Google Inc. has invested $38.8 million in two North Dakota wind farms, the Internet giant's first direct investment in utility-scale renewable energy generation.

The Mountain View, Calif., company said in a Monday blog post that it invested in wind farms built by NextEra Energy Resources, a unit of FPL Group Inc. The wind turbines, made by General Electric Co., generate 169.5 megawatts of power, enough to serve more than 55,000 homes.

The...