Facebook has revealed the carbon footprint and energy use of its US datacentres, and has pledged to use 25 percent sustainable energy by 2015.
Across the US, Facebook's datacentres used 509 million kWh of energy, and produced carbon emissions of 207,000 metric tonnes of carbon dioxide equivalent in 2011, the company said on Wednesday.
Facebook has two US datacentres, located in Oregon and North Carolina, as well as two colocation facilities, one on the East coast and one on the West.
The Facebook colocation facilities accounted for the majority of Facebook's datacentre carbon output, totting up 105,000 metric tonnes of emissions for its East coast facility, and 70,000 tonnes for the West coast — noticeably higher than the 28,000 tonnes of emission produced by the the Prineville Oregon datacentre, and the 4,000 tonnes by Facebook's Forest City, North Carolina datacentre.
Facebook's decision to locate one of its datacentres in Prineville led to Greenpeace's 'Unfriend Coal' campaign, which began in 2010, due to Prineville being supplied by utility Pacific Power, which gets a significant amount of energy of its energy from fossil fuel.
Facebook currently gets 23 percent of its energy from clean and sustainable sources — a figure it plans to increase slightly, to 25 percent by 2015, it said on Tuesday.
Greenpeace said that Facebook had set an "important benchmark" with the pledge.
"Facebook has committed to being fully renewably powered, and today's detailed disclosure and announcement of a clean energy target shows that the company means business and wants the world to follow its progress," Greenpeace International senior IT analyst Gary Cook said in a statement.