Risk Informed Design of Offshore Wind Turbine Structures in the U.S. Outer Continental Shelf

Abstract

The United States has enormous potential offshore wind energy resources in the Atlantic, Pacific, Great Lakes and the Gulf of Mexico. However, progress in developing these resources has lagged behind that in Western Europe and no offshore wind farms have been built to date in the U.S. Continental Shelf. Uncertainties in U.S. siting and design criteria, specific regulations and standards, along with a lack of experience have challenged development by increasing both cost and the time to deployment. The reliability of offshore wind turbine farms is critical to industry success and should be secured efficiently with respect to cost. The ability to employ probabilistic risk management and decision theory in the design process of support structures would afford more transparent system reliabilities and more flexibility in design compared with prescriptive design standards. A general framework for risk informed design of offshore wind turbine structures is demonstrated on a typical monopole support structure. The structural parameters are manipulated to adjust the risk and to achieve the desired wind turbine performance at acceptable cost. In order to implement such a design procedure in practice, regulations must stipulate clear performance requirements in terms of system reliability for project approval.