Technology and Innovation for 2030 and Beyond
Presentation Description: Floating offshore wind plants are currently at a major disadvantage to other energy sources due to accessibility constraints and large capital expenses required simply to keep the turbine above water. The ideal wind energy system would eliminate all mass that is not directly capturing energy from the wind. For a floating offshore wind turbine, this objective is even more significant as increased mass above the water level must be supported by more massive floating platforms. By this metric, vertical-axis wind turbines (VAWT) are ideal for floating offshore sites and have several advantages over horizontal-axis wind turbines (HAWT) at this scale. Large VAWTs have improved aerodynamic efficiency over HAWTs in addition to the ability to have a lower center of pressure to reduce the thrust overturning moment. More significantly, the platform-level placement of the drivetrain greatly reduces the demands placed on the floating platform and its mass and cost.
This presentation will provide a brief history of land-based VAWT development and to debunk some common myths about VAWTs. The challenges and benefits of VAWTs will also be established for floating offshore deployment where the platform costs are the single largest contributor to the cost of energy. Updates will also be provided from a recently awarded project to perform a system optimization based on a novel VAWT design developed by Sandia. The ARCUS turbine is a Darrieus VAWT which goes beyond a conventional design by removing the massive tower and replacing it with tensioned guy wires. The tower accounted for 80% of the rotor mass in previous studies by Sandia, and ARCUS results in even lower topside mass moments of inertia than traditional VAWTs, greatly minimizing platform and system costs.