Operating Strategies and Design Recommendations for Mitigating Local Damage Effects in Offshore Turbine Blades

Two major barriers to widespread US acceptance of offshore wind energy is reliability of rotor blades and the difficulty to access for inspection and maintenance. This work presents operation and design strategies aimed to increase blade reliability and maximize power production. Operating strategies that prolong blade life while optimizing energy output allow for smarter maintenance planning and lower maintenance costs. Offshore plants require significant balance of station costs associated with each turbine, leading to large rotor diameters to capture the most energy per turbine. Rotor diameters have already approached 130 m, so this work extends that trend to 100 m blade (205 m diameter) designs. A combined aero/structural optimization process was used to produce new 100 m blade designs. A high-fidelity analysis method is presented to assess the local damage effects of a common damage type. The operation and design strategies are then compared for their effect to mitigate the local damage effects. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC0494AL85000.