This is an excerpt from the Third Quarter 2012 edition of the Wind Program R&D Newsletter.

In 2010, the University of Maine's (UMaine) Advanced Structures and Composites Center received funding from the U.S. Department of Energy (DOE) and the National Science Foundation to launch an offshore wind research program: the DeepCwind Consortium. The DeepCwind Consortium comprises 36 industrial, university, and national laboratory partners with the shared goal of developing floating offshore wind technologies. Since its formation, DeepCwind has made significant strides toward the commercial development of floating offshore wind technology.

The gross U.S. offshore wind potential is more than 4,000 gigawatts (GW) — more than four times the combined generating capacity of all U.S. electric power plants.  Although this wind resource is located within 50 nautical miles from shore, most of it is located in deepwater that would be cost prohibitive to develop without floating offshore wind technology.

To pursue commercial development of floating wind turbine technology, DeepCwind researchers at the center are working to validate numerical modeling tools that will accurately predict system behavior for use in efficient design and optimization. Currently, there are very few coupled numerical modeling tools for simulating the performance of floating wind turbines. Codes, such as the Fatigue, Aerodynamics, Structures, and Turbulence (FAST) code developed by the DOE's National Renewable Energy Laboratory (NREL), have yet to be fully validated against real data because little published information of this type currently exists.

In 2011, the National Science Foundation Partnerships for Innovation and the DOE Wind Program funded the center's DeepCwind researchers to perform 1/50th scale model testing of three floating wind turbine concepts at the Maritime Research Institute Netherlands in Wageningen, the Netherlands.  The experiments used a scaled version of NREL's horizontal-axis 5-megawatt reference wind turbine atop three different platforms: a tension-leg, a spar-buoy, and a semisubmersible. These models were tested under 60 different metocean conditions found in the Gulf of Maine. UMaine and NREL are now analyzing the test results and will use the test data to validate NREL's coupled numerical tools for accurate modeling of future offshore designs, including the UMaine semisubmersible pilot-scale turbine that the university plans to deploy in 2013 at its Deepwater Offshore Wind Test Site near Monhegan Island, Maine.

Additional work underway employs the DeepCwind model test data to further advance the knowledge base of the offshore floating wind turbine industry. This work includes:

  • Floating wind turbine model scaling method improvements
  • Additional data analysis and investigation of coupled physics and validation of FAST for spar-buoy and semisubmersible systems
  • Design, deployment and testing of a pilot-scale floating turbine using composite components in 2013
  • Additional work with the composites industry to integrate components, such as tower systems, into full-scale floating offshore wind turbines.

For more information, visit DeepCwind.org and composites.umaine.edu.