4,000 megawatts

Amount of new wind-power generating capacity installed in the United Stated in the first six months of 2009, according to the American Wind Energy Association. That's enough to power the equivalent of up to 1.2 million homes, and an increase of 38 percent over the first two quarters of 2008.

The AWEA reports that wind power offsets an average of 54 million tons of greenhouse-gas emissions annually. What's more, this developing industry might spin off new jobs: The Union of Concerned Scientists estimates that generating renewable energy could also create nearly 300,000 new jobs.

Essential information: Check out the October 2009 issue of Consumer Reports, online and on newsstands in September, for reports on pellet stoves and solar water heaters, expert advice on saving energy at home, and ratings of compact fluorescent lightbulbs.