Successful trial of composite 'stealth turbine' opens up "9GW" of wind potential
Thursday 22 October 2009
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| On test: The stealth turbine was recently trialed at Swaffham, Norfolk |
A successful trial of a "radar friendly" wind turbine was announced today (October 22 2009), which could prevent radar operators confusing the moving blades for aircraft and shipping and so reduce objections to planned wind farms, writes Will Nichols.
Wind manufacturer Vestas and technology company QinetiQ said they have successfully developed the radar friendly turbine - known as a the stealth turbine. A 44m long prototype blade was trialled last week at a wind farm owned by energy company Enertrag UK at North Pickering, near Swaffham, Norfolk (see this NewEnergyFocus.com story). This was a culmination of a five year, £1 million project - supported by £400,000 of funding from the government funded Technology Strategy Board.
QinetiQ claim that the ‘stealth turbine' technology can significantly reduce the size of the radar signature made by individual turbines to the point where they can be effectively ‘factored out' of air traffic control and air defence systems.
It was revealed on Friday that the Ministry of Defence (MoD) has objected to 51 wind farm applications for radar related reasons since January 2008, and QinetiQ estimate that this technology could open up 9GW of potential sites currently blocked by objections from radar operators.
"We believe that Stealth Turbine technology could be a genuine game-changer for the renewable energy industry by removing a major barrier to its development," said Mark Roberts, strategic business director at QinetiQ.
Technology
Dr Dave Moore, business development manager at QinetiQ told NewEnergyFocus.com that the metal of the surface and internal structure of the wind turbine reflects the radar. Blade tips moving at almost 200mph can be mistaken for aircraft, causing radar operators to divert other air traffic in the vicinity.
Dr Moore said this problem can also affect shipping, where offshore wind farms can fool ships' radar operators into thinking that the turbines are other ships.
The 'Stealth Turbine' uses a modified composites for nacelle and blades, and sprayable RAM coatings that can be applied directly onto the tower and other static surfaces. Dr Moore said that this adds a marginal weight, but most importantly can be integrated into the current manufacturing processes for turbine components.
Weight has to be controlled as the heavier a blade is, the more energy it takes to turn it and the less it generates. The trial in Norfolk saw one 'stealth' blade fitted with two normal blades onto a Vestas V90 turbine - an increase in weight would have unbalanced the turbine and caused wear problems if the trial had not been successful.
Research
On Tuesday Energy and Climate Change secretary Ed Miliband announced that £5.15 million was to be spent on a research project in conjunction with the Crown Estate, wind companies, and a group of developers aiming to solve the problem of radar interference from wind turbines (see this NewEnergyFocus.com story).
This project was prompted by objections to wind farms made by the UK's leading air traffic control provider, NATS, as well as the Civil Aviation Authority. On Friday, defence minister Kevan Jones revealed that the MoD was consulted on 3,502 pre-planning applications between January 2006 and October 7 2009 and had expressed concerns to 1,054 of them "on the grounds of interference with defence equipment and or operations."
After a successful trial of the 'stealth turbine', the two companies will be looking to move the blade into production soon, possibly as early as next year.
"We are in dicussion about how we move to the next stage. Vestas will decide production dates but we're hopeful that within the near future a mitigation solution will be out there," Dr Moore said.
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