This study presents an analysis of a wave energy converter (WEC) system consisting of a buoy, a mooring system, and a power cable connected to a hub. The design service life of the investigated WEC is 25 years. During this long period, its service life will be influenced by marine biofouling due to the biological activity in the water.
The purpose of this study is to investigate the effect of biofouling with regard to the energy performance of the WEC and the fatigue lives of the mooring lines and power cable. The marine biofouling is modelled by an increase in the masses and drag coefficient of the mooring lines and power cable. Coupled response analysis using the DNV-GL software SESAM was conducted to simulate hydrodynamic and structural response of the WEC system. Energy performance analyses and stress-based rainflow counting fatigue calculations were performed separately using an in-house code. The results show that, for a WEC system which has been deployed for 25 years, biofouling can reduce the total power absorption by up to 10% and decrease the fatigue life of the mooring lines by approximately 20%.