Study of Hard and Soft Countermeasures for Scour Protection of the Jacket-Type Offshore Wind Turbine Foundation

Hsin-Hung Chen,Ray-Yeng Yang,Hwung-Hweng Hwung

doi:10.3390/jmse2030551

Hsin-Hung Chen, Ray-Yeng Yang + Show 1 more

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https://doi.org/10.3390/jmse2030551

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Abstract

Physical model tests with the scale of 1:36 are carried out in the Near-Shore Wave Basin (NSWB) at Tainan Hydraulics Laboratory (THL) with the jacket-type offshore wind turbine foundation (jacket-type foundation) and the combination of hard or soft scour protection in the test area. Scouring around the jacket-type foundation exposed to wave and current was conducted in the NSWB with a mobile bed experiment. Two locations (a water depth of 12 m and 16 m) of the foundations are separately simulated in this study. Based on the analysis from the former NSWB experimental results, one traditional hard scour protection usually used in Taiwan with four layers around the foundation is proposed for the mitigation of scouring. From the experimental results, a four-layer scour protection is tested and found to be effective in preventing scouring around the jacket-type foundation. Besides the hard scour protection countermeasure, the scour protection effect of an integrated offshore wind turbine and cage net aquaculture facility as a soft countermeasure for scour protection of the jacket-type foundation is further evaluated in this study. Meanwhile, a detailed analysis for stakeholders’ opinions on the integration of offshore wind farms and coastal aquaculture is also considered to obtain important experience and knowledge; and furthermore, to understand the real demand for adjusting the feasibility of this soft countermeasure.

Highlights

The growing concern in the 1990s over CO2-forced global warming has given new life to the prospects for the greater use of wind turbines, because of their credentials as non-polluting generators powered by winds created by solar energy, a renewable resource
This study evaluates the feasibility of an integrated offshore wind turbine foundation with a cage net aquaculture facility with respect to the effect as a soft scour protection
The stakeholders’ opinions are collected from four groups, including government, offshore wind farm developers, environmental groups and residents. From this preliminary feasible analysis for stakeholders’ opinions, the results show that the four groups can accept the concept of an integration of offshore wind farms and cage net aquaculture for the western Taiwan coastal water utilization

Summary

Introduction

The growing concern in the 1990s over CO2-forced global warming has given new life to the prospects for the greater use of wind turbines, because of their credentials as non-polluting generators powered by winds created by solar energy, a renewable resource. As a direct consequence of the Kyoto Protocol, there is a new impetus in developing the capacity of offshore wind farms to provide a significant percentage of the target renewable energy quota. Offshore wind energy began in the shallow waters of the North Sea, where the abundance of sites and higher wind resources were more favorable by comparison to Europe’s land-based alternatives. All of today’s offshore wind farms producing energy (starting 2007) are located in shallow waters; they are either founded on monopiles or on gravity-based caissons [1]. The transitional substructure of the offshore wind turbines will be replaced by fixed bottom systems that use a wider base with multiple anchor points, like those frequently used in the oil and gas industry

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