Wind turbines are fantastic green energy generators, but what if the wind changes direction? Modern wind turbines come equipped with a mechanism that allows them to turn facing the wind. But this clever feature makes those huge and slow wind turbines less suitable for urban environments where wind directions change constantly due to many obstructions.

. The vertical spindle allows the Eddy wind turbine to operate with wind from any direction. The unit is small enough to fit on any rooftop, can be assembled in under an hour and... the Eddy is silent; the noise level produced by the turbine is 38 dB(A) at 12 m/s, according to IEC 61400-11, which is halfway between the sound level of whispering (15 dB) and normal conversation (60 dB).

Eddy has a rated power of 600 watts and a cut-in speed of just 3.5 meters per second. The unit has a maximum safe wind speed of more than 120 mph (55 m/s) and a projected lifetime of 20 years. The carbon fiber and fiberglass composite blades spin at a maximum of 200 revolutions per minute.

Wouldn't mind having one of these on my roof.