Facebook has begun building a data centre in Lulea, Sweden, where it will benefit from cheap electricity and year-round free air cooling, the company announced Thursday.
The data centre will be Facebook’s first in Europe, and its third worldwide. The company expects to begin fitting out the first server hall by the end of next year, and will begin serving the first Facebook users from it in April or May 2013. Three other server halls in the same 28,000 square-meter building will be ready for fit-out by 2014. The site has room for two other buildings of the same size, but Facebook has no plans to begin constructing them yet.
Lulea is on the edge of the Arctic Circle, and has a mean annual temperature of around 1 C, with average summer highs of around 20 C, allowing Facebook to save money by cooling its data centre with fresh air rather than air conditioning.
Using free air cooling will help Facebook increase a key measure of data centre efficiency, its PUE (power usage effectiveness). PUE is calculated as the total power consumption of the data centre, including cooling and lighting systems, divided by the power consumption of IT systems. The less power wasted on ancillary functions such as cooling and lighting, the more energy-efficient the data centre becomes.
Average PUEs for major data centres typically lie between 1.6 and 1.99, according to a survey published by the Uptime Institute in May. Capgemini said last December that its Merlin data centre in the U.K. had a factory-tested PUE of 1.1.
Facebook has not yet announced its target PUE for the Lulea data centre.
The servers there will run primarily on hydroelectric power from the nearby Lule river, Facebook said. Lulea has the cheapest electricity in Europe, according to the city’s business development agency.
Facebook has developed its own power-efficient servers and power supplies for data centres, publishing technical specifications and CAD files for them through the Open Compute Project. That organization will hold a summit in New York later Thursday.