Structural safety improvement of offshore tall wind turbines under wind and wave loadings

Objective

Wind energy has rapidly developed as a clean and renewable energy source in recent years in order to meet the increasing demand for power. The European Union has already installed over 50GW of wind power generating capacity and has planned to increase the use of wind energy in order to reduce carbon dioxide emissions by 20% by the year 2020 (Tabassum et al., 2014). The use of wind turbines is nowadays the principal technology for generating electrical power from wind, and therefore wind energy converters need to be thoroughly investigated with respect to their capacity, effectiveness and integrity. It is widely known that wind energy potential (greater wind speeds) is greater in higher atmospheric levels, where wind flow is smooth enough as is far from the disturbed built environment. Therefore, higher towers are needed in engineering practice as the technology develops. The space used for offshore wind farms is also more flexible than that on land. For offshore wind turbines, their environmental loads are more complex than onshore ones including higher average wind velocity and wave loadings. Thus, this makes the development of a new tall offshore tower configuration imperative for the construction of offshore structures under wind and wave loadings.