The 110MW Keechi wind farm, located 70 miles northwest of Fort Worth, will power a Microsoft data centre in San Antonio, Texas. It follows the company's announcement last year that it planned to become carbon neutral.
Construction of Keechi will begin early next year and will use Vestas 2MW turbines. The PPA is for 20 years.
This is Microsoft's first move into wind energy. In doing so it is following a path set by Google, which has bought around 570MW of wind power in Texas alone. It had also invested and bought wind farms elsewhere in the US.
Google and Microsoft are not the only tech companies looking at using wind to power data centres.
As revealed in Windpower Monthly, MidAmerican is in talks with social media giant Facebook, which is interested in using a part of Wind Vlll's power to provide renewable energy credits for a new data centre in central Iowa.
Although it is not yet clear how Facebook's involvement affects the funding of the project, MidAmerican said the expansion will be built at no net cost to the company's customers.