Craftsbury, Vt.

In their seemingly quixotic efforts to reduce emissions, energy companies have increasingly tilted towards windmills. The United States now houses some 45,000 wind turbines on nearly 900 wind farms. That’s enough to power about 1.6 million homes, according to the American Wind Energy Association. Despite the much-hyped natural gas boom, wind is now the number one source of new power generation in the country; 43 percent of the generating capacity that came online last year was from wind.

The main benefit of wind power is obvious: It generates no air or water pollution, and none of the carbon emissions that are thought to contribute to climate change. What’s more, wind itself is free, meaning that over the long term, wind farms should prove profitable for utility companies. It also doesn’t hurt that energy companies benefit from a bevy of federal subsidies and tax credits for investing in wind farm projects.