Google says that it will reach 100% renewable energy for its global operations - including both our data centers and offices, by 2017.

Google was one of the first corporations to create large-scale, long-term contracts to buy renewable energy directly; the search giant signed our first agreement to purchase all the electricity from a 114-megawatt wind farm in Iowa, in 2010. Today, Google is the world's largest corporate buyer of renewable power, with commitments reaching 2.6 gigawatts (2,600 megawatts) of wind and solar energy. That's bigger than many large utilities and more than twice as much as the 1.21 gigawatts it took to send Marty McFly back to the future.

To reach this goal Google will be directly buying enough wind and solar electricity annually to account for every unit of electricity its operations consume, globally.

Over the last six years, the cost of wind and solar came down 60 percent and 80 percent, respectively, proving that renewables are increasingly becoming the lowest cost option. Electricity costs are one of the largest components of Google's operating expenses at its massive data centers, and having a long-term stable cost of renewable power provides protection against price swings in energy.

Google's 20 renewable energy projects also help support communities, from Grady County, OK, to Rutherford County, NC, to the Atacama Region of Chile to municipalities in Sweden. To date, Google's purchasing commitments will result in infrastructure investments of more than $3.5 billion globally, about two-thirds of that in the United States.

In the immediate future, Google also plans to broaden its purchases to a variety of energy sources that can enable renewable power, every hour of every day.