Spotlight: Developing Floating Offshore Wind Turbines 2

Part 2: Design Selection

Turbine Modeling

AnthonyAnthony Viselli, a Ph.D. in Civil Engineering, took me through the steps of the rest of the process. First, they must make models that are 1/50th of the real size.

"The full-size 5 MW turbines are about a football field tall," Anthony explained.

The engineers then need to test their models to determine which designs and materials function best in the ocean environment. For this step, they utilize large "wind-wave" tanks—"massive swimming pools" as Anthony described them. These tanks have the ability to simulate the ocean environment by creating large waves and strong winds. The models are tested in these tanks to determine how well they perform, and ranked accordingly. (They also use the data to validate the models Andy studies.)

At this stage in the process, the best platform designs are selected, based on performance in the wind-wave tank.

Three designs are being considered. The spar-buoy design sits largely underwater, weighted down by concrete and water in its base, while still displacing the right amount of water to remain floating. The tension-leg platform utilizes taught mooring lines to hold it partially submerged. Finally, the buoyancy-stabilized platform functions as a barge, floating on the surface of the water. Each design will be judged by wind and wave stability, fabrication cost, and anchoring/mooring expenses to determine which will finally be deployed.


The Challenge Ahead

Once all the data collection, modeling, and validating has been completed, the DeepCWind Consortium can finally begin building a 1/3 scale turbine. This 120 kW prototype will be situated at the University of Maine Deepwater Offshore Wind Test Site off Monhegan Island, and will actually generate electricity. This ushers in simultaneous wave observation studies and data collection. Activities at the test site will require the assistance of other DeepCWind Consortium members like Cianbro and Bath Iron Works.

The time has never looked more promising for renewable energy development. The Department of Energy recently set an ambitious goal of 20% Wind Energy by 2030, and the aggressive funding of wind projects across the country certainly shows that they are serious. Why wouldn't they be? We are gaining our energy independence, reducing carbon emissions, and creating jobs in the process.

A floating wind farm of 5 MW turbines, quietly and cleanly generating electricity miles offshore is an inspiring idea. Engineers at AEWC are developing that idea into reality.