Oh, this is good! A company that mainly develops unmanned aircraft has turned its skills to making rooftop wind turbines. Small and light (no price yet so I don’t know if it’s cheap) and mounted on the building parapet – to make best use of the structure’s aerodynamic properties – it requires only 3.1m/s of wind-speed to work. That’s a huge drop from the 12m/s average for larger windmills.

Full article :: EcoGeek at Wired NextFest