Dutch specialist vessel builder IHC Merwede has designed two innovative vessels and a blade installation system.
Dutch specialist vessel builder IHC Merwede has designed two innovative vessels and a blade installation system in readiness for the forthcoming dramatic expansion of offshore wind farms. These include offshore wind vessels specifically designed for jacket installation, turbine installation and blade installation. The company is convinced that such thinking 'outside the box' is going to prove vital for a new industry where it is said that to build the UK's Round 3 wind farms alone there will be 5,000 5MW turbines to install, with a similar figure expected for the rest of Europe.
All three of the conceptual designs have one aim, to improve the safety and efficiency of offshore wind turbine installation.
The IHC Merwede offshore wind vessel designed with jacket installation in mind provides a stable, cost effective and efficient means of installing jacket foundations for future offshore wind farms. The floating system is independent of water depth and seabed conditions so avoids the need for time consuming jacking operations. Installation of jacket piles is achieved by the use of an onboard mobile crane. In the present configuration the concept allows the load out of four jackets simultaneously.
To allow rapid mobilisation and deployment, the jackets are secured to the vessel using hydraulic seafastenings, and are transferred to and from their stowage positions by two mobile lifting gantries. Gantry movement is achieved using standard skidding units.
The second vessel designed for the offshore wind market is the turbine installation vessel. This is a self propelled jack-up vessel with dynamic positioning capability, and will be able to transport and install multiple fully assembled wind turbine generators. The vessel incorporates a rotating installation system that is able to lift and transfer wind turbines from their stowage positions to their offshore foundations, safely and efficiently. Turbines are then seafastened using radial, hydraulic clamping systems.
The third concept is for a dedicated blade installation system. Blade installation is a critical phase of offshore wind construction, due to the sensitivity of the lifted blade to wind, its vulnerability and the accuracy required to properly align the blade and hub flanges.
The Blade Installation System has been developed to improve the safety and efficiency of blade installation operations, and can be used in conjunction with a wide variety of installation vessels and techniques.
Ideally the system is mounted onto a tower and loaded with blades at port, with the tower and blades transported vertically to site for installation. Alternatively blades and towers can be transported to site and the system mounted around the tower and loaded with blades on the vessel's deck, prior to installation to the foundation.
The system is secured to the tower using two sets of friction clamps.
The clamps are linked with hydraulic cylinders that create a walking action to drive the carousel upwards and downwards as required. Each of the three blade grippers features hydraulic actuation to allow precise alignment of the blades within the hub.
IHC"s UK subsidiary IHC Engineering Business (EB) continues to support the development of tidal stream technology. Engineering Business Consultancy (EBC) has recently completed the 4th phase in a programme of studies for German hydro power specialists Voith Siemens Hydro.
This latest phase has seen EB focus on the development of a specialist handling system to allow the installation and retrieval of a modular tidal turbine from a standard offshore barge. The system will be deployed for the first time in 2009, when Voith is due to install and maintain a 1/3 scale tidal turbine between the Korean Islands of Jindo and Hajodo. This pilot project is the precursor to an ambitious project to build a tidal power plant with a nominal output of 600 MW in Korean waters.