In August 2008, the Crown Estate of the UK purchased Clipper’s 7.5 MW Britannia turbine for testing in its laboratory. Following successful tests, Clipper is planning to open a manufacturing facility in the UK and planning to produce its 7.5 MW turbine in the third quarter of 2010. In 2012, the company is expecting to produce a 10 MW, 145 metre prototype turbine for Round 3 offshore projects.
Clipper has thus far received a GBP 4.4 million grant from the UK government to develop this turbine. This design is based on its 2.5 Liberty model, which uses a lightweight two-stage helical design with four permanent magnet generators and has lower individual gearbox component loads than conventional models. It is expected that the gearbox for the turbine will weigh 36 tonnes, half that of a conventional turbine of the same capacity. Carbon fibres will also be used to keep the weight down.
Competition to this turbine will be Sway’s 10 MW, 145 metre floating turbine, which is still in the development stages. Sway is a Norwegian consortium including Statoil, Statkraft, Shell, Lyse and Inocean as partners. The consortium is developing its turbine using a NOK 137 million (EUR 17 million) grant from Enova, the Norwegian state utility. The turbine has already undergone two years of testing on land. Once operational, it should capture more energy than existing models, as it will be piloted at a site 50 km off the coast of Norway in depths of 100 to 300 metres where wind conditions are considerably better than those at the Horn’s Rev Site.
As well as developing their own project, Sway and Areva Wind are collaborating to adapt Areva’s 5 MW turbine model for a floating offshore installation.
Research on the economics of a 10-MW direct-drive offshore turbine is being conducted by the US Department of Energy in collaboration with American Superconductor. As part of the collaboration they have developed a 10 MW turbine.
There are some early signs that a 15 MW may be feasible and commercially viable. The UK’s New and Renewable Energy Centre (Narec) announced plans to build a 15 MW wind turbine and nacelle testing facility in Blythe, Northumberland. The facility is expected to be operating by the end of 2011. As mentioned earlier Upwind has developed a 20 MW prototype, but there are significant barriers to its deployment.