The remaining four turbines have been delivered and installed, meaning the full introduction of the eight-turbine wind farm can begin later this year.

The controversial plans to build the £13m wind farm at Knabs Ridge south of the A59 Harrogate to Skipton road is the first development of its kind in the district and the newest wind farm in North Yorkshire for 15 years.

But the scheme has not been without its problems. In November 2004 when the application came before Harrogate Council there were objections from local parish councils, Nidderdale AONB's Joint Advisory Committee, the Campaign to Protect Rural England, North Yorkshire County Council, the Ramblers' Association, Harrogate Civic Society, Civic Aviation Authority and Leeds-Bradford Airport.

Nidderdale Against Wind Turbines, formed in protest to the development, submitted 300 letters of objection while those in favour of the plans sent more than 100 letters and 205 petition signatures to the council.

Once approved at a public inquiry in 2005, it was hoped all eight turbines would be functional by December 2007, but a series of problems saw the last four being finished just last week, more than half a year behind schedule.

Npower Renewables hopes the eight wind turbines, located in the 197-acre site outside the Nidderdale AONB, should generate 16 megawatts of electricity – enough for around 5,400 homes.

Npower renewables' project manager for the Knabs Ridge wind farm, Tim Daldry, said: "The building of Knabs Ridge Wind Farm is a substantial step forward for renewable energy provision in North Yorkshire and will make a valuable contribution towards the fight against global warming.”

Experts calculated the potential output of the wind farms by using wind speeds monitored in the local area.

This enabled project managers to estimate the average annual energy production for the site based on eight turbines each generating 2 megawatts of energy.