A feasibility study by the UK’s Energy Technologies Institute concludes that deepwater floating wind turbines would be able to take advantage of stronger, more consistent wind speeds.
Current offshore wind turbines are mounted on fixed foundations, which would not be suitable in deepwater. Instead, in water 70-300 m deep, turbines could be mounted on floating, tension-legged platforms.
“The traditional view is that the cost of offshore wind becomes increasingly more expensive as turbines are located in deeper water,” says ETI chief executive, David Clarke.
But while the costs of foundations do indeed increase in deeper waters, wind speeds are significantly stronger resulting in more reliable and higher energy output. Over time, the increased output of deepwater turbines more than outweighs the additional costs.
“This project has shown that it may be possible to use floating turbines to exploit deeper water sites off the coast of the UK… to produce electricity at a similar cost to existing and proposed offshore sites in shallower water up to 40 m,” says Clarke.
The study, Project Deepwater, was launched in January 2009 and has been carried out by a consortium led by wind farm developer Blue H with BAE Systems, the Centre for the Environment, Fisheries and Aquaculture (CEFAS), EDF, Romax Technology, SLP Energy and PAFA Consulting Engineers.
The waters off the west coast of the UK could be particularly suitable for deepwater installations, says Neal Bastick, CEO of Blue H.
The ETI says it will decide on the next steps in its offshore wind programme, which could include funding for a demonstrator project, after two more feasibility studies report back their findings. These projects, Nova and Helm Wind, are looking at the benefits of innovative vertical axis turbine and potential designs for offshore wind turbine arrays, respectively.
The first floating wind turbine, Hywind, was inaugurated by Norwegian energy company StatoilHydro in 2009 in deep waters 10 km off the island of Karmøy in northern Norway for a two-year test run.