One of the primary reasons that current wind turbines have to be so large is that most of the energy is lost as the air flows off the end of the blades. That size increases the cost and reduces the density of turbines that can be installed. FloDesign has developed a wind turbine that incorporates ideas from jet engines, including a shroud to duct air over the turbine blades. Unlike previous ducted turbine designs, this one is claimed to be able to self align and still work effectively at up to 20 degrees off axis from the wind direction. FloDesign also claims that the turbine can operate effectively over a much wider range of wind speeds.
This new design should theoretically be much less expensive to produce and install. The smaller size would also allow up to three times the installation density compared to current conventional types. You can check out a video here.
[Source: MIT Technology Review