Abstract
Floating offshore wind is an emerging industry. The first floating offshore wind turbine designed by Principle Power was deployed offshore Portugal to support a 2-MW wind turbine generator in 2011. The turbine is supported by a proprietary semi-submersible concept named WindFloat. Since then, more than ten floating offshore wind turbines including eight additional WindFloat platforms have been installed and commissioned to produce power offshore. There are significant experiences built from the engineering delivery of the FOWT units.
Compared with offshore oil and gas industry, the offshore wind energy industry is still young. A great part of the design methodology for FOWT is inherited from the offshore oil and gas industry. But there are many design aspects which are unique to the FOWT because of the operational differences between FOWT and FPU for oil and gas industry. This paper will give a brief description of the design methodology for FOWT based on the experience built from the delivery of multiple WindFloat floating foundations. The methodology, which is inherited from oil and gas, but being improved or customized for FOWT will be discussed in detail. The subjects to be addressed in the paper include the engineering interface between WTG and the floating substructure, the floating stability assessment, wind load simulation, the determination of the duration of the numerical simulations and the number of random seeds, and the validation with model test results.
As the wind turbine power capacity becomes larger, the floating substructure and its associated mooring system follows a trend of growing dimensions, which is more comparable with the FPU. The growth of the floating offshore wind industry will leverage the lessons learned from offshore oil and gas industry.
