Another concept design for a floating offshore wind turbine, but this time packaged as a mode switching spar buoy type structure. Initially a sketch on a post-it note, the central idea was to create a design that would allow for a vertical axis wind turbine arrangement but with the three large blades set on buoyant hulls that would allow for the load of those blades to be in some part removed from the central column.
Towing mode
The initial aim was to create a design that allowed for the wind turbine to be towed to the field with the blades in what would be a retracted position with their pivoting hulls forming a barge-like structure around the central column. This required some trial and error to form shapes that would come together in this way while operating with pivoting joints and connection points.
Below the water line the submerged section of the turbine tower can be seen, with some general design to illustrate a spar column, counter balancing the surface parts of the structure. Some nods are given to spar design features here, but in general the overall form is purely indicative for the purposes of communicating the concept.
Arrival at the field
Upon reaching the site for installation the wind turbine would be positioned accurately with the assistance of three vessels each rigged to the structure in the three sections. At the site the subsea infrastructure will have been installed previously ready for the arrival of the topsides element. A submerged buoy with mooring lines in place and flexible umbilical would be at a depth for the turbine to be brought into position.
Time was spent modelling a suitable subsea arrangement for the animation, but again this is purely illustrative and intended to help explain the sequence of events. However, technology such as this is currently in use with subsea arrangements being deployed and installed prior to the arrival of topside assets.
From here the turbine would be connected up with the submerged structure to form a complete system – this is very much a concept design opposed to a fully engineered plan but nonetheless helps show how flexible a design such as this could be with options for disconnecting turbines and replacing them in the future as needed with the subsea infrastructure remaining in place.
Switching to production mode
With the turbine connected to the subsea elements and anchored into position, the vessels would now be used to deploy the blades, switching the structure to production mode. With the rigging in place, each vessel would haul their respective blade/hull assembly out and away from the central column.
As they do so, the central column would lift up out of the water, rising and taking the subsea elements with it. A lift of around 25m is required in this particular concept in order for the blades to be fully deployed. The tubular frames between the central column and the blades are all pivoted at their connection points allowing for the required range of movement. The blades would be connected to rotating “hubs” at two locations on the central column where the generator would operate.
This concept is entirely unconventional but that is the point where disruptive thinking is intended to spark other ideas that can form more practical approaches.
In this view the formation of the blades, hulls and connecting frames can be seen with the vessels hauling the blades away from the central column. The design of those hulls (in yellow) is such that they can come together and fit around the central column with cut-outs for the tubulars.
Riding on the waves
Once operational the purpose of the concept can be seen with the three large blades each riding on the waves via their hulls, with pivoting joints allowing for those hulls to rotate to suit the sea state. Each of the three blade assemblies are free to ride up and down independently with the load taken off the central column and the generators within and onto those floatation hulls. The idea here was to try and address one of the main issues with vertical axis wind turbines where much of the load of the structure is having to be carried by the central column and the mechanical parts within. Drag or friction has been added here with this concept however using those hulls.
Here the full design subsea can be seen with the blades rotating above and their hulls riding across the sea surface.
Hopefully this concept demonstrates some disruptive thinking but also how 3D modelling of very simple ideas can be achieved and brought to a point of effective visualisation. Ideas can be fully formed from rough sketches and discussions, even without CAD drawings or dimensions, with animations produced showing concepts in context and in high quality, ready for presentations and promotional material.
If you or your company have early stage concepts that you would like to develop further, in topics such as renewables or energy production in general, then please have a look across this website and get in touch using the Contact page or watch the full animation for this wind turbine concept below.
