The aim of the project is to develop a new cost-effective floating offshore wind turbine that will reduce bottom disturbances at water depths of 30-100 metres. The floater will use a commercial but gigantic wind turbine of up to 20 MW. It is anchored to the bottom with a single anchor and a single mooring line with integrated electric cable. Thus, it is rotating around the anchor point. The floater including turbine have a limited draft and will be very easy to install using a tugboat. In addition, it can simply be towed ashore if extensive maintenance is required. Not at least, it will be easy to remove.
The floater has been given a shape which is directionally stable and will resist the weather in close interaction with the anchoring system. It will be stable even with a very large turbine. Typically a generator height of 137 meters above the water surface.
The floater can be assembled at yards with shallow water depths, which opens for series production in many countries. The assembly will utilize existing shipyards to keep the cost low.
In the project, the development company GFMS will recieve support from important offshore wind operators such as Vattenfall, Fosen Yard (production) and APL (anchoring system). In addition, some important expert companies such as Norconsult, SIMIS, EDR&Medeso and CFDMarine will be partners in the project. The technical university NTNU will contribute with both model tests and studies.
After qualification of the most important elements of the concept, further work will be towards detailed design and prototyping. This is planned over a five-year period. There will be a large marked for the concept in the Baltic Sea and the North Sea. Due to flexible fabrication, the concept is targeting towards a large world market.
WindBarge is at present a floater design with single line mooring developed for large offshore wind turbines from at least 15 MW. The design enables floating wind turbines in water depths from 30 to 100 meters. These are depths with a large energy potential in the shores surrounding Europe, USA and other areas like the Taiwan Strait. It is especially suited for the Northern Sea and Baltic Sea supporting the ambitious plans for 120 TWh annual offshore wind production in Sweden and thus compete with bottom fixed technology. Due to its simplicity, the WindBarge will significantly reduce the costs for production, installation, maintenance and removal of offshore wind turbines. The cost of energy is targeted to reach the same level as the established bottom fixed offshore wind technology.
The combination of the single line mooring system, the triangular shape and the barge simplicity will reduce the cost of the floater by utilizing shipyard types of production facilities and cost-efficient integrated installation bayside on the yard. The shape has a stabilizing effect on the weather vanning capabilities of the mooring system, and it increases the ability to protect access vessels and thereby increase the weather window for access vessels.
There are several research challenges related to the novel approach of the design since some risks must be addressed to obtain radical cost savings and yield improvements. The project will develop a method for an optimal design of the triangular shaped floater and single line mooring with the integrated electrical cable using advanced numerical modelling tools. Focus is also on reducing loads on the turbine with the use of the simulation program SIMIS. Experimental verification will be performed by NTNU and supported by comprehensive numerical CFD simulations.
Vattenfall, with an interest in pursuing the barge based conceptual design for shallow water depths with a potential available demonstration site ready for deployment, will ensure relevance and competitiveness in all planned activities.