離岸風機打樁噪音量測及減噪機制研究

Study of Pile Driving Noise and Mitigation Mechanism

王煒傑(Wei-Chieh Wang)

指導教授 ： 陳琪芳

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201704511

摘要

近年台灣亟欲發展綠色能源，而風力發電技術較為純熟，因此成為重點發展項目。但台灣地狹人稠，陸地使用面積諸多限制，因而離岸風力發電成為重點發展項目，而目前所規劃的潛力場址和中華白海豚重要棲息地鄰近，為避免施工噪音影響海洋哺乳類的生態，需進行離岸風機打樁的噪音量測和減噪研究。2016年9月初，上緯新能源股份有限公司於西海岸規畫的離岸風場架設兩支示範風機，分別為21號及28號風機，本團隊則於施工點位附近佈放底碇式聲學儀器及進行船載式噪音量測。
為降低風機打樁時造成的高強度之低頻噪音，利用氣球幕減噪可將噪音影響範圍縮小，達成環境保育的目的，但目前在國內此減噪技術僅於實驗水槽做過測試，尚未應用於實海域，因此藉由此次合作計畫，並參考了國內外研究成果，於距打樁處230米處放置了2組水下錄音器，其中一組於水下錄音器周圍架設氣球幕，另外一組則無，並比較兩組錄音器資料並針對單擊打樁聲的聲曝值(SEL , Sound Exposure Level) 做統計，可發現其減噪效益都介於5至10 dB。除氣球幕減噪，以玻璃瓶幕作為另一減噪機制，並應用於實海域亦是本研究另一重點，研究於實驗室內部水槽進行，使用的玻璃瓶尺寸一致，並透過改變體積分率測試其減噪效益，結果呈現約有5至10 dB的減噪效果，而隨著玻璃瓶數量的增加，其減噪效益亦有相當程度的增幅。

關鍵字

打樁噪音 ； 減噪工法 ； 氣球幕

並列摘要

Due to the Green Power Policy in Taiwan, wind power becomes one of the primary focuses because it is refined, renewable, and well established. Because of limited land availability and dense population, the government is taking Offshore Wind Farms (OWF) into consideration. However, the planned location for potential OWF is close to the habitat of the Sousa chinensis (also called Indo-Pacific humpback dolphin or Chinese White Dolphin). In order to protect the marine mammals from the noise produced from the construction and operation of OWF, it becomes necessary to monitor and provide measures for mitigation of the noise generated by pile driving during the construction of the Offshore Wind Turbines.
In September 2016, Swancor Renewable Energy Co., Ltd constructed two models of the Offshore Wind Turbines, numbers 21 & 28, off the western coast of Miaoli, northern Taiwan, which allowed us to use bottom-mounted hydrophones and ship-measurements to record the noise created during the piling. This paper reports on the mitigation measures of using balloon arrays to reduce low frequency noises produced by pile driving, which can protect the environment by minimize the noise impact zone. Prior, this noise mitigation technique had only been tested in a laboratory setting. Therefore, through this opportunity for cooperation, the mitigation effect provided by the balloon arrays was tested by setting up two bottom-mounted hydrophones, with recording systems, 230 meters away from the piling location; one set was covered with balloon arrays, the other without. The data analysis results show that the balloon arrays are an effective means to reduce underwater noise. The statistical measurement of the Sound Exposure Level for a single strike, there was a 5 - 10 dB noise reduction.
Another part of this research was to apply Helmholtz Resonator to underwater noise mitigation. The experiment was done in a tank within a lab, keeping the size of glass bottles constant, and tested the mitigation effect by changing volume fraction. The results show there was a 5 - 10 dB noise reduction , and by increasing the number of the glass bottles, the noise reduction also showed a considerable degree of improvement.

並列關鍵字

pile driving noise ； noise mitigation ； balloon curtain

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