The design by Dutch company 2-B uses two blades rather than the standard three, an innovation it says could dramatically reduce the time required for turbine installation and cut the long-term cost of generating power.
The firm's's two-bladed machine has been in development since 2006 and has already been heralded as potentially revolutionising the design of offshore turbines (Windpower Monthly, September 2008).
Chief executive Mikael Jakobsson said that the design has a number of advantages over standard three-blade models, not least the fact that it is quick to install. "When you go offshore you always have an issue with the installation of the third blade," he says. "Everyone's trying to figure out ways of managing this process."
Each blade of a three-bladed model has to be attached individually to the turbine rotor. This results in installation times of seven to eight metres per second. But a two-bladed turbine can be transported in one piece and installed in a single lift, allowing installation times of 12-13 m/s, Jakobsson explains.
"If you are further offshore and installing hundreds of machines, this process dramatically reduces the weather window and the cost of expensive equipment that will be sitting offshore and, therefore, the total project time," he says.
The use of two blades is only one element of the 2-B design. Jakobsson says the proposed machine is also upwind rather than downwind, meaning the blades bend away from the tower and eliminate tower clearance issues. The overall design of the turbine aims to minimise operations and maintenance, which reduces the whole-life cost of the machine and, therefore, the cost of the energy it generates.
The design is now poised for trials following an announcement in August by the Crown Estate, which owns and manages the UK seabed, that it has given permission for the development of four test sites aimed at demonstrating the viability and effectiveness of new offshore technologies.
Two of the sites will be in English waters, with the Crown Estate awarding leases to the New and Renewable Energy Centre (Narec) in Northumberland and to a UK-based subsidiary of Dong Energy to develop facilities.
Narec, which has also received an ú18 million grant from the UK government to develop a test facility, has been given the green light to press ahead with its Blyth offshore demonstration site. This will offer a 100MW grid-connected site to test up to 20 pre-commercial offshore turbines.
The organisation says it has already received a number of inquiries from manufacturers looking to occupy the limited spaces. It plans to have the first turbines installed by 2013.
Meanwhile, Dong Energy will test up to two next-generation turbines in an extension of its Gunfleet Sands offshore wind farm, the first phase of which is already operational.
The other two sites will be developed in Scottish waters. Two of 2-B's turbines will be tested at the Methil wind farm off the coast of Fife in Scotland. The European Offshore Wind Employment Centre off the coast of Aberdeen will be used to test up to 11 next-generation wind turbines and other technologies. The facility will be operated by Aberdeen Offshore Wind, a company 75% owned by Danish manufacturer Vestas.
According to the Crown Estate, the awarding of leases to the offshore test sites will help companies develop the necessary technologies to support the planned growth of offshore wind energy in the UK.
"Technical innovation is essential to cutting offshore wind costs," says Rob Hastings, the organisation's director of marine estate. "Awarding the four sites supports the growing UK offshore wind industry's efforts to demonstrate new offshore wind turbines and other technologies in the marine environment."
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