Current Status of Large Output Offshore Wind Turbines
There are a number of wind turbine manufacturers in Europe developing 4 or 5MW output wind turbines in response to the UK Crown Estate offering large areas for lease and development of offshore windfarms. (The Crown Estate is the landowner of the seabed and foreshore within British territorial waters and leases areas to windfarm operators for development among other things to offshore windfarms).
These areas are the farthest from the British coast and in the deepest waters so far allocated by the Crown Estate for windfarm development.
This means that larger capacity wind turbines can be used because of the increased wind velocities available. However because of the depth of water, the turbines will have to be mounted on typical tried and tested oil and gas structures that will either be fixed to the seabed using a conventional steel jacket of a floating structure such as a semi-submersible.
Below are sketches of a fixed steel jacket and a floating structure from the author’s experience in the offshore oil and gas industry. These are suitable supports for large capacity wind turbines as they move out into deeper waters.
The large output of power will be transmitted by subsea cables, and to prevent loses the power will be converted to High Voltage Direct Current (HVDC) using the latest state of the art Voltage Source Converter (VSC) system, such as the Siemens 800MW capacity VSC.
This will be installed on a moored floating platform along with the rest of the electrical equipment required by the VSC system. The author's interpretation of this is shown below.