Greensburg, Kansas

Energy efficient windmills in Greensburg, a Kansas town. [Photo/Agencies]

It was only through total disaster that the aptly-named Greensberg, a sleepy, Republican whistle–stop on the Kansas prairie, was able to transform itself into America's greenest town.

After a massive tornado destroyed 95% of the buildings in the town in 2007, the 1,400 residents had to choose if they would rebuild or relocate. A tough choice in a town that had been in decline for decades.

About half the townspeople left, but a group of residents established a master plan to rebuild the town as an energy-saving, renewable energy haven. Just outside the town, they built a 12.5MW wind farm. This supplies 300% of the town's electricity, with the excess pumped into the Kansas grid.

But key to this green resurrection has been energy efficiency. Because of the ability to rebuild from scratch, residents were able to apply the most modern building techniques to Greensberg 2.0.

The town now has the highest concentration of gold and platinum eco-design rated buildings in the US and all of its street lights are LED. All large government buildings are now rated platinum. This saves the town over $200,000 a year and, more importantly, reduces the town's dependence on generating electricity.