Website : www . facebook . com / LuleaDataCenter On the northern coast of Sweden , you ’ ll find the city of Luleå , home to one of Facebook ’ s many data centres . To balance out the company ’ s sizeable carbon footprint , Facebook has made a point of improving all data centres . Its Swedish facility has a PEU of just 1.1 . Since northern Sweden is already fairly chilly all year round , Facebook uses the already cold air and treats it with water vapour . With the proper humidity , it can not only cool down the energetic servers , but it can also heat up the normal offices . The hydroelectric power at Facebook ’ s Sweden centre is so efficient that the company has been able to save costs on its on-site backup power too .

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