A new collaboration between Denmark Technical University (DTU) and international partners from the wind industry and research community will explore the idea of 20-MW floating turbines. The 4-year project called DeepWind was launched October 1, with Risø DTU coordinating the consortium of 12 international members.
“Our objective is to develop more cost-effective offshore wind turbines, rather than advance existing concepts that are based on transporting onshore technology to the sea environment,” says DeepWind Project Manager Uwe Schmidt Paulsen. “Offshore wind energy today is twice as expensive as onshore technologies. That means that there is plenty of room for improvement.”
Studies show that for sea depths exceeding 30-60 m, floating structures are economically more feasible than present offshore technology based on piled, jack-up, or gravity foundations. Members of the consortium say the cost of material and logistics used in these constructions is simply too high. Furthermore, floating wind turbines will open up the possibility of placing offshore wind turbine plants with excellent wind potential near large cities with a deep-water coastline in, for example, Europe, Asia, and North America.
Risø DTU scientists explain that the concept combines a vertical-axis wind turbine, new blade technology, and full power transmission and control system combined with a rotating and floating offshore substructure. The basis for the vertical-axis wind turbine is the Darrieus design. This provides a very simple MW turbine, but also contains challenges, including the long sub-sea support structure needed. The concept also includes a direct-drive MW generator with its electronic control system at the bottom of the sub-sea shaft, together with the electrical power transmission cables. Combining the relevant technologies and designing the components properly will positively re-address the issues of distribution, cost, and competitiveness of the concept compared to existing technology.
Paulsen says the technology behind the proposed concept requires technological breakthroughs. “We need explicit research in a wide area of different technology fields and materials,” he says. “For example, we foresee research in the dynamics of the system, pultruded blades with adequate material properties, sub-sea power generators and converters, turbine control and safety systems, wave and current loading on the rotating and floating shaft, and also the mooring and torque absorption system.”
Researchers say one of the definite outcomes of this project will be the demonstration of a kW-sized wind turbine to be placed in open waters of Roskilde Fjord next to Risø DTU. In this phase, dedicated experiments will be carried out and simulation tools will be developed for design purposes. These will be used to design a 5-MW concept and evaluate the prospects of an up-scaled, future 20-MW turbine.
Filed Under: Offshore wind, Turbines