離岸風力發電-建設離岸風場

離岸風場建設EPCI(Engineering, Procurement, Construction and installation)以大統包為例

大統包(EPCI contractor)通常要做:

• 工程規劃與設計
• 採購
• 生產製造
• 運輸與安裝
• 也許要包含五年的風機運維(視統包合約而定)

Engineering(Design and manufacturing)

Turbine and foundation design iteration

Foundation 生產製造-興達海基為例

海底基礎的安裝Foundation installation - monopile

Monopiles may be installed from a jack-up vessel or a floating vessel. The transition piece is usually lifted and grouted or bolted in place from the same vessel but two-vessel strategies have been used successfully.

Monopiles (up to 10m diameter) are generally moved into position using the main crane and upending tool and held in position by a gripper tool. They are the driven into the sea bed using a hammer and anvil system before mounting and grouting transition pieces.

Transition pieces are usually carried and installed by the same vessel, although a two-vessel strategy in which transition pieces are installed by a separate vessel has been used on several occasions. This focuses the utilisation of the monopile installation vessel, which is likely to have higher day rates than the transition piece vessel. A disadvantage is the costs of mobilising and demobilising two vessels.

Feeder strategies have been used for monopiles, notably with Van Oord’s Svanen, which has no useable deck space for transporting components. In this case, the monopiles are floated to site using tugs or transported using platform supply vessels.

An approximate timetable for installation once at the wind farm site is:

• Transport and positioning: 2 hours for floating vessels; 4 hours for jack-ups
• Preparations: 1 hour
• Lifting and pile positioning: 1 hour
• Driving: 6 hours, and
• Grouting: 2 hours.
• The full cycle time is 2-3 days per monopile, a figure that takes into account mobilisation and demobilisation, loading and waiting on weather.
• Under some ground conditions, monopiles are grouted into a pre-drilled rock socket. Under conditions with boulders, a combination of drilling and driving is required.

海底基礎的安裝Foundation installation - Jacket

Jacket foundations may be installed by floating vessels or jack-ups. Installation usually involves pre-piling using a reusable template. The jacket is then lowered into place over the pin piles and grouted. Post-piling, in which the pin piles are driven (or lowered into pre-drilled sockets) through a sleeve on the jacket legs, may alternatively be used. Pre-piling has the advantage of decoupling the piling and jacket installation, enabling a lower cost vessel to be used for piling and maximising the use of deck space of the main jacket installation vessel.

An approximate timetable for installation once at the wind farm site is:

• Transport and positioning: 2 hours for floating vessels; 4 hours for jack-ups
• Preparations: 1 hour
• Lifting and pile positioning: 4 hours
• Driving: 8 hours, and
• Grouting: 2 hours.
• The full cycle time is 3-5 days per jacket, a figure that takes into account mobilisation and demobilisation, loading and waiting on weather.
• Under some conditions, suction buckets may be used as the sea bed connection. This technology offers potentially lower installation costs because less equipment is needed. Suction buckets have been deployed commercially with jacket foundations but can be used with monopiles as well.

氣泡帷幕(bubble curtain)減噪技術

• 氣泡幕（bubble curtain）是一個常用的水下噪音減輕對策。原理是在基樁的周圍、從海底持續製造氣泡，在氣泡往上飄的過程捕捉噪音。
• 氣球帷幕（Hydro Sound Dampers）的原理類似。一般來說，這些方法可降低約10分貝的噪音。
• 而環評承諾則是離基樁750公尺半徑的監測範圍，水下噪音聲曝值不超過160分貝(Sound Exposure Level，SEL)，這個數值是根據美國國家海洋暨大氣總署（NOAA）2016年針對人為噪音對鯨豚影響所定的技術指南及德國StUK4（2013）的環評標準。

風機的安裝

防淘刷(scour protection)

• 防淘刷通常通過傾倒岩石或石頭袋或其他材料(如輪胎)在海底基礎結構的底部。
• 岩石傾倒可能使用在挖泥工業中廣泛使用的落管。
• 要使用落管船或一般駁船來進行拋石作業，袋子會是海流強度及深度降到適當的位置再拋放。
• 拋放後，還要經ROV或潛水人員確認拋石厚度與設計值相同才算完成。

海纜佈放(Cable laying)

• 電纜鋪設可分為陣列電纜(inter array)、輸出電纜(export cable)以及陸上電纜等三項。
• 通常,電纜安裝活動從預鋪式碎石片開始,以清除電纜線路上的碎屑或檢查碎屑的替代方法。

• 輸出電纜將從裝出埠或電纜製造商收集。輸出電力電纜的安裝需要專用電纜鋪設船 (CLV) 或駁船。CLV 或駁船必須具有轉盤或旋轉電纜存儲設施,才能裝載、運輸和安裝這些電纜。
• 特定電纜的屬性將定義電纜處理限制,例如彎曲半徑限制,安裝人員在設計處理和安裝方法時必須注意這些限制。在轉運到工地後,"岸上拉扯"將電纜帶到岸上過渡接頭坑,最終將與岸上電纜連線。通常,此階段涉及沿電纜長度每隔一段時間使用浮選裝置和/或滾子將電纜浮到岸邊。長距離浮動要求區域
• 著陸環境和當地條件通常決定必要的 CLV 規範。滿載船舶的通風可能至關重要,而岸深剖面決定了船隻離海岸有多近。
• 當使用長和重的輸出電纜時,在單長度裝載電纜(避免電纜接頭)和此重量對容器最大通風量的影響之間進行權衡。在某些情況下,當地條件將要求船隻在登陸地點附近擱淺,從而減少可供使用的適當船隻的數量。
• 有限的水深需要仔細管理電纜管,因為短的護套幾乎沒有出錯的餘地,並且很容易造成電纜完整性的降低。通過在淺水中鋪開錨點來確保船舶位置,將有助於滿足所需的鋪設精度,同時不影響電纜的完整性。

電網併聯到商業運轉(COD)

• 在離岸風場中，電網併聯代表將電力經由陸上或海上變電站的蒐集、海底電纜及陸上電纜的傳送、一直到連結於陸上變電站。
• 台灣的陸上變電站皆由台電公司經營，一般民眾所使用的電力由台電公司負責配置與傳送。
• 電網併聯進行測試後，便可開始商業運轉(COD)，此為風場開發重要節點。