(Dow Jones) Google Inc. (GOOG) struck a 20-year deal to buy clean energy from a NextEra Energy Inc. (NEE) wind farm, a move that places the Internet search giant in the wholesale energy market.

In a blog post Tuesday, the Mountain View, Calif.-based company said it will begin buying 114 megawatts of wind generation at a fixed price from the NextEra Energy Resources Story County II facility in Iowa on July 30. The company will sell the power back to the energy grid via the regional spot market.

The move will help Google partially protect itself from future increases in power prices as well as reduce its carbon footprint. It will also give the wind farm developer financial certainty so that it can build additional clean-energy projects.

The agreement follows a series of recent moves by Google in the energy sector and is the first by Google Energy LLC, an entity formed last December that allows it to procure large volumes of renewable energy by participating in the wholesale market. Google has invested in early-stage companies developing solar-, wind- and geothermal-power technologies, and surprised observers in February by winning regulatory approval to trade in U.S. wholesale electricity markets.

In May, Google invested $38.8 million in two North Dakota wind farms, Google's first direct investment in utility-scale renewable-energy generation. Output from those facilities, which have been operating since last year, is being sold to utilities under power-purchase agreements.

Google's power usage is unclear. The company doesn't disclose how many data centers it operates or where they are located. Last year, Google said its data centers were the most efficient in the world, so far as it was able to determine, but declined to say how much power it actually uses.

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