Today, the final phase of Europe's largest onshore wind farm is being turned on in Scotland. The 322-megawatt (MW), 140-turbine Whitelee wind farm was built by ScottishPower Renewables, which is part of the Spanish power business Iberdrola.

In Spain and internationally, the Iberdrola Group, is the world’s largest developer of wind power, with nearly 9700 MW of installed capacity. The wind farm uses Siemens 2.3-MW machines.

Positioned 370 meters (1200 feet) above sea level, 15 kilometers (9 miles) outside of Scotland’s largest city, Glasgow, the new wind farm has over half a million people living within a 30-km radius of it. It’s one of the first large-scale wind farms to be constructed close to a large population center. The first phase of the wind farm started feeding power into the grid in January 2008.

Potentially, the wind farm could be extended to a massive 600 MW: this became more likely today when a proposal to extend the existing scheme by another 130 MW was been approved by the Scottish Government, thus powering an additional 70,000 homes.

But the company is also carrying out scoping work on a potential second extension, which could add a further 140 MW. It is anticipated that an official planning application will be submitted for this later in the summer.

At the ceremonial switch-on today, Iberdrola and ScottishPower Chairman Ignacio Galán was joined today by Scotland’s First Minister Alex Salmond. The company considers Scotland and the UK core markets in its current and future growth plans.

“Whitelee is a milestone in the history of Scotland, not only representing the largest wind farm in Europe but also one of the largest in the world," Galán said.

The Scottish government has a target of generating 31% of Scotland's electricity demand from renewable sources by 2011 and 50% by 2020. It’s an ambitious target, and the majority of this is likely to come from wind power.

“Our potential for electricity generation from renewables is up to 60 gigawatts — more than ten times our peak demand. We have launched the world’s greatest single prize for innovation in marine energy, the £10 million Saltire Prize; we are developing and applying clean fossil fuel technology; we have an unrivalled competitive advantage in carbon capture and storage; we have approved Siadar, one of the largest wave energy projects on the planet; as well as developing and consenting hydro and biomass projects. Harnessing all these opportunities has the potential to create more than 16,000 jobs in Scotland over the next decade," Salmond said.

ScottishPower Renewables’ Keith Anderson said he believed further onshore wind farms would follow in the United Kingdom, but also added that said more work was needed on infrastructure. Improved grid connections are key in the UK, as in so many other parts of the world.

Anderson told reporters, "We're currently in conversations with the Crown Estate and the Scottish government about the development of an offshore wind farm off the west coast of Scotland, which could be anything up to 1800 MW, at least five or six times the size of Whitelee."

At the end of April, ScottishPower Renewables announced that Whitelee was set to be completed ahead of schedule.

“To complete Europe’s largest on-shore wind farm ahead of schedule is a major achievement. A wind farm on this scale has never been attempted before, and every one of the 500 people who have worked on the project deserves huge credit," ScottishPower director Keith Anderson said.

“Our project management team and our contractors, Morrison Balfour Kilpatrick, have developed techniques and a level of expertise that allows us to work effectively in difficult terrain and under testing conditions, and this understanding has helped to keep the project firmly on track," saidn Anderson.

As well as the physical construction of the turbines, the £300 million (US $466 million) project has also seen the creation of a 90 km "floating" road network to protect the underlying peatland and the connection of over 970 km of cables to link the turbines to the national grid. A state-of-the-art visitor center is also in the process of being completed.