Simulation of Topograpical Change in an Offshore Wind Farm

Wang, Hsing-Yu (National Taiwan Ocean University) | Fang, Hui-Ming (National Taiwan Ocean University) | Chiang, Yun-Chih (Tzu Chi University) | Su, Jung-Chang (SINOTECH Engineering Consultants, Ltd.) | Lu, Chun-Sen (SINOTECH Engineering Consultants, Ltd.) | Hsiao, Sung-Shan (National Taiwan Ocean University) | Lin, Ting-Chieh (National Kaohsiung University of Science and Technology) | Hsu, Hao-Teng (Ship and Ocean Industries R&D Center)

OnePetro 

ABSTRACT

The objective of this study was to adequately examine potential wave fields, flow fields, and coastal geomorphological changes in an ocean near an offshore wind farm after installation of a wind powergenerating set. Accordingly, this study applied hydrodynamic and geomorphological modules to simulate the waves, currents, and geomorphological changes in the study area. The simulation results revealed that geomorphological changes (i.e., scouring and silting variations) engendered by ocean waves and flows before and after the installation of offshore wind turbines were not considerably affected by the jacket-type foundation piles (diameter: 3 m) of the turbines. From a macroscopic perspective, the installation of the wind turbines did not sufficiently affect the geomorphology of the study area. From a microscopic perspective, changes in the seabed geomorphology were only limited to areas surrounding the submerged piles after the installation of the wind turbines.

INTRODUCTION

As an island country, Taiwan imports more than 90% of its energy resources. Previously, Taiwan generated electricity mainly through fossil fuels and nuclear power, which provided substantial economic benefits. However, because of increasing environmental awareness in recent years, people have begun to consider the problems of air pollution and nuclear waste treatment caused by fossil fuel and nuclear power generation, respectively. Therefore, determining economically beneficial and environmentally friendly power generation methods has become an imperative task for Taiwan. Over the past 10 year, Taiwan has been actively developing terrestrial wind farms. Currently, a total of 24 wind farms have been established on the island. Nevertheless, favorable locations for developing wind farms has been exhausted, and wind turbine generators cause considerable noise engendered by wind shear; therefore, establishing offshore wind farms will become a future trend for Taiwan.

For offshore wind power research, J.H. den Boon et. al (2004), R.J.S. Whitehouse et. al (2006), E.A. Hansen et. al (2007) and R.Y. Yang et. al (2011) study has been performed on the occurrence and prevention of erosion holes (scour) around mono pile foundations of offshore wind turbines on sandy soils. J.F. Lu & D.S. Jeng (2007) developed a coupled model to investigate the dynamic interaction between an offshore pile, poroelastic seabed and sea water. R.J.S. Whitehouse et. al (2011) analysis and interpretation of monitoring data for the seabed bathymetry local to offshore windfarm foundations has shown how the scour develops in time and highlighted variations between sites with different seabed sediment characteristics, i.e. sands and clays. Y.C. Chiang et. al (2014) presented a numerical model for the simulations of the morphological changes in large coastal area and local seabed evolutions near turbine foundation, and an assessment of the possible long-term morphological evolution.