Google wants to harness the wind.

The tech giant announced today that it invested nearly $40 million in two North Dakota wind farms, to spur the use of renewable energy "in a way that makes good business sense." The investments are part of Google's ongoing foray into the industry and may both be a first step toward a "big play," and serve the company's long-term interest.

The search giant raised eyebrows in January when it announced that it was awaiting government approval to buy and sell power like a utility company. That approval was granted in February and could help Google someday power its many data centers, Google Green Energy Czar Bill Weihl said at a conference last week.

While a spokesman said the North Dakota wind farms will not be used to power those data centers, Weihl outlined a very similar scenario -- one in which they would, in the long run. To build a wind farm to serve Google's needs, a developer would need the tech giant to sign a 10- to 20-year agreement, Weihl said. As that farm is built out, Google would continue to receive energy under its current utility contract, thus losing money. By being able to buy and sell energy, Google can avoid that waste.

"That's fundamentally the type of thing we want to do," Weihl said, reiterating that the company has no grand goals. "We don't want to become an energy trader, or God forbid the next Enron."