1. Current Status of Phase VI Floating Design Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy by the Alliance for Sustainable Energy, LLC IEA Wind Task 30 Kick-Off Meeting June 8, 2010 Jason Jonkman, Ph.D. Senior Engineer, NREL

2. IEA Wind Task 30 Kick-Off Meeting 2 National Renewable Energy Laboratory TLP & semi-submersible were both suggested candidates for Phase VI More interest in semi-submersible b/c: –Greater system motions & couplings –Importance of hydrodynamic radiation & diffraction –Catenary moorings Principle Power Inc. (PPI) has kindly agreed to design a semi-submersible, based on the WindFloat, & make it available to Task 30 participants Spar Concept by SWAY Phase VI Floater Concept

3. IEA Wind Task 30 Kick-Off Meeting 3 National Renewable Energy Laboratory WindFloat by PPI, USA Designed to support existing WTs: –Modifications only to tower & controller Pitch & roll restoring through waterplane area & fixed water ballast Tower mounted on one column Active ballast system maintains zero- mean pitch angle Heave plates improve natural response periods & damping Spar Concept by SWAY WindFloat Key Design Features WindFloat (Image: D. Roddier, PPI)

4. IEA Wind Task 30 Kick-Off Meeting 4 National Renewable Energy Laboratory Tower would be moved to center: –Simplify system’s asymmetry –Avoid issues associated with shift in origin Heave plates would be eliminated by compensating with larger columns: –Heave plates require empirically derived drag –Heave plate IP protected by PPI However, design iteration revealed: –Tower in center requires a lot of extra support structure –Columns would have to be unreasonably large to achieve desired response periods Spar Concept by SWAY Original Design Plan by PPI Semi-Submersible Concept (Image: D. Roddier, PPI)

5. IEA Wind Task 30 Kick-Off Meeting 5 National Renewable Energy Laboratory Keep tower on one column Keep heave plates: –PPI will supply suitable drag properties Platform will support NREL 5-MW WT Aiming for response periods similar to that of OC3-Hywind spar buoy Scaled system will be tested in a wave tank within DeepCWind project: –Data will become available for model validation Design status: –Design iteration in progress –Developing specifications report –Expected completion in Summer, 2010 Spar Concept by SWAY Current Design Plan by PPI Semi-Submersible Concept (Image: D. Roddier, PPI)

6. IEA Wind Task 30 Kick-Off Meeting 6 National Renewable Energy Laboratory Spar Concept by SWAY Preliminary Design Details ParameterValueUnit Column diameter9.7m Length of heave plate13.7m Column center to center46.0m Operating draft16.8m Airgap10.0m Pontoon diameter2.1m Bracing diameter1.5m Displacement4552tonnes

7. Thank You for Your Attention Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy by the Alliance for Sustainable Energy, LLC Jason Jonkman, Ph.D. +1 (303) 384 – 7026 jason.jonkman@nrel.gov