Siemens will build the 140 turbines for the 322 MW project for which the first turbines will arrive in October next year and the site fully commissioned in summer 2009.
Contracts have also been awarded to Morrison Construction and Balfour Kilpatrick for site infrastructure works including 90 km of access roads and turbine foundations.
Scottish Power intends to spend £1 billion ($1.9 billion) on onshore wind projects by 2010.
