating structures only because they are the dominant wind turbine technology, not because someone thought rationally about how best to make a floating wind turbine. This creates a huge opportunity. The key technologies enabling the opportunity are water-based hydrostatic perimeter support bearings, direct drive HVDC generation at the perimeter and tension and compression design principles," AOE said.

AOE said it took a page from Americas Cup Sailboat Racing to build a lightweight but powerful aerodynamic rotor that may be "trimmed" to conditions."©piccaya - AdobeStock

"Because of the fluid film bearing technology, axial and radial loads are separated; this means that the axial bearings, carrying the weight of the rotating assembly, may push down or pull up on a float, but cannot introduce a moment load. Because the floats are loaded in only tension or compression, they may be made from fiberglass at a tenth of the weight per MW of the oil derrick-like floats required for HAWT [Horizontal Axis Wind Turbine] designs," AOE added.

According to the company, HAWT have the loads and masses at the top of a long pole, they are cantilevered, so a 50-ton force at the top of a 100-meter tower puts more than 500 tons of force into a floating base that is holding the bottom 10 meters.

"This is why they require so much steel. The AOE design avoids this," AOE said.

AOE says that its design has no need for forgings, castings, rolling element bearings, gearboxes, conventional generators, or AC/DC conversions at sea.

"Being so much lighter, they may be manufactured and launched from sites not appropriate for launching floating HAWTs, and so are not competitive in regard to coastal real estate either," AOE says.

Made in the U.S.

"The fact that they may be towed and serviced by existing Jones Act-compliant vessels sidesteps another logistical supply chain problem. The AOE turbine is constructed of fabricated steel and fiberglass structures, both active industries here in the USA that could easily scale up," AOE says.

Drew Devitt, CTO of AOE notes, "Being completely American-made, we will avoid having to wait to buy European-made nacelles; that is another reason we may be able to deploy faster and less expensively." He goes on: "We are not competing with HAWT; we really offer a completely different 'Iron in the Fire' with regard to deploying utility-scale floating wind turbines."

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