Gravity Base Offshore Wind Turbine Installation via Removable Caissons
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Solution Overview
Problem
The installation of large offshore wind turbines poses challenges due to the need for significant crane capacity and high costs associated with transporting and installing massive support structures, which are difficult to assemble and operate at sea.
Innovation Solution
A method involving a gravity base with flotation elements, where additional buoyancy and ballast boxes are used to facilitate towing and immersion, allowing for controlled ballasting and deballasting to stabilize and position the structure on the seabed without requiring large cranes, and enabling easy recovery of the flotation elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional traction lifting means with crane-type lifting equipment are used to install gravity base structures, then the support structures can be installed on the seabed, but large cranes with height greater than the structure are required, which are difficult to assemble, transport, and operate at sea
Solution Approach 1:
The invention uses buoyancy as a counterweight force to the gravity base structure. By attaching flotation elements to the structure, buoyant force is generated to offset the weight of the structure, enabling it to be lifted and positioned without requiring large cranes. This transforms the installation problem from a heavy lifting challenge to a controlled buoyancy management process.
Solution Approach 2:
The invention introduces flotation elements as an intermediary between the gravity base structure and the installation vessel. These elements serve as a mediator that transfers the structure from a heavy, crane-dependent object to a buoyant, easily transportable unit. The flotation elements enable the structure to be towed to the installation site and then controlled to settle on the seabed without requiring complex crane operations.
2Ease of operation
If large crane means are used to transport and install gravity base structures at sea, then the structures can be positioned on the seabed, but the costs of transporting and installing massive support structures increase significantly
Solution Approach 1:
By using buoyancy to counteract the weight of the gravity base structure, the invention eliminates the need for expensive heavy-lift crane operations. The buoyant force naturally supports the structure during transport and installation, converting a high-cost mechanical lifting operation into a low-cost buoyancy-controlled process.
Solution Approach 2:
The flotation elements enable the gravity base structure to be self-floating and self-positioning. Once the structure is equipped with flotation elements and towed to the installation site, it can be controlled to settle on the seabed through ballasting or releasing buoyancy, without requiring expensive external crane assistance for the actual installation.
3Reliability
If gravity base structures are made solid or filled with ballast means to ensure anchoring by weight, then the structures provide stable anchoring, but they require large crane means to install them because they do not float
Solution Approach 1:
The invention makes the gravity base structure dynamically adjustable in terms of its buoyancy characteristics. By attaching flotation elements that can be ballasted or de-ballasted, the structure can transition between floating and sinking states. This dynamic control allows the structure to float during transport for easy installation, then settle on the seabed for stable anchoring, combining the benefits of both floating and heavy anchoring.
Solution Approach 2:
The invention changes the physical parameter of the structure's overall density by controlling the ballast water in the flotation elements. When the flotation elements are empty, the structure has low density and floats. When ballast water is added, the density increases and the structure sinks to the seabed. This parameter change enables the structure to adapt its buoyancy state according to the installation phase.
4Quantity of substance
If hollow box bases are filled with sea water during immersion to reduce material quantity and cost, then the bases are lighter and require less material, but they still require large crane equipment to install them
Solution Approach 1:
The invention applies buoyancy as a counterweight force to compensate for the reduced weight of the hollow box structure. By attaching flotation elements to the hollow box base, the structure gains sufficient buoyant force to float and be towed to the installation site without requiring large cranes, while still using minimal structural material.
Solution Approach 2:
The flotation elements serve as an intermediary that enables the hollow box structure to be transported and installed without large cranes. These elements provide the necessary buoyancy to tow the structure to the installation site and control its settlement on the seabed, eliminating the need for expensive heavy-lift equipment while maintaining the material-efficient hollow box design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method reduces the need for large crane operations, lowers installation costs, and provides a stable and efficient means to deploy wind turbine support structures, optimizing material usage and simplifying the installation process.
Implementation Method 1
a plurality of second hollow buoyancy and ballast caissons are removably fixed to the external surface of said first block or first gravity caisson
Implementation Method 2
in step a), at least a portion of said second caissons are at least partially emptied, and in step b), sea water is added to said second caissons to lower said base to the seabed
Implementation Method 3
a gravity base comprising a first solid block or preferably first hollow caisson filled at least partially with ballast means, resting on the seabed and ensuring anchoring by its own weight
Data Source
Figure 1A
Figure 1B~2B
Figure 2A
AI summary
The invention relates to a method for transporting and installing an underwater structure on the seabed, said underwater structure being intended to support and anchor marine equipment and comprising a gravity base (1) including a first solid block or first hollow caisson (2) having an upper outer surface (2b) and a side outer surface (2a), said method comprising the steps of: a) towing the base (1) equipped with flotation elements, and subsequently b) lowering the base to the seabed, characterised in that: prior to step (a), a plurality of second caissons (3, 3-1, 3-2) are removably secured to at least part of the aforementioned outer surface; in step (a), the second caissons are at least partially emptied; in step (b), the second caissons are filled with more seawater; and, after step (b), the second caissons are detached and emptied, such that they float back up to the surface (10).