These additional 842MW of power will come from a range of locations across three countries and a number of clean energy technologies, from a wind farm in Sweden to a solar power plant in Chile.
Put in context, 1 megawatt can power roughly 200 homes, so Google's latest purchase could power about 168,000 homes.
Google's announcement comes on the heels of a historic multi-national agreement at the United Nations Climate Summit in Paris to double R&D investments in clean energy.
On Monday, President Obama and Bill Gates announced that the U.S. is joining 19 other countries and 28 technology innovators to double funding and other resources for clean energy research and development.
Along with public funding, the high-profile investors -- known as the Breakthrough Energy Coalition -- also plan to provide money for the development of zero-emission energy technology. The group, being lead by Microsoft co-founder and philanthropist Bill Gates, includes Salesforce.com founder and CEO Marc Benioff, Amazon founder and CEO Jeff Bezos, Virgin Group founder Richard Branson and LinkedIn founder Reid Hoffman.
Along with 13 of the largest companies from across the America, Google recently pledged to triple its purchases of renewable energy by 2025.
A power purchase agreement is a long-term contract to buy power from one utility at a set rate. Google has partnered with the U.S.'s largest utility, Duke Energy, to buy power generated from photovoltaic solar farms.
"These long-term [clean energy] contracts range from 10-20 years and provide projects with the financial certainty and scale necessary to build these wind and solar facilities — thus bringing new renewable energy onto the grid in these regions," Google stated in a blog. "For our part, these contracts not only help minimize the environmental impact of our services — they also make good business sense by ensuring good prices."
Since 2006, Google has been investing heavily in renewable and clean energy. In 2011, Google invested $94 million in four photovoltaic power generation projects around Sacramento, Calif.
"Since we opened our very first owned data center in 2006, we've been working to promote renewable and sustainable energy use in several ways," Google stated.