December 1, 2009

Top Plants: Hywind Floating Wind Turbine, North Sea, Norway

Angela Neville, JD

Technical Innovations

Henrik Stiesdal, chief technical officer of Siemens Wind Power told POWER in October how the Hywind Floating Wind Turbine Project benefited from recent design innovations.

"The attractive simplicity of the Hywind slender cylinder concept comes at a price," Stiesdal said. "It is moored and sits on a floating foundation, and the motion of the sea causes the tower to pitch. Such pitching movements add to the fatigue loading of the structure."

Creating solutions for a floating structure has been one of the core elements of the Hywind concept, Stiesdal explained. As a consequence, an advanced adaptive regulation has been developed, using the pitch system of the rotor blades to stabilize the movements. That development both improves power production and minimizes loads on the blades and the tower. The software that controls this process is able to measure the success of previous changes to the rotor angle and uses that information to fine-tune future attempts to dampen wave-induced movement.

Permitting Issues

The regulatory framework for offshore wind turbine projects in Norway is not yet in place. The consultation paperwork for legislation on offshore renewable energy production was set for public hearing in February 2009 but has not yet taken place.

"Lack of regulations for offshore wind has been a challenge for the Hywind Project," Bratland said. "Close cooperation with The Norwegian Coastal Administration and The Norwegian Water Resources and Energy Directorate has been necessary for solving several challenges linked to the installation of the Hywind demonstration project such as the location of cable and installation and highlighting of the floating wind turbine."

Because this is a two-year research and development project, only a short version of the standard application for onshore turbines was required, Bratland explained.

If this innovative project is successful, we may see Norway became famous not just for its Vikings but also for a new type of ocean-focused activity that increases the nation’s prosperity.