Swiss engineer ABB has won an $11 million contract to power Facebook's first data centre outside the United States, covering an area in the Arctic Circle equivalent to 11 soccer pitches, it said on Thursday.

Facebook chose Lulea, northern Sweden, as the site for its green data center -- set to be the largest of its kind in Europe -- because of its access to renewable energy and the cold climate that is crucial to help cool the huge server buildings.

Data centers are set to boom as companies shift to cloud computing and traffic soars on social media sites such as YouTube and Facebook. One data center consumes as much power as 25,000 U.S. houses.

ABB, whose products are also used by oil, mining and utility companies, will build two high- and medium-voltage air and gas insulated switchgear substations to supply power to the data center, which is due to become operational next December.

(Reporting by Caroline Copley; Editing by David Hulmes)