Facebook and Greenpeace have called a truce over a clean energy feud that had the environmental group using the social network's own platform to campaign against it. Greenpeace and Facebook said that they will work together to encourage the use of renewable energy instead of coal. The strife dates to 2010: Facebook opened a data center in Prineville, Or Oregon, using the area's cool nights and dry air to save energy while keeping its systems from overheating. It also received generous tax breaks for adding jobs to the economically struggling region. But Greenpeace was not happy that Facebook choice of sites for its data center that was served by a power company that generates most of its electricity from coal. Greenpeace started a campaign to get the social network operator to use renewable energy, attracting some 700,000 supporters on Facebook. Greenpeace said it was ending the campaign and declared victory on its "Unfriend Coal" Facebook page. The page has more than 180,000 followers. Facebook said it will work with the group to promote clean, renewable energy and encourage other technology companies to do the same. The company said it will now state a "preference for access to clean and renewable energy" when choosing where to build its data centers. But it stopped short of saying it will only build on such sites. Clean energy has also been big issue Google Inc. The online search leader has been trying to prove that its business model is environmentally friendly and recently revealed exactly how much electricity it uses (2.3 billion kilowatt-hours of electricity last year, about the same as what 207,000 US homes would use in a year). It has also invested nearly $1 billion in renewable energy projects such as wind farms and solar projects. Follow Ynetnews on Facebook, Twitter and Google+