JP-7856476-B2 - Floating structures and offshore wind power facilities

Inventors

• 大庭 直樹
• 浦 優介
• 高 東熙
• ▲高▼橋 茜
• 宮川 昌宏
• 白枝 哲次
• 小林 伸司

Assignees

• 清水建設株式会社

Dates

Publication Date

20260511

Application Date

20220427

Claims (2)

1. A floating structure installed on the ocean, comprising an annular floating body having a vertically extending through hole, wherein the annular floating body divides the area into the outside world and an internal area surrounded by the annular floating body, It has a connecting section that connects to the external environment and the internal region and functions as a water channel, The annular floating body comprises a plurality of island-like sections projecting vertically upward from the waterline, connecting sections that connect the island-like sections underwater, a bridge section located vertically above the connecting sections in the water that connects the island-like sections, and a bulkhead extending in the vertical direction and the direction through which the connecting sections penetrate, connecting the connecting sections and the bridge section. The aforementioned connecting portion is located vertically above the aforementioned connecting portion. A floating structure characterized in that a cross-shaped partition wall is arranged in the internal region when viewed from vertically above, and the internal region is divided into four parts by the cross-shaped partition wall .
2. A floating structure according to claim 1 , A wind power generation facility installed on the aforementioned floating structure, An offshore wind power generation facility characterized by having the following features.

Description

This invention relates to a floating structure used as a foundation for, for example, an offshore wind power generation facility, and to an offshore wind power generation facility. Traditionally, offshore wind power generation facilities have been classified into two main types: fixed-bottom and floating. Fixed-bottom facilities involve installing wind turbines on foundations fixed to the seabed, while floating facilities involve installing wind turbines on floating structures suspended on the sea. Fixed-bottom offshore wind power generation facilities face structural challenges and rapidly increasing costs as water depths increase. Therefore, the practical application of floating offshore wind power generation facilities is in demand. In particular, unlike Europe, Japan has many coastlines where water depth increases rapidly rather than being shallow, giving floating facilities a wide range of applicability. Floating structures used in floating systems are mainly classified into four types: barge type (also called pontoon type), TLP type, semi-submersible type, and spar type (see, for example, Non-Patent Document 1). Each floating structure is moored to the sea using anchors and mooring lines installed on the seabed. Structural materials for manufacturing floating structures include steel, reinforced concrete, and composite structures (hybrid structures) using both. Floating offshore wind power facilities are currently undergoing demonstration experiments in Japan and Europe for each of the floating types mentioned above (see, for example, Non-Patent Document 2). Each floating type has its own characteristics, and its applicability varies depending on the scale of the power plant, location, sea conditions, and manufacturing site. For example, a barge-type float has a flat bottom, resembling a box, and its stability is enhanced by increasing the contact area with the water surface. This barge type has the advantage of allowing for smaller float dimensions due to its large waterline area and strong restoring force against tilting. However, it suffers from problems such as a large projected area near the sea surface where wave forces are strongest, resulting in strong wave forces acting on it, and the fact that the wave and float's oscillation periods are close, leading to violent swaying. As an example of a barge-type motion reduction measure, a known design features an annular floating body with a through-hole in the center when viewed from vertically above (see, for example, Non-Patent Document 3). This configuration utilizes the vibration of water confined within the annular floating body for stabilization. However, in this structure, at certain frequency bands, the water mass within the moonpool has an out-of-phase effect on suppressing the vertical motion (heave) of the floating body, resulting in an increased vertical motion. Similarly, at certain frequency bands, it has been pointed out that the water mass within the moonpool causes sloshing, increasing the motion of the rotational system (pitch in forward waves, roll in transverse waves) (see, for example, Non-Patent Document 4). Ministry of Land, Infrastructure, Transport and Tourism, Ports and Harbors Bureau website, "Study Group on the Ideal Form of Base Ports for Achieving Carbon Neutrality by 2050 (1st Meeting), May 18, 2021, Document 3, p. 37," [online], [Accessed March 15, 2022], Internet <URL: https://www.mlit.go.jp/common/001404624.pdf>National Research and Development Agency, New Energy and Industrial Technology Development Organization (NEDO) website, "Supplementary Materials to the Guidebook on Floating Offshore Wind Power Generation Technology, National Research and Development Agency, New Energy and Industrial Technology Development Organization, March 2018, p. 129," [online], [Accessed March 15, 2022], Internet <URL: https://www.nedo.go.jp/content/100891425.pdf>"Study on the motion characteristics of various floating body types," Yuka Kikuchi et al., Wind Energy Utilization Symposium, Vol. 39, pp. 315-318, 2017."A Study on the Effect of Moonpools on the Motion Characteristics of Pontoon-Type Floating Bodies," Hayato Moritsu et al., Proceedings of the 2019 Academic Conference of the College of Science and Technology, Nihon University, pp. 669-670, 2019. Figure 1 is a schematic perspective view showing Embodiment 1 of the floating structure according to the present invention, where (1) is a view from diagonally above and (2) is a view horizontally from the waterline.Figure 2 is a schematic perspective view showing Embodiment 2 of the floating structure according to the present invention.Figure 3 is a schematic perspective view showing a modified example 1 of the floating structure according to the present invention.Figure 4 is a schematic perspective view showing a modified example 2 of the floating structure according to the present invention.Figure 5 is a plan view showing an example of wind turbine installation work on a quay. The fol