£7m wind turbines at standstill over radar fears

Two wind turbines which were installed six months ago have still not been switched on because they interfere with radar systems at a nearby airport.

The pair of 130m tall turbines in Spondon, Derby, which cost a combined £7 million, were designed to produce 10,000 megawatts of electricity – enough to power 3,000 homes.

But the rotating blades pose a problem for air traffic controllers because they cause a blinking signal to appear on radar screens at nearby East Midlands Airport and obscure genuine aircraft.

Severn Trent Water, which operates the turbines in Spondon, Derby, said it was now working with the airport to install extra radar technology and hopes to combat the issue “as soon as possible”.

But local residents are furious the equipment was installed before it was ready for use, claiming it has scarred the landscape without bringing any benefit.

Ray Mellor, 80, said: “The thing is they went up with such phenomenal speed. I can't see why it has been so prolonged.

“If they are not producing energy yet, then they have no benefit. I'm not very impressed with it and it's not good enough. I also think they are hideous and spoil our views.”

Terry Rogers, 55, added: “It's the start of May and they're still not spinning. They'd be more use as washing lines.”

Wind turbines are problematic if they infringe on controlled airspace because radar signals can be deflected by the giant blades, making them appear like aircraft to air traffic controllers.

Because the blades are constantly moving the signals frequently disappear and reappear, making it even harder to distinguish them from aeroplanes.

NATS, the national air traffic controller, says in more than 90 per cent of cases it does not object to wind farms but in the remainder where they are too close to radar sites, allowing the turbines to operate would compromise safety.

It has recently developed a solution to the radar problem, which has occurred at several sites across the UK, using a second radar from a different angle to wipe the turbines off the map.

Where there is no second radar nearby wind farm developers can face paying millions to install a new facility, although in some cases alterations to the existing radar and software upgrades are able to filter out the signal.

David Hawken, engineering director at NATS told the Telegraph: “What we could not tolerate until quite recently is developments quite close to a radar site, and because our radars are generally on top of hills around the country they are also sites that are windy and attractive to wind farm developers.

“We have got a solution now that we worked on with the suppliers of our radars that can mitigate some of the developments.”

A spokesman for East Midlands Airport said: “The airport is currently working alongside Severn Trent Water and a technology provider to install radar technology that will mitigate any effect that their wind turbines will have on the radar at the airport.

“Safety at East Midlands Airport is paramount and will not be compromised, which is why it is essential that the technology is in place, before the turbines can fully operate.”

Martin Dent, Severn Trent's renewable energy manager, said the radar technology was required as part of the planning permission which was granted for the turbines.

“This equipment is needed to maintain the safe operation of the airport when the wind turbines are operating,” he said.

“Even though they are located 10km from the airport, the turbines are still within the controlled airspace of East Midlands and therefore they need to have some specialist equipment fitted to enable them to run.”