Development of Marine Turbine Using a Direct Drive Permanent Magnet Generator

79729S Ocean currents constitute a potentially enormous renewable energy resource; however, existing technologies for capturing this energy are only in the prototype stage, are small in scale (less than 1 megawatt), and are not grid-connected. Although there is a considerable overlap in technology with the more mature field of wind energy, new robust technologies will have to be developed that are capable of withstanding the harsh environment of the open ocean, in order to commercialize this technology. An additional problem involves cavitation at higher blade-tip speeds, resulting in efficiency degradation and potential blade damage. This project will address these issues by adapting an existing 1.5 megawatt direct-drive, permanent magnet generator drivetrain to the marine turbine application. The system will use advanced "canning" technology to protect its sensitive components, anti-biofouling materials, and seawater for cooling. The blade design will address the issue of cavitation at higher rotational speeds. In Phase I, preliminary designs will be created for the turbine tower, rotor, blade and drivetrain. The design will incorporate features for sealing of the drivetrain, optimizing power production; minimizing blade cavitation, providing yaw control, and cooling the generator and power electronics components. A life-cycle cost-of-energy analysis will also be performed. Commercial Applications and Other Benefits as described by the awardee: The multi-megawatt marine turbine could be used to capture marine current energy from either steady currents or tidal currents. The larger size, smaller number of moving parts and robustness of design will all contribute to lower-cost, lower-maintenance operation. The potential for commercial application is enormous, as this is currently an unexploited renewable source of energy. Unlike most other renwables, ocean currents are extremely predictable, allowing this energy source to be a steady source of power when connected to the grid.