Energy experts claim the two controversial wind turbines in Spondon could have provided nearly two thousand homes with electricity if they were working.
A spokesman for Enviko Renewable Energy Solutions revealed the stats to the Derby Telegraph yesterday.
It has been more than 450 days since the turbines were erected in Megaloughton Lane.
The spokesman said that figure would have been calculated from when they were first installed, in December 2013, to now.
When installed, it was found the turbines are located in a “sensitive area”, which means when they are switched on, they appear as unidentified objects on the air traffic control display at East Midlands Airport.
Ray Mellor, a long-term critic of the turbines, said he questions if they will ever work.
He said: “I’m not surprised they are still not working, in fact it wouldn’t surprise me if they one day have to be removed.
“It’s terrible. I’m not a fan of wind turbines anyway, I don’t believe they are efficient. But I live in Spondon and I think everybody questions, and is frustrated, by their lack of progress.”
Spondon councillor Evonne Williams residents in the village “were getting tired of this saga”.
She said: “We all know they could be producing that much energy, if they were working.
“People want to know if they will start working or go away. I want them to stay and work and I believe testing needs to take place to ensure they are safe.
“People have got used to them being there and being part of the landscape, and now they want to see them work. I’ll support them unless it comes out that they can’t work, in which case it will be a colossal and a total disaster.”
A 3D holographic radar system has been installed to try to resolve the problem. But there is still no date for when they will be fully operational.
A spokesman for Severn Trent said any figures were estimates and it said it was working closely with East Midlands Airport and radar specialist Aveillant.
He said the turbines will be tested and generate power intermittently as part of the development and installation of the world’s first 3D radar system.
Moves to build the turbines began in 2007 and planning permission was granted in 2012. But building them was not a straightforward process and lifts and motors needed to be installed before power could be sent to the National Grid.
Among local residents’ main concerns was the prospect of noise, but these fears have been largely allayed during testing, although Severn Trent said it would be monitoring the situation.