Facebook is stepping up its commitment to renewable energy today.while announcing a new data center in fort worth,which happens to be entirely powered by wind energy,the social network also set a new goal of having 50 percent of its data centers relying on renewables by the end of 2018.that follows an earlier self-imposed goal to have 25 percent of its data centers powered by clean energy come the end of this year.naturally,facebook plans to have all of its operation powered by renewable energy eventually.