I want one of these ducted wind turbines in my backyard (well, to be precise I want one up at the Lodge).  Well, not this exact one – I don’t need to power 15 houses.  I am very intrigued by the claims of Sheerwind (I hope it’s really as good as they say).  In New Zealand Pacificwind have the license to sell these (though I don’t believe they’ve sold/installed any here yet).  I don’t understand why they aren’t targeting the residential market?  I hope it’s not because they’re not effective as they decrease the size…

UPDATE:  Below is a different solution from Archimedes (based in Rotterdam) – with a claim of being able to achieve 80 percent of Betz’ limit.  Archimedes says that “The Liam F1 generates an average of 1,500 kilowatt-hours of energy [per year] at a wind-speed of 5 m/s [16.4 ft/s], which resembles half of the power consumption of a common household.”