May 27, 2008 The world desperately needs viable sources of renewable energy and wind power is among the most promising solutions, but one downside is that the erection of large numbers of huge turbines can be considered a blight on otherwise picturesque landscapes. The solution seems obvious enough - move the towers far out to sea where not only are they out of sight, but where the wind is at its strongest and most consistent. We first encountered this idea back in 2006 when we examined the efforts of MIT researchers to integrate a turbine with a floating platform similar to those used by offshore oil rigs. Now news that Norwegian oil and gas company StatoilHydro plans to invest around US$80 million to build a full scale offshore floating wind turbine. Known as HyWind, the system will be tested over two years, with the project due to commence in mid-late 2009.
HyWind is based on the use of floating concrete constructions similar to those used in North Sea oil installations. The project will see a 2.3 MW wind turbine attached to the top of a “Spar-buoy”; a solution used in production platforms and offshore loading buoys.
The rotor blades on the floating wind turbine will have a diameter of 80 meters (262 feet), and the nacelle – the part of the turbine that houses the generating components – will tower some 65 meters (213 feet) above the sea surface. The flotation element will have a draft of some 100 meters (328 feet) below the sea surface, and will be moored to the seabed using three anchor points. The wind turbine can be located in waters with depths ranging from 120 to 700 meters (394-2,297 feet).
Alexandra Bech Gjorv, head of New Energy for StatoilHydro, said that the decision to take wind turbines to sea was primarily driven by environmental factors. “The wind is stronger and more consistent, areas are large and the challenges we are familiar with from onshore projects are fewer,” he said. However, one of the issues the research will need to overcome is the ability of the turbine to function optimally even in large waves.
StatoilHydro has already successfully tested a three meter (almost 10 feet) high model in SINTEF Marintek’s wave simulator pool in Trondheim. The 5,300 ton full scale turbine will be constructed by Siemens with Technip building the flotation element and taking responsibility for the offshore installation.
The HyWind-prototype will be situated around 6.2 miles off the west coast of Norway with the goal of proving the technology and reducing costs to a level that will make floating wind turbines a viable competitor with other energy sources.
“If we succeed, then we will have taken a major step in moving the wind power industry offshore. Floating wind turbines can make a major contribution to providing the world with clean power, but there are major technical and commercial challenges that need to be resolved. If we are to succeed, we will need to cooperate closely with the authorities. As with other technologies for renewable energy, floating wind power will be dependent on incentive schemes to be viable,” says Alexandra Bech Gjørv.
The news follows another recent announcement in the field of offshore wind farms - the Greater Gabbard Offshore Wind Farm Project in the UK that will have the ability to supply energy to more than 400,000 homes.