Google has invested in a wind farm in Oklahoma to help offset the environmental impact of its data centers, even as Greenpeace stepped up its criticism of big Internet companies for using "dirty power" that contributes to global warming.
Google signed a 20-year purchase agreement to buy all the power generated by a 100-megawatt wind farm to be built near one of its data centers in Mayes County, Okla., Google announced in a blog post Thursday.
It's Google's second investment of this type in the past year. Both were made by a subsidiary company, Google Energy, which is certified to buy and sell power on the U.S. wholesale market.
"These purchases represent long-term, meaningful actions to reduce our carbon footprint and power our operations with clean electricity," Google said.
The company also published a white paper Wednesday that explains the complexities of trying to use renewable energy to run a data center. For regulatory and other reasons, Google can't take the power generated by the wind farms and apply it directly to its data centers.
"At our data centers, Google is a retail customer -- we have no way of taking power off the grid wholesale and applying it to our load," it says in the white paper. "We have to buy power just like you do: from our local regulated utility."
Instead, Google sells the power it agrees to purchase back to the grid at local, wholesale prices. The purchase agreements provide the financial incentive for the wind farms to get built, it said, and Google gets to collect Renewable Energy Credits for the wind power it sells. RECs are akin to carbon offsets, except Google says they are more effective because they represent renewable power that has actually been produced.
"Even if we can't legally or physically transfer the [wind] power to our facility, being in the same power market ensures we are contributing to greening the grid where we operate," the company said.
Both the wind farms are being built by NextEra Energy, in which Google has made an investment. It said the Oklahoma facility will be operational by late this year.
Google made its announcement at GigaOm's GreenNet conference in San Francisco. Greenpeace was also there, to step up its campaign against Internet companies that it says rely on power from coal-fired plants to run their data centers.
A new Greenpeace report, "How Green is Your Data?" criticizes Facebook, Google and Apple for building data centers in North Carolina, where it says "cheap and dirty coal-powered electricity is abundant."
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