The role of Silicon Valley in promoting and scaling up green energy continues to grow. Amazon announced at the weekend that it will develop its largest wind farm yet—a 253 megawatt facility—in Texas. It expects to commission the scheme in late 2017. A handful of well-resourced technology giants are effectively in an ideological competition to burnish their reputations: Google wants to source all of its energy demand from renewables; Apple said 93% of its energy was green last year; Facebook wants half of its data center power to be green by 2018. Amazon Web Services is lagging a bit, at an estimated 40% by the end of this year. All of them are paying handsomely for their environmental laurels. Somebody has to pay over the odds to make new technologies viable. Far better this way than to force the taxpayer to pick up the tab for the transition to a lower-carbon future. Fortune