What Google has done over the last decade, with relatively little fanfare, is participate in a number of large-scale deals with renewable producers, typically guaranteeing to buy the energy they produce with their wind turbines and solar cells. With those guarantees, wind companies can obtain bank financing to build more turbines. The power created by the renewable is plugged into the utility grid, so that Google’s usage presents no net consumption of fossil fuels and the pool of electricity gets a relatively larger share of renewable sources.
Here's a Snippet from an Article in NYTimes:
“We are the largest corporate purchaser of renewable energy in the world,” said Joe Kava, Google’s senior vice president of technical infrastructure. “It’s good for the economy, good for business and good for our shareholders.”" NYTimes December 2016 This article covers a few other companies too.Moreover Google is not disclosing how much it’s paying for renewable energy. At this point in wind and solar power technology, the cost to purchase or rely on green electricity is extremely prohibitive to most people and businesses. Google is using a lot of profit that would go to stock holders to promote renewable energy in hopes that one day technology will advance to the point where such energy will be cost effective. The idea is in good conscience, but a horrible business plan. They should be investing in research and technology that advances green energy and makes it efficient instead of just promoting it. The cost of the project is probably 50 times the cost as it would be using traditional power sources.